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Blackham Resources has potential open pit gold at Brothers Reef

Published: 10:30 03 Oct 2014 BST

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Blackham Resources (ASX:BLK) has identified open pit potential at its Brothers Reef deposit that is located in close proximity to its Wiluna Gold Plant in Western Australia with drilling recording shallow oxide mineralisation.

Initial results include 20 metres at 1.28 grams per tonne gold from 44 metres and 4 metres at 4.58g/t gold from 68 metres.

Underground targets have also been defined on Brothers and Republic reefs adjacent to the Golden Age reef that already has underground mine development in place.

Brothers, Republic, Golden Age and Galaxy are free-milling gold targets within open pit or shallow underground depths and in close proximity to the Wiluna Gold Plant.    

Discovering new deposits that match these criteria will complement existing resources and provide the impetus to recommence mining activities at Wiluna.

Brothers and Republic reefs rank as high-priority exploration targets owing to their proximity to existing mine infrastructure, and their analogous structure relative to the Golden Age reef which produced 160,000 ounces gold at a head grade of 9g/t.

The Republic and Brothers reefs are situated just 250 metres above and 150 metres below the Golden Age reef, respectively, yet have received little systematic exploration below 70 metres from surface. 

Golden Age is open up- and down-dip and along strike to the east, and will be targeted along strike, at depth, and at shallow levels.

Infill and extensional had recently found high grade, open pittable gold at the Galaxy deposit with results including 5 metres at 2.02g/t gold from 96 metres and 1 metre at 8.63g/t from 30 metre.

Brothers Reef Open-Pit Target


Blackham drilled three reverse circulation holes totalling 306 metres to target the Brothers Reef inflection zone where it intersects a mineralised NE-SW trending shear zone, and the NE-SW trending shear zone.

The intersection of the Brothers Reef and the NE-SW trending shear zone is an analogous structural position to the Golden Age North resource area, which has an Inferred and Indicated Resource of 519,000 tonnes at 2.1g/t for 36,000 ounces of gold.

On the Golden Age reef, NE-SW structures are known to upgrade the pre-existing quartz reef mineralisation where they intersect; these latest results from surface drilling at Brothers suggest that similar up-graded zones may be found at depth with further drilling.

BRRC0002 intersected broad zones of potentially economic quartz reef and peripheral mineralisation of 4 metres at 1.35g/t from 20 metres, 20 metres at 1.28g/t from 44 metres and 4 metres at 4.58g/t from 68 metres. 

These are 4 metre composite samples, which may reveal higher-grade narrower zones when 1 metre samples are assayed.

Further drilling will follow up the quartz reef intersections in BRRC0002 and the NE-SW structure.

Brothers and Republic Reef Underground Targets

The Republic, Brothers and Golden Age reefs were mined historically as high-grade shallow underground mines in the early 1900’s, and remnant resources on the Republic and Golden Age reefs were mined as small oxide pits during the early 1990’s. 

The majority of historical drilling has targeted the shallow oxide portion of the reefs, although many holes yielded disappointing results, having intersected stoped areas or low-tenor zones between the mined ore shoots.

 Despite the lack of deeper drilling, holes that have targeted other nearby resource areas have also produced sporadic hits on passing through the Republic and Brothers lodes at depth.

The Golden Age reef was best-endowed close to the East Lode Fault and associated splay faults, which thickened the reef and introduced a second pulse of gold-bearing fluids. 

Interaction with the East Lode fault also resulted in a flatter-dipping orientation in areas of high-grade. 

Analogous flatter-dipping sections of the Republic and Brothers reefs will be targeted initially with diamond core drilling from surface, and from underground drilling sites around the existing Golden Age mine development.

Golden Age Mine Extensions

The Golden Age mine demonstrates the potential for high-grade, free-milling quartz reef deposits in the Wiluna district to yield significant ore bodies at depth, and was still being mined when the plant shut in June 2013. 

This is the only portion of the extensive quartz reef system at Wiluna that has been systematically explored to below depths of 70 metres. 

Golden Age was only discovered as it terminates against the East Lode Fault which was being mined at the time, rather than through systematic exploration.

The shallow portions of the reef as tested from underground are situated 400 metres below surface and more than 200 metres below the surface holes drilled around the Golden Age historical artisanal workings.

Attractive intersections of more than 200 metres below the existing underground development indicate potential for the reef to pinch and swell again into wider lenses at depth.

Analysis

Blackham Resource’s intersection of shallow oxide mineralisation over widths amendable to open pit mining at the Brothers Reef deposit is encouraging as it could complement existing resources, leading to a restart of mining activities at Wiluna.

It also validates the company’s exploration focus on free milling targets that are within open pit or shallow underground depths and in close proximity to the Wiluna gold plant.    

Exploration is expected to continue on the targets that show good prospects for high grade mineralisation that if successful could be added to the mine plan in the near term.

The aim is to bring the 100,000 ounce per annum Wiluna Gold Plant into production before the end of 2015 and building a 5 year-plus mine plan.

Proactive Investors has calculated a 12 month share price target of $0.23 - $0.27 based on the continuing exploration success at Matilda.



Proactive Investors Australia is the market leader in producing news, articles and research reports on ASX “Small and Mid-cap” stocks with distribution in Australia, UK, North America and Hong Kong / China.

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