Augusta Gold-Antimony Mine

1

AUGUSTA GOLD-ANTIMONY MINE

Authors:

Melanie McCarthy

Andrew Fowler

Shane Marshall

Narrow Vein Mining Conference 2008

Contact:

Melanie McCarthy

AGD Operations Pty Ltd

PO Box 662

Heathcote Vic 3523

[email protected]

Ph 0407 633 540

Fax 03 5433 3976

mailto:[email protected]

2



Authors:

Melanie McCarthy

Mining Manager


PO Box 662

Heathcote Vic 3523

[email protected]

Andrew Fowler

Head Geologist


PO Box 662

Heathcote Vic 3523

[email protected]

Shane Marshall

Senior Mining Engineer


PO Box 662

Heathcote Vic 3523

[email protected]




3



List of Headings

Abstract

Introduction

Location and history

Geology and mineralisation

Resource estimation*

Mine development

Dilution and grade control

Ore drive development

Stoping

Dewatering

Ventilation

Geotechnical challenges

Process plant

Technical support

Personnel recruitment and retention

Conclusion

Acknowledgements

References

4

Abstract

The Augusta underground mine at Costerfield in Central Victoria has been in operation

since mid 2006, however AGD Operations Pty Ltd have explored and undertaken open

pit operations in the area for over 20 years. The high grade, narrow gold-antimony

orebody is being mined using both mechanised and hand held methods, to produce up to

70,000 tonnes per annum at ten grams per tonne gold and six per cent stibnite. AGD

Operations Pty Ltd processes the ore on site using gravity and flotation to produce two

products, a concentrate which is sold to Chinese smelters and a gravity concentrate which

is refined off-site. The circuit achieves up to thirty percent recovery of gold from gravity

methods. There are many challenges in the underground mine including an orebody with

an average width of 300 mm, very poor rock mass conditions in the host rock and

variable dips in the ore along strike, between 45 and 90 degrees. The upper levels of the

mine have been developed ready for stoping however their depths range from 20 to 70

metres below surface in both oxide and transitional material. A major fault structure

consisting of mud has been encountered underground and is associated with the orebody

causing very poor ground conditions, water inflow and requiring additional

reinforcement. The northern limit of the mine is defined by the proximity of historical

workings in the South Costerfield Mine, which is being continuously dewatered.

Introduction

Various gold-antimony deposits have been mined in the Costerfield gold-antimony field,

in Central Victoria, since its discovery in the 1860’s. Production has however been

sporadic, being highly dependent on metal prices and extractive technology

developments (Hazeldene, 2007). The AGD group has been actively exploring the area

since the 1980’s. During the mid 1990’s AGD mined the upper levels of the Brunswick

Deposit for oxide gold by open cut, then in 2001, began delineating the Augusta Deposit

under cover at the southern end of the field (Hazeldene, 2007). Mining began in 2006.

Location and History

The Costerfield Project is centred on the Costerfield township in Central Victoria, located

about ten kilometres northeast of Heathcote and 50 kilometres east of the City of

5

Bendigo. Heathcote is serviced from either Bendigo or Melbourne via the

McIvor/Northern Highway.

Small antimony deposits were first discovered and worked in 1853 in the Costerfield

area. It was not until 1860 that prospectors Coster, Field and Youle discovered the main

Costerfield Deposit comprising antimony sulphide (stibnite) with visible gold. The

Costerfield Mine and its associated deposits, Minerva and Bombay produced 14 761

ounces of gold and 21 804 tonnes of 40 per cent stibnite concentrate between 1860 and

1883 (Bannear, 1993).

Between 1904 and 1925, mines in the Costerfield area produced 114 131 tonnes of ore

for 63 445 ounces of gold and 25 768 tonnes of 49.8 percent stibnite concentrate.

Development of the Costerfield mine reached 309 metre depth.

Following a lull in production, the Costerfield Mine started producing again between

1934 and 1939. 1623 tonnes of Stibnite concentrate was produced during this period

under the management of Gold Exploration and Finance Company of Australia (WMC)

(Hazeldene, 2007).

