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Best Practice Guideline - A3: Water Management in Hydrometallurgical Plants -- July 2007
____________________________________________________________________________________________________________________________________
i
Published by
Department of Water Affairsand Forestry
Private Bag X313
PRETORIA
0001
Repblic of Soth Africa
Tel: (012) 336-7500
Copyright reserved
No part of the pblication
may be reprodced in
any manner withot
fll acnowledgement
of the sorce
T rport o ct a:
Department of Water Affairs and Forestry, 2007. Best Practice Gideline A3: Water
Management in Hydrometallrgical Plants.
dcamr:
Althogh the information contained in this docment is presented in good faith and
believed to be correct, the Department of Water Affairs and Forestry maes no
representations or warranties as to the completeness or accracy of the information,
which is only based on actal information received, and maes no commitment to
pdate or correct information.
Contant:
Plles Howard and de Lange Inc.
P O Box 861
AuCkLAND PARk
2006Repblic of Soth Africa
Golder Associates Africa (Pty) Ltd
P O Box 6001
HALFWAY HOuSE
1685
Repblic of Soth Africa
isbN 978-0-9802679-0-7
stat Final Jly 2007
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Best Practice Guideline - A3: Water Management in Hydrometallurgical Plants -- July 2007
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This docment is the third in a series of the following Activity Best Practice Gideline
docments:
BPG A1: Small-scale Mining
BPG A2: Water Management for Mine Reside Deposits
BPG A3: Water Management in Hydrometallurgical Plants
BPG A4: Polltion Control Dams
BPG A5: Water Management for Srface Mines
BPG A6: Water Management for undergrond Mines
dOCuMeNT
iNdeX
Ator
Ms Palette Jacobs (Palette Jacobs Conslting)
Mr William Plles (Golder Associates)
spcat
Ms Jennifer L. Broadhrst (private)
Ms kerry Slater (private)
Ms Riana Mnni (DWAF)
Solomon Tsheo (DWAF)
Since 1999 a nmber of steering committee meetings and staeholder worshops were held
at varios stages of the development and drafting of this series of Best Practice Gidelines for
Water Resorce Protection in the Soth African Mining Indstry.
We are deeply indebted to the steering committee members, ofcials of the Department of
Water Affairs and Forestry and staeholders who participated in the meetings and staeholder
worshops held dring the development of the series of Best Practice Gidelines for their
inpts, comments and ind assistance.
The Department wold lie to acnowledge the athors of this docment, as well as the
specialists involved in the process of developing this Best Practice Gideline. Withot their
nowledge and expertise this gideline cold not have been complemeted.
ACKOWledGe-
MeNTs
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APPROVAlsT ocmnt approv t dpartmnt of Watr Affar an
Fortr
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PReFACeWater is typically the prime environmental medim (besides air) that is affected by mining
activities. Mining adversely affects water quality and poses a signicant risk to South Africa’s
water resorces. Mining operations can frther sbstantially alter the hydrological and
topographical characteristics of the mining areas and sbseqently affect the srface rnoff,soil moistre, evapo-transpiration and grondwater behavior. Failre to manage impacts on
water resorces (srface and grondwater) in an acceptable manner throghot the life-of-
mine and post-closre, on both a local and regional scale, will reslt in the mining indstry
nding it increasingly difcult to obtain community and government support for existing and
ftre projects. Conseqently, sond management practices to prevent or minimise water
polltion are fndamental for mining operations to be sstainable.
Pro-active management of environmental impacts is reqired from the otset of mining activities.
Internationally, principles of sstainable environmental management have developed rapidly in
the past few years. Locally the Department of Water Affairs and Forestry (DWAF) and the
mining indstry have made major strides together in developing principles and approaches for
the effective management of water within the indstry. This has largely been achieved throghthe establishment of joint strctres where problems have been discssed and addressed
throgh co-operation.
The Bill of Rights in the Constittion of the Repblic of Soth Africa, 1996 (Act 108 of 1996)
enshrines the concept of sstainability; specifying rights regarding the environment, water,
access to information and jst administrative action. These rights and other reqirements are
frther legislated throgh the National Water Act (NWA), 1998 (Act 36 of 1998). The latter is
the primary statte providing the legal basis for water management in Soth Africa and has
to ensre ecological integrity, economic growth and social eqity when managing and sing
water. use of water for mining and related activities is also reglated throgh reglations that
were pdated after the promlgation of the NWA (Government Notice No. GN704 dated 4 Jne
1999).
The NWA introdced the concept of Integrated Water Resorce Management (IWRM),
comprising all aspects of the water resorce, inclding water qality, water qantity and the
aqatic ecosystem qality (qality of the aqatic biota and in-stream and riparian habitat). The
IWRM approach provides for both resorce directed and sorce directed measres. Resorce
directed measres aim to protect and manage the receiving environment. Examples of resorce
directed actions are the formlation of resorce qality objectives and the development of
associated strategies to ensre ongoing attainment of these objectives; catchment management
strategies and the establishment of catchment management agencies (CMAs) to implement
these strategies.
On the other hand, sorce directed measres aim to control the impacts at sorce throgh
the identication and implementation of pollution prevention, water reuse and water treatment
mechanisms.
The integration of resorce and sorce directed measres forms the basis of the hierarchy
of decision-taking aimed at protecting the resorce from waste impacts. This hierarchy is
based on a precautionary approach and the following order of priority for mine water and waste
management decisions and/or actions is applicable:
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ResOuRCe PROTeCTiON ANd WAsTe
MANAGeMeNT hieRARChy
stp 1: Poton Prvnton
↓stp 2: Mnmaton of impact
Water rese and reclamation
Water treatment
↓stp 3: dcarg or poa of wat
an/or wat watr
Site specic risk based approach Pollter pays principle
The docmentation describing Watr Rorc
Protcton an Wat Managmnt in Soth Africa
is being developed at a nmber of different levels, as
described and illstrated in the schematic diagram on
this page.
The overall Resource Protection and WasteManagement Policy sets ot the interpretation of
policy and legal principles as well as fnctional and
organisational arrangements for resorce protection and
waste management in Soth Africa.
Operational policies describe the rles applicable
to different categories and aspects relating to waste
discharge and disposal activities. Sch activities from
the mining sector are categorised and classied, based
on their potential riss to the water environment.
Operational Guidelines contain the reqirements for
specic documents e.g. licence application reports.
Best Practice Guidelines (BPG’s) dene and document
best practices for water and waste management.
scmatc dagram of t Mnng sctor Rorc Protcton an Wat Managmnt
stratg
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The DWAF has developed a series of bt Practc
Gn (BPGs) for mines in line with International
Principles and Approaches towards sstainability. The
series of BPGs have been groped as otlined below:
besT PRACTiCe GuideliNes dealing with aspects of
DWAF’s water management hieRARChy are prefaced
with the letter h. The topics that are covered in these
gidelines inclde:
• H1. Integrated Mine Water Management
• H2. Pollution Prevention and Minimisation of Impacts
• H3. Water Reuse and Reclamation
• H4. Water Treatment
besT PRACTiCe GuideliNes dealing with GeNeRAl
water management strategies, techniqes and tools,
which cold be applied cross-sectoral and always
prefaced by the letter G. The topics that are covered in
these gidelines inclde:
• G1. Storm Water Management
• G2. Water and Salt Balances
• G3. Water Monitoring Systems
• G4. Impact Prediction
besT PRACTiCe GuideliNes dealing with specic
mining ACTiViTies or AsPeCTs and always prefaced
by the letter A. These gidelines address the prevention
and management of impacts from:
• A1 Small-scale Mining
• A2 Water Management for Mine Residue Deposits
• A3. Water Management in Hydrometallurgical Plants
• A4 Pollution Control Dams
• A5 Water Management for Surface Mines
• A6 Water Management for Underground Mines
The development of the gidelines is an inclsive
consltative process that incorporates the inpt from
a wide range of experts, inclding specialists within
and otside the mining indstry and government. The
process of identifying which BPGs to prepare, who shold
participate in the preparation and consltative processes,
and the approval of the BPGs was managed by a Project
Steering Committee (PSC) with representation by ey
role-players.
The BPGs will perform the following fnctions within the
hierarchy of decision maing:
• Utilisation by the mining sector as input for compilingwater se licence applications (and other legally
reqired docments sch as EMPs, EIAs, closre
plans, etc.) and for drafting licence conditions.
• Serve as a uniform basis for negotiations through the
licensing process prescribed by the NWA.
• Used specically by DWAF personnel as a basis for
negotiation with the mining indstry, and liewise by
the mining indstry as a gideline as to what the DWAF
considers as best practice in resorce protection and
waste management.
• Inform Interested and Affected Parties on goodpractice at mines.
The information contained in the BPGs will be transferred
throgh a strctred nowledge transfer process, which
incldes the following steps:
• Workshops in key mining regions open to all interested
parties, inclding representatives from the mining
indstry, government and the pblic.
• Provision of material to mining industry training
grops for inclsion into standard employee training
programmes.• Provision of material to tertiary education institutions
for inclsion into existing training programmes.
• Provision of electronic BPGs on the DWAF Internet
web page.
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CONTeNTsdOCuMeNT iNdeX ii
ACKOWledGeMeNTs ii
APPROVAls iii
PReFACe iV
AbbReViATiONs ANd TeRMiNOlOGy iX
1 iNTROduCTiON ANd ObJeCTiVes 11
2 GeNeRAl PRiNCiPles ANd CONsideRATiONs 14
3 leGAl FRAMeWORK 18
3.1 Focs and role of DWAF . . . . . . . . . . . . . . . . . . . . . . 18
3.2 National Water Act . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.3 DWAF Waste Management Series - Minimm Reqirements 19
3.4 Best Practice Gideline series . . . . . . . . . . . . . . . . . . . 19
4 CONsideRATiONs WiThiN The MiNe liFe-CyCle 20
4.1 Exploration, prospecting, planning, feasibility and design phase 21
4.2 Commissioning and operational phase . . . . . . . . . . . . . 23
4.3 Decommissioning, closre and post-closre phase . . . . . . 23
5 FiNANCiAl CONsideRATiONs (sTePs 1 ANd 2) 24
5.1 Water, a ey bsiness asset (Step 1) . . . . . . . . . . . . . . . 25
5.2 Tre vale and cost of water (Step 2) . . . . . . . . . . . . . . 25
6 iNFORMATiON GATheRiNG (sTePs 3, 4 ANd 5) 28
6.1 Site and process nowledge (Step 3). . . . . . . . . . . . . . . 28
6.2 Water and salt/load balances (BPG G2: Water and salt balances)
(Step 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.3 Mine/plant water sers (Step 5) . . . . . . . . . . . . . . . . . . 30.
7 hOuseKeePiNG ANd WATeR MANAGeMeNT sysTeMs
(sTeP 6) 31
7.1 Minimize water se/ water conservation . . . . . . . . . . . . . 31
7.2 Water segregation . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.3 Storage of materials . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.4 High contamination ris areas . . . . . . . . . . . . . . . . . . . 33
7.5 Storm water management (BPG G1: Storm water management) 33
7.6 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.7 Eqipment and maintenance . . . . . . . . . . . . . . . . . . . 34
7.8 Sstainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
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8 WATeR QuAliTy ANd CONsTiTueNTs OF CONCeRN
(sTeP 7) 35
8.1 Minimize generation of contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.1.1 Review intae/inpt/raw materials . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.1.2 Optimize polltion prevention and redction at sorce. . . . . . . . . . . . . . 37
8.2 Water qality reqirements for mine/plant water sers . . . . . . . . . . . . . . . . . . 37
8.3 Monitoring, maintenance, inspections and adits. . . . . . . . . . . . . . . . . . . . . . 38
9 WATeR Reuse ANd ReClAMATiON (sTeP 8) 39
10 PROCess ChANGes OR CleANeR TeChNOlOGy (sTeP 9) 42
10.1 Need and signicance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
10.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
10.3 Barriers preventing cleaner prodction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.3.1 Economic barriers/constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.3.2 Technology barriers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.3.3 Legislative barriers/pressres . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.4 Overcoming barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.4.1 Governmental intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.4.2 Edcation and training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.4.3 Improved planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
11 iNTeGRATed WATeR ANd WAsTe MANAGeMeNT PlAN (sTePs 10 ANd 11) 46
12 ReFeReNCes ANd FuRTheR ReAdiNG 52
FiGuRes
Figre 1.1 Best Practice Gidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figre 2.1 Stepwise procedre for water management at a hydrometallrgical processing plant. 4
Figre 4.1 Considerations in the mine life-cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figre 4.2 Process design constraints (Marr, 2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
APPeNdiCes
APPENDIX A: WATER QuALITY ISSuES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
APPENDIX B: VARIOuS HYDROMETALLuRGICAL PROCESSES. . . . . . . . . . . . . . . . . . . . 58
APPENDIX C: EXAMPLE OF DETAILED RISk ASSESSMENT PROCESS AT PLANT
DESIGN STAGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
APPENDIX D: CHECkLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
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AMD: Acid mine drainage
Axiliary inpts: Materials added to the process to help or assist the process or increase
the speed at which it occrs.
Berm: A ban/border (raised or piled p area) constrcted (from soil/cement)
to prevent water owing over it thereby forcing the water to ow along a
specic path as directed by the berm.
BPG: Best Practice Gideline (docments in this series)
Bund: An articial embankment to ensure containment in a desired area.
Classier: Process to arrange or distribute in classes.
COC: Contaminants of concern
Chpt: Chapter
DWAF: Department of Water Affairs and Forestry
ECA: Environment Conservation Act, 1989 (Act 73 of 1989)
Filters: Filtration is the physical separation used for the removal of ne
suspended solids. May be effected in granular media lters (e.g. sand
lter) or membrane lters (e.g. Nanoltration).
Flotation: The physical separation and removal of sspended material that settles
slowly by bbbling air throgh the soltion and allowing particlates to
oat to the surface on air bubbles, where it is skimmed off.
Grinding: The process throgh which the particle size is redced by crshing
between two hard srfaces. The physical characteristics are thereforechanged (smaller particles/powder) bt not the chemical characteristics.
Hydrometallrgical: Incldes milling and grinding circits; separation circits (magnetic
or other); rening circuits; classiers, hydrocyclones, screens, lters,
thickeners, otation processes, electro-winning, leaching, solvent
extraction, metal recovery and precipitation
IWWM: Integrated water and waste management
IWWMP: Integrated water and waste management plan
Leaching: To let liqid percolate throgh some material with the objective of
removing solble constitents from the material and captring them in
the liqid phase. Leachate is the reslting liqid containing the dissolvedsbstance.
Milling: See grinding. using a mill for the grinding process.
NEMA: National Environmental Management Act, 1998 (Act 107 of 1998)
NWA: National Water Act, 1998 (Act 36 of 1998)
PGM: Platinm Grop Metal; incldes platinm, palladim, rhodim, rthenim,
osmim and iridim
Precipitation: The process dring which a sbstance (the precipitate) is separated from
AbbReViATiONs
& TeRMiNOlOGy
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the liqid (throgh the action of a chemical reagent or heat) in which it was previosly dissolved
and deposited in the solid state.
Pyrometallrgy: The branch of extractive metallrgy in which processes employing chemical reactions at elevatedtemperatres are sed to extract metals from raw materials, sch as ores and concentrates, and
to treat recycled scrap metal.
Raw water: Water obtained from otside the operations; it may inclde water from the local service provider
(mnicipality), bl service provider or another water ser and may be of a potable qality
(drining water spply from mnicipality) or water treated to a certain degree (treated sewage
water)
Rening: To free from impurities; to make purer or of a ner quality; to purify or cleanse.
Separation: The separation of material into two streams based on some physical characteristic sch as its
magnetic properties of its specic gravity
Thickener: It increases the density of the solution. A non-lter device for the removal of liquid from a
liqid-solids slrry to give a dewatered (thicened) solids prodct; can be by gravity settling or
centrifgation
unreactive: Materials that will not readily dissolve in water or react with water
WRC: Water Research Commission
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The Hydrometallrgical Processing Plant is an integral part of the mining operation on many
mines, inclding gold, coal and platinm. Hydrometallrgical processing plants typically featre
as a central component of the mining operation in that these receive the raw ore from the mine
and may produce the saleable product, the solid waste streams and a signicant portion of the liquid efuent. While the operations and water balance of the average hydrometallurgical
processing plant are integrally lined with the preceding mining operation and the sbseqent
reside disposal facility and its associated retrn water systems, there are particlar featres
that relate to water management within the hydrometallrgical processing plant itself. This
Best Practice Guideline (BPG) focuses specically on water management issues within
the hydrometallrgical processing plant, while water management isses within the mining
operations are covered in BPG A5: Water management for Surface Mines and BPG A6:
Water Management for Underground Mines and water management associated with a reside
disposal facility is covered in BPG A2: Water Management for Mine Residue Deposits.
This BPG (BPG A3: Water Management in Hydrometallurgical Plants) therefore only
deals with water management isses within the bondary fence of the hydrometallrgicalprocessing plant (see Figre 1.1 below) and excldes water management associated with the
mining process/operation and the reside disposal activities. This BPG ths starts when ore
(inclding water/moistre) and water from the mining operation arrives at the hydrometallrgical
processing plant for processing and nishes when residue (tailings) leaves the processing site
(generally via a pipeline) for disposal.
1iNTROduCTiON
ANd ObJeCTiVes
The type of hydrometallrgical processing
plant that is addressed in this BPG is one
that focses on the nit processes typically
encontered in sch a plant and wold inclde:
milling and grinding circits; separation
circuits (magnetic or other); rening circuits;
classiers, hydrocyclones, screens, lters,
thickeners, otation processes, electro-
winning, leaching, solvent extraction, metal
recovery and precipitation.
