Caving Underground Mining Methods (longwall, Sublevel caving, & Block caving)

A short series of lectures prepared for the

Fourth year of Geology, Tanta University

2014- 2015

by

Hassan Z. Harraz

[email protected]

This material is intended for use in lectures, presentations and as handouts to students, and is provided in Power point format so as to allow customization for the individual needs of course instructors. Permission of the author and publisher is required for any other usage. Please see [email protected] for contact details.

Topic 7: Underground Mining Methods Longwall

Sublevel Caving

Block Caving

mailto:[email protected]





Outline of Topic 7: Longwall

Longwall in coal

Longwall in Hard Rock

Sublevel Caving

Characteristics of the ore body and mining method

Development

Production

Equipments Used

Block Caving Introduction

Historical evolution of the method

Condition deposit

Principles of the method

Methodology of block caving

Basic issues of geomechanical to the black caving method:

1) Caveability 2) Mine design 3) Fragmentation and extraction control 4) Subsidence associated

Advantages and Disadvantages of Block Caving

Prof. Dr. H.Z. Harraz Presentation

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We will explore all of the above in Topic 7.

Longwall (LW)


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Longwall (LW)

The Longwall is a very old method, originated in

coal mines in Europe in the 7th century.

The most important application of Longwall

relates to coal mining.

Much of the production of coal from countries

like USA, Australia and China are obtained by

Longwall.

Conditions of applicability of the method: Stratiform tabular bodies, little thick, horizontal (tilt up to 20°);

Uniform distribution of thicknesses / levels;

High degree of continuity of the ore body;

Geological discontinuities (e.g., faults) are highly detrimental to the method;

Applicable in hard rock (metalliferous mines) and fragile (coal).


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Longwall (LW) in Coal

"As applied to longwall coal mining, is not maintained the

integrity of the immediate roof above the newly mined coal. This

ceiling should desplacar the main ceiling, separating into blocks and

falling into the void left behind the line automarchantes brackets. The

process of peeling is accompanied by swelling (about 50%). Ceiling

and immediately occupies the void left by coal mined, acting as a

natural bed against which converges the main ceiling. The greater role

of the immediate roof is desplacar and blistering, filling the void

mined and retaining the convergence of the main roof, maintaining its

integrity. "

Ref.: Brady & Brown, 1993, Rock mechanics for underground mining,

cap.12.4.6.


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LW in Coal carvão


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Longwall in Coal


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Longwall (LW) in Coal

Preferred conditions (beyond those already

mentioned): immediate roof of coal consists of shales, siltstones or other brittle rocks,

enough to produce peeling fracturing;

competent main roof, which can deform without breaking on the immediate

roof has collapsed.

competent flooring to withstand the stress produced by the monkeys;

Situations in which there is an advantage in applying LW in relation to the

R & P:

bad roof (fragile), preventing bolting ceiling;

great depths (e.g., beyond 500m), causing much loss of coal pillars;

reduced thickness of coal seams.


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Types of Longwall

Longwall advancing

Longwall retreating

Longwall advancing


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Longwall retreating


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Longwall in Coal

Setup room: where the face of

longwall begins operation;

Recovery room: where the

longwall finishes and equipment

are removed from the panel;

Barrier pillar: pillars to protect

main and bleeder galleries axis.


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Advantages of LW in coal

Greater than the recovery room and pillar panel;

High rate of production and productivity - over 100 ton / man / shift "face

productivity" - the highest of underground methods;

The lower production costs in underground mines (next to the block caving);

Ease of hand-to-work training.

Adequate to poor roof;

Coal generally produces better quality (lower dilution);

Better able to control venting and elimination of gases and dust;

Good control of subsidence.

It is safer - the workers are all the time under the roof bracing.


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Disadvantagesof LW in coal

Does not work well in layers of irregular thickness;

Stops result in a large variation in production (high production / low

availability);

Geological discontinuities (faulting or problems with the ceiling) can

cause long downtime;

Dust control often difficult;

Problems of methane under high production;

Variability and intermittency in production between simultaneous

fronts cause overload in the discharge of mine system;

Impact on the construction of the surface (subsidence);

High initial investment in equipment;

Significant development in the preparation of mining panels;

Need for immediate ceiling collapse after the withdrawal of support

from apes;

Long delay to exchange panel;

Rock bursts: e.g. big problem in depth beyond 750m.


