TRIAL mining and processing by ABM Resources at the Old Pirate Gold Project in the Northern Territory has proved successful with head grades exceeding expectation and tail grades indicating high rates of in-plant recovery from gravity only processing. The company expected to wind up the trial by the end of December.

Coarse gold in pan concentrate from a drill hole at ABM Resources’ Old Pirate Northern Extensions.
Coarse gold in pan concentrate from a drill hole at ABM Resources’ Old Pirate Northern Extensions.

By mid-November more than 5000 tonnes of the stage one trial processing had been completed and based on daily throughput of 180-220 tonnes, ABM expected to complete the trial processing by mid-December.

The company has been conducting weekly gold shipments since early October. By mid-November about 1200 ounces of gold valued at about Aus$1.7 million had been delivered to the Perth Mint Refinery. In addition a further 4kg of high-grade gold concentrate had been produced from 400 tonnes processed since the previous shipment.

The head grade and tail assaying lag production by about two weeks due to laboratory sample turn-around times but information received by ABM continues to show strong in-plant recoveries averaging 91%.

By mid-November the gold in circuit was building-up, principally in the ball mill. The build-up was then estimated at 945 ounces, which is considered standard in the early stages of gold processing, especially for material with a high free/gravity gold content for similar reasons that makes the project amenable to gravity recovery as the principal processing method.

Overall gold out-turns were increasing as gold in circuit built up and approached steady state. Following completion of the trial processing, the ball mill will be stripped clean and final reconciliations will be possible.

The company has mined the 10,000 tonne trial parcel of gold-bearing material from the numerous trial pits including Golden Hind, Old Pirate South, East-Side veins, SE Veins, Old Pirate Central/Eastern Limb and the Western Limb. This included about 7000-8000 tonnes of material extracted on the basis of known mineralization, and a further 2000-3000 tonnes of material not previously thought to be mineralized, where re-sampling determined a gold content between 5 and 15 grams/tonne.

Trial mining has revealed a number of new structures and has improved understanding of the detailed shape, orientation and thickness variation of the mineralized veins. The plunge of various high-grade zones is slightly shallower than previously thought, around 20 degree southerly plunge. These observations will improve targeting of near surface high-grade extensions to potentially increase open pit resource areas.

ABM is now updating its existing models and open-pit optimizations to reflect the increased knowledge and is reviewing near-deposit/near-surface extensional targets for drilling.

ABM is an exploration company developing several gold discoveries in the Central Desert region of the Northern Territory. It has a multi-tiered approach to exploration and development.

Coarse gold in pan concentrate from a drill hole at ABM Resources’ Old Pirate Northern Extensions.

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