A series of different operators explored and mined the area from 1939 to 1981 including

the South Costerfield Antimony and Gold Company, Victorian Antimony Mines Ltd.,

Mid East Minerals, Metals Investment Holdings, and Forsayth Mineral Exploration and

Costerfield Mining Pty Ltd. During this time production was comparatively limited

(Hazeldene, 2007).

In 1981 the Victorian Mines Department explored the area and discovered mineralisation

under shallow alluvial cover that was later defined as part of the Augusta Deposit.

Following discovery, and up until 2005, Federation Resources and Australian Gold

Development (AGD) delineated an ore reserve with Probable status of 204 000 tonnes at

10.9 grams per tonne gold and 5.7 percent stibnite. Open cut mining down to ten metres

below surface began in early 2006 and underground development began in mid 2006

(Hazeldene, 2007).

Geology and Mineralisation

The Costerfield Project is located in the Melbourne Zone of the Lachlan Fold Belt and is

divided structurally from the Bendigo Zone to the west by the crustal-scale discontinuity,

6

the Mount William Fault (Vandenberg et al., 2000). Mineralization in the west of the

Melbourne Zone is characterized by an association between gold and antimony

(Vandeberg et al., 2000). The Augusta Deposit comprises six mineralized veins that

predominantly dip to the west, south-west at approximately 60 degrees and strike north,

north-west. They are composed of massive stibnite with quartz, which occurs either

intermingled with the stibnite, as a stibnite/quartz breccia, or along the margins of the

stibnite as laminated quartz. Gold is commonly microscopic (< 20 microns) and is

generally included within stibnite grains. Free gold has been observed in the weathered

zone and also in some recent drill holes, below 100 m depth. (Figure 1). The

mineralization is interpreted as occurring in two episodes: first was a gold-in-arsenopyrite

phase, which was then followed by a stibnite-rich fluid that re-mobilised the gold and

included it within the stibnite (McArthur, 2005).

Geometrically, the veins are arranged in an en-echelon pattern, and are generally sub-

parallel. The largest of the veins, “E lode”, is continuously mineralized along a strike

length of approximately 400 metres, and is on average 298 mm with a grade of 52.4

grams per tonne gold and 29.2 percent stibnite (Figure 2,3).

Two veins are currently being mined: “E” lode and “W” lode. Both contain ore shoots

that plunge to the north at approximately 35 degrees (Figures 4,5). Maximum lode width

and grade observed in an ore shoot was 1750 mm of massive stibnite grading 28.6 grams

per tonne and 33.6 percent stibnite. The ore shoots are spatially correlated where the

lodes intersect major cross-cutting, un-mineralised structures that trend northeast-

southwest. These major crosscutting structures are highly sheared, containing up to a

metre of pug material and generally disrupting the hanging wall and/or foot wall across

several metres width. The cross-cutting structures do not significantly displace the lode

structures in a strike slip sense (dip slip displacement unknown). The maximum strike-

slip displacement observed is approximately six metres, however the mineralisation is

consistently observed to continue through and around this displacement, suggesting that

the mineralization post-dates the main phase of movement on these north-west striking

faults.

Grade and lode width appears to be distributed in an en-echelon arrangement. The ore

shoot in “W” lode, which is to the west and in the hanging wall of “E” lode, is offset to

7

the south, and continues significantly further down plunge than the ore shoot in “E” lode.

Furthermore, on a level, “W” lode starts to become ore grade at the approximate northing

where E lode becomes sub-economic.

The mineralization is hosted by the ubiquitous and largely featureless, Silurian

Costerfield Siltstone. Regionally, the siltstone is interpreted to form the core of an

Antiformal Dome, with the gold-antimony deposits occurring along the axis of the dome

(Edwards et al., 1998). In the Augusta Mine, the hinge of the major antiform has not been

observed. The bedding predominantly dips to the west-south-west, in a similar orientation

to the lodes, suggesting the Augusta Deposit was precipitated on the western limb of the

north, north-west striking antiform. There are exceptions where bedding is observed to be

rotated in the vicinity of faults. Mapping in the ore drives shows a gentle warping of

bedding near the lode structures with fold hinges plunging down the dip direction of the

bedding, approximately west, south-west. This suggests minor north-south compression,

possibly related to the mineralizing event.