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Basic equipments Longwall (coal)

AFC = Armored Face Conveyor


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Equipment for Longwall method in coal


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Equipment for longwall method in coal (shearer)


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The extraction is

done with the aid

of rotary cutters

will fragmenting

the carbon layer.

The coal falls on a

channel of

transmission and is

transferred to a

continuous

transport.

Longwall in Coal: operation


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• A very attractive

feature of this method

is the protection

system roof that

provides complete

safety to operators.

• The hydraulic

cylinders move as the

carbon layer is drawn,

creating an area

without support on

the back of falling

relieving stress on the

system.


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After completion of

mining in the panel, it

is necessary to change

the equipment.

This change takes 10 to

30 days to be

performed and is

performed, on average,

1 to 3 times a year.


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Equipment for Longwall method in coal (plough)


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Typical dimensions of a panel longwall :

Extension panel: 900 - 5300m;

Width. the gal. Face: 2.4 - 3.6m;

Length of face: 200 - 360m;

Height: 0.9 - 4.5mm;

Cutting Thickness: 80 - 800mm;

Depth: 60 - 800m.


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Capital price/longwall: 30 million $ for a face equipment;

Need for large reserves … minimum of 50

million tons;

Producing a front … 2-6 million tons / year;

Employment of a shearer …. 200-500

minutes / day.

Compared with a front operating with

continuous miner ... Capital of 3-5 million $;

Production 0300000-0800000 t/year;

3 Continuous miners are needed in developing a

front LW;

Continuous miner is flexible and can be easily

availed in other reserves. Prof. Dr. H.Z. Harraz Presentation

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The mine Kuhn-

town (Pensilvânia)

achieves a

production of up

46.000 t/d of iron

ore by plowing a

layer of 900mm

coal cutting at a

rate of 2.700 t/h.

Longwall: examples


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Mine in Colorado operates production until 4.500t / h, reaching 22.700t / day in a coal seam thickness of 1.07m.

The power cutter has cutting 1.100kW, moving from 8 to 12 m / min along the face.

Longwall: examples


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Experimental longwall at Mine Leão I - Rio Grande do Sul, 80s.

Extension panel = 800m

Face-width = 70m

Height layer = 2m

1 double drum cutter (300 hp), diameter 1,09m;

Hydraulic cylinders 54 automarchantes type "chock" (6 legs capacity of 240t)

1 panzer front 65hp, with 64m long and capac. 600t / h;

Side galleries of the panel developed by Roadheader;

Daily production of around 800t.

Longwall: exemplos


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Longwall:

Leão I


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Longwall in Hard Rock In this case, the method must maintain the integrity of the

floor and ceiling; cover and lapa must be composed of hard,

competent rock.

Temporary support (near side) and permanent (eg uprights of

wood and / or concrete columns) are used to prevent

discontinuities in the stope.

Used in metalliferous deposits; differs greatly for the Longwall

coal.

During the work of the scraper, the roof is anchored with

temporary supports that are later replaced by permanent

concrete supports.

Additional information about the LW method for coal on the Internet ...

Wollongong University-Austrália

www.ouw.edu.au/eng/current/longwall

------------------


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http://www.ouw.edu.au/eng/current/longwall

Longwall in Hard Rock

The extraction proceeds during the strike, with the dismantling of the face done with the aid of explosives.

The ore is disassembled collected with a scraper and taken to a orepass.


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Sublevel

Caving

Topics Characteristics of the

ore body and mining

method

Development

Production

Equipments Used


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Characteristics of the method ...

Sublevel Caving in the process of

fragmentation of the ore is done by explosives

(induced caving) and the ore is detonated with

drilling in ascending fans. The sterile overlying

should crumble as the ore is removed.


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Characteristics of the orebody and enclosing

massive and/or tabular (varying inclinations are allowed);

Diving > 50o case is thin;

competent body with mineral rock wall rock (cover) fractured;

stable development of the footwall to access;

the method requires minimal stability to the ore body, because the

galleries sublevel should be self-supporting piece and can receive

routine bolting;

significant dilution, very little sensitive to fragmentation;

likely surface subsidence;

rock cover must accompany the ore in a continuous felling,

producing subsidence at the surface. The ideal condition is

that the enclosing fragment into larger blocks which ore

disassembled to facilitate flow separation at the extraction

drift.