Hydrometallrgical processing plants need
to operate within an external environment
where water is becoming an increasingly
scarce and valable resorce with
competing demands, primarily from the need
to satisfy the demand for hman se and
ecological functioning. As a signicant user
of water and a prodcer of water containing
waste, the minerals indstry, with their
hydrometallrgical processing plants have an
Fgr 11: bt practc gn
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important role to play in ensring that water is conserved
and sustainably used and managed to the benet of all
the water sers. The mining and minerals indstry is
already exposed to the tre vale of water in having toconfront areas where water is in short spply, or where
poor qality water needs to be treated before it can be
sed or discharged. In addition, legislative developments
sch as the waste discharge charge system are set to
have a major inuence in dictating the economics of
water spply, water treatment and discharge.
Within this external environment, hydrometallrgical
processing plants are reqired to tighten p the degree
of water rese and redce the amont of wastewater
discharged. This obviously has signicant implications
for water qality within the hydrometallrgical processingplants’ water circuits, both in terms of potential effects on
the efciency of various unit processes within the plant,
as well as on the eqipment that maes p the plant in
terms of scaling and corrosion. To ensre that improved
water management within hydrometallrgical processing
plants avoids, or at least signicantly reduces, the
potential negative effects, while still complying with
the strategic imperatives imposed by the external
environment within which these plants operate, it is
necessary that water management operations are rmly
based on sond and correct principles. It is the objective
of this BPG to provide gidance on these ey isses.
Hydrometallrgical processing operations, if not managed
correctly, have the potential to negatively impact on the
srronding environment and case environmental
damage on nmeros fronts. Beginning with the
exploration of prospective sites, through to the rening
and beneciation of minerals, many contaminating wastes
are generated both directly and indirectly. If not managed
correctly, these waste streams may pose serios threats
to ecosystems and to hman qality of life, and cold
also deteriorate resorces, particlarly water and soil. It
is therefore important to minimize all polltants, inclding
air emissions, wastewater discharges and solid wastesas well as energy and water consmption.
An integrated water and waste management (IWWM)
approach is based on the DWAF water management
hierarchy for decision-taking and focuses rstly on
waste and polltion prevention/avoidance. If complete
prevention is not possible, waste and polltion
minimization becomes the next area of focs and this
may inclde the economic redction of waste stream
volmes and se of chemicals via process design.
Thereafter rese (recycling) and reclamation (recovery)
becomes important and lastly, if all of the above have
been considered, treatment (redction of volme or
hazardosness) and environmentally safe disposal
remain the only options left to ensre the minimisation of the environmental impact.
Waste creation needs to be controlled dring the
prodction processes by integrating a series of highly
effective polltion prevention measres, state-of-the-
art environmental management practices and efcient
treatment technologies/strategies in the pollting
sections of the operation. Individally and/or collectively,
these minimization strategies will redce the qantities
of polltants released to small, manageable amonts,
and will also enable treatment and removal of any toxic
chemicals that may otherwise have been destined for discharge into the environment. In addition to preserving
the environment, liabilities and operational cost will be
redced throgh sch practices.
The prevention and management of polltion from
hydrometallrgical processing plants is based on the
environmental and water management systems in place
on these sites as well as the prodction processes.
These management systems shold inclde a practical
environmental policy, organizational procedres,
research and development programmes, environmental
responsibilities, allocation of dedicated resorces and
spport, training, monitoring, management and treatment
and operational adjstments and control.
This BPG is specically aimed at water containing waste
within hydrometallrgical processing plants associated
with all types of mines and can also be applied to small-
scale mines if simplied (refer to BPG A1: Small-scale
Mining ). Pyrometallrgical and smelter operations are
not considered, althogh many of the principles and
procedres covered in this BPG may be applicable to
sch operations. This BPG will also draw extensively on
other BPGs that have already been prodced and will
cross-reference to these BPGs wherever it is appropriateto do so.
The primary objectives of this docment are formlated
as follows:
• To promote a strategic water management approach
at hydrometallrgical processing plants that views and
manages water as a ey bsiness asset with social,
cltral, environmental and economic vale.
• To provide a practical and logical process whereby
water management within hydrometallrgical
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processing plants can be optimized.
The rst objective is a broad strategic objective, taken
from a strategic framewor docment prepared by theMinerals Concil of Astralia in 2006. This objective
is entirely consistent with sstainable development
imperatives and is considered appropriate in a water-
scarce contry sch as Soth Africa where there is
increasing competition and demands on the scarce and
limited water resorce. The second objective addresses
the practical isses and gidance that will be reqired to
give effect to the rst objective.
The layot of the docment is as follows:
• Chapter 2: General principles and considerations
for water management on a hydrometallrgicalprocessing plant and the stepwise procedre to follow
for efcient and effective water management on a
hydrometallrgical processing plant.
• Chapter 3: Legal framework and legislation
to consider in terms of water management at a
hydrometallrgical processing plant.
• Chapter 4: Considerations within the different
phases of the mine life-cycle and the importance
to incorporate considerations into the planning and
design phases already.
• Chapter 5: Financial considerations assessingthe tre cost and vale of water as well as looing at
water as a ey bsiness asset.
• Chapter 6: Information gathering to gain
nowledge of the site and process, do water and salt
balances and understand the mine/plant water users’
reqirements.
• Chapter 7: Hoseeeping and water management
systems aiming to:
- conserve water;
- segregate water of different qalities;
- store material in the correct manner;- deal with high contamination ris areas;
- manage storm water;
- clean spillages efciently and effectively;
- maintain and repair eqipment; and
- mae the operation sstainable.
• Chapter 8: Water quality and constituents of
concern specically preventing the deterioration
of water qality by minimizing the generation of
contaminants and establishing the water qality
reqirements of the mine/plant water sers.
• Chapter 9: Water reuse and reclamation smmary
as per details contained in BPG H3: Water Rese and
Reclamation.
• Chapter 10: The need and signicance of process
changes or cleaner technology, the implementation
of changes or technologies, barriers preventing
implementation and how to overcome these barriers.
• Chapter 11: Integrated water and waste
management plan compilation from information
collected and strategies implemented by following the
process stiplated in this BPG.
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Figre 2.1 below shows an effective stepwise procedre that shold be followed in a
hydrometallurgical processing plant to ensure the efcient management of water. Details
pertaining to the diagram are discssed frther on in the docment in the different Chapters
as indicated.
2
GeNeRAl
PRiNCiPles ANd
CONsideRATiONs
Fgr 21: stpw procr for watr managmnt at a ro-
mtargca procng pant
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In order to spport the two primary objectives of this
BPG as listed in Chapter 1, a nmber of ey principles or
considerations are identied that need to be considered
when implementing best practice water management
within hydrometallrgical processing plants.
unrtan t tr cot an va of
watr: (Captr 5)
The tre cost and vale of water incldes all direct costs
of water se on site as well as its vale as a bsiness
asset reqired for contined operation, for example:
• Cost of exploration and extraction of groundwater;
• Social, cultural, environmental, and economic
feasibility stdy costs;
• Waste stream disposal costs;
• Cost of water supply;
• Reticulation costs such as pumping, storage, power
consmption;
• Water treatment costs;
• Mitigation and remediation costs in the event of
spillage;
• Construction and rehabilitation costs of engineering
wors e.g. river diversions, clean/dirty water diversions
etc;• The value of ecosystem services reliant on the same
water spply;
• Competing social and industry demands on the same
resorce;
• Competing industry demand for the same resource;
• Economic value to allow production and processing to
tae place; and
• Loss of income, jobs or market share if there are
prodction ct-bacs and interrptions as a reslt of
water excess or shortage.
App gnra “goo” okpng
an opratng practc: (Captr 7)
• Avoid cross-contamination of materials and chemicals
by eeping the wor area clean and organized;
• Segregate waste streams (consider piping and storage
facilities) based on their level of contamination.
• Install proper safeguards (bunded areas, diversion
berms, concrete paving) and implement better
cleanp practices (washing, sweeping etc);
• Consider general layout of the site and process plant
as well as placement of facility;
• Know and have a good understanding of the plantand water circits.
Optmz poton prvnton an
rcton at orc: (Captr 7)
• Bund, contain and recycle certain high risk areas;
• Roof areas to prevent water inltration;
• Concrete areas to prevent seepage into underlying
grondwater;
• Slope areas to minimize erosion and maximize
rnoff.
• Divert storm water around major pollution sources.
Optmz watr managmnt tm:
(Captr 7)
• Design and operate for the separation of water circuits
based on the level of contamination and possible ses.
In particlar, ensre a separation between process
water circits and the storm water system and ensre
that process spillages cannot nd their way into storm
water systems;
• Develop and maintain an accurate water and
contaminant balance for all water circits – not only
for potable water;
• Based on knowledge of which are the primary
contaminants of concern (COC) for that particlar
process plant, develop contaminant balances for
each COC and identify potential options for redction
of contaminant load;
• Dene the water quality requirements of the different
water users within a process plant. Dene the
worst possible water qality that each ser can se
withot experiencing process or water qality related
problems (e.g. corrosion and scaling);• For storm water management, make provision for
ftre sealing of areas and constrction of roofs that
case increase in volme of rnoff;
• Keep clean water clean – (refer to BPG G1: Storm
Water Management ) by reroting grondwater
springs and srface water streams to prevent contact
with contamination/polltion sorces;
• Construct diversion berms and channels to carry clean
rnoff away from solvent exchange, leach and tailings
disposal areas or other possible polltion sorces;
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• Control erosion through measures such as retention
ponds to intercept rnoff and protection of stream
bans;
• Manage process water. Contain dirty water (refer to
BPG G1: Storm Water Management ) in bnded
areas for recycling in the bnded area or channel
contaminated runoff and spills in drains to articial
basins and srge ponds (Polltion Control Dams) for
containment and possible rese and/or reclamation
(refer to BPG H3: Water Reuse and Reclamation).
• Separate circuits to prevent cross-contamination of
circits;
• Setup water management systems in the different
phases of development to ensre sstainability. Water
management systems incorporated dring the design
and constrction phases of an operation can be tailor-
made to the application. With an existing operation,
the water management system has to consider the
existing system infrastrctre.
unrtak npcton/montorng/
atng an mantnanc: (Captr 8)
• Ensure that equipment/machinery inspection and
maintenance schedles are followed and that
eqipment/machinery is in pea woring order to
prevent wastage of raw materials and/or loss of prodction/processing time thereby ensring prodct
is not compromised;
• Ensure data availability on plant pollutants (refer to
BPG G3: Water Monitoring Systems);
• Ensure sufcient water ow meters are installed,
maintained and monitored.
Rvw rorc ntak/npt/raw
matra: (Captr 8)
• Minimize or reduce raw material use;
• Use lowest possible chemical concentrations at which
process can operate effectively throgh tight process
control measres to prevent overdosing;
• Control purchasing, handling and storing of
materials;
• Substitute raw and auxiliary materials with less
harmful ones that can be more efciently recycled
ths feedstocs with fewer inherent by-prodcts;
• Consider products and/or catalysts with longer lives
and rese possibilities;
• Minimize raw water intake into process (water
conservation principle);
• Consider novel energy sources and efcient energyse;
• Avoid extraneous water streams being introduced to
the process such as off-site runoff nding its way onto
the site.
Optmz r an rcamaton
(rccng an rcovr): (Captr 9)• Minimize waste by retrieving/recovering usable
process materials and resorces from waste
streams;
• Convert in-plant waste and wastewater streams toclean feed, ths allowing for reclamation of chemicals
and water for rese in the plant (refer to BPG H3:
Water Reuse and Reclamation);
• Recycle process spillages as close as possible to
their sorce and do not allow to mix into one mixed
contaminated waste;
• Evaluate waste streams for properties that make
them sefl rather than for properties that render
them wastewater streams;
• Introduce waste into external recycling networks:
industrial ecology. One industry’s waste may become
another industry’s raw material;• Consider new uses for otherwise valueless byproducts.
Reclaim byprodcts to sell;
• Save money through more efcient use of valuable
resorces (sch as water and raw materials) and
redced treatment and disposal cost for waste.
invtgat proc or tcnoog
modications: (Chapter 10)
• Modify products and technologies to eliminate
nnecessary prodction steps;
• Modify processes to minimize waste production and
resorces se;
• Improve process selectivity and/or conversion;
• Operate at lower temperatures and/or pressures to
save energy and redce the nmber of processes
reqired to create these high temperatre/pressre
conditions;
• Implement efcient equipment design;
• Consider innovative unit operations and innovative
process integration;
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• Avoid heat degradation of reaction products and
eliminate leas and fgitive emissions;
• Perform product life cycle assessment (LCA)
inclding process/activity, extraction, processing,
manfactring, recycling and disposal.
Conr opton for appcaton of
canr tcnoog: (Captr 10)
• Evaluate the need and signicance of cleaner
technology to achieve higher prodction rates,
improve product quality, increase operating efciency,
redce environmental impact, redce cost, ensre
higher percentage on-line time and safe operating
conditions;
• Assess the characteristics of cleaner technology;
• Implement cleaner technology in different areas of
bsiness sch as policy development and instittional
relations, environmental and social impact
assessment, technological development, company
strategy and edcation, research and training. Steps
to implement;
• Applications (examples);
• Review barriers such as economic, technologic and
legislative barriers that prevent the implementation of
cleaner technology;
• Overcome barriers and implement cleaner technologythrogh governmental intervention, edcation and
training and improved planning.
Watr an wat managmnt
programm: (Captr 11)
• Ensure the programme is organized, comprehensive
and represents a continos effort to systematically
redce waste generation;
• Include pre-audit phase (adequate resources,
commitment, objectives, scope, employee
involvement), adit phase (data and informationcollection, cost acconting) and feasibility analysis
(technology transfer, continos review);
• Improve environmental auditing and implement
environmental policies to achieve improved
environmental goals;
• Shift emphasis of training programmes (from treatment
to prevent, minimize and control);
• Redesign plants to better accommodate wastes;
• Setup baseline and continual monitoring (refer to
BPG G3: Water Monitoring Systems) of grond,
srface and process water as well as eqipment and
the sbseqent implementation of action plans based
on the reslts.
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31 Foc an ro of dWAF
The Department of Water Affairs and Forestry (DWAF) is the cstodian of all water resorces in
Soth Africa and therefore responsible for the protection of these water resorces. The protection
of these resorces incldes preventing deterioration of water qality in these resorces. From
this perspective, DWAF generally focses on the impact a hydrometallrgical processing
plant has on the water resorces and srronding environment, ths otside the plant area.
DWAF is therefore generally not too interested in the details pertaining to the site/plant and
hydrometallrgical process. It is only once it has been established that the hydrometallrgical
processing plant does in fact negatively impact on the srronding environment and water
resorces that DWAF becomes concerned with the operation and water management within
the bondaries of the plant. At this stage DWAF may investigate water management on the
hydrometallrgical processing plant to establish the origin of the impact noted on srronding
water resorces.
In terms of any mine hydrometallrgical processing plant and its water and waste management,the following legislation shold be considered as a minimm and these can be obtained from
internet sites (http://www.acts.co.za or http://www.info.gov.za/gazette/acts):
• Environment Conservation Act, 1989 (Act 73 of 1989) with GN R1182 and GN R1183.
• National Environmental Management Act, 1998 (Act 107 of 1998).
• Minerals and Petroleum Resources Development Act, 2002 (Act of 28 of 2002).
• National Water Act, 1998 (Act 36 of 1998).
• Water Act, 1956 (Act 54 of 1956) (repealed) with GN R1560 re dams with a safety risk.
• Water Services Act, 1997 (Act 108 of 1997).
32 Natona Watr ActThe National Water Act of 1998, Act 36 of 1998 (NWA) is the principal legal instrment relating
to water resorce management in Soth Africa and it is obtainable from the DWAF internet site
(http://dwaf.gov.za/docments). The following is of particlar importance:
• Chapter 3, Part 4 states that anyone who owns, occupies, controls or uses land is deemed
responsible for taing measres to prevent polltion of water resorces.
• Chapter 4 deals with water use regulation;
• Chapter 12 deals with water management in terms of dam safety;
• Section 19 deals with water management at mines in terms of pollution prevention and
control;
• Section 21 states the water uses requiring authorization;
• Section 26 (1) provides for the development of regulations requiring monitoring, measurement
and recording as well as the effects to be achieved throgh management practices prior to
discharge/disposal.
Rgaton on of watr for mnng an rat actvt am
at t protcton of watr rorc
Government Gazette 20118 (volme 408) notice 704 (GN 704), pblished on 4 Jne 1999,
stiplates reglations on the se of water for mining and related activities aimed at the protection
of water resorces. The following conditions are worth noting here:
3leGAl
FRAMeWORK
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• Condition 4 regarding restrictions on the location of
mining activities.
• Condition 5 regarding the restrictions on use of material.
• Condition 6 regarding the capacity requirements
of clean and dirty water systems as well as the
containment to prevent spillage between the systems
more than once in 50 years.
• Condition 7 regarding the protection of water
resorces throgh polltion prevention measres
that deals with the collection, containment and rese/
evaporate/treat/dispose of water containing waste;
water and waste management; minimizing water
contact with mining activities or infrastrctre; damstability; erosion control; recycling of process water
and the prevention of process spillages; maintenance
of water systems; disposal of waste and wastewater.
• Condition 8 regarding security and additional
measres.
• Condition 9 regarding temporary or permanent
cessation of activities.
33 dWAF Wat Managmnt
sr - MnmmRqrmnt
The Waste Management Series prodced by DWAF
(second edition pblished in 1998 and sbseqently
being revised) indicate DWAF’s requirements in terms
of the management of waste and consists of a series of
docments, namely:
• Minimum Requirements for the Handling, Classication
and Disposal of Hazardos Waste.