Resource Estimation*

An updated Mineral Resource estimate for the Augusta Mine has been prepared. The data

set is as of 30 June 2008 and includes all recent diamond drilling and face sample

information and is reported depleted of development and stoping.

The summary Mineral Resource Table 1 is as follows and excludes the estimate for “N”

Lode that was completed in 2007. There has been no new data added to “N” Lode that

can yet be incorporated into a Mineral Resource estimate.

Diamond drill data has been loaded from the site databases and validated for downhole

surveys and assay information. Face samples have been spatially located to represent 3D

channel samples in their correct location. All mineralised intercepts have been coded by

lode and composited to the full thickness of the lode in each location. True widths have

been calculated for the diamond drill intercepts. For the face sample information the true

width is as measured at the face by the geological team.

The Mineral Resource estimate has been constructed using a 2D estimation methodology.

All data has been transformed to a common 2D plan. Metal accumulations (true width *

Au ppm and true width * Sb %) are calculated for each face sample or diamond drill

8

intercept. Block models for the face sampled or developed areas of the mine are 2.5

metre strike by five metres high. In the diamond drill areas the dimensions are 20 metres

strike by ten metres high. Two separate models were estimated for each data set then

combined together for reporting and mine planning purposes. The true thickness and

metal accumulations have been estimated by ordinary kriging. Variogram and search

ellipses were determined using the face sample information and scaled appropriately for

use in the diamond drill areas. Gold and antimony grades are back calculated by dividing

the accumulation by the estimated true thickness.

For each of “E” lode and “W” lode a series of structural domains were modelled that

define areas where the true dip and strike are similar. For each of these domains (seven

“E” lode domains and four “W” lode domains) a strike and dip correction factor is

calculated that can be utilised to calculate the corrected lode volume for each block.

Volumes, tonnes and grades diluted to a minimum width of 1.2 metres have been

calculated for each block. Density has been estimated based upon an historical regression

calculation with Sb % that has been consistently applied at Augusta mine.

The Mineral Resource has been classified based upon the quality of the estimates (slope

of regression of the estimate), the drilling density and more importantly demonstration of

continuity of the lodes. Areas that have been accessed by development top and bottom

have been classified as Measured Resource.

The Mineral Resource has been reported above a cutoff of 4.6 grams per tonne gold

equivalent (AuEq) (Aueq = Au + Sb *1.9) and at a minimum mining width of 1.2 metres.

The Mineral Resource is depleted for mining based upon surveys of underground

workings completed 30 June 2008 and estimates of the material yet to be recovered from

stoping areas.

In addition to the resource quoted above, there are some additional tonnes in the “N” lode

and “C” lode, however, currently there are no plans to mine these lodes.

*The information in this report as it relates to Resource Estimations was compiled by Mr.

Dean Fredericksen, MAusIMM, who is a consultant geologist to AGD operations, with

sufficient experience relevant to the style of mineralisation and type of deposit under

consideration and to the activity which he is undertaking to qualify as a Competent

9

Person as defined in the 2004 Edition of the ‘Australian Code for Reporting of

Exploration Results, Mineral Resources and Ore Reserves’.. Mr. Fredericksen consents

to the inclusion of this information in the form and context in which it appears in this

report.

Mine development

The Augusta mine is accessed via a boxcut which is formed from the original open pit

developed in 2006. A concrete pillar was installed in the base of the open pit prior to

underground development commencing. AGD Operations Pty Ltd worked with mining

contractors to operate a road header for the initial 50 metres of decline and one level to

“E” lode.

The initial mining of “E” lode for the 400 metre strike length was an exploration exercise

to prove up continuity of the lode along strike, since initial exploration drill spacing was

40 metres. “W” lode is 200 metres in strike length and was not considered to be a

significant contribution to production, but has since proven more consistent in lode width

and contains higher grades than “E” lode. The initial mining in the upper levels (one and

two level) was by air leg boring and bolting with some air scraper work, constructing a

2.4 metre wide by 2.8 metre high drive, and bogging with Toro 151 loaders. Water

flowing from the orebody and the created mud was a significant hazard especially in “E”

lode two level, where after 200 metres of advance the floor level had washed away up to

500 mm deep requiring road base to be continually brought in. During this time the four

metre wide by four metre high, one in seven spiral decline progressed with a single-boom

Atlas 126 jumbo, and cable bolting was required to be both drilled and installed out of a

tele handler basket. Bogging was performed by a Elphinstone R1700G loader.