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Design alternatives for dips and varying thickness of

the ore body

Tabular ore body and thick makes all production galleries are always in

the ore, avoiding fans incomplete perforation (loss of ore), open galleries in

sterile (the roof support problems and expenses), losses along the footwall


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Design alternatives for dips and varying thickness of

the ore body

Losses ore


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Design:

transverse sublevel caving – for thick bodies


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Design: transverse sublevel caving - this case, the galleries of production (drifts) are perpendicular to the

strike of the ore;

- Mining recoveries are greater than the longitudinal layout.


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Design:

longitudinal sublevel caving – for narrow bodies

and sharp dip


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Development in Sublevel Caving

The method requires significant development, being part of ore (in high producing mines, 6% of the

total ore mined comes from developing).

The cost / ton of ore in the development is several times higher than in production. Should

maximize production and minimize development.

The ore body is divided into panels whose height varies from 50 to 250 m in height, depending on

the scale of production and reserves per vertical meter.

Each panel is divided into sublevels spaced 20-30 m (increasing the spacing between sublevels

minimizes the development) which will be issued successively downward.

The lower level of the panel is characterized by a main gallery of transportation that serves all

"orepasses", connecting the premises of the extraction well.

Access to sublevels is accomplished by a ramp situated between the ends of the ore body. The

ramp is linked to gallery transporting each sublevel. This gallery of transporting each sublevel must

accompany the footwall contact at a distance 15-20 m.

In transverse sublevel, crosscuts traverse the deposit, going to the hanging wall; development is in

the footwall. Starting in the transport gallery, galleries are open from distant production center-to-center 15-25 m, parallel to each other, extending to the contact with the footwall. Have dimensions

(width x height) 5x4 m; 6x5 m; 7x5 m.

Sublevel of the galleries, just above the ore is drilled and drilling with longholes in range.


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Production in Sublevel Caving

The production begins when the galleries of a sublevel reach the subsequent

contact.

These galleries do not come into general production while, but should not retreat in a

un-organized way. In some mines, adopts the recoil so that its edges are coarsely

contained in a plane.

In other cases, the recoil is done so that the galleries production of more distant

"orepasses" are the first to reach the main gallery.

Equipment used for production drilling (ascending): carts with two spears, with

sectioned stems and crowns of up to 115 mm. Currently, the drills used are electro-

hydraulic and DTH's.

Drilling targeting the production is made in the form of irradiated fans of the galleries

of the sublevel. The holes made are long (up to 50 m long) and is used in this drilling

process "longholes".

Charging is done by pneumatic devices. ANFO explosive is the most common. In the

case of explosive in cartridge, it uses a similar device, equipped with blades to break

through the cartridge.


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One way to start is

dismantling create a free face

(slot relief) with a hole pattern

up to an inclination of approx.

80 to 90.

Another way is to open the

slot from a raise.


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LHD's perform the loading, transport and unloading of ore in the end "orepasses" being

sublevels designed for better efficiency of loaders.

Drilling operations and loading are performed independently and at different levels.

Due to the large number of galleries sublevel there are many fronts production

The explosive consumption is high due to the fact the dismantling be carried out

against the mass of fragmented rock.

Must be careful in removing the ore from drawpoints (you need to control levels at the

point of load):

removal of the material causes little lower recovery;

removal of too much material causes excessive dilution.

There is a cut-off grade given below which do not remove more ore in crosscut and

should detonate new range.

Production


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Equipment for development and production


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In the design of production drifts, the Sublevel Caving uses the

principles of "gravitational flow" ore dismantled, with subsequent

collapse of the host rocks.

Approaches used to issue a gravitational flow:

A) The physical-scale models B) field experiments in real scale C) models mathematical / numerical.

The solutions found so far are not fully satisfactory from the

standpoint of optimization of the gravitational flow of the ore.


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These models are the oldest, made with particles (e.g., sand),

leaking containers of small size.

A) Example test with physical scale models:


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Two major factors related dilution and ore recovery (*)

Width (c) extraction of the gallery;

Clearance (V) between ranges of production

(*) View Article : Theory and pratice of very-large-scale Sublevel Caving. Underground Min. Methods: Eng. Fundamentals and International Case Studies, 2001, W.A.Hustrulid & R.Bullock. Chapter 46, p.381-384.


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Width (c):

A gallery of production should be as wide as possible;

When the ceiling of the gallery is concave, the flow of

ore is very centralized and inefficient sides, requiring

closer galleries.

The amount of ore away from LHD's increases with

the increase of the height of the gallery production.

Therefore, the height should be as low as possible.


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Examples of ancient settings production galleries...


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Are directly executed in underground mines,

where they put up markers (markers) numbered, to be

retrieved and counted after detonation.