• Minimum Requirements for Waste Disposal by Landll(revised in 2005).
• Minimum Requirements for Monitoring at Waste
Management Facilities (revised in 2005).
• Minimum Requirements for Waste Management
Training (envisaged).
• Minimum Requirements for Upgrading Waste Disposal
Operations (envisaged).
• Minimum Requirements for Waste Management
Facility Aditing (envisaged).
34 bt Practc Gn
r
A mine and therefore a hydrometallrgical processing
plant associated with a mine are reqired to implement
the principles of IWWM throghot its life cycle.
There is no legal or reglatory obligation for a mine or
hydrometallrgical processing plant to se the procedres
and gidelines provided in this BPG docment as crrently
the only legally reqired docments associated with
IWWM is the Environmental Management Plan (EMP)
and Water use Licences/athorisations Applications
(WuLA). The procedres and gidelines presented in
this BPG need to be incorporated into the EMP and willassist in implementing IWWM. The docmentation of the
IWWM principles into an IWWM plan can be sed as
motivation dring the WuLA. Practical motivation for sch
a plan is clear as access to sch a docmented IWWM
plan will greatly assist the mine and hydrometallrgical
processing plant in meeting its obligations in terms of the
varios environmental laws and reglations that affect
water and waste management over the fll life-cycle of
the mine.
Frther, if a mine and hydrometallrgical processing plantadhere to this BPG and others in this series as well as
the principles of IWWM they will be considered to have
met the DWAF reqirements in terms of sorce directed
reglatory measres.
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4
CONsideRATiONs
WiThiN The MiNe
liFe-CyCle
Water management is aimed at ensuring the effective use of South Africa’s scarce water
resorces and therefore assists with water conservation and the protection of the water
resorces in general. The stepwise process depicted in Figre 2.1 allows for review at each
stage/step. In addition, fully dening the problem and gathering the required data in the initialstages ensres that ftre decisions are based on complete information. Figre 4.1 below sets
ot the ey points to consider dring each of the life-cycle phases.
Fgr 41: Conraton n t mn f-cc
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41 exporaton, propctng,
pannng, fat an
gn pa
Cano-Riz and Mc Rae (1999) indicated that inclding
environmental considerations in the problem framing
exercise increases the nmber of constraints on the
design process. Generating process design alternatives
may inclde the application of existing design concepts
or the generation of new ones from rst principles. Time
available dring design, limits the nmber of alternatives
that can be generated and considered as well as
the level of detail to which these alternatives can be
analysed (trade-off between comprehensiveness and
economy). Engineering analysis sally begins with
evalation of mass and energy balances for each of
the candidate process ow sheets and these are then
used to determine ow rates, compositions, pressure,
temperatre, and physical state of all material streams,
as well as the energy consmption rates from varios
sorces. Analysis evalates the design alternatives
against a predetermined set of performance indicators
(economic and environmental impacts) or objectives.
The design process is an iterative process gided by
opportnities for improvement. The athors propose that
frther incorporation of integration principles will reveal
opportnities to decrease raw material consmption,
realising increased cost savings. Refer to this and
other references (Chapter 12) for frther reading on the
importance of design.
Figre 4.2 below indicates all the aspects and constraints
that need to be considered dring design. External
constraints to consider dring the design inclde:
• Resources
• Safety regulations
• Economic controls• Socio-political considerations
• Government controls
• Environmental regulations
• Standards and codes
• Physical laws
Fgr 42: Proc gn contrant (Marr, 2003)
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Internal constraints to consider dring the design
inclde:
• Process conditions
• Level of control
• Choice of process
• Methods
• Time
• Personnel
• Environmental performance
• Materials
• Cost: 85% of the life cycle cost, nancial and
environmental, are determined by decisions made in
the planning and design phases (Marr, 2003) and the
importance of this phase can therefore not be over-
emphasised. The early stages of the design process
offer the greatest exibility in selecting the process
rotes for a facility and decisions made dring this
stage are therefore critical and have major impacts
on ftre phases. A frther estimated 50% of capital
expenditre on new plants is associated with isses
pertaining to environmental management (Marr,
2003).
• Life Cycle Assessment (LCA): Address all material
and energy transformations over “cradle to grave”.
This means emissions and the consmption of
resources at every stage in a product’s life cycle,
from its cradle (raw material extractions, energy
acqisition) to its grave (se and waste disposal)
needs to be considered. An inventoried listing of
environmental technologies, treatment processes,
and toxic chemicals sed, shold be made p front.
• Environmental Impact Assessments (EIA):
Generally, at the stage at when the EIA is condcted,
it is not easy to incorporate EIA information in the
design process in order to redce the environmental
impact of hydrometallrgical processing facilities,
bt it is essential. It is therefore important to ensre
that EIA information is incorporated into the design
phase and that environmental and commnity
related impacts are considered. Some impacts to
be considered inclde acid mine drainage, metals in
the environment, toxic reagents inclding cyanide,
sedimentation and water se, waste, emissions.
• Environmental impact considerations: Review
and tae accont of the environmental impacts of
exploration, infrastrctre development, mining or
processing activities, and condct the planning,
design and development of all facilities in a manner
that optimises the economic se of resorces while
redcing adverse environmental impacts to acceptable
levels. It is widely recognised that early consideration
of environmental matters dring the design is needed
to obtain good environmental performance at lowest
cost (set environmental concerns as constraints
on economic optimisation). The early stages of
conceptal process design which are generally
rather exible provide the greatest opportunities for
identication of potential environmental impacts and
to tae remedial action.
• Risk assessment and management: Employ ris
management strategies in planning and design,
operation and decommissioning, inclding the handling
and disposal of hazardos materials and waste. If a
preliminary ris assessment indicates nacceptable
riss for hman health or the environment, the lac of full scientic certainty should not be used as a reason
to delay the introdction of cost-effective measres
to redce environmental and hman health riss
to acceptable levels. An example of a detailed ris
assessment process sed and implemented dring
the project design phase is shown in Appendix C.
• Efciency and optimisation: Plan, develop
and design facilities and processes taing into
consideration the efcient use of energy, water and
other natral resorces and materials, inclding their
recycling and rese, the minimization of waste and
the responsible management of residal materials.
• Feasibility studies: undertae detailed planning and
feasibility stdies on the overall water balance, site/
plant layot, infrastrctre development and operation
in consltation with design and process engineers.
• Technologies: Consider and evalate different
hydrometallrgical process technologies and designs
in order to optimise the overall water balance, rese/
reclamation and water management.
• Inputs: Identify possible water sorces (water service
providers, local and srronding catchments, captred
rainwater, or water imported with raw materials)and undertake nancial assessment of water cost.
Review the intae of other resorces (energy etc) and
raw materials. Determine water qantity and qality
reqirements based on process design.
• Outputs: Aim to minimise emission of contaminants
of concern, mass of waste generated, contribtion
to specic environmental problems, and overall
environmental impact.
• IWWMP: Compile and inclde above into an Integrated
Water and Waste Management Plan.
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42 Commonng an
opratona pa
• Implementation: Implement designs and processes
based on reslts of planning, design and feasibility
phase.
• Health and safety measures: Apply control
measres to ensre the contined health and safety
of all worers on as well as visitors to the site.
• Pollution prevention: Optimise polltion prevention
and redction/minimisation at sorce. Experience has
shown that any IWWM plan is more easily and cost
effectively applied if polltion prevention strategies
were optimally applied rst. It is therefore considered
advisable to rst investigate, develop and implementappropriate polltion prevention strategies wherever
possible, e.g. early recognition of the potential
for spillages and the adoption of appropriate ris
management strategies.
• General: Apply general “good” hoseeeping and
operating practices.
• Technologies: Continosly evalate process
technologies and facilities in terms of their
water reqirements and se. Consider whether
modications, improvements or new technologies can
be applied to redce these water reqirements and
ses.
• Environmental Management System (EMS):
Implement an EMS to ensre more effective control
and redce environmental impacts and shold
inclde organizational procedres, responsibilities,
processes, implementation strategies, measrement
and evaluation criteria, efciency measures, staff
training and goals for improvement.
• Review: Continosly review and improve water
management. Review and revise IWWM plan annally
based on performance assessments and changes in
the system.
• Monitoring: Implement monitoring system to
verify performance. Perform reglar maintenance,
refrbishment, inspections and performance
assessments. Environmental adits at reglar
intervals shold also be implemented and inclde
a thorogh investigation of every indstrial system
and process. Refer to BPG G3: Water Monitoring
Systems.
• Database: Store and manage information collected
in a database. The database shold show baseline
conditions as well as allow assessments of data to
determine when changes in conditions occr.
• Water and salt balance: Refer to BPG G2: Water
and Salt Balances.
43 dcommonng, cor
an pot-cor pa
• Residual impacts: Verify latent/residal impacts
throgh monitoring systems, performance
assessments and predictive modelling.
• Water management: Dene post-closure water
management options and determine best practicable
environmental option, e.g. treatment and discharge,
irrigation, sstainable development projects, etc.
• Finances and contracts: Finalise nancial and
contractal arrangements/agreements for post-closre
water management and maintenance of infrastrctre
with ftre landowners and/or responsible parties
and/or water sers.
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51 Watr, a k n at (stp 1)
De to the limited water resorces available in Soth Africa, the competition for this valable
resorce is continosly increasing. DWAF as cstodian of the natral water resorces is
responsible for the allocation and management of the demand on the water resorces as well
as the protection of these water resorces against nacceptable qality deterioration. Globally
5
FiNANCiAl
CONsideRATiONs
(sTePs 1 ANd 2)
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and nationally, the trend has been to prioritise water for
hman se (domestic se), food prodction (agricltral
se) and aqatic ecosystems (ecological fnctioning)
ahead of indstry sch as mining. This trend is evident
in South Africa and reected in our legislation and
reglations (NWA, reserve determinations).
With attitdes changing, water is increasingly seen as
a valable resorce. Increasing water demands have
reslted in a higher proportion of water being recycled
internally in indstries as well as the se of relatively
impure make-up water such as treated efuents rather
than potable water spplies. The impact of process
water qality has therefore also become an important
consideration.
It has therefore become important for the mining and
hydrometallrgical processing indstry to:
• not take water for granted as it is a limited, scarce and
valable commodity in Soth Africa that needs to be
conserved;
• follow a pro-active approach in terms of water
management whereby measres are implemented to
prevent impacts rather than mitigating impacts after
occrrence;
• incorporate water issues into strategic business
decision-maing to ensre sstainable se and
development of the indstry;
• ensure all current and future water users are not
adversely affected by the metallrgical activities as
water is a shared commnity resorce and other
users’ interest and rights need to be respected;
• reduce operating cost over the long term due to
efcient water use through water conservation; and
• optimise reuse and reclamation (refer to BPG H3:
Water Reuse and Reclamation); and
• realise water is a key business asset with social,cltral, environmental and economic vale.
Mines and hydrometallrgical processing plants shold
therefore identify opportnities and minimise ris in
terms of their water management plan. Responsible
water management will improve the public’s view of the
industry, the holding company and the specic operation.
Water management is now more often scrtinised by
external parties in applications for fnding and legal
athorisations. It has therefore also become important to
incorporate water ris into ey bsiness decisions.
52 Tr va an cot of watr
(stp 2)
In Soth Africa, water remains relatively cheap and
is therefore seldom broght into the prodction cost
eqation. The marginal economic advantage of effective
water management therefore requires it to be inuenced
by other factors sch as social pressres, coercion
from athorities, compliance with legislation or intent to
operate in an environmentally responsible manner. Water
management can accont for p to 15% of the cost of
hydrometallrgical processing (Wates and Van Nieer,
1991) and it depends on water use efciencies (wastage
and losses) and the relative density of process plps. As
the relative density of the process plp decreases, the
water volme in circlation increases, which reqires
an increase in transport and storage capacity, casing
increases in costs. Prodct lost in the water sed for
transport shold also be considered as a cost factor.
Water costs money and in order to save money
an operation needs to redce water sage (water
conservation), recycle more water (refer to BPG H3:
Water Reuse and Reclamation) and eep sed water
as clean as possible (polltion prevention) for rese and
ltimate disposal.
The tre cost of water incldes all direct and indirectcosts associated with water and incldes:
• Exploration, prospecting and planning cost –
inclding:
- grondwater extraction in exploration area;
- water sed by exploration/prospecting opera-
tions and worforce;
- conceptal and detailed designs;
- environmental impact assessments;
- feasibility stdies;
- ris assessments;
- constrction;- engineering wors;
- capital otlay etc.
• Water supply cost – inclding:
- obtaining water from a water service provider
(raw water charges);
- establishing connections to the main water
spply line;
- abstracting water from boreholes or srface
water bodies;
- competing industries’ demand for same
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resorce;
- trading of water se entitlements in a water
scarce catchment;
- excess or shortage of spply etc.
• Social and cultural cost – inclding:
- perception by society and srronding water
sers;
- responsible water management to improve
pblic view;
- responsible care;
- ensring water availability to other sers as
reqired;
- water sed by indstry and therefore lost to
srronding commnities and downstream
sers;
- responsibility to commnity etc.
• Environmental and ecological cost – inclding:
- water sed and discharged thereby affecting
the natral srronding environment inclding
aqatic ecosystems;
- limited resorces and regional water shortages;
- environmental responsibilities;
- move the focs from site bondary conditions to
catchment level impacts (broader focs);
- conseqences of releasing materials to
srronding ecosystems etc.
• Economic feasibility cost – feasibility of the
operation considering all expenses and incomes.
• Waste management cost – inclding:
- the handling, transport, treatment and disposal of
all solid waste resides as well as wastewater;
- waste discharge charges (refer to waste
discharge charge system);
- discharge/disposal cost based on volmes/
qantities;
- contaminants load and receiving environment
etc.
• Operational cost – inclding:
- water spply;
- eqipment;
- reticlation/pmping;
- maintenance and refrbishment;
- labor/personnel;
- power consmption;
- waste management;
- engineering and infrastrctre;
- clean and dirty water separation etc.
• Water reticulation costs – inclding:
- pmps;- pipelines;
- energy/power consmption;
- pmping for transport;
- storage facilities with reqired capacity;
- water losses and wastage etc.
• Water treatment cost – inclding:
- the treatment of water to improve qality for se
or to allow for rese in the process;
- treatment for se by another indstry;
- treatment for discharge prposes etc.
• Maintenance cost – inclding:
- maintaining water infrastrctre sch as storage
facilities, pipelines and pmps as well as
monitoring equipment such as ow meters;
- maintenance of water infrastrctre de to
corrosion/scaling etc.
• Labour/personnel cost – inclding:
- personnel responsible for monitoring water se,
sampling water, managing water, information
captring, doing assessments and reporting,
maintenance;
- training and sills development;
- jobs;
- interaction and relationships with staeholders;
- allocation of dedicated hman resorces;
- spport fnctions etc.
• Remediation cost – inclding:
- mitigation and remediation of spillages dring
operation;
- remediation and rehabilitation of site after
decommissioning and closre etc.
• Legal cost – inclding:
- acqisition of necessary licenses and
athorizations;
- nes for breaches of regulations;
- reglatory demands etc.
• Risk cost – inclding:
- technical ris (ris of sing a “poorer” water
qality verss the saving in water prchasing
cost);
- environmental ris that may lead to liabilities;
- maret price changes etc.
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The tre vale of water incorporates perceptions of
water by external parties and the vale for the contined
operation of the bsiness, for example:
• Cultural or spiritual associations with water or the land
on which water infrastrctre is planned;
• The value of ecosystem services reliant on the same
water spply;
• Competing social demands on the same resource
(e.g. domestic water spply or recreational se);
• Social, cultural, environmental or economic impact on
downstream water sers if water qality is affected by
operations or not available to other water sers;
• Impact on reputation for perceived poor water
management performance;• Cost to the operation if water excess or wastewater
cannot be discharged;
• Economic value to allow production and processing to
tae place; and
• Loss of income, jobs or market share if there are
prodction ct-bacs as a reslt of water excess or
shortage.
A strategic water management approach shold ths
ensure that water is more efciently managed and valued
as a vital bsiness and commnity asset.
The rese of process water in hydrometallrgical
processing plants is often desirable not only for
environmental protection reasons bt also for the cost
saving associated with it. Cost savings are seen in
terms of redcing the qantity of external water to be
prchased and consmed, simplifying operations, saving
in infrastrctre cost by redcing the transportation
infrastrctre reqirements (piping) etc.
In terms of nancial considerations, it is also important
to realize the benets industry often brings to an area or
commnity which may inclde:
• The establishment of water supply infrastructure and
water spply to commnities in the area;
• Social benet in terms of job creation, infrastructure
and services establishment, improvement of qality
of life; and
• Economic benet in terms of nancial investments
made in the region and contry.
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61 st an proc knowg (stp 3)
Only isses nown and nderstood can be managed. To apply “good” hoseeeping practices
and operating procedres (Step 6), it is therefore essential to have a good nowledge and
nderstanding of the plant. knowledge and nderstanding abot the following items are
reqired:
• Site: General site and plant layot; site locality in proximity to power/electricity spply,
water supply, roads, rail and other support infrastructure has obvious benets; site
location in relation to water resorces is important in terms of impacts on water resorces;
nderlying geology of the site in terms of possible grondwater impacts; site limitations
sch as bondary, possible expansions, topographical gradients, soil conditions; site water
management plans; site location in terms of locality of ore body (mine) will affect transport
cost etc.
