AUGUSTA GOLD-ANTIMONY MINE. Narrow Vein Mining Conference 2008

Transcription

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 Ph Fax

2 AUGUSTA GOLD-ANTIMONY MINE Narrow Vein Mining Conference 2008 Authors: Melanie McCarthy Mining Manager AGD Operations Pty Ltd PO Box 662 Heathcote Vic 3523 Andrew Fowler Head Geologist AGD Operations Pty Ltd PO Box 662 Heathcote Vic 3523 Shane Marshall Senior Mining Engineer AGD Operations Pty Ltd PO Box 662 Heathcote Vic

3 AUGUSTA GOLD-ANTIMONY MINE Narrow Vein Mining Conference 2008 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 3

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 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 4

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 ounces of gold and tonnes of 40 per cent stibnite concentrate between 1860 and 1883 (Bannear, 1993). Between 1904 and 1925, mines in the Costerfield area produced tonnes of ore for ounces of gold and 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 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 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, 5

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 subparallel. 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 northeastsouthwest. 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 strikeslip 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 6

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 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 7

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 8

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 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 9

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 10

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 11

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 12

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. 13

14 Process Plant Process plant design head grade is six percent Stibnite and fifteen grams per tonne gold and a throughput 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. 14

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. 15

16 References Bannear, D., 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 Heathcote, and parts of Woodend & Echuca. 1:100,000 Map Area Geological Report, Geological Survey Report No Hazeldene, R.K., MIN 4644, EL 3310, & 4848, Costerfield Project. Annual Technical Report for the Period 1 July 2006 to 30 June AGD Operations Pty. Ltd. Report. McArthur, G., 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., The Tasman Fold Belt System in Victoria. Geol. Surv. Vict. Special Publication. 16

17 AUGUSTA GOLD-ANTIMONY MINE Narrow Vein Mining Conference 2008 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 7,000 Indicated 180, ,000 10,700 Inferred 85, ,000 2,100 Total 331, ,000 19,800 17

18 AUGUSTA GOLD-ANTIMONY MINE Narrow Vein Mining Conference 2008 List of Figure and Table captions Figure 1. Elode, MH m down hole, Sample: P Assay results: 113 g/t Au, 30.6 % Sb. Qz 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 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 Only blocks above 4.6 g/t Au equivalent are displayed. In Costerfield Mine Grid 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 0.6m W4 sub level at 4335mN. Stope was 3.5m high from backs to floor and open 15 metres along strike 18

19 Figure 1. Elode, MH m down hole, Sample: P 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. 19

20 Figure 3. Schematic cross section through the Augusta Deposit on 4400mN in Costerfield Mine Grid. Looking north 20

21 Figure 4. Long section of the E Lode block model estimated by D. Fredericksen in July Only blocks above 4.6 g/t Au equivalent are displayed. In Costerfield Mine Grid 21

22 Figure 5. Long section of the W Lode block model estimated by D. Fredericksen in July Only blocks above 4.6 g/t Au equivalent are displayed. In Costerfield Mine Grid Figure 6: Example of a grade control chart currently being used underground for a shanty-back ore drive profile 22

23 Figure 7: Part face example from W Lode, 1 level at 4361mN in Costerfield Mine Grid, looking south. 23

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. 24

25 Sb Au Qz 330µm Figure 1. Elode, MH m down hole, Sample: P Assay results: 113 g/t Au, 30.6 % Sb. Photo: 7465, Digital image, Objective: 20X, Light: Reflected, Nicols: Uncrossed Barren Siltstone Massive Stibnite 75.6 g/t Au, 34.2 % Sb Barren Siltstone 0.6m Figure 2. Elode, 2 Level, north drive: 4567mN in Costerfield Mine Grid. Looking north.

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

27 Figure 5: Example of a grade control chart currently being used underground for a shanty-back ore drive profile lode 3.3m mullock 2.6m Figure 6: Part face example from W Lode showing fired mullock and ore intact, 1 level at 4361mN, looking south.

28 ~ 600mm stope width ~ 400mm lode width 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