In July 2007 a twin boom Atlas Copco M2D was commissioned for the decline, as well

as a single boom Atlas Copco H104 for the ore development. This enabled cable bolt

drilling to be performed with the jumbo and increased rates in decline and cross cut

development. At the same time the decline was re-designed to include long straights and

a 1:6.5 gradient. A Wagner MT 426 Truck is used to cart ore and waste to surface.

Difficult ground conditions were experienced at the entrance to four level “E” lode. The

entrance to 4 level “E” lode was at the intersection of a large fault and the rock mass

10

conditions were so poor that drill and blast methods were not used. An excavator was

taken underground and cut the profile of both north and south “E” lode drives for some

ten metres until the ground conditions improved. An excavator with a cutter head

installed was also trialed, and was able to cut the host rock easily. The intersection

required shotcrete, which was applied using dry application methods, as well as concrete

re-enforcement of the pillars, to ensure that it remained stable for the life of the level.

The decline is designed to be developed to ten level (120 metres below surface) and

further exploration drilling in 2008 has extended the life of mine to 18 level (190 metres

below surface) with “W” lode open at depth.

Dilution and grade control

The mine classifies ore as stope, high and low grade and stockpiles them separately.

Grade is controlled by the shift supervisor in close consultation with the mine geologist

and shift samplers. For the ore drives, samplers visit each face on a daily basis and advise

the shift supervisor of the predicted grade based on measurements of the lode width,

quartz content and the width of the drive. Refer to Figure 6.

For stoping, the grade and width of the lode in the stope panel is estimated by the mine

geologist when it is designed. The estimation is based on the face samples in the drives

above and below the stope panel. As the stope is mined, the samplers, mine geologist and

production engineer monitor the stope width and dilute the lode grade accordingly.

Ore drive development

In late 2007 to reduce dilution, part-facing was trialed in ore development. This involved

positioning the ore on one side of the drive, and using the ore contact as the hanging wall.

The waste was bored out and fired, and the waste cut width dimension being such that the

1.4 metre wide Toro buckets could bog the majority of the waste from the face. Refer

Figure 7. The ore was then stripped in. Experimentation with boring on the hangingwall

contact or in the ore was trialed, as the former resulted in large lumps of stibnite greater

than the process plant grizzly aperture of 250 mm, and would require secondary breakage

with a rock breaker. The increase in grade delivered to the mill was significant, however

full face mining has since resumed due to a number of issues. The number of faces on

line to enable efficient part facing is at least ten, to enable flexibility with the mid shift

and end of shift firings being undertaken. The ore stripping cut took less than an hour to

11

bore and charge, but the face would remain idle until firing time. The drives would

generally result in widths greater than the 2.4 metre design, to enable the loader bucket to

fit in beside the ore. This required more waste movement. The positioning of the ore as

the hanging wall also posed problems for the production drill rig, as it required at least

250 mm additional room to drill on the correct angle for stoping. After the part facing

trial, the ore drive width dimension was reduced to 2.2 metres and part facing is now

implemented only when the ore width in the face would result in low grade being

delivered to the mill.

“W” lode development is a challenge as its average dip is 50 degrees. Sublevels are

developed so that at least a 1:1 pillar is the result along the dip of the ore. Shanty back

profiles are mined. There is significant survey control required when developing “W”

lode to ensure the drives do not interact. All ore drives are normally developed under

geological control but in “W” lode a laser is used to control both the development line

and grade. The level drives are advanced at least 20 metres in front of sub levels as an

additional control to ensure the drives do not interact.