6
iNFORMATiON
GATheRiNG
(sTePs 3, 4 ANd 5)
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• Environment/catchment: Geology of the area;
grondwater/aqifer characteristics; boreholes and
springs; geohydrology; topography of the area; climate
(precipitation, evaporation etc); biogeochemical
cycles; dams and water corses; hydrology; wetlands;
water sers; srronding land ses; sensitivity
of receiving and srronding environment; water
qantity and qality (grondwater and srface water);
contaminants of concern in terms of the environment;
variability of environmental conditions (droght,
seasonality etc); reserve determination (obtain from
DWAF) and water qality objectives; catchment
management agency etc.
• Process: Process ow diagram; piping and
instrmentation diagrams; process featres
(pH, oxidation-redction conditions); process
methodologies; process exibility (expansion);
eqipment and infrastrctre; power/electricity
reqirements for the process; inpts and otpts;
contaminants of concern in terms of the process
technology sed; process sensitivity to variability and
changes; technology design and operation; type and
scale of operations; steps inclding ore preparation,
concentration of metal minerals, solbilising metals,
prifying soltions throgh removal of imprities,
recovery of metals from soltion (oxide ores arefor example not well known for their oatation
characteristics and are ths treated as whole ores
in hydrometallrgical facilities by heap, vat or high-
pressre acid leach, or redctive pyrometallrgical
processes whereas slphide ores can be treated in
concentrators to separate a concentrate, from the
tailings material, which cold be frther processed in
a roaster or smelter followed by a hydrometallrgical
facility, or directly by a hydrometallrgical facility).
• Raw material/ore: Type of roc/ore being mined and
processed (slphide/oxide); characteristics of the
mined material (geochemistry); mineral ore grade;
variability and non-homogeneity of ores in terms of
metal content; mineralogy; imprities present in the
ore body; complexity and variability (qantity and
qality) of the feed.
• Other inputs: Characteristics of other materials/
chemicals sed in the process; concentrations of
elements; form of elements (speciation).
• Water resources: Be pro-active in investigating
potential water spply sorces; consider grond- and
srface water resorces; excess or scarcity of water;
sstainability of resorces; sensitivity of receiving
water resorces; water qantity and qality as well as
its variability (seasonality); contaminants of concern;
assess impacts of water spply sorces on process/
plant performance.
• Other resources: Allocation of dedicated resorces;
personnel and teams; training and sills development;
infrastructure (equipment); nances (funding);
accontabilities; responsibilities; time investment;
management commitment and spport.
• Mine/plant water users: Process water qantity and
quality requirements (sulphide ore otation has strict
requirements in terms of the water phase’s chemical
composition de to wet oxidation); laboratory/pilotstdies to investigate impact of water spply on mine/
plant water sers; process sensitivity to qantity and
qality as well as variability; contaminants of concern;
possibility of water rese and reclamation in or
between processes (refer to BPG H3: Water Reuse
and Reclamation); water treatment reqired to mae
water t for use (refer to BPG H4: Water Treatment ).
Also see Section 6.3 below.
• Waste: Solid, liqid and gaseos waste generated
on site; handling and management of waste; waste
transport; waste treatment to redce volme,
hazardosness or impact; disposal/discharge of
waste.
• Water reticulation: Reticlation systems; limitations;
different and separate circits; closed circits; storm
water management and incorporation of contaminated
storm water into water circits (refer to BPG G1:
Storm Water Management ); management of process
water and spillages; prevention of losses from system
(maintenance and inspection); inpts to the system
(precipitation, spply water, grond- and srface
water abstraction, recycled water); otpts from the
system (evaporation, rnoff, seepage, reglatedand nreglated discharges, losses); storage in the
system.
• Monitoring: Water measring and monitoring;
monitor all inpts and otpts; assessment of impacts
on grond- and srface water resorces de to
operation; polltion plmes; water and salt balances
(refer to BPG G2: Water and Salt Balances).
• Future: Ftre plans; changes in technology (cleaner
technology – Step 9); expansions; research and
development.
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62 Watr an at/oa aanc
(bPG G2: Watr an at
aanc) (stp 4)
BPG G2: Water and Salt Balances deals with the design,
compilation, implementation and management of water
and salt balances in detail and the details will therefore
not be repeated here. The following are however, worth
noting in this docment:
• Objectives: Clear objectives shold be stated for the
water and salt balance; the objectives shold consider
the crrent as well as possible ftre scenarios in the
plant (plant life-cycle).
• Divisions: The water and salt balance for a large
complex operation shold be divided into smaller management nits; the same formats and procedres
shold be employed for each management nit to
allow the exchange of information over management
nits; establish bondaries for individal balances;
differentiate between different water circits.
• Updates: The water and salt balance shold be
pdated reglarly to inclde process changes,
new information, expansions, new data lined with
monitoring (refer to BPG G3: Water Monitoring
Systems Systems), management measres
implemented etc; pdates shold be an iterative
process in order to obtain higher levels of accracyand for renement; the water and salt balance should
be exible to allow for and accommodate changes.
• Loads: Conservative salts shold be sed to
constrct overall water and salt balances; polltants
or contaminants of concern can be sed to determine
polltion loads;
• Calculation of unknowns: unnowns can be
calclated throgh the simltaneos soltion
of eqations; develop sch eqations; address
imbalances.
• Hydrological cycle: Consider seasonal changes;
wet and dry seasons; precipitation; evaporation; rn-off; percolation/inltration to groundwater aquifer;
seepage etc.
• Output: Level of detail is based on objective; validation
of reslts/otpt; manal calclations; spreadsheet
based balance; PC-based software; high-end
engineering software; compterized system.
Water and salt balances are important water management
tools to be sed to provide gidance in terms of
management actions reqired, areas to focs on in terms
of polltion load, major water consmers, etc.
63 Mn/pant watr r
(stp 5) As part of the site and process information gathering,
nowledge shold have been obtained in terms of the
water sorces available. It is eqally important to obtain
information on the mine or process plant water sers in
terms of:
• Water quantity requirements - Major water consmers.
• Water quality requirements – Is potable qality water
required or can efuent from another user/processpossibly be sed? Consider that some mine/plant
water sers may be sensitive to certain constitentsin the water and these constitents may in certain
instances have a negative effect on the specic mine/
plant water ser or its process performance (seecontaminants of concern).
• Sensitivity to quantity and quality changes as
well as variability – Spply water may change in
qality over time, for example if water is continosly
recycled, some constitents (sch as TDS or salinity)may increase in concentration (accmlation) with
each cycle (de to evaporation and sbseqent
concentration of dissolved salts) and may thereforealter the chemistry of the system. Eqalization or
stabilization ponds (tans/dams) may be reqired
to ensre less variability to the ser sensitive tochanges.
• Contaminants of concern – These are contaminantsor constitents in the water that may affect/impact
process performance.
• Pollution loads – Constitents fond in water at
higher concentration than expected. The sorce
of the additional concentration of the constitent/contaminants is a direct reslt of an activity sch as
processing. Contaminants are also added to water as
it is sed and recycled.
• Water reuse and reclamation – Examine the
possibility of water rese and reclamation in or between processes. Refer to BPG H3: Water Reuse
and Reclamation. Consider the time-lag between
water being reqired and water being available dringdifferent phases of the mine (for example, processing
which reqires large qantities of water starts mchlater than dewatering for bl sampling and access
to the ore body which generates large qantities of
water).
• Water treatment – Establish water treatment reqire-
ments (softening, etc to redce corrosion/scalingpotential). Refer to BPG H4: Water Treatment .
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Water is nown as the niversal solvent since it has the ability to dissolve, to some degree, every
substance in the earth’s crust and atmosphere. Water is therefore also the main medium for
transportation of pollutants/contaminants within the connes of a mining or hydrometallurgical
processing operation and from these operations to the otside environment. Water dissolves
gasses from the air (SO2gas dissolves in rain water to yield acid rain); minerals from the earth’s
crst (slphide in pyrite dissolves in water nder aerobic conditions to yield slphric acid
soltions); and it pics p sspended matter from the earth and air (soil particles are carried in
rnoff dring erosion and when water is applied for dst control). Ths, the more water there is
to manage, the more difcult the control of pollutant/contaminant migration becomes.
71 Mnmz watr /watr conrvaton
It is important to minimize the amont of water sed in a hydrometallrgical processing
operation. The areas of high water consumption should be targeted rst in terms of water
minimization strategies. Water and wastewater minimization has been driven by the rising
7
hOuseKeePiNG
ANd WATeR
MANAGeMeNT
sysTeMs (sTeP 6)
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cost of raw/potable water from service providers and
efuent treatment or discharge charges as well as
more stringent environmental legislation. Also refer to
water pinch techniqes and analyses as described inreferences (Section 12) and BPG H3: Water Reuse and
Reclamation. Generally, hydrometallrgical processing
involves the se of water for the initial processing of the
mined ore and incldes amongst others the following
fnctions/applications:
• Dust control: Control of wind-borne particles and
prevention of polltion. Reqired on roads becase
of vehicle movement; reqired on waste dmps de
to drying of material; reqired in wet scrbbers to
prevent dst release into atmosphere.
• Water-based hydraulic mechanical equipment: Water affects the hydraulic uid characteristics in
terms of emlsion stability, lbricity, corrosivity and
erosive tendencies.
• Reticulation/transport: Transport of tailings material
to a thickener/clarier or residue disposal facility
for wet deposition; water is often seen as an inert
transport medim; transport of wet ore after washing
and wet separation processes.
• Cooling and heating: Chilled water circit; condenser
cooling system; evaporative cooling especially dring
exothermic reactions; steam generation; boilers.
• Processing and reaction medium: Ore preparation
sch as washing of mined material and milling and
grinding processes. Concentration processes sch
as separation circuits; magnetic separation; otation;
hydrocyclones; screens; lters; classiers; thickeners;
precipitation. Solbilisation processes sch as
leaching. Prifying processes to remove imprities
such as electro-winning, precipitation, otation and
solvent extraction.
• Plant cleaning: Spraying of water for cleaning of
spillages
In terms of the above ses, it is important to eep water reticlation circits separate from each other and closed
in certain instances to prevent cross-contamination. For
example, the water transporting the milled ore might
be considered ncontaminated in terms of chemical
composition if the water was ncontaminated to start off
with and not mixed with water from another area in the
process (ths a closed circit) since no chemicals are
generally added neither do any major chemical reactions
tae place dring the initial milling process of mined
material. The sspended material in the water (physical
composition of water) is easily removed in a thicener
or clarier through precipitation or via some lter or
screen. Wet processes shold also be replaced with dry
process technologies where possible to redce water
consmption.
72 Watr grgaton
Water containing waste (contaminated water) shold
be classied and separated based on the level of
contamination and possible ses. Very often at
hydrometallrgical processing plants, storm water that
is not highly contaminated is combined with process
spillages within water storage or management facilities
(refer to BPG G1: Storm Water Management ). This
limits the rese possibility of a large volme of water that
was only moderately contaminated (contaminated stormwater) as it has become more contaminated de to the
addition of process spillages. Implementing segregation
of wastewater and mltiple storage or management
facilities will ensure the more efcient reuse of water
on the site. Less contaminated water recovered
will have nmeros rese possibilities when not mixed
with highly contaminated process spillages (refer to
BPG H3: Water Reuse and Reclamation). The
separation of water based on level of contamination
will also redce the qantities of highly contaminated
water eventally reqiring treatment before rese or
discharge.
73 storag of matra
Avoid cross-contamination by storing all materials,
chemicals, prodcts etc separately.
• Site layout and positioning: Storage areas shold
also be organized and planned in sch a manner
within the general site layot to allow easy access
from the area reqiring the particlar material and
avoiding the crossing or bypassing of other different
storage areas in an attempt to reach the reqired
material.• Reactive chemicals: Reactive chemicals (chemicals
sch as lime that readily dissolve in water or
chemicals that can react with water) shold be stored
in closed areas to prevent water (rain or rnoff) from
contacting them. This storage may inclde silos
(powder chemicals), closed tans (soltions), sealed
drms (oils), closed hoppers (to allow direct addition
to process) or sealed bags on pellets within a bilding
with a roof and concrete oor (granular chemicals).
Where a process spillage ris exists, appropriate
bnding strctres shold be constrcted.
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• Unreactive materials: unreactive materials
(materials that will not readily dissolve in water or
react with water) sch as mined ore or dried milled
ore might be stored in mch simpler strctres. Thesestructures’ main objective would be to prevent material
from washing away and losses (rnoff control). This
storage may inclde anything from an open stocpile
to a stocpile area with concrete bondaries and a
roof.
74 hg contamnaton rk
ara
Some areas may present a high contamination ris and
therefore reqire special measres to be pt in placeto prevent any of the contents from reaching any area
otside the location. This may inclde acid storage
areas and specic plant areas. To prevent contaminants/
chemicals from sch areas reaching the otside
environment, it is recommended that the area of location
be bnded and sealed with a concrete base (acid brics
or other approved prodcts may also be sed for this
prpose). The concrete base will prevent any spillage
from inltrating and contaminating the underlying soil
and grondwater aqifer. The bunding will prevent any
spillage from reaching srface areas located otside the
bnd and contaminating srface rnoff. The bnding
shold be designed according to approved gidelines
to contain 110% of the capacity of the tan or reactor it
contains. To ensre proper spillage clean-p and control,
the following is reqired:
• Bunded area’s base should be sloped to allow
drainage to a low point within the bnd. A smp will
be located at this point.
• The sump will be eqipped with a sitable pmp
which will be level activated. This means that as soon
as the liqid in the smp reaches a certain level the
pmp will atomatically be switched on and start
pmping.• The pump (sitable to pmp the particlar liqid) will
pmp all liqid ot of the smp at a set rate into the
tan or reactor from which the spillage occrred.
• This system ensures the management of a spillage
within the area where it occrs and therefore
recirculates spillages bac to their origin, eeping
the system closed.
• In emergency or extreme events (sch as the
rptring of a tan/reactor dring a 1:50 year storm
event), where the bnd with smp-and-pmp system
cannot handle the spillage, a second pmping system
may be reqired.
• The second pumping system will only be activatednder sch emergency or extreme conditions and
pmp the excess liqid to an emergency spillage
control dam/tank .
75 storm watr managmnt
(bPG G1: storm watr
managmnt)
Storm water management is dealt with in BPG G1:
Storm Water Management and the details will therefore
not be repeated here. The following points are however worth noting in this docment:
• Hydrological cycle: Impacts of the hydrological cycle
(seasonal variation) on an operation/process and vice
versa; dealing with oods (emergency or extreme
events); dealing with srface water rnoff in a plant;
sstainability of a storm water management plan over
different hydrological cycles and different phases
of the plant (the plant life cycle: design, operation,
closre, decommissioning and post-closre).
• Clean and dirty catchments: Division of an area
into dirty and clean areas or catchments and eepingwater from one separate from water from the other; no
lin between clean and dirty circits/areas to prevent
cross-contamination.
• Clean areas and clean water: keep clean areas
clean; eep clean storm water clean by diverting this
rnoff arond possible polltion sorces to prevent
contact with these polltion sorces thereby preventing
contamination of clean storm water (constrct
diversion berms); maximize extent of clean areas
and the amont of clean rnoff (roofs on bildings
with possible contamination sorces will prevent
rain inltration to the area and therefore contact with
polltion sorces, reslting in clean rnoff from the
roofed area); direct/rote clean storm water towards
water resorces for replenishment (grondwater
aqifer and srface water bodies); clean storm water
only reqires containment when the volme poses a
ris (attenate in retention ponds and control release
to prevent soil erosion, damage of stream bans and
bildings or life loss); incorporate very small clean
area into larger dirty area considering site layot
limitations.
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• Dirty areas and contaminated water: Minimize
dirty or contaminated areas; captre and contain
contaminated storm water from dirty areas for
rese; consider any rnoff that has been in contact
with pollution sources as contaminated and unt for
discharge into the receiving environment; prevent
seepage of contaminated; prevent overows of
contaminated water from storage facilities; manage
captred and contained contaminated water
according to the DWAF hierarchy for water qality
management (see preface); moderately pollted
water (sch as contaminated storm water) shold not
be frther pollted by mixing it with process spillages
(see Section 7.4).
76 Canng
Clean-p practices are important and the following
shold be considered:
• Clean immediately: All spillages shold be cleaned
as soon as they occr and before these spread and
contaminate other areas or materials.
• Report spillages: All spillages shold be reported to
the appropriate cleaning team immediately for action.
• Water for cleaning: The cleaning of spillages with
water (oor washing) should be prevented wherepossible. Cleaning of spillages with water shold be
limited to spillages of water soltions or water-solble
liqids. Preferably se process water or dirty storm
water for cleaning prposes (also see reincorporation
of spillages below). Spillages of solids (powders,
granlates etc) shold be physically/mechanically
piced p (sweeping, dry scing, scooping etc) and
not merely be washed with water (hosing) into storm
water drains.
• Reduce cleaning water quantity: Redce water
sed for cleaning by pipe restrictions in hoses (smaller
diameter pipes), sing spray jets (cover larger srfacearea), sing mops rather than hoses.
• Reincorporation of spillages: Where possible,
spillages shold be re-incorporated into the
circit from which the spillage occrred to prevent
nnecessary losses. This is obviosly provided that
the spilled material has not been contaminated by
another sorce since this may impact prodct qality
at the end.
• A waste: Spillages that cannot be resed or be re-
incorporated shold be considered to be waste.
• Hydrocarbon spillages: Hydrocarbon spillages
shold be handled in a separate system (oil/grease
traps) by an expert in this eld.
77 eqpmnt an mantnanc
The following is important:
• Alternative equipment: Eqipment sch as liqid
ring pmps can be replaced with mechanical sealed
pmps; once-throgh cooling systems can be
replaced with recirclating ones etc.
• Check for leakages: Check pipes, anges and ttings
reglarly to mae sre these are in good condition
and not leaing.
