Successful discovery of new open pit or shallow underground deposits will complement existing resources and provide the impetus to recommence mining activities at Wiluna.
Historical production indicates these quartz reefs are free-milling gold with good recoveries and low processing costs.
This will follow on its recent drilling at the Galaxy quartz reef, which returned shallow high grade deposits:
- 9 metres at 13.4 grams per tonne gold from 73 metres including 4 metres at 27.9g/t gold;
- 2 metres at 28.9g/t gold from 23 metres;
- 6 metres at 8.82g/t gold from 13 metres;
- 4 metres at 19.6g/t gold from 37 metres including 1 metre at 43.3g/t gold; and
- 4 metres at 8.68g/t gold from 4 metres.
Further drilling is planned to test the extensions of Galaxy and the resource estimate is in the process of being updated.
A program of metallurgical test work is being developed and mining studies over the Galaxy deposit have commenced.
The additional high grade mineralisation encountered both at surface and at the base of the optimised pit should provide improved mining economics, making Galaxy an attractive feed for re-commissioning the Wiluna Gold Plant.
Further Quartz Reef Targets
Early gold production in the Wiluna district came from quartz reefs, exploited at shallow levels where supergene enrichment of gold grades occurred and water ingress was manageable.
The surface expression of these shoots has been worked by artisanal miners during the early 1900's though limited production records are available.
Despite this, the quartz reef systems have had very little systematic exploration in modern times .
There are 3 main quartz reef trends: predominant northwest (stratigraphy parallel) reefs, and minor north northwest and East-West reefs.
The free milling quartz reefs formed prior to the main refractory gold event and have been affected by the latter mineralising event and late-stage faulting.
Blackham geologists have developed several exploration targets around the Golden Age mine and along the "Caledonian Reef System", situated between the Galaxy and Golden Age deposits.
This was achieved using existing shallow rotary air blast and reverse circulation drilling data, geochemistry, regolith interpretation, aeromagnetic structural interpretations and historical mine records.
Golden Age Reef
The Golden Age Reef demonstrates the potential for high-grade, free-milling mineralisation in the Wiluna district to yield significant quartz reef deposits at depth.
It has produced 160,000 ounces of gold at a head grade of 9g/t and was still being mined when the plant shut in June 2013.
This is the only portion of the extensive quartz reef system that has been systematically explored to below depths of 70 metres.
The Golden Age underground mine was only discovered because it terminates up against East Lode Fault which was being mined at the time.
Golden Age Reef will be targeted along strike, at depth, at shallow levels, and off-set positions across the East Lode Fault and Creek Shear.
It is open up- and down-dip and along strike to the east.
Along strike, multiple zones in some holes east of the existing underground development indicates the presence of a proximal hanging wall lode that has not been adequately drill tested nor mined.
Attractive intersections in two holes over 200 metres below the existing underground development indicates potential for the reef to pinch and swell again into wider lenses at depth.
The Brothers Reef is situated 200 metres northeast of the Golden Age Reef and can be traced in outcrop for approximately 1 kilometre.
Historically about 2,100 ounces of gold at 26.8g/t gold was produced from artisanal workings to a depth of 50 metres below the surface over a strike length of 250 metres.
The north-western extent of the Brothers Reef is a priority target where the reef is dragged into the East Lode Fault- analogous with the Golden Age deposit.
The Caledonian Reef system is interpreted as the offset portion of the Golden Age Reef and extends in outcrop for over 3 kilometres.
Targets are higher-grade shoots and intersections between the reef and N-S and NW-SE cross- structures
Recorded gold production from various historical artisanal workings totals 3,500 tonnes at 30g/t for 3,400 ounces, with additional production from the historical Lake Way gold mine estimated to be about 15,000 ounces.
These artisanal workings have been mined to a depth of 50 metres with very limited drilling below these levels.
In modern times, the Caledonian pit produced 27,980 tonnes at 2.79g/t with high grade shoots modelled beneath the pit.
Lake Violet Reefs
The Lake Violet Reefs lie to the north of Lake Violet, trending northwest and are interpreted to be extensions of Golden Age and Republic.
Anomalous results were returned from rotary air blast and aircore drilling in the 1990's.
During 2002, follow-up reverse circulation drilling intersected oxidised quartz veins with moderate-tenor gold grades. The reefs are untested at down-plunge and along strike.
The Lawless Reef is situated southeast of the East Lode pit.
The reef was worked historically by artisanal miners and more recently open pit mining produced 375,000 at 2.73g/t for 33,000 ounces.
Drilling will target the high-grade pod of mineralisation intersected in ELN0035 (12 metres at 29.2g/t from 84 metres).
That Blackham has identified five priority high grade targets in close proximity to the Wiluna Gold Plant highlights the prospectivity of the area.
With historical production reports indicating these quartz reefs are free-milling gold with good recoveries and low processing costs is a significant plus for project economics.
This will in turn lead to near term cash flow from the plant, which has a capacity of 1.1 - 1.5 Mtpa and is able to treat oxide ores for production of 80,000-100,000 ounces of gold annually.
This provides further momentum for Blackham and additional share price catalysts that look likely to propel the share price further.
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