Stoping

Geotechnical consultants in both the feasibility stage and initial development stage were

skeptical whether short bench stoping over any length of hanging wall expanse would be

possible. The mine was scheduled to assume that short bench stopes were possible and a

level spacing of ten metres floor to floor on “E” lode was planned. Trial stoping

commenced on “E” lode in January 2008, in an area that ranged from 67 to 65 degrees

dip. The production drill rig being used is a Boart Longyear Stopemate which has a

shorter feed cylinder installed so that in the narrow drives it can achieve 360 degrees

movement. “E” lode on three level south was stoped in the initial six months of 2008,

with the trial parameters changing as stope performance was assessed. Initially drill

patterns were dice five, with holes in the footwall, hanging wall and in the ore. Fifty

percent strength ANFO was used for all firings including the initial slot. For the first

stope in three Level “E” lode, the initial slot dimensions were 1.2 metre square, and this

and subsequent firings were encouraging as they resulted in a stope width matching

design of 1.2 metres. However, once the stope was open for approximately eight metres

along strike, parallel beds of mudstone within the hanging wall would slide off under

12

gravity, and cause in some cases stope widths of in excess of 3 metres. Minimal

overbreak occurred on the footwall. The loaders operators were able to bog these large

slabs and stockpile them separate to the ore in some cases. Extensive cable bolting of the

hanging wall was trialed, at less than favourable orientations achievable from the drill

and extraction drives. W strapping and cable bolt tensioning was completed and stopes

fired with this extra support installed. However, in most cases the hanging wall

continued to fail under gravity around the cables. Geotechnical consultants indicated that

the transitional and weathered nature of the rockmass was partly the cause of cable bolts

being unable to hold the hangingwall.

Stoping in “W” lode where the rock mass is generally blockier than “E” lode has had

success in achieving better than the predicted stope widths of 1.2 metres wide. Current

drill and blast methods are successfully achieving 700 mm average stope width over 15

metres open along strike. Refer to Figure 8. Hole spacing is 400 mm with one hole

rings drilled 100 mm into the footwall. Generally holes must be lined with poly as they

squash after 24 to 48 hours of being drilled. In each firing the next hole behind is

damaged and is providing a shadowing effect, so essentially a burden of 800 mm is being

fired each firing. Hole diameter is 57mm charged with a fifty percent strength ANFO

product. Ore is bogged and backfilled immediately with waste. A void must be created

on the free face to allow successful firing of the narrow 700 mm wide stope. Further

work with different backfill materials including cemented fill, is currently ongoing in an

attempt to increase recovery and reduce dilution.

Dewatering

The South Costerfield mine included workings on the modern “E” lode and is dewatered

to 65 metres below surface, the mine workings being approximately 60 metres from the

northernmost extent of the Augusta Mine workings. An evaporation dam with 40ML

capacity holds any excess mine water, surface storm water and South Costerfield shaft

water and is set up with sprays to increase evaporation. The mine has recently reached

below the depth of the South Costerfield shaft pump and has experienced between five to

eight litres per second inflow from both the decline and ore headings, as water is

transferred along the lodes and through fault zones. The host mudstone does not transmit

13

water. The current mine plan is to push the decline to ten level and cross cut to the lode

structures in an attempt to dewater the lodes prior to extensive mining of the lower levels.

Ventilation

Primary ventilation is provided by a 110kW axial fan installed underground at one level.

An overpass arrangement was designed and constructed so that air lock ventilation doors

would not be required, as access to the magazine requires personnel to travel past the

primary fan chamber and return airway infrastructure.

Primary ventilation upcast shafts are approximately three metres in diameter and also act

as the second means of egress. The primary fan has been installed with the capability of

reversing it in the event it is required to be downcast. Secondary ventilation is currently

being supplied by 75kW axial fans and a 110kW centrifugal fan located on surface,

which was the dust extraction fan when the road header was in operation. Ventilation

testing is performed by the geology samplers along with remote re-entry time monitoring

and Nox personal Draeger tube testing of loader operators. Results are communicated to

operators personally and published on notice boards.

Geotechnical challenges

Augusta mine previously used contract geotechnical expertise for monthly inspections

and ground support design and has recently employed a part-time geotechnical engineer.