• Inspect condition: Chec piping, tans and valvesfor repair, refrbishment and corrosion.
• Pro-active maintenance: Implement a pro-active
maintenance programme in which eqipment is
reglarly checed/inspected, replaced/repaired
before water losses are experienced.
78 stanat
Water management systems incorporated dring
the design and constrction phases of an operation
can be tailor-made to the application. These water
management systems can then be designed at the start
to last throghot the different phases of the mine and
processing plant life cycle to ensre sstainability. With
an existing operation, the water management system
has to consider the existing system infrastrctre and
layot, ftre expansions etc.
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8
WATeR QuAliTy
ANd CONsTiTueNTs
OF CONCeRN
(sTeP 7)
81 Mnmz gnraton of contamnant
811 Rvw ntak/npt/raw matra
Contaminants are sbstances or constitents fond in a medim sch as water at a concentration
higher than expected from other considerations sch as the natral environment, and where
the sorce of the additional concentration of the sbstance/constitent is as a direct reslt of
hman activity (sch as mining or processing).
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To be a constitent of concern and pose an environmental
ris, the constitent mst have an inherent capacity or
potential to case harm or impact on another ser; the
constituent must be present in environmentally signicantqantities; the constitent mst be available for ptae or
absorption within the environment. Refer to Appendix A.
• Input optimization: Raw materials and reagents sed
as input to a hydrometallurgical plant’s processing
are costly and many inclde/contain hazardos
sbstances. It is therefore necessary to review the se
of these raw materials and consider the following:
- Reduce raw/potable water intake: Water
obtained from a water service provider (sch
as a mnicipality) or otside sorce is costly
and may constitute a signicant portion of themonthly operational cost on a hydrometallrgical
plant. Minimizing raw/potable water intae helps
towards water conservation. It is not always
essential to se water of a potable qality for all
applications/processes. Investigate sing water
of a lesser qality withot affecting process
performance or prodct yield. It is important
to now process water qality reqirements
as well as the composition of the inpt water.
(Example: se water stored ndergrond, refer
to BPG H3: Water Reuse and Reclamationand BPG: A6: Water Management for
Underground Mines)
- Eliminate/reduce auxiliary inputs: Consider
eliminating or redcing inpt materials sch
as chemicals/occulants added to the process.
Establish the minimm qantity of the chemicals
reqired or the minimm concentration of the
active ingredient reqired to yield the same
prodct qality and qantity withot redcing
process performance. Overdosing is costly. By
redcing the qantity of the chemical added, theqantity of any hazardos/harmfl sbstances
contained in it and added to the process is also
redced and fewer inherent by-prodcts reslt.
Frthermore, establish how critical the chemical
is for process performance and prodct
reqirements.
- Locality of input: It is possible that by adding
the chemical at a different point in the process,
its qantity reqired can be redced as its se
would be more efcient/effective.
- Alternative inputs: Consider replacing/
sbstitting some inpt materials with less
hazardos/harmfl materials. Determine which
other materials available on the maret also
contain the active ingredient reqired for the
process. Alternatives may be more cost-effective
and less hazardos withot compromising
process performance or prodct qality.
• Logistics: Improve control of the resorces in terms
of:
- Purchasing: Compare prices and sppliers
of resorces; logistics of placing orders and
ordering resorces from reliable sppliers;
tracking of resources’ supply; timeous delivery
of resorces on site by a reliable transport
company; payment of sppliers; monitor
resorces available to ensre timeos ordering;
plan for periods of short spply.
- Handling and storage: Deliver; proper storage
of materials to prevent losses (secre, prevent
wash-away); on-site transport (conveyor belts);
maintenance of storage or transport facilities
to prevent losses (roofs of bildings). Also see
Section 7 on hoseeeping.
- Addition/control during processing: Prevent
overdosing dring addition; mixing to improveeffectiveness and redce qantities reqired;
moving the point of addition in the process
to increase efciency and reduce quantities
reqired.
• Reuse and reclamation: Refer to BPG H3: Water
Reuse and Reclamation and Section 9. use
inpt materials that can be regenerated or resed;
materials with longer lives and rese possibilities;
recycling of sed oil/grease; rese of contaminated
water; regeneration of lters used in the process;
cleaning and maintenance to ensre contined
process performance and operation withot reqiringreplacement of eqipment.
• Energy optimization: Redce energy reqirements
as it is also a large monthly expense in any
hydrometallrgical plant; alternative process
technologies that reqire less energy; investigate
novel energy sources; ensure efcient energy use.
• External material/streams: Avoid contact with non-
process chemical and extraneos water streams
(such as off-site runoff nding its way onto the site,
also refer to storm water management in Section 7
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and BPG G1: Storm Water Management ); prevent
external material/streams from entering the circit.
812 Optmz poton prvnton anrcton at orc
Mine-related/derived polltion is one of the major
cases of water qality degradation in many parts of
the world and potential sorces of polltion from a mine
or hydrometallurgical processing plant include efuent
discharges, leachate or rnoff from reside disposal
facilities, storm water and the intentional or accidental
release of process streams to srronding areas.
Each mineral has a set of niqe physical and chemical
properties, and therefore requires the use of specic
extraction and rening techniques. Environmentalcomplications therefore vary between sites principally
becase of the mineral targeted for extraction, the
geological setting in which the mineral occrs and the
se of different chemical reagents (see Section 8.1.1)
and processing techniqes (see Section 10).
The nderlying theory behind polltion prevention is
that it is economically more sensible to prevent wastes
rather than implement expensive treatment and control
technologies to ensre that waste generated does not
threaten hman health and the environment. Polltion
prevention, which lessens or eliminates waste generation,
is classied as source reduction. Source reduction is oneof the least expensive methods of waste minimization
and is often achievable with minor process changes or
simple improvements to hoseeeping techniqes.
Source control is dened as any activity that reduces or
eliminates polltion/contamination or the generation of
waste at the sorces throgh either practice or process
changes and may inclde:
• Product changes;
• Material or resource input changes (see Section
8.1.1);
• Technology changes (see Section 10 on cleaner
technology); and
• Implementation of good operating practices (see
Section 7 on hoseeeping).
Polltion minimization is mainly addressed in Section 7
in terms of hoseeeping and the following points are
reiterated here bt not discssed in detail again:
• Segregation of clean and dirty water including the
separation of process water and storm water as
well as the separation of clean storm water from
contaminated storm water.
• The capturing, containment, and reuse of process
water and contaminated storm water on the site.• Bunding, containment and recycling of water and
spillages in certain high ris areas to recirclate/rese
as close to sorce/origin as possible.
• Construct roofs over storage and process areas to
prevent water inltration and maximize clean runoff.
• Place concrete in storage and process areas to
prevent seepage into nderlying grondwater.
• Slope areas to minimize erosion and maximize runoff
volme and rate in order to minimize contact with
possible polltion sorces.
• Diversion of storm water around major pollutionsorces to minimize contact with polltion sorces
thereby increasing clean storm water available to
replenish water resorces.
82 Watr qat rqrmnt
for mn/pant watr r
Certain water qality related problems sch as scaling
(see Appendix A) may be experienced by certain mine/
plant water sers depending on the qality of the water
spplied. Water qality related problems are directly linedto the constitents of concern and it is therefore possible
to determine the constitents responsible for water
qality problems being experienced. Different mine/plant
water sers may experience different problems relating
to the same water qality and therefore each mine/plant
water ser has its own niqe water qality reqirements.
Since water qality reqirements are determined by site-
specic factors including locality, mining and processing
methods, and commodity mined, only general principles
and considerations are noted here.
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For water to be resed within the mine or
hydrometallurgical processing plant, a clear denition of
the water qality reqirements of the mine/plant water
sers mst be prepared. This will consider constitentsthat may interfere with the performance of processes or
with prodct qality or yield.
It is important that the constitents of concern be
determined based on a reliable data record over an
extended period (refer to BPG G3: Water Monitoring
Systems) and with the appropriate statistical calclations
(minimm, maximm, 95th percentile etc) as well as
throgh consideration of the water qality related
problems experienced by the sers (see Appendix A).
The water qality objectives for the mine/plant water
sers will represent the worst possible water qality thatcan be tolerated bt that still eliminates/redces any
process or other problems experienced to an acceptable
level.
The concentration or qantities of prodct in wastewater
or process water depends on the efciency of the
process technology sed. Prodct losses also increase
with increasing water consmption and poor water
management therefore leads to poorer extraction
efciency. Consequences of poor management can also
inclde poor process water qality and the associated
corrosion and scaling, which ltimately again redce
process efciency. Recovery efciency and product
qality may sffer de to the presence of contaminants
in process water.
83 Montorng, mantnanc,
npcton an at
Monitoring: Reference is made to BPG G3: Water
Monitoring Systems which provides clear gidance on
why (objectives), how (procedres), what (parameters),
when (freqency) and where (location) to monitor. It
frther provides details from the design phase of amonitoring programme throgh the implementation
and data collection phases, throgh to reporting (data
management, maniplation, presentation and reporting
format) and aditing (internal/external review) phases.
Maintenance: All eqipment and machinery associated
with the hydrometallrgical plant shold be maintained
(e.g. cleaning of pipes to prevent scale bild-p) on a
reglar basis to prevent process failre or redced
process performance de to malfnction. If reglar
maintenance is not condcted, raw materials may be
wasted, processing time may be lost or prodcts may
be compromised. A maintenance schedle will ensre
that all eqipment and machinery are in pea woring
condition.
Inspections and audits: It is important to condct
inspections (internally) to ensre monitoring and
maintenance is condcted as planned and to ensre
appropriate action is taen based on the monitoring and
inspection otcomes. Internal and external adits will
also highlight problem areas that reqire management
actions.
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9
WATeR
Reuse ANd
ReClAMATiON
(sTeP 8)
In order to maximize water rese and reclamation, it is important to minimize water qality
deterioration by preventing polltion. See previos sections (Sections 7 and 8).
The scarcity of water resorces available to the mining and hydrometallrgical processing
industry (due to the demand of other users) and the desire to reduce efuent discharges from
mining and hydrometallrgical processing operations are the main reasons for the rese and
reclamation of process water in the mining and hydrometallrgical processing indstry.
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A separate BPG docment was prepared on water rese
and reclamation (refer to BPG H3: Water Reuse and
Reclamation) and the details are therefore not repeated
here. The following points are however worth noting inthis docment:
• Opportunities for water rese and reclamation:
- Areas where large volmes of water are sed or
disposed;
- Areas where good qality water is imported and
poor qality water is lost;
- Areas where good qality water is prchased/
abstracted while water of a poorer qality is
acceptable for se; and
- Areas where the implementation of polltionprevention measres/strategies do not reslt in
the elimination of polltion.
• Benets of water rese and reclamation:
- Cost saving de to redced raw water intae
from otside (abstraction from water resorces
or prchasing from water service provider),
more efcient use of valuable resources as
well as redced disposal and treatment cost for
wastewater;
- Legal compliance as waste minimization and
water conservation goals are met;- Limit liabilities by redcing and minimizing
release to and impacts on the srronding
receiving environment;
- Protect pblic health by preventing polltion of
the environment and water resorces;
- Protect the environment throgh polltion
prevention, especially the water resorces
(minimize water qality deterioration);
- Water conservation throgh redced intae and
consmption;
- Reclamation of materials that have a highreclamation vale and/or a severe impact on the
environment; and
- Improve pblic image de to concern shown for
the environment.
• Water sources: Identify and consider all possible or
alternative water sorces inclding boreholes from
which grondwater can be abstracted, streams/dams
from which water can be abstracted in the local or
neighboring catchment, captred rainwater, water
imported with the raw materials, other srronding
indstries with excess water and having to discharge
water, mine/plant process nits discharging water
(water/efuent generating processes), water service
providers (mnicipality etc). Implement all possible
measres to prevent/minimize the polltion of these
water sorces. Characterise the water sorces with
respect to ow rate (quantity), quality and variability
throgh a monitoring system (refer to BPG G3: Water
Monitoring Systems Systems). Aim to se water
sorces with minimm amont of treatment de to
the cost associated with water treatment (refer to
BPG H4: Water Treatment ). Ionic strength of water
source is important as it may inuence solubility of
other constitents present in process materials.
• Minimize water intake: Only prchase water (potable) from water service providers for processes
reqiring sch good water qality or additional water
reqirements that cannot be spplied in the system.
Only obtain water from otside sorces (environment
or other indstries) that cannot be spplied within the
system.
• Mine/plant water users: Establish clear and accrate
water quantity and quality requirements/criteria (t-
for-prpose) for all mine and process related water
sers. Establish water qality constitents affecting/
impacting on prodct qality or yield and/or process
performance and determine minimm acceptablestandard reqired from water spply. Mine/plant
water sers shold be provided with the poorest
possible water qality bt which does not case
signicant user, product quality or process related
problems (scaling etc). Compile water se inventory
- list of existing and potential mine/plant water sers
(indirect or direct). Grop mine/plant water sers with
similar water qality reqirements (in terms of ey
constitents) together to provide a nmber of different
water qality grops/ categories. Water sorces,
depending on the origin and contaminants, may have
a deleterios effect on certain hydro-metallrgicalprocesses and it is therefore essential to establish the
contaminants within the sorces that may impact on
or adversely affect the process.
• Minimize consumptive water use and losses:
Minimize evaporation from evaporative cooling
systems and clean water storage facilities. Limit
evaporative cooling systems (investigate air cooling).
Minimize seepage (throgh appropriate lining) and
overow (through sufcient capacity, GN 704) losses
from all water systems.
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• Process technology: Investigate alternative process
technologies or modication/changes to existing
process technologies that cold be applied and that
se less water (see Section 10).
• Water reticulation systems: Optimally match mine/
plant water users with the identied water sources,
taing cognizance of economic and practical restraints
with regard to having different water reticlation
systems. Therefore, identify opportnities for resing
efuent water from one process as inuent water to
another process. Establish where water reticlation
networs and storage facilities may need to be
installed or extended/enlarged or modied. Align and
allocate recycled water qality and qantity to varios
mine/plant water sers. Achieve the minimm se of
raw water or optimal ow conguration in the particular
system of operations.
• Unused internal water sources: Categorize all
nsed internal water sorces (inside the mine or
hydrometallrgical processing operations) that have
not been allocated for reuse to a specic mine/plant
water ser based on one of the following factors:
poor qality; srpls water in the system; very
small qantity; or isolated location. If water qality
is acceptable, consider an athorized discharge in
consltation with DWAF.
• Discharge/dispose: All potential dischargesconsidered shold be discssed with DWAF in terms
of discharge points and qality limits. All discharges
or disposals reqire an athorization (NWA, Section
21). Specialist investigations and ris assessments
may be reqired.
• Treatment: Decide on a potential water treatment
technology (active or passive, chemical or biological)
based on contaminants of concern. Refer to BPG H4:
Water Treatment and also consider the following:
- Water ser reqirements – mine/plant water
sers, srronding indstries, downstream
sers, aqatic ecosystem and environment;
- Technology reliability and technical feasibility;
- Treatment technology requirements - ow rate/
volme; qality; qantity and qality variation,
srface land area reqired and available;
- Reside/waste streams - characteristics,
disposal, redction of qantity, sldge
stabilization and stability, byprodct recovery;
- Financial reqirements and responsibilities -
capital cost and operating expenditre;
- Technology performance ris assessment
- performance redction or failre and its
impacts;
- Sstainability - different phases, life-cycle;
variations; and
- Laboratory/pilot plant stdies - address
ncertainties.
• Alternative uses: Reassess possible se of water
after treatment either on the mine/plant, at srronding
indstries or for downstream sers. Indstrial ecology
- introduce wastewater or efuent into external
recycling networks; one industry’s waste may become
another industry’s raw material.
• Monitoring:Institte monitoring and aditing to ensre
that adverse effects of nacceptable reclaimed water
qality are not manifested, i.e. corrosion, scaling,
redced process performance. Evalate performance
and implement corrective actions if necessary.
• Sustainability: Ensre water rese and reclamation
strategy is sustainable over the plant’s life cycle and
different hydrological cycles.
• Materials or byproduct recovery: Evalate waste
streams for properties that mae them sefl rather
than for properties that render them waste. Minimize
waste by retrieving/recovering sable process
materials and resorces from waste streams. Ths,not only water reclamation bt also reclamation of
chemicals for rese in process, new ses or sale.
• Future: Develop water and salt balance projections
(refer to BPG G2: Water and Salt Balances) for ftre
scenarios, inclding closre and post-closre. Long-
term planning and sstainability shold be considered
and therefore predictions on water qality and qantity
into the ftre shold also be incorporated (predictive
modeling) to ensre that rese and reclamation
strategies are not affected by ftre processes/plans.
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10
PROCess ChANGes
OR CleANeR
TeChNOlOGy
(sTeP 9)
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10.1 Need and signicance
Cleaner prodction technology and process changes/
modications are pro-active and preventative measures,
which aim for process- and/or prodct–integrated
solutions that are ecologically and economically efcient
(eco-efciency). The objective is to tackle possible
polltion problems before they develop rather than
remediate them after they have occrred, ths redcing
levels of polltants in waste streams (contaminants of
concern) prior to release or redcing water reqirements.
In this regard, cleaner prodction also ties in with
polltion prevention and redction. Cleaner prodction
is very mch in line with the DWAF water management
decision-maing hierarchy and international wastemanagement hierarchies, which also follow preventative
approaches. Maret and reglatory pressres lead most
companies to invest in the development or acqisition of
new technologies and management practices to achieve
cleaner prodction.