A recent experiment shows that the

flow of ore is mainly formed by the

material above drawPoint, but he is not

very predictable.

(Quinteiro, C R, Larsson, L and Hustrulid,

W A., 2001. Theory and practice of very

large scale Sublevel caving. Underground

Min. Methods- Eng. fundam. and

Intern. Case Studies SME)

B) Real Scale Experiments:


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Experiments on real scale: Recently, Sublevel Caving mines have increased lateral spacing interval

drifts and sublevels.

This has increased production, but also increased dilution.

There are still several outstanding questions about the best production

design in this method.


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There are several numerical models being investigated to explain the influence

of the main variables of the method.

Among the principal's PFC - numerical code developed by Itasca group since

the 1990s PFC = Particle Flow Code.

C) Mathematical / numerical models:


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Principles of choice of the configuration of production galleries: the idea of minimization of production costs leads to employ the maximum vertical spacing

between sublevels (currently around 30m);

essential for maximum spacing between sublevels ... ability to drill and carry long, straight holes

and large diameter factor;

the largest possible diameter hole, which allows drilling and loading, is ideal (the maximum is

now 115mm);

large galleries (7x5m, for example) allow the use of drill pipe and longer rectilinear holes (few

rods provide increased rigidity to the drillstring). There are projects of fans with holes up to 50m

in length;

distance between planes of fans (B):

depends on the hole diameter (D) and the type of explosive.

Initial estimate for ANFO ... B = 20 D.

For higher energy explosives ... B = 25 D.

D = 115mm and assuming emulsion as an explosive has been B ≈ 3m.

Number of holes in the array:

should follow the S / B ratio ≈ 1.3; where S is the distance between the ends of

neighboring holes in the same range.

In this case (B = 3m), S is 4m.

Interval between sublevels:

is chosen based on the maximum drilling capacity and the ability to maintain satisfactory

alignment of the holes.

As an example, assume 25m.

Lateral spacing between production galleries:

makes an angle of 70o between the upper gallery of the reference and the midpoint of

the gallery just above the sublevel (this is the angle of minimum theoretical expected to

drive the ore detonated). The center-to-center spacing resulting from side galleries is

approx. 22m (see Figure A1 in the next slide).

This initial configuration (Figure A1) was adapted in the 1990s to become more practical

operational point of view (Figure A2). Prof. Dr. H.Z. Harraz Presentation

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Figura A1 Figura A2


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Principles of choice of the configuration of

production galleries:

For adaptation:

effecting up to 55 lateral holes of inclination. Function of these holes ...

ore fragment lying in the slope of approximately 70 and reduce the

length of (longer) central holes of the fan.

Holes smaller than 55o inclination are difficult to load with explosives,

due to the angle of repose of the ore in drawPoint.

The fans may be vertical or inclined (α generally uses up 70 to 80o to the

horizontal). The steepening improves the stability of the roof drawPoint and

easy access for loading the holes with explosive.


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High production rate;

Many And efficient fronts of simultaneous mining;

Possibility of high degree of mechanization;

Method Safe for operators.

advantages

disadvantages

Dilution may be high (15-30%) and moderate recoveries (75-85%);

subsidence on the surface;

high consumption of explosives;

high cost of development;

intensive drilling and disassemble to generate a suitable granular product to flow ore;

controlling the cut-off level can result in low recovery of ore.


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Block Caving

Block

Caving Prof. Dr. H.Z. Harraz Presentation

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Introduction:

Block Caving* is method in which volumes of rock are left without support and suffer rebate under its own weight; the overlying rock fragments-along with the ore. The fracturing and the disposal of ore are obtained by the action of gravity and efforts resulting from tectonic and lithostatic stress.

* Translation: Allowance for blocks.


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Block caving


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Historical evolution of the method ... End of the century. xix: block caving applied to iron ore mines in

Michigan, USA;

Beginning of the century. xx: block caving applied in the USA for iron ore

and copper states in the west side;

20s: block caving starts in Canada and Chile;

50s: block caving starts in South Africa, diamond mines and asbestos;

Beginning of the 60s: LHD vehicles developed for underground mining;

1970: LHD's used with block caving mine in El Salvador, Chile;

1981: panel mechanized caving introduced in the primary ore of El

Teniente, Chile;

90: Planning new generation of mines with greater height block and ore

bodies more resistant (eg Northparkes, Palabora).


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Operating mines closed and planned using the method …


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Some data using block caving mines...