Mesh is installed to grade-line in all areas, and in poor ground faces are required to be

meshed before boring and charging can occur. Bedding is generally parallel with the

lode and cross cutting structures cause hanging wall failure in stopes. These structures

are identified during initial mapping and have a quartz/calcite infill, making blocks slip

under gravity when exposed. The lodes are associated with a major mud shear /fault zone

which dips north west. The faults contain puggy shear zones and polished fault surfaces.

Regions where the “mud” fault are intersected are also hazardous due to the mud

crumbling after it has dried out back from the advancing face, which usually requires

rehabilitation. It is anticipated that mining and stoping “W” lode at depth will be

problematic and a current study is whether or not dry fibrecrete can be utilized for safe

and efficient narrow vein mining.

14

Process Plant

Process plant design head grade is six percent Stibnite and fifteen grams per tonne gold

and a throughput 75 000 tonne per annum (15 tonne per hour). The grizzly aperture is

250 mm. The grinding circuit consists of two ball mills and achieves p80 of 106 micron.

Gravity circuit recovery is up to thirty per cent of the total feed gold, and incorporates

spirals on the cyclone underflows from both milling circuits. The spiral concentrate

reports to a Knelson concentrator which is tabled. The flotation section incorporates two

stages of cleaning to produce a concentrate assaying 52 percent Stibnite and 60 grams per

tonne gold. Flotation concentrate is filtered and bulka bagged then shipped to customers

in China. Penalties occur for any concentrates below 52 percent Stibnite. 75 percent of

the concentrate produced is sold under contract and the operation is currently reviewing

options for the remainder to be sold to a different customer.

Technical support

The mine technical staff consist of head geologist, mine geologist and two samplers who

work dayshift only, senior mining engineer and recently a mine production engineer and

two mine surveyors working an eight and six roster.

Personnel recruitment and retention

AGD Operations Pty Ltd has a labour and equipment hire contract with a mining

contractor, and the contract specifies that personnel are to be sourced from the local area.

The towns of Seymour, Heathcote and other smaller communities are targeted for

potential recruitment of heavy mobile equipment operators who are usually well suited to

underground mining. A personnel bus is run from Bendigo for the shift workers who

work seven on seven off, 12 hour continuous day and night shifts. All supervision,

training and personnel development is provided by AGD Operations and employee

turnover is very low. The underground mining crews are between eight and ten people

who are required to be multi-skilled. This provides an opportunity to learn hand held

mining methods, loader and truck operations, development and production charging,

production drilling and jumbo operations in a relatively short time compared to larger

mines.

Conclusion

Augusta mine is successful in mining a difficult orebody in transitional material.

15

The “W” lode stoping is proving better than ore reserve assumptions of a 1.2 metre stope

width and a significant reduction in dilution has been achieved. Further work is planned

to quantify dilution being bogged against fill and trialling different filling methods to

reduce dilution. Mechanisation of the underground mine has a further step to go, to

remove the operator from hand held bolting if at all possible. Geotechnically the orebody

is challenging and may involve an improved method of ground support at depth. The

“W” lode orebody is the widest and richest lode and is currently open along strike and at

depth.

Acknowledgements

The authors wish to acknowledge AGD Operations Pty Ltd and its parent Cambrian

Mining plc for enabling this paper to be published.

16

References

Bannear, D., 1993. North Central Goldfields Project, Historic Mining Sites in the

Heathcote (Waranga South) Mining Division, Part two: Site Gazetteer, Department of

Conservation and Natural Resources, North West Area.

Edwards, J., Wohlt, K.E., Slater, K.R. Olshina, A. Hutchison, D.F. 1998. Heathcote, and

parts of Woodend & Echuca. 1:100,000 Map Area Geological Report, Geological Survey

Report No. 108.

Hazeldene, R.K., 2007. MIN 4644, EL 3310, & 4848, Costerfield Project. Annual

Technical Report for the Period 1 July 2006 to 30 June 2007. AGD Operations Pty. Ltd.

Report.

McArthur, G., 2005. AGD Operations Pty. Ltd. Augusta Project, Costerfield Sb/Au

Mineragraphy.