Cleaner production and process modications can
achieve the following:
• Higher production rates as unnecessary production
steps are eliminated throgh innovative process
integration;
• Minimize waste production and disposal by avoiding
heat degradation of prodcts, recycling, eliminating
spillages and fgitive emissions;
• Improved product quality and yield by considering
prodct life cycle assessment (how prodcts are
prodced, processing, extraction, manfactring,
etc., as an integrated approach);
• Increased operating or production efciency through
improved process selectivity and/or conversion and
more efcient equipment;
• Higher percentage on-line time and long campaign life
between rebuilds (shut-downs) through more efcient
eqipment design;
• Safe operating conditions considering for example
how waste is handled, transported and disposed of;
• Signicant reductions in environmental impact, in
terms of redced liqid/water, solid and gas/air
emission generation;
• Conservation of resources such as materials, energy
and water de to their redced se (for example
operating at lower temperatres and/or pressres);
• Reduced operating and/or production costs (compare
with conventional “end-of-pipe” clean-p technology);
and
• Decreased liabilities due to reduced environmental
impacts and waste prodction (minimization/redction,
rese, recovery and disposal).
Cleaner prodction therefore combines gains in
prodctivity with improvements in environmental
management. The mining indstry has already made
some progress by employing cleaner prodction
practices sch as redction in noxios air emissions,
decrease in levels of toxic contaminants in efuent
discharges, major pgrading in land management
etc. These improvements have led to a redction of
conventional end-of-pipe treatment in favor of polltionprevention practices at sorce. Integration of cleaner
technologies and strategies can be achieved by inclding
highly efcient equipment and control systems, state-
of-the-art environmental management measres and
comprehensive environmental management plans.
De to the large qantities of material, energy and
water sed in the mining and hydrometallrgical
industry, signicant opportunities are available for waste
redction/minimization and cleaner prodction. Polltion
prevention by “cleaner technologies” is important not only
becase of the environmental protection advantage bt
also becase of the cost savings associated with these.
Waste redction/minimization as sed in this context
refers to in-plant modications that reduce the volume
or degree of hazardosness of waste and wastewater
generated.
102 impmntaton
Cleaner production should address ve major areas of
bsiness:
• Policy development and institutional relations –
woring towards setting performance standards;establishing nancial arrangements and corporate
buy-in; implementing efcient environmental
management systems.
• Environmental and social impact assessment – using
social indicators to monitor societal effects over
time; promoting staeholder participation; monitoring
environmental impacts.
• Technological development – promoting research
and development; introdcing life-cycle assessment
to operations; developing technological soltions.
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• Company strategy – continuously improving
management systems; monitoring predicted impacts
and nexpected events; designing incentives for
employees to engage in environmental practices.
• Education and training – enhancing environmental
awareness within the worforce; training for
innovative commnity relationships; collaborating
with independent agencies.
impmntaton tp:
• Identify existing and proven cleaner technologies
available on the maret.
• Assess existing cleaner technologies in terms of
applicability and practicality.
• Conduct feasibility study - analyze investment;research options or adaptations reqired, etc. May
inclde laboratory or pilot plant stdies.
• Monitor to ensure cleaner technologies play their
appropriate role over the long-term.
103 barrr prvntng canr
procton
Often barriers of an economical, technological and
legislative natre hinder the implementation or adoption
of cleaner technology bt these can be overcome throghimproved planning, employee edcation and increased
government intervention.
1031 economc arrr/contrant
Conventional end-of-pipe abatement reqires less
capital investment, less development and less disrption
to prodction processes than cleaner technologies and
strategies. Economic barriers are particlarly relevant to
smaller mining companies who have less fnds available
and are more economically driven. These companies
mostly eep to the minimm standard (discharge etc)
reqired withot prosection realizing that their operationmay still impact on the environment.
Commodity market price: The mining indstry cannot
control the vale of the commodity and a downtrn in
price affects how each mine is managed. A shift to
reglatory compliance is noted with price drops since
fnds are no longer available to invest in proactive
technologies. Economic pressres may force a company
to abandon “cleaner” methods and adopt less expensive
methods instead, which are more prone to environmental
degradation.
Lack of resources (fnds, time, personnel etc): A
limited environmental bdget restricts spending on highly
efcient, expensive pollution prevention and cleaner
prodction technologies and only a mode of reglatory
compliance is maintained. Limited bdget means less
personnel and time spent on this fnction as well.
Financial incentives: Incentives are needed to shift to a
mode of cleaner prodction and these are limited within
most governments.
1032 Tcnoog arrr
Structural barriers: Investments (nancial and
resorces) in crrent systems sed may prevent changes
to other technologies since a) employees with sills andknowledge pertaining to the specic current system
may then have to be trained in another technology or
otside assistance may be reqired, reqiring additional
investment; and b) the infrastrctre spports the crrent
system and applying a new technology may reqire
additional and/or new infrastrctre to be established,
reqiring frther investment.
Lack of time to conduct pilot plant or laboratory
studies: The mining indstry is pressed for time de to
prodction pressres and there is limited time available
to condct pilot plant and/or laboratory stdies to test theapplication and feasibility of new technologies. Research
and development are often not priorities as the focs is
on production. Industries therefore often nd themselves
going with a proven technology which is the safer option
in cases where no pilot plant or laboratory stdies have
been condcted (refer to BPG H4: Water Treatment ).
Lack of available systems: A signicant portion of
global mineral prodction originates from grassroots
operations, which lac the appropriate technologies
to avoid environmental problems. Also refer to small-
scale mining operations (refer to BPG A1: Small-scale
Mining ).
Technology and information gaps: Insufcient
nowledge of cleaner prodction and cleaner technologies
available on the international maret; ncertainty in
impact predictions; inactiveness in the environmental
management arena; shortage of necessary expertise;
lac of promotion and dissemination of cleaner
prodction and cleaner technologies may prevent its
implementation.
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1033 lgatv arrr/prr
Environmental legislation is continally developing
and being amended/changed to sch an extent thatsystems that are now recognized as being effective
polltion prevention methods cold easily become
otdated in the years to come. The volatile natre of
best practice technologies and the freqently changing
reglatory environment maes the selection process for
environmental technologies difcult and can discourage
implementation of cleaner technologies. Crrent cleaner
technologies may in ftre be mere environmental
compliance machines. Ths changing reglations can
trn existing cleaner technologies into ftre compliance
investments. Mines, in general, therefore tend to operate
in line with set standards in environmental legislation
and only change operations when necessary. Long-
term planning to invest in proactive environmental
measures is difcult since it is difcult to hit a “moving
target”. Thogh Soth Africa as a developing contry has
strict environmental reglations, effective enforcement
programmes are often lacing thereby preventing the
implementation of cleaner prodction.
Environmental legislation shold inclde:
• Clear, continuous policies to support waste
minimization and cleaner prodction.
• Regulatory frameworks and enforcement.• Consideration of characteristics of industrial
prodction processes.
• Clear understanding of the difference between
compliance investments and cleaner technology.
• Coordination among different governmental agencies
at different levels.
104 Ovrcomng arrr
1041 Govrnmnta ntrvnton
Often nancial support and appropriate technology is
reqired to improve prodction processes. Government
shold tae a leading role in promoting cleaner
prodction and indicate it as a national and provincial
goal for economic and environmental policy. Priorities
may inclde:
• Economic instruments and assistance: Economic
instruments or nancial incentives to motivate mines
to implement cleaner prodction may inclde levies,
tax breas and sbsidies. Government crrently
nances research such as that by the Water Research
Commission (WRC) and provides gidelines sch
as the BPG series. Ensring that bans, insrance
companies and other lending instittions favor
cleaner technologies in their investment decisions.
• Technical incentives and assistance: Woring
with edcational facilities (niversities) and private
sector (indstry). Government-academic-indstrial
partnerships. Each partner provides a different area
of expertise (technical, training and edcation).
Environmental technology demonstration projects.
• Provision of information: Government to obtain
and disseminate appropriate information concerning
cleaner technologies and strategies, otlining their
contribtion to economic aims. Provide docmented
reslts of sccessfl cases and edcational materials
in press.
• Certication: Developing and implementing a
cleaner technology certication system for products,
processes and services.
1042 ecaton an tranng
Edcation and training is reqired for an increased level
of awareness and to increase employee and commnity
nowledge. Awareness training shold not only aim to
acqaint people with environmental problems bt also
to ensre that ecological effects are flly nderstood.
Edcation shold be inclded for employees involved in
research, material prchasing, environmental eqipment
design, installations, running and management of nal
technological setps. Promotion campaigns for cleaner
technology will also contribte to creating awareness.
1043 improv pannng
For new mines, environmental isses mst be acconted
for in the original bleprints. An inventoried listing of
environmental technologies, treatment processes, and
toxic chemicals sed, shold be made p front. In the
design of the mine, ecological “sitations” shold be
acconted for when determining where to implement
specic environmental technologies.
For existing mines, an environmental management
system (EMS) wold ensre more effective control
and redce environmental impacts and shold inclde
organizational procedres, responsibilities, processes,
implementation strategies, measrement and evalation
criteria, efciency measures and goals for improvement.
Environmental adits at reglar intervals can also be
implemented and shold inclde a thorogh investigation
of every indstrial system and process. Environmental
monitoring and technological assessments are also
important.
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11
iNTeGRATedWATeR ANd WAsTe
MANAGeMeNT PlAN
(sTePs 10 ANd 11)
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The integrated water and waste management plan
(IWWMP) shold aim to continosly and systematically
redce waste generation, prevent polltion and minimize
impacts.
To implement a comprehensive IWWMP, the following is
reqired:
• Adequate resources in terms of nances, competent
personnel, infrastrctre and other reqirements.
• Commitment of the company, management and
employees to the objectives of the IWWMP.
• Montorng which incldes data and information
collection, cost acconting and feasibility analysis
(continos review).
• Environmental impact monitoring and environmentalpolicies to achieve improved environmental goals.
• Training and awareness programmes emphasizing
polltion prevention, impact minimization and control/
management.
• Hydrometallurgical plants designed to better
accommodate wastes, prevent polltion and minimize
impacts.
• Baseline and continual operational monitoring (refer
to BPG G3: Water Monitoring Systems) of grond,
srface and process water as well as eqipment
and the sbseqent implementation of action plans based on the reslts.
The IWWMP shold inclde detailed discssions on the
following sbjects:
• General information: Applicant details, holding
company details, plant locality, spporting srface
infrastrctre (road, rail, power), land ownership and
se, plant srface infrastrctre, processes (raw
materials and chemicals, prodcts and waste).
• Legislation: Applicable legislation, existing permits,
legal reqirements.
• Current water environment:
- Climate – regional; temperatre; precipitation;
evaporation; wind; extremes.
- Topography and geology.
- Srface water catchment - water corses (rivers/
streams) and dams; wetlands.
- Affected grondwater zone – aqifers; boreholes;
springs.
- Water quantity (volumes/ows/yields) and quality
- monitoring points, freqency, parameters,
baseline and operational; data management.
- Water authority (regional DWAF ofce); water
ses (plant and downstream); water spply.
• Water management:
- Water sorces – availability; spply and available
to operation; droght and water restrictions; water
service providers; water sppliers; srronding
indstries with excess water, boreholes, srface
water bodies (streams/dams), process water on
the mine/plant.
- Water rights - legal standing; licence conditions.
- Water sers on mine/plant - consmption
patterns; individal processes; water
reqirements in terms of qantity and qality;
sensitivity to variations.
- Water rese and reclamation (refer to BPG H3:
Water Reuse and Reclamation). Refer to Step
8, Chapter 9.
- Water conservation - minimisation of water
se; long term redction of consmption; set
objectives.
- Process water management - water and salt
balance; possible polltion sorces; polltion
prevention measres; minimisation of waste
loads in water; high contamination ris areas;
safety factors; system failres; accident andemergency plans; monitoring and aditing. See
Chapter 7.
- Storm water management - separation of clean
and contaminated storm water; release of clean
storm water; containment of contaminated storm
water; maintenance; erosion and sediment
control. See Chapter 7.
- Grondwater management – possible polltion
sorces; polltion prevention measres;
polltion plmes; impacts; management
measres; monitoring.- Water treatment (refer to BPG H4: Water
Treatment ).
- Disposal/discharge – alternatives/options
considered; socio-economic impacts; impact
assessment; monitoring; management; nancial
provision; consltation with DWAF.
• Waste management: Site selection; classication
of waste; hazardos sbstances in waste; handling;
transport; leach potential; lining systems; leachate
interception; disposal practices etc.
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• Commitments:
- Monitoring – water and waste qality and qantity;
monitoring points; freqency; parameters;
baseline; operational; data management;
record-eeping; impact and ris assessments;
performance reviews; inspections and adits;
indicate action/target levels and water qality
objectives.
- Management – maintenance; minimizing
impacts; polltion prevention; minimize
discharges/seepage; set targets; health of
water dependent ecosystems; reporting to
management; reporting to athorities; training;
responsibilities; accontability; emergency and
contingency measres; review processes in
place and implement action plans as reqired;performance indicators to evalate sccess of
management strategies and plans.
• Consultation process: Staeholder commnication;
reglatory athorities; interested and affected
parties; commnity expectations; forms/process
for information sharing; meetings; database; pblic
participation; advertisements and notications
in media; complaints register; water as a shared
commnity resorce; respect water rights of other
sers; consider downstream water qality problems
(DWAF water quality guidelines for specic uses).
For each water se it is therefore important to ensre the
following points are addressed:
• problem statement and/or impact;
• management plan or operational procedures;
• maintenance and inspections procedures;
• performance indicators and compliance monitoring;
and
• emergency contingency procedures.
Water and waste management system designs shold
be based on the following considerations:
• Pilot scale testing is not considered completely
reliable.
• The treatment of supply water is seldom a viable option
de to the complexity of water treatment processes
and sldges prodced as well as the cost associated
with treatment and sldge management. However,
intae water or raw water qality deteriorates and
the industry may nd itself required to pre-treat water
for sage in certain nit processes (refer to BPG
H4: Water Treatment ). Loo at new water treatment
technology.
• Flexibility should be incorporated into the reticulation,
storage and distribtion systems and networs to
ensure efciency. Systems must be able to absorb
variations/srges and spply a variable demand fromnit processes. Design based on average process
ows is thus inappropriate. Centralized water storage
facilities shold be considered (refer to BPG G1:
Storm Water Management ).
• Consider water demand and efuent generation
patterns of different nit processes. For example
water available from shaft dewatering peas over the
weeend whereas consmption of water by the plant
tails off dring this period. Process or contaminated
storm water mst be consmed in preference to
raw water (refer to BPG H3: Water Reuse and
Reclamation). Also consider mineral and prodctrecovery from efuent streams in future.
• Numerous unit processes exist, each with their own
demands patterns and water qality objectives.
unit processes mst manage their own water
systems throgh a water and salt balance (refer to
BPG G2: Water and Salt Balances). An efuent
generator remains responsible for the water ntil it is
absorbed in an alternative nit process or disposed
of in accordance with water qality objectives for the
catchment.
• Contamination of water used to transport material
leads to progressive deterioration of water retrnedand available as process water. Consider closed
circits or separate circits in certain instances.
• Increasing volumes of water to be managed increases
reqirements for pmp, piping and storage facilities
thereby increasing cost.
• Minimize contaminants discharge/emission;
inefciency and wastage; contribution to specic
environmental problems; overall environmental
impact.
• Improve automation and communication systems.
There is also the temptation to follow a principle of “minimm compliance” where costs are not considered to
be signicant. This type of water and waste management
(reactive or ad-hoc) is less efcient and environmentally
friendly than a pro-active system with fll commitment
to effective management of the water cycle. An effective
water and waste management system establishes
objectives and ensres these are integrated into the
day-to-day management of the mine/plant. A water
management system mst therefore satisfy the qality
and qantity demands by all nit processes bt also the
objectives of the environment on which it impacts.