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Condition deposit Resistance ore: weak to moderate, preferably soft or friable ore with intense

fracturing;

Resistance the wall rock: similar to the ore, distinct interface between /

barren ore;

Diving: vertical is better, but can be flat if the deposit is thick;

shape: large areal extent and thick (> 30 meters);

uniform and homogeneous distribution of levels (suitable method at low

levels);

Depth: moderate (> 500m and <1200m).

Principles of the method ... In block caving method, the ore is moved by subsidence (caving) to a

cavity formed almost always without the use of drilling and blasting. Drilling

and disassemble are used in establishing the initial "enhancement".

The base of the ore is excavated by removing their support, this results in

fracturing of the ore which migrates to the enhanced vacuum and which is

then removed.


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Methodology of block caving: develop below the panel to be mined, a layout extraction of ore;

above the level of extraction, a horizon of "undercut" (highlight) will provide free

face below the ore body, causing the collapse;

temporary pillars in the "undercut" horizon are removed and the collapse of the ore

starts;

ore haggard blister and fills the void of the "undercut";

remove fragmented material in the extraction horizon, inducing flow of ore and ore

loss of support has not beaten down that is also subject to collapse;

vertical progress of "caving" is related to the extraction of fragmented ore and its

blistering.

During the flow of the fragmented ore is reduced the size of the blocks.

Primary fragmentation is done by natural mechanical process, advantageously in

terms of cost. Sometimes explosive is used in production, making long and spaced

holes to induce fracturing.


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Basic issues of geomechanical to the black caving method:

1) Caveability 2) Mine design 3) Fragmentation and extraction control 4) Subsidence associated


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1) Caveability: The process is still not well understood, but it is known that the main factors

involved.

The caving is principally defined by the rock quality (RMR, Q, etc.) and its

hydraulic radius - RH.

The basic requirement for the method to work is that the rebate (caving) occurs.

The slump of the ore is the result of the action of gravity, being influenced by:

pattern of fracturing the middle ... for good fracturing at least two families cross sub-vertical joints between

themselves and one horizontal family;

stress distribution in the area to be mined.

It is not easy to predict whether the resulting fragmentation which occurs rebate or.

A rule of thumb: For an ore body be subject to abatement, approx. 50% of the fragments should have a maximum size of

1.5m.

There are several geomechanical classifications to forecast caving and fragmentation. The

most commonly used: RMR, Q system, classification of Laubscher (1981) system.


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Geomechanical parameters observed in some mines:

Palabora Mine (copper) in South Africa ... MRMR between 57-70, which is

among the highest values for block caving (this method is not advised when

MRMR >50).

Henderson Mine (molybdenum) in Denver- USA ... with RMR 27-60.

Northparkes (copper-gold) in Australia ... features RMR between 33-54, for Lift

1 (upper part of the ore body).

El Teniente, Chile ... MRMR between 55-74, for various lithologies of the mining

area (andesites, diorites, breccias).


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Note .:

RMR classification

Developed by Bieniawski

Ranges 0-100

Main parameters:

RQD (Rock Quality Designation)

Spacing between discontinuities

Uniaxial compressive strength of rock

Quality of discontinuities

Presence of water in the rock mass

Orientation of discontinuities relative orientation of the

excavation

Rating MRMR (dev by Laubscher,. Page 413 SME book.) Similar to RMR, but includes stress induced by mining and blasting in the calculation of MRMR parameter.


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2) Mine Design : Key elements in establishing the layout of mine ...

2.1) is possible division of the area to be mined :

division separated by pillars of security blocks sequentially to be

mined;

division into blocks without pillars, with continuous mining.


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2.2) Selection of extracting ore system : The extraction system is complex, time consuming and costly preparation. Usually

requires several years of work to be put into production.

a) traditional by gravity system; b) by slusher system; c) by LHD's system.

a) Traditional gravity system - ideal for very fragmented ores: loading and transportation system developed under each block

orepasses are open and finger raises with grids

the level of fragmentation is controlled louvers

Finally enhancement is done in the block which begins the fragmentation and

migration of the ore and racks through the undercut up to the level of transport.

b) By slusher system- for medium or little fragmented ores:

development is simplified by omitting grids level. The cones migration ore bind

directly to points of discharge.

the high wear on the pillars discharge requires very resistant concrete coating.

c) By LHD's system - more modern system, to little fragmented ore: Provides greater productivity drawPoint simpler design eliminates the need for a

orepass for each drawPoint but need area larger tube (strut costs!) Due to the

size of the equipment.