Vandenberg, A.H.M., Willman, C.E., Maher, S., Simons, B.A., Cayley, R.A., Taylor,

D.H., Morand, V.J., Moore, D.H. & Radojkovic, A., 2000. The Tasman Fold Belt System

in Victoria. Geol. Surv. Vict. Special Publication.

17



Table 1 – Summary of “E” and “W” lode mineral resources*

Augusta Grade Contained Metal

Category Tonnes

Au

ppm Sb%

Au

Eq

Undiluted

True Thick

(m)

Au

(Oz's)

Sb

(Tonne)

Measured

66,000

18.2

10.5

38.2 0.42

39,000

7,000

Indicated

180,000

11.7

5.9

23.0 0.42

67,000

10,700

Inferred

85,000

4.8

2.5

9.5 0.38

13,000

2,100

Total

331,000

11.4

6.1

23.0 0.41

119,000

19,800

18



List of Figure and Table captions

Figure 1. Elode, MH070 128.8m down hole, Sample: P553101

Assay results: 113 g/t Au, 30.6 % Sb.

Photo: 7465, Digital image, Objective: 20X, Light: Reflected, Nicols: Uncrossed

Figure 2. Elode, 2 Level, north drive: 4567mN in Costerfield Mine Grid.

Looking north.

Figure 3. Schematic cross section through the Augusta Deposit on 4400mN in Costerfield Mine Grid. Looking north

Figure 4. Long section of the E Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t

Au equivalent are displayed. In Costerfield Mine Grid

Figure 5. Long section of the W Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t


Table 1 – Summary of “E” and “W” lode mineral resources*

Figure 6: Example of a grade control chart currently being used underground for a shanty-back ore drive profile

Figure 7: Part face example from W Lode showing fired mullock and ore intact, 1 level at 4361mN, looking south.

Figure 8: Example of a stope taken looking down from W4 sub level at 4335mN. Stope was 3.5m high from backs to floor

and open 15 metres along strike

Qz

0.6m

19

Figure 1. Elode, MH070 128.8m down hole, Sample: P553101

Assay results: 113 g/t Au, 30.6 % Sb.

Photo: 7465, Digital image, Objective: 20X, Light: Reflected, Nicols: Uncrossed

Figure 2. Elode, 2 Level, north drive: 4567mN in Costerfield Mine Grid.

Looking north.

20

Figure 3. Schematic cross section through the Augusta Deposit on 4400mN in Costerfield Mine Grid. Looking north

21

Figure 4. Long section of the E Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t Au

equivalent are displayed. In Costerfield Mine Grid

22

Figure 5. Long section of the W Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t



23

Figure 7: Part face example from W Lode, 1 level at 4361mN in Costerfield Mine Grid, looking south.

24

Figure 8: Example of a stope taken looking down from W4 sub level at 4335mN. Stope was 3.5m high from backs to floor.

Figure 1. Elode, MH070 128.8m down hole, Sample: P553101 Assay results: 113 g/t Au, 30.6 % Sb. Photo: 7465, Digital image, Objective: 20X, Light: Reflected, Nicols: Uncrossed

Figure 2. Elode, 2 Level, north drive: 4567mN in Costerfield Mine Grid. Looking north.

330µm

Sb

Au

Qz

Massive Stibnite

270mm @ 75.6 g/t Au,

34.2 % Sb

Barren Siltstone

Barren

Siltstone

0.6m

Figure 3. Long section of the E Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t Au equivalent are displayed. In Costerfield Mine Grid

Figure 4. Long section of the W Lode block model estimated by D. Fredericksen in July 2008. Only blocks above 4.6 g/t Au equivalent are displayed. In Costerfield Mine Grid


Figure 6: Part face example from W Lode showing fired mullock and ore intact, 1 level at 4361mN, looking south.

2.6m

3.3m

mullock

lode

Figure 7: Example of a stope taken looking down from W4 sub level at 4335mN. Stope was 3.5m high from backs to floor and open 15 metres along strike

~ 400mm

lode width

~ 600mm

stope width

Date post:	17-Nov-2023
Category:	Documents
Upload:	independent
View:	0 times
Download:	0 times

Augusta Gold-Antimony Mine

Documents