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The proposed strctre and contents of an IWWMP is
as follows:
i eXeCuTiVe suMMARy
Briey covering:
• Background
• Process description
• Environmental description
• Water system characterization
• Management Programmes
- Waste Minimization and Recycling
- Water Use Efciency
- Water Containing Waste
- Storm Water Management
- Grondwater Management
- Remediation and Rehabilitation
- Water Monitoring
- Emergency and Contingency Discharge
Management
ii MAiN dOCuMeNT
1 Introdction
1.1 Bacgrond
1.2 Contact Details
1.3 Location of project
1.4 Property description
1.5 Legal Assessment
1.5.1 Existing Lawful Uses
1.5.2 Summary of Water Uses
1.5.3 Summary of Relevant Exemptions
1.5.4 Summary of General Authorizations
1.6 Section 27 Motivation
2 Projct dcrpton
2.1 Prpose of the Docment
2.2 Objectives of the project
2.3 Physical project description
2.3.1 Extent of operation
2.3.2 Mining method
2.3.3 Project life description
2.3.4 Infrastructure requirements
2.4 Reside and Emissions
2.4.1 WasteStreamIdentication
2.4.2 Waste Stream Characterisation2.4.3 Waste Management
2.4.4 Waste Recovery and Reduction
3 envronmnta stat qo
3.1 Climate
3.1.1 Regional Climate
3.1.1.1 Mean rainfall
3.1.1.2 Evaporation
3.1.1.3 Maximm Rainfall
3.1.1.4 Temperatres
3.1.1.5 Meteorological climate
3.2 Soil and Land capability
3.3 Srface Water
3.3.1 Water Management Area
3.3.2 Srface Water Hydrology
3.3.3 Srface Water Qality
3.3.4 Mean Annal Rnoff (MAR)
3.3.5 Resource Class and River Health
(Applicant)
3.3.6 Set Resource Class Objectives
(DWAF/Reserve)
3.3.7 Surface Water User Survey
3.3.8 Sensitive Areas Survey
3.4 Grondwater
3.4.1 Aquifer Characterisation
3.4.2 Groundwater Quality
3.4.3 Hydro-census
3.4.4 Potential Pollution Source
Identication
3.4.5 Groundwater Model
3.5 Socio-economic Environment
4 Qanttatv Rk Amnt
4.1 Safety, Health, Environment and Qality
Policy
4.2 Objectives and Strategies
4.3 key Performance Area and Indicators
4.4 Methodology Followed
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4.5 Possible Impacts on the Environment
4.6 Signicance of possible impacts
4.7 Ris to the Environment4.8 Riss to hman health
5 Cost-benet analysis
5.1 Methodology and Selection Criteria
5.2 Management Options (Evalation of
alternative options)
5.2.1 Short-term alternatives
5.2.2 Long-term alternatives
5.3 Selected Management of Identied Risks
5.3.1 Short-term solutions5.3.2 Long-Term Solutions
5.4 Financial Provisioning
6 intgrat envronmnta Managmnt
6.1 Environmental Management Philosophy
6.2 Environmental Management Systems
6.3 Water use and Management
6.3.1 Water Spply
6.3.2 Potable water spply
6.3.3 Process water spply
6.3.4 Clean water management facilities
6.3.5 Dirty water containments systems
6.3.6 Sewage Management Facilities
6.3.7 Storm Water Management
6.3.8 Operational Water Balance
6.4 Solid Waste Management
6.4.1 Domestic waste
6.4.2 Industrial Waste
6.4.3 Hazardous Industrial Waste
6.4.4 Other wastes
6.5 Rehabilitation and Mitigatory measres
6.6 Soil and Land Capability Management
7 Montorng tm
7.1 Water Monitoring
7.1.1 Groundwater Monitoring
7.1.2 Surface Water Monitoring
7.1.3 Bio-monitoring
7.2 Data Management and Reporting
7.3 Waste monitoring
7.3.1 Waste Rock
7.3.2 Mine Tailings
7.3.3 Slime wastes
7.3.4 Slag wastes
7.4 Environmental Management System
7.5 Recording of Incidents
7.6 Environmental Impact Register
7.7 Aditing and Reporting
8 Opratona Managmnt
8.1 Organisational Strctre
8.2 Environmental Management: Resorces
8.3 Awareness and Training
8.4 Commnication
8.4.1 IdenticationofStakeholders
8.4.2 Public liaison and forum participation
8.4.3 Distribution of information
8.4.4 Public meeting
8.4.5 Documents for public review
9 Rfrnc an spcat t
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Levay, G, Smart, R. St. C, Skinner, W.M. 2001. The impact of water quality on otation performance. The Journal of the
Soth African Institte of Mining and Metallrgy, Volme 101, Nmber 2, March/April 2001.
Liu, L, Rao, S.R, Finch, J.A. 1993. Technical note – Laboratory study of effect of recycle water on otation of a Cu/Zn
slphide ore. Minerals Engineering, volme 6, no 11, pages 1183 – 1190, 1993. Pergamon Press, Great Britain.
Lotz, Peter. 2004. Minte. Personal commnication.
Marr, S.M. 2003.Environmental considerations in the design of base metals reneries. Metals in riverine systems.
Thesis submitted in fulllment of the academic requirements for the degree of Master of Science in engineering at the
school of chemical engineering, university of Cape Town
MCMPR. 2006. Framewor for strategic water management in the minerals indstry. Draft. April – Jne 2006. Ministerial
Concil on Mineral and Petrolem Resorces (MCMPR) and Minerals Concil of Astralia.
Minerals Concil of Astralia. 1997. Minesite water management handboo.
Ng’andu, D.E. 2001. The effect of underground mine water on performance of the Mufulira otation process. The
Jornal of the Soth African Institte of Mining and Metallrgy, Volme 101, Nmber 7, October 2001.
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Petrie J.G, Hansen, Y, Broadhrst, J.L. 2006. Solid mineral waste impact predictions. WRC k5/1550. Tas 1: Compilation
of solid waste otpts from the Soth African minerals processing indstry. DRAFT.
Rao, S.R, Finch, J.A. 1989. A review of water reuse in otation. Minerals Engineering, volume 2, no 1, pages 65 – 85.
Pergamon Press, Great Brittain.
Samsiov, E.A. 2002. Ecological concerns in metallrgy. Steel in translation, volme 32, no 3, pages 87 – 90. Allerton
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Sarvinis, J, Voermann, N, Crowe, C, Bianchini, J, Wasmnd, B. 2002. Frnace design for modern, high-intensity
pyrometallrgical processes. Astralasian Institte of Mining and Metallrgy Pblication Series, nmber 2, April 2002,
pages 318 – 331.
Schumann, R, Levay, G, Dunne, R, Hart, S. 2003. Managing process water quality in base metal sulde otation.
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Stewart, M and Petrie, J. 2006. A process systems approach to life cycle inventories for minerals: Soth African and
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Wates J.A, kelley, R.J. 1985. Water management on a gold mine. The Soth African Institte of Mining and Metallrgy,
Colloqim, Treatment and rese of water in the mining and metallrgical indstry, 9-10 May 1985.
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Schmann, R, Levay, G, Dnne, R, Hart, S. 2003.
Managing process water quality in base metal sulde
otation. Water in mining conference, Brisbane, Australia,
QLD. 13 – 15 October 2003. The Astralian Institte of Mining and Metallrgy, Pblication series no 6/2003.
Stewart, M and Petrie, J. 2006. A process systems
approach to life cycle inventories for minerals: Soth
African and Astralian case stdies. Jornal of Cleaner
Prodction, 1, pages 1042 – 1056.
A2 Gnrc conttnt of concrn
n romtargca procng
Broadhrst (2007) smmarized the generic groping of
the constitents of concern to tie p with potential water management objectives as follows:
Dissolved solids - expressed as total dissolved solids
(TDS), electrical condctivity (EC) or ionic strength: The
presence of salts can generally be lined to both feed
ores and processing operations (e.g. as leachants etc).
Salts can be divided into two frther sb-grops:
• Major solble salts: These inclde the slphates,
chlorides and carbonates of Ca, Mg, Na and k. These
salts are relatively abndant and common in natral
environments and ncontaminated water de to their
abundance in the earth’s crust and their relative highsolbility. They are all essential elements and only
exhibit toxic effects at relatively high concentrations.
Gidelines are based on aesthetic and physical
properties rather than toxicity. They are the major
cases of corrosion and scaling of plant eqipments
and, as a combined grop, can reslt in salinization of
soil and water resorces.
• Minor solble salts: These inclde F, Br, I, phosphate,
nitrate and nitrite salts. These salts are also essential
elements, bt are generally present at lower
concentration levels in natral environments and
have a greater toxicity than the major solble salts.
Trace metals and semi-metals: These generally
arise from the feed ore. These elements can vary qite
considerably in terms of both their biological effect and
environmental concentrations. These, thogh present in
the earth’s crust, do not occur in a natural uncontaminated
environment in solble or bioavailable form.
Anthropogenic processing reagents: These inclde
plant inpt reagents or chemicals prodced as side-
prodcts dring processing which do not generally occr
in natral environments. These inclde cyanide, organic
extractants, and srfactants (oil, grease, tars etc). These
elements are generally non-essential and harmfl to the
eco-system and mammals at low concentrations. There
are however, generally more opportnities to redce
these at sorce than those elements arising from the
feed ore.
Physical characteristics: These comprise mainly of pH
and sspended solids and have a greater effect on plant
performance (corrosion, scaling etc). The main effect of
pH is indirect, as pH has an inuence on solubility. pH
is therefore considered to be one of the main variables
controlling the leachability of constitents from materials
(also redox potential).
A3 Pca watr-rat prom
xprnc n t ro-
mtargca ntr
In hydrometallrgical processing, the need for higher
mineral recoveries has led to more elaborate recovery
methods, most of which involve the extensive se and
recycling of water. These operations necessitate stricter
control over the condition of the circit/process water in
order to maintain efciencies and to avoid water-related
operational problems sch as scaling, corrosion andfoling which are discssed in Table A.2 below.
The solble inorganic componds most commonly
encontered in these waters are a sorce of potential
troble throgh deposition in water pipes, eqipment
and boiler tbes. Contingency action plans to handle
redced process performance or process failre shold
also consider these in that deposits might have formed
and once process conditions have been corrected, these
deposits may still exist and need to be dealt with.
In the operation of every cooling, heating and steam
generating system, the water changes temperatre.
Higher temperatres and sbstance bild-p increase
both corrosion rates and scale forming tendencies.
Evaporation in open cooling systems and boilers
increases the dissolved solids content of the remaining
water and these increased concentrations can become
the cause of either scale formation or intensied corrosion
nless corrective treatment is applied. Sspended
solids or microbial organisms, in the mae-p water or
scrbbed from the air, can reslt in considerable physical
and microbial foling problems.
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Ta A2: Watr-rat prom xprnc
scang Corroon Fong
Denition Precipitation of sbstances,whose solbility in water hasbeen exceeded, in a verydense and adherent form, ontothe srronding srfaces.
Metal reverts to a compondsimilar to those fond innatre. Electrochemicalprocess in water.
Deposits form from materialsspended in water or fromgrowth of microbiologicalorganisms. Often associatedwith scaling and/or corrosion.
Origin/formation/case
Change in water temperatre or increase/decrease indissolved solids content or concentration, specically calciumand magnesim. Pipe velocity (speed at which water isconveyed)
Sspended solids or microbialorganisms in mae-p water or scrbbed from the air.
Physicalrecognition
A chemical deposit (material)bilding p on the srfacethereby clogging the pipes.
Thinning of metal; metal iseaten away.
Bild-p of material onto thesrface thereby clogging thepipes.
Effects Affect heat transfer rates.Impede ow of liquids.
Process throghpt may bedecreased de to redcedow.
Plg distribtion systems.
Waste of sefl metal. Highmaintenance cost.
Affect heat transfer rates.Impede ow of liquids.
Create differential concentrationcell corrosion.
Harbor anaerobic corrosivebacteria.
Plg distribtion systems.
Factors reqiredfor formation
Spersatration.
Ncleation.
Adeqate contact time for
adherence.
usally nder cathodiccontrol (cathode reaction israte determining).
uneconomical to eliminate- control rate by controllingpH, EC and alalinity.
Material sspended in water.
Microbiological organisms(bacteria, algae, fngi).
Factorspromotingformation
Increased pH.
Increase temperatre.
Reduced ow velocity.
Long lengths of piping.
Dissolved gasses (O2, CO
2,
H2S, NH
3).
Dissolved solidsconcentration (increasedEC, SO
4and Cl interfere
with protective lm).
Increased temperatre -increase chemical reactionrate.
Differential concentrationcells (galvanic crrent nder deposits).
Large volme pmps.
Conditions for growth of microbiological organisms.
Reduced ow velocity.
Ammonia, carbon componds,hydrocarbons (oil), phosphatesas ntrients for microbialorganisms.
Examples of types
Calcim carbonate
Calcim slphate
Magnesim silicate
Iron oxides
General srface corrosion.
Pitting (crater-lie), incldinggalvanic.
Physical.
Microbiological.
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scang Corroon Fong
Monitoring Deposit monitors, chemical
analysis, deposit analysis.
Corrosion copons,
electrical devices, depositmonitors, chemicalanalyzers, test heatexchangers, eqipmentinspections.
Deposit monitors, chemical
analysis, deposit analysis,biological monitoring (bacterialconts).
Inhibition or control
Limit critical specieconcentration (controlledbleeding or pretreatment).
Redce alalinity (acid dosing).
Alter system design or operation (increase ow,
redce temperatre, limitpasses in heat exchanger,reduce heat uxes bydecreasing heat load or increasing size)
Inhibitors (threshold inhibition,crystal modication, chelation,dispersion, conditioning for sldge formation).
Maintain srfaces deposit free.
Increase pipe velocity (>2m/s).
Inhibitors interfere withanodic or cathodic reactions:
Anodic – chromate,orthophosphate, nitrite,silicate, ferrocyanide;Cathodic – calcimcarbonate, polyphosphate,
zinc, magnesim; Anodicand cathodic – organiclming amines.
Metallic coatings.
Control water chemistry.
Oxidizers (chromate).
Film formers (solble oil,phosphates).
Reactive metal (Mg/Znblocks as sacricial anodes).
Increase pipe velocity(> 2m/s).
Water clarication (inorganicand polyelectrolyte polymer occulants).
System design (ensre trblentow).
Limit concentrations (decrease
by increasing blowdown rate).Slipstream lters (reducesspended solids).
Air rumbling and back ushing(pressrized air stream toincrease ow velocity, dislodgematter settled in low ow areas).
Limit ntrients for organisms.
Dispersants (bio or chemical).
Biocides (penetrants or dispersants)
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Below are a number of process ow sheets taken from the WRC report 1550/1/07 (Broadhurst,
Hansen and Petrie: 2007) representing some of the different sb-sectors in the mining and
mineral processing industry. A process ow sheet is a representation or schematic diagram
showing the steps of a process in seqential order. These are for example prposes only andtherefore not discssed in detail bt merely explained in terms of the terminology. Frther
discssion and information is contained in the WRC report and reference shold be made to
this for frther detail.
APPeNdiX b:
VARiOus hydRO-
MeTAlluRGiCAl
PROCesses
Figure B.1: Coal hydrometallurgical processing ow sheet (WRC 1550/1/07)
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Figure B.2: Gold hydrometallurgical processing ow sheet (WRC 1550/1/07)
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Figure B.3: PGM hydrometallurgical processing initial beneciation ow sheet (WRC 1550/1/07)
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Figure B.4: PGM base metals rening ow sheet (WRC 1550/1/07)
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Figure B.5: General ferro-alloy ore processing ow sheet (WRC 1550/1/07)
Figure B.6: Stainless steel ow sheet (WRC 1550/1/07)
See WRC 1550/1/07 for further ow sheets on Fe-Si, Si-Mn, Fe-Cr, Fe-Mn, Fe-V.
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TeRM AbbReViATiON deFiNiTiON
Basic Oxygen
Frnace3
BOF A towering cylinder lined with heat-resistant (refractory) brics,
sed by integrated steel mills to smelt iron from iron ore. Its namecomes from the “blast” of hot air and gases forced p throgh the
iron ore, coe, and limestone that load the frnace.
Calciner/Calcining
Frnace2
A heating device, sch as a vertical-shaft iln, that raises the
temperatre (bt not to the melting point) of a sbstance sch as
limestone to mae lime.
Calcine2 To heat (a sbstance) to a high temperatre bt below the melting
or fsing point, casing loss of moistre, redction or oxidation,
and the decomposition of carbonates and other componds.
Cementation2 A metallrgical coating process in which iron or steel is immersed
in a powder of another metal, sch as zinc, chromim, or
alminim, and heated to a temperatre below the melting point of either.
Cementation is the process by which one sbstance is cased to
penetrate and change the character of another by the action of
heat below the melting points of the sbstances.
Carbon in
Leach2
CIL Activated carbon is added to a gold ore slrry contained in
leach tans. The carbon adsorbs the gold from the soltion as
cyanidation of the ore proceeds.
Carbon in
Plp2
CIP Milled gold bearing ore is mixed with a cyanide soltion, which
cases the gold to complex with the cyanide, and activated
carbon particles. The activated carbon is pmped p throgh
tans conter-crrent to the cyanide slrry soltion. As activated
carbon and loaded cyanide soltion meet, the solble gold-cyanide
complex adsorbs to the activated carbon. These particles are
removed from the slrry and gold is recovered.
Clarier 2 A piece of equipment used to lter a liquid.
Conditioning A process in which reagents and ore are allowed to come to steady
state before frther processing of the ore contines.
Convert2 To change (something) into another form, sbstance, state, or
prodct.
Corex3 COREX® is a patented coal-based smelting process that yields
hot metal or pig iron. The otpt can be sed by integrated mills or
EAF mills.Dense Media
Separation4
DMS Separation of relatively light (oats) and heavy (sinks) particles, by
immersion in a bath of intermediate density. This is the dense or
heavy media, a nely ground slurry of appropriate heavy material
in water. Barite, magnetite ferrosilicon, and galena are in principal
se.
Direct Redced Iron3 DRI DRI is processed iron ore that is iron-rich enogh to be sed as a
scrap sbstitte in electric frnace steelmaing.
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TeRM AbbReViATiON deFiNiTiON
Electric Arc Frnace3 EAF Steel-maing frnace where scrap is generally 100% of the
charge. Heat is spplied from electricity that arcs from thegraphite electrodes to the metal bath. Frnaces may be either an
alternating crrent (AC) or direct crrent (DC).
Electrostatic
Separation2
Process of separating non-condctive particles from condcting
particles. Electrostatic separation of nely pulverized materials is
carried ot in electrostatic separators.
Electrowin5 EW Most metals occr in natre in oxidized form in their ores and
ths mst be redced to their metallic forms. The ore is dissolved
following some pre-processing in an aqeos electrolyte or in a
molten salt and the reslting soltion is electrolyzed. The metal is
deposited on the cathode (either in solid or in liqid form), while
the anodic reaction is sally oxygen evoltion. Several metals are
natrally present as metal slphides; these inclde copper, lead,
molybdenm, cadmim, nicel, silver, cobalt and zinc. In addition,
gold and platinm grop metals are associated with slphidic base
metal ores. Most metal slphides or their salts are electrically
condctive and this allows electrochemical redox reactions to
efciently occur in the molten state or in aqueous solutions.
Ferro Alloy5 Any alloy of iron and another metal, especially one of silicon,
manganese, chromim and vanadim, sed in the prodction of
specialist steels as they have a lower melting point than the pre
metal.
Flotation2 The process of separating different materials, especially minerals,
by agitating a plverized mixtre of the materials with water, oil,and chemicals. Differential wetting of the sspended particles
cases nwetted particles to be carried by air bbbles to the
srface for collection.