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Systems ore extraction by gravity


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Systems ore extraction by gravity


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Systems ore extraction


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Ore extraction system for LHD's


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Isometric view of a system of extraction of ore per LHD`s :


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Plan view of the level of

extraction of ore to a

system with LHD`s:

Drawpoints


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2.3) Location of permanent facilities The block caving is generally used in low resistance of rocks, but

the developments and openings production (drawpoints, etc.)

must be kept in places where the rock has better quality.

2.4) Other important aspects ... drawPoint size, spacing (small fragments implies closer drawpoints),

geometry of the pillars, sequence and direction of mining.


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Typical design parameters …


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Typical design parameters …


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3) Fragmentation and extraction control: Fragmentation is difficult to predict and influence

the choice of ore extraction system and spacing

drawpoints.

The rate of ore extraction affects fragmentation:

very rapid extraction : very rapid extraction can create voids near the surface enhancement; fragments of ore become larger because they suffer fewer burdens on the mass of collapsed overlying materials; for better fragmentation stack height of caved ore must be maximized;

very slow extraction : very slow extraction can cause compaction of the ore and restore locally stable structures.

Modes of observation of progress caving: see SME Min. Eng. Handbook, 1992 pg.1820.

Accident Northparkes (1999) by sudden collapse of the ore in the abatement process.


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Examples of fragmentation obtained in some mines…

Mina

Tamanho do

fragmento

médio D50mm

Espaçamento

entre os pontos de

drenagem (m)

Grace 1.500 6,0 x 9,0

Urad 700 9,0 x 9,0

Clímax 350 10 x 10

El Salvador Minério fino

Bell Mine

Com rastelamento Com Trav Carregamento

7,6 x 7,6

12,2 x 12,2


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Examples of fragmentation inferred from borehole...


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Types of fragmentation :

• In situ ... represented by the blocks that are naturally present in the rock before mining activities;

• Primary ... represented by blocks in the vicinity of the cavity abatement and separate themselves from the massive intact when the rebate is started;

• Secondary ... occurs when blocks of primary fragmentation move for drawpoints.


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Examples of fragmentation observed in drawpoints :

Northparkes E26, Austrália Esmeralda Sector, El Teniente Mine, Chile


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Cumulative distribution

of fragmentation observed in

Premier Mine, South Africa


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4) Subsidence associated : subsidence is discontinuous and affects large

areas of the surface;

the final geometry of the subsidence area is quite

varied, depending on ... resistance ore;

resistance overburden;

presence of significant structural features (e.g., dykes, faults);

depth of mining;

natural slope of the surface.


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Examples of subsidence - kimberlites in West Africa


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Examples of subsidence - Mine El Salvador, Chile


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Examples of subsidence - San Manuel Mine, USA


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higher production rate than any other method in underground-coal

High productivity

lower production cost of underground methods, side of the Longwall (e.g., production

costs of $ 6.0 / t in the Premier Mine-South Africa)

High recovery (90% or more), but with significant dilution

production (not development) runs for abatement; i.e. there is no need for drilling and

blasting

can be highly mechanized

good ventilation and security for workers

Advantages of Block Caving

Disadvantages of Block Caving

subsidence and collapse in large scale

high dilution

control resumption is critical to the success of the method

development is slow

costly operations of support

reduction and fragmentation difficult to predict and control

method with little flexibility and no selective

possibility of oxidation of the ore due to the long time of percolation water


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the International Caving Study (ICS) Stages I and II (ICS II sponsors:

Codelco Chile, De Beers Consolidated Mines, LKAB, Newcrest Mining

Limited, Northparkes Mines, Rio Tinto Technical Services, Sandvik

Tamrock, WMC Resources Limited);

the ICS I monograph, Block Caving Geomechanics, published by the

JKMRC, 2003;

Proceedings, MassMin 2000, Brisbane;

Proceedings, MassMin 2004, Santiago, and PowerPoint presentations

made to that conference;

Rock Mechanics for Underground Mining, 3rd edition, by B H G Brady and

E T Brown, 2004;

Block Caving Geomechanics by E T Brown;

Individual works of GP Chitombo, BA Eadie, GE Flores, NJ Harries, E

Hoek, The Karzulovic, DH Laubscher, The Logan, The Moss, IA and I

Oñederra Ross.

Important References …


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Date post:	29-May-2015
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Caving Underground Mining Methods (longwall, Sublevel caving, & Block caving)

Engineering