AUZ purchase the head lease to the East Location 45 freehold block of 110 m2 in july 2007, but did not gain control of the Mt Martin gold mine until January 2010 when an existing sublease arrangement expired.
Since gaining control of Mt Martin the company has been actively interpreting the gold system and has now drilled 8 deep diamond holes plus 18 RC holes to increase the gold resources.
Historic Gold Production
Mt Martin gold mine has produced to date approximately 200,000 ounces of gold from intermittent mining dating back to 1923.
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Gold ore was initially produced from a set of 4 shafts with the deepest underground workings at the 6 level which is 165 metres below the surface.
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- In 2009-2010 Dioro Exploration N.L steepened the ramp and mined down to a maximum depth of 115 metres in the central portion of the pit, to recover 743,223 tonnes of ore grading 1.5 g/t for 31,231 ozs of gold.
Geology
The Mt Martin Fault system is interpreted to be a first order splay off the regional ‘Woolibar to Boorara Shear’ , and at the Mt Martin gold mine the host lithology is a series of folded and faulted ultramafic flow units.
Ore has been mined from two north trending systems , namely the ‘Main Shear Lodes’ and the ‘East Shear Lode’ plus orehoots along the north west trending splay known as the ‘West Shear Lodes’.
The gold shoots are hosted in ultramafic rocks which have been altered and silicified by quartz veining and ore bearing fluids, such that the ground conditions are judged to be suitable for mechanised mining.
Figure 1: Mt Martin surface geology plan
Main Lode potential
The bulk of the current resources are located on the ‘Main Shear Lodes’, which are interpreted as a series of stacked ore lenses which have been mined selectively from high grade underground airleg stopes.
The current pit has mined the Main Shoot lenses to below the 4 Level, and there is sufficient diamond drilling to suggest that bulk mining of the remnant resource may be feasible.
The Australian Mines diamond drilling programmes have supported the model and geotechnical logging of the holes has demonstrated that the ground conditions are good.
The resource model will be refined to include the recent drilling and a mining optimisation study is being progressed.
Figure: Main Lode intercepts from AUZ diamond drillholes.
East Lode Potential
The ‘East Shear Lode’, is interpreted to be a continuous ore surface which has been mined selectively by high grade underground airleg stoping from above the 6 Level.
The Australian Mines diamond drilling programme has extended the resource model at depth and geotechnical logging of the holes has demonstrated that the ground conditions are moderate to good.
A pattern of 6 infill diamond holes for 1,100 metres is currently being drilled from the pit floor to further test the East Lode, which may have the potential to support an underground mining operation.
Table: East Lode intercepts from AUZ diamond drillholes.
Future Work
The company is pushing to build up mining reserves at Mt Martin and to this effect the following programmes are underway:
- The resource model is being updated
- An open pit optimisation study will be completed
- A programme of 6 diamond holes for 1,100 metres is currently being drilled from the pit floor to increase the drill density on East Lode ore located below the 6 level.
- A programme of 13 shallow RC holes for 400 metres was drilled at the historic East Lode pit, which was mined to a maximum depth of 13 metres.(results awaited)
Figure: Oblique cross-section (20m slice) through Mt Martin with selected drill intercepts and mining potential highlighted.
Gold Resources
(a) Mt Martin Gold Mine
The lode system at Mt Martin was interpreted and wireframed around > 0.5g/t material in Surpac mining software by Australian Mines Limited and a consulting resource geologist from ‘CSA Global’ was engaged to construct the graded block model. Grade in the ore blocks was interpolated from assays derived from 183 diamond and 1,427 RC drillholes utilising ‘ordinary krieging.
(b) Swift Resource
The Swift Pit is located near the southern end of the Mt martin pit on a shear which is interpreted to be parallel to the main shear system.
A shallow oxide pit has been mined to a depth of 13 metres, and previous operators have drilled a close spaced pattern of RC grade control holes into the oxide ore below the pit floor.
The remnant oxide resource at Swift is tabled below:
Table: Swift gold resource_ february 2010
Figure: Swift pit cross section with drillholes and down plunge potential.
Near Surface Exploration at East Lode Pit
Phase 1 drilling
Five RC holes were drilled on two sections immediately north-east of the shallow East Lode pit, which is located approximately100 metres east of the main Mt Martin Pit.
The drill lines were spaced 15 metres apart along strike so as to test for possible extensions to the near surface oxide ore which was historically mined from the East lode Pit.
Results from the recently completed RC programme are tabled behind:
The recently completed optimisation study has indicated that an open pit mine would make a significant profit with various treatment options producing 50,000 - 60,000 ozs of Au at a gold price of A$1,300/oz
Encouraging results have been received from recent drilling of East Shear North
exploration target which lies to the east of the main Mt Martin pit.
Australian Mines Limited (ASX:AUZ) is pleased to announce an increase of approximately 50% in gold resources at the Mt Martin mine.
Australian Mines Limited (ASX:AUZ) is pleased to announce that surface drilling will recommence at Mt Martin on Monday 14th June 2010 to further define new resources at Mt Martin.
Australian Mines Limited (ASX:AUZ) is pleased to announce very encouraging results from its latest RC drilling under the East Lode pit at the Mt Martin Project
AUZ Mines which announced encouraging results on 6th April from drilling its 100% owned Mt Martin gold project will be recommencing drilling this week.