Gravity
Concentration2
Any of varios methods for separating a mixtre of particles, sch
as minerals, based on the differences in density of the varios
species and on the resistance to relative motion exerted pon
the particles by the uid or semi uid medium in which separation
taes place. The separation of liqid-liqid dispersions based on
settling ot of the dense phase by gravity.
Gravity Separation6 If there is a certain difference in density between two minerals
or roc fractions they can be separated by sing this difference.
Separation by gravity covers two different methods.
Separation in water (Gravity concentration)
Separation in a heavy medim (Dense Media Separation, DMS)
Hot Acid Leach HAL A hot slphric acid leach (HAL) circit to remove iron coatings
from the non-magnetic heavy minerals dring mineral sands
beneciation
____________________________________________________4 http: www.maden.hacettepe.edu.tr/dmmrt/dmmrt320.html
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TeRM AbbReViATiON deFiNiTiON
Leach3 In the chemical processing indstry, leaching is nown as
extraction. Leaching has a variety of commercial applications,inclding separation of metal from ore sing acid.
In a typical leaching operation, the solid mixtre to be separated
consists of particles, inert insolble carrier A and solte B. The
solvent, C, is added to the mixtre to selectively dissolve B. The
overow from the stage is free of solids and consists of only
solvent C and dissolved B. The underow consists of slurry of
liquid of similar composition in the liquid overow and solid carrier
A. In an ideal leaching eqilibrim stage, all the solte is dissolved
by the solvent; none of the carrier is dissolved. The mass ratio
of the solid to liquid in the underow is dependent on the type of
eqipment sed and properties of the two phases.
Leaching is widely sed in extractive metallrgy since many
metals can form solble salts in aqeos media. Compared to
pyrometallrgical operations, leaching is easier to perform and
mch less harmfl, becase no gaseos polltion occrs. The
only drawback of leaching is its lower efciency caused by the low
temperatres of the operation, which dramatically affect chemical
reaction rates.
There are a variety of leaching processes, usually classied by
the types of reagents sed in the operation. The reagents reqired
depend on the ores or pre-treated material to be processed. A
typical feed for leaching is either oxide or slphide.
Magnetic Separation4 By creating an environment comprising a magnetic force (Fm), agravitational force (Fg) and a drag force (Fd) magnetic particles
can be separated from nonmagnetic particles by magnetic
separation. Magnetic separation is widely sed to remove tramp
iron from ores being crshed, to remove contaminating magnetics
from food and indstrial prodcts, to recover magnetite and
ferrosilicon in the oat-sink methods of ore concentration, and to
pgrade or concentrate ores. Magnetic separators are extensively
sed to concentrate ores, particlarly iron ores, when one of the
principal constitents is magnetic.
Matte2 A mixtre of a metal with its slphides, prodced by smelting the
slphide ores of copper, lead, or nicel.
Mill2 To grind, plverize, or brea down into smaller particles in a mill.
___________________________________________5 www.wikipaedia.com6 http://www.metsominerals.com/inetMinerals/mm_home.nsf/FR?ReadFormandATL=/inetMinerals/mm_segments.nsf/WebWID/WTB-041213-2256F-
B42B4
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Sinter 2 Process in which a coherent bonded mass (sinter) is formed by
heating metal powders withot melting; sed mostly in powder metallrgy.
Separation6 After liberation of all individal minerals in a roc or an ore feed,
either by grinding or by natral size redction (beach sands a.o.)
they can be separated individally. Depending on their behavior,
different technologies are applied.
Slag5 Slags are the by-prodct of smelting ore to prify metals. They can
be considered to be a mixtre of metal oxides; however, they can
contain metal slphides and metal atoms in the elemental form.
While slags are generally sed as a waste removal mechanism
in metal smelting, they can also serve other prposes, sch as
assisting in smelt temperatre control and minimizing re-oxidationof the nal bullion product before casting.
In natre, the ores of metals sch as iron, copper, lead, alminim,
and other metals are fond in impre states, often oxidized and
mixed in with silicates of other metals.
Dring smelting, when the ore is exposed to high temperatres,
these imprities are separated from the molten metal and can be
removed. The collection of componds that is removed is the slag.
Different smelting processes prodce different slags. In general
they can be classied as ferrous or non-ferrous. The smelting of
copper and lead in non-ferros smelting, for instance, is designed
to remove the iron and silica that often occrs with those ores andseparates it as an iron silicate based slag. Slag from steel mills in
ferros smelting, on the other hand, is designed to minimise iron
loss and so mainly contains calcim, magnesim, and alminim.
Slag has many commercial ses, and is rarely thrown away. It is
often reprocessed to separate any other metals that it may contain.
The remnants of this recovery can be sed in railroad trac ballast,
and as fertilizer. It has been sed as a road metal and as a cheap
and drable means of roghening sloping faces of seawalls in
order to progressively arrest the movement of waves.
Grond granlated slag is often sed in concrete in combination
with Portland cement as part of a blended cement. Grond
granlated slag has latent hydralic properties, which means thatit reacts with water to prodce cementitios properties. Concrete
containing grond granlated slag develops strength over a
longer period, leading to redced permeability and better drability
properties. Since the nit volme of Portland cement will also be
redced, concrete is less vlnerable to alali-silica and slphate
attac.
Slimes Ore that has been milled to such a ne grind that, when mixed with
water, it forms a slime material.
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TeRM AbbReViATiON deFiNiTiON
Slow Cool Matte from a smelter is pored into a mold and allowed to cool
extremely slowly (over a period of days) in order to prodcevarios crystalline prodcts allowing frther separation of material
downstream.
Smelter 2, 5 A smelter is a specialised metallrgical frnace that allows smelting
to occr. Smelting is a method of separating gold, silver, and other
metals from their ores with re and heat intense enough to melt the
ores.
Solvent Extraction2 SX A techniqe, also called liqid extraction, for separating the
components of a liqid soltion. This techniqe depends pon the
selective dissolving of one or more constitents of the soltion
into a sitable immiscible liqid solvent. It is particlarly sefl
indstrially for separation of the constitents of a mixtre according
to chemical type, especially when methods that depend pon
different physical properties, sch as the separation by distillation
of sbstances of different vapor pressres, either fail entirely or
become too expensive.
Indstrial plants sing solvent extraction reqire eqipment for
carrying ot the extraction itself (extractor) and for essentially
complete recovery of the solvent for rese, sally by distillation.
See also Distillation.
Tailings Tailings (also nown as tailings pile, slicens[1] or gange) are the
waste materials left over[2] after removing the minerals from ore.
Tailings and gange represent external costs of mining. As mining
techniqes and the price of minerals improve, it is not nsal for tailings to be reprocessed sing new methods, or more thoroghly
with old methods, to recover additional minerals.
In coal and oil sands mining, the word ‘tailings’ refers specically to
ne waste suspended in water and the word ‘gangue’ is not used.
Thicener 5 A non-lter device for the removal of liquid from a liquid-solids
slrry to give a dewatered (thicened) solids prodct; can be by
gravity settling or centrifgation.
Waste Roc/
Overbrden2
Material overlying a sefl mineral deposit.
ZADRA Elution1 A process for the removal or recovery of gold from activated
carbon (see AARL eltion)
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A strategy for the ris-based environmental assessment of a proposed new hydrometallrgical
process plant is presented in this docment. This is a practical strategy that was actally
implemented for a new process that was developed before the rst plant was built. The process
that was followed is shown in Figre C1 below.
Fgr C1: envronmnta Rk Amnt Proc
APPeNdiX C:
eXAMPle OF
deTAiled RisK
AssessMeNT
PROCess AT PlANT
desiGN sTAGe
stp 1: Prpar or otan
matra aanc aron t
mtargca proc
A detailed material balance mst be
constrcted arond the metallrgical
process (inclding all air, solid and liqid
control systems). The balance will inclde
all inpts raw materials, ore, chemicals,
water) and all otpts (prodcts, air
emissions, solid wastes, liqid wastes).
In ndertaing the balance, it will be important
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to ndertae probabilistic modelling in order to properly
dene the resultant material balances.
Step 4: Dene industry norms andtanar (ncmark)
If there are no other identical process plants in operation
and therefore, no norms or standards for environmental
emissions, sch norms and standards shold be
available for other similar processes. The emission
norms and standards for these applicable processes
shold be collated into a reference docment. The norms
and standards will include denition of “Best Available
Technology” in terms of emission controls as specied
internationally.
Step 5: Dene minimum legal/regulatoryrqrmnt
The legal and reglatory reqirements which will apply
to the planned process plant must be dened for the
Soth African sitation. Whereas it will be important to
ensre that the proposed process complies with legal
and reglatory reqirements, these reqirements shold
be viewed as the minimm, and the environmentalris assessment process shold evalate the real
environmental problems independently of these
reqirements. The reason for adopting the ris approach
is that the reglatory reqirements reglarly change and
lining the performance of the proposed process to these
changing goalposts will make it difcult to dene and
manage the environmental performance over the whole
plant life cycle.
stp 6: unrtak nvronmnta rk/
mpact amnt of proc
The environmental ris/impact assessment process
shold be rigoros and designed to withstand any local
or international scrtiny. This Step of the overall process
has been frther divided into 5 separate tass as shown
in Figre C3 and described in the text.
Fgr C3: dta envronmnta Rk/impact Amnt Proc
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Tak A: evaat matra aanc prpar n
stp 1 an 3
The material balances which were prepared in Steps 1and 3 should be critically evaluated in order to dene
those aspects which pose some potential environmental
ris. Particlar focs shold be placed on the varios
waste streams which are generated, their proposed
disposal rotes and any environmental riss/impacts
which may arise there, both throgh application of
approved management and operation procedres and
throgh failre of these approved procedres. This tas
should culminate in the denition of all contaminant
sorce terms in terms of location, qantity and qality for
best and worst case scenarios.
Tak b: Prpar ta nvronmnta
patwa mo for proc, ncng a
mon
Tas C and the sbseqent Tass D and E apply for the
assessment of the site-specic risks of the process at a
particlar location. The potential critical receptors mst
be dened for each of the best and worst case scenarios
identied in Task A. The critical receptor concept is based
on dening a hypothetical, conservative but realistic
hman or ecological receptor which may be affected by
the proposed process and its waste streams throgh one
or more pathways. The critical receptor(s) is/are chosen
to represent the most highly impacted-pon receptors
such that there is condence that if the critical receptor
is assessed to be exposed to an acceptable ris, then
all other potentially exposed receptors are sbject to an
even lower ris.
Using the identied critical receptors, a comprehensive
contaminant and exposre pathway analysis shold
be undertaken in order to dene all the air, water and
land pathways throgh which the varios contaminants
from the dened source terms may travel. This pathway
analysis shold be ndertaen sing an appropriatecompter code developed for this prpose and shold
inclde all pathway interactions which may reasonably
occr.
Tak C: unrtak tranport mong to
dene contaminant concentrations at critical
grop rcptor
Once the pathway analysis has been completed, the
transport of contaminants along these pathways will
need to be modelled. For example, for the atmospheric
pathway, the dispersion of particlate and gaseos
emissions will need to be modelled sing appropriate
compter codes in order to derive the concentration
of these contaminants at the critical receptor. Similarlyfor the srface and grond water rotes, taing into
accont other intermediate receptors sch as macro-
invertebrates, aqatic species, sediments, livestoc and
irrigated crops wherever appropriate. The otpt of this
task would be a specied concentration, duration and
probability of ey contaminants at the critical receptors.
Tak d: unrtak toxct amnt of
wat tram
With the information provided in Tass A, B and C, a
toxicity assessment can be undertaken to dene thedeleterios effects, if any, reslting from the varios
contaminants in the varios waste streams. Sch a
toxicity assessment mst be based on the methodologies
proposed by the Department of Water Affairs and will
focs on the potential maximm toxicity (the conservative
approach) of the waste streams and the mobility of the
contaminants into different environmental pathways.
Task E: Dene pathway-specic, contaminant-
specic and cumulative environmental risk to
crtca grop rcptor
Based on the toxicity assessment which were ndertaen
in Tas D and the pathways and transport modeling
undertaken in Tasks B and C, it will be possible to dene
the environmental riss for each contaminant or for each
pathway or cmlatively for all contribting ris factors.
This will enable later phases of the project to focs
remediation or design changes to those components
of the process train which directly contribte most
signicantly to the unacceptable risk which needs to
be addressed. In this way, the benecial effects of any
remediation measres can be rapidly assessed in terms
of real effect at the particlar receptor of interest.
stp 7: i rmaton rqr n trm
of stp 4, 5 an 6?
The environmental riss/impacts which are assessed
in Step 6 need to be evalated in terms of the indstry
norms and standards and the minimm legal/reglatory
requirements dened in Steps 4 and 5. The risks
shold also be evalated in terms of the assessed
consequence to the critical receptors as dened in Step
6. If unacceptable risks are identied, then appropriate
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remediation measres will need to be evalated in terms
of modifying the existing design of the process plant.
Shold it be fond that no remediation is reqired, then
the existing process design will need to be evalated interms of monitoring systems to ensre that these are
adeqate.
Step 8: Dene and apply remediation
mar to proc gn
If the assessment in Step 7 indicates that nacceptable
environmental or legal riss are associated with the
proposed process as it is crrently engineered, then
appropriate remediation measures should be identied.
The correct place to apply the remediation measres will
be highlighted by the pathways and transport modelling
exercise ndertaen as part of Step 6. For example, it may
be decided to add a water treatment plant to the process
train to ensure that liquid efuent discharges pose no
signicant risk to the receiving environmental media, or it
may be decided to separate certain solid waste streams
and dispose of them nder tightly controlled conditions or
treat them to a less toxic form.
Step 9: Dene and apply monitoring
mar to proc gn
In order to ensre that the proposed process can
demonstrate to reglators and other interested and
affected parties that it poses no nde environmental ris,
it will be necessary to design, implement and maintain
an appropriate environmental monitoring programme.
This monitoring programme will also provide the plant
operators with the reqisite information for ensring that
appropriate management controls are applied at the
earliest possible stage. Even the best designed process
can have eqipment malfnctions and the monitoring
systems shold be designed to identify sch malfnctions
timeosly before serios environmental impacts are
cased. The monitoring programme which will incldeboth sorce and receptor monitors will also provide the
proof that the environmental ris/impact is acceptable.
stp 10: Prpar comprnv
environmental risk /impact prole
ocmnt for t proc
Detailed docmentation shold be prepared which
clearly describes the rigoros evalation process which
the proposed plant will have been sbjected to. The
environmental ris to the critical receptors for the different
evaluation scenarios should be clearly specied and the
reqired emission control and monitoring eqipment to
ensure acceptable risk should also be clearly dened.
The report shold also draw comparisons between the
proposed process plant and other similar operations in
terms of environmental ris/impact.
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iTeM yes NO ReCOMMeNded ACTiON/
ReAsON
sTeP 3: Are details on the site and process provided?• Layouts, infrastructure and support services
• Environmental details in terms of particularly the water
environment and its sensitivity
• Process details
• Inputs including raw material/ore and other chemicals
• Water resources - availability, sustainability, variability etc
• Other resources – personnel, nances, infrastructure
• Waste details
• Water reticulation
• Monitoring programme
• Future planssTeP 4: Does a water and salt balance exist? The water and salt
balance shold state clear objectives, be reglarly pdated and
consider the different hydrological cycles. Refer to BPG G2: Water
and Salt Balances.
sTeP 5: Are details provided in terms of the mine/plant water users
and their water reqirements (qantity and qality), their sensitivity to
changes/variability and contaminants of concern (COC)?
sTeP 6: Is water se minimized? (Are water conservation strategies
therefore implemented?)
Is water of different qualities segregated and are there different
water management systems for each of these?
Are materials stored in an appropriate manner on site based on itsreactivity with water and the area in which it is sed?
Is there a specic water management system for areas with a high
contamination risk to prevent it from impacting on other water
management systems and other plant areas?
Is a storm water management system in place? Refer to BPG G1:
Storm Water Management .
Does the storm water management system ensre that clean water is
ept clean and released to the receiving environment?
Does the storm water management system ensre that contaminated
storm water is captred and contained?
Are spillages cleaned qicly and handled in an appropriatemanner?
Is equipment reglarly inspected and maintained?
Are housekeeping and water management practices sustainable
over the life-cycle of the mine/plant? See Chapter 4.
sTeP 7: Is the generation of contaminants minimized throgh
inpt optimization, polltion prevention and polltion redction at
sorce?
Are the water quality requirements for the mine/plant water users
established?
Are monitoring, maintenance, inspections and audits condcted?
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iTeM yes NO ReCOMMeNded ACTiON/
ReAsON
sTeP 8: Is a water reuse and reclamation strategy implemented?Refer to BPG H3: Water Reuse and Reclamation and BPG H4:
Water Treatment . The water rese and reclamation strategy shold:
• Identify opportunities for water reuse and reclamation
• Indicate the benets of water reuse and reclamation
• Identify and consider all water sources available
• Attempt to minimize water intake, consumptive water use and
water losses
• Maximize water reuse and reclamation by providing mine/plant
water sers with the poorest water qality possible withot affecting
the process or prodct qality
• Optimize the water reticulation system• Consider the destiny of unused internal water sources in terms
of the water management hierarchy by considering treatment to
allow rese, alternative ses, otside sers, discharge/disposal.
• Consider the advantages of material or byproduct recovery
sTeP 9: Are process changes and cleaner technologies
considered for implementation?
What are the barriers preventing the implementation of cleaner
production and how are they overcome?
sTeP 10 an 11: Is an IWWMP , which considers and docments all
the above considerations and principles, in place?