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17/09/16
11:14
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Originally posted by Nabaru01
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I'll have one more go - there is no problem with the "sulphide" circuit. The BIOX process works well with overall recoveries +80% (often closer to 90%). The issues that arose during Apex time was the insistence of the then MD to empty BIOX tanks to find the gold locked in there (which didn't exist). Taking a tank out of the circuit every few weeks caused major problems with bacteria health and there were times when the tanks actually stank of dead bacteria (and almost zero oxidisation occurred as a result = lower recoveries, more losses, more insistence gold lock up was occurring, more tanks emptied and so on). Combine this with erratic ore delivery from underground due to maintenance issues, seismic activity (rock bursts), power shortages (couldn't afford repairs on gas units) and so on - it was a nightmare. At times, we had to drop raw sulphure into the tanks to keep the bugs alive.
Mechanically and metallurgically speaking, the plant was fine - able to meet throughput targets and recovery targets when running at steady state, something that has not been missed by BLK management. This is the reason they are building contingency into their plans. They are also taking the highest margin ore up front, the oxide ore from pits (not available to Apex) and Golden Age underground (Apex did mine some of this).
Sure, things can always go wrong but the approach taken by BLK for the start and growth of this company is the lowest risk, highest reward option they have available - in my opinion only.
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The issues that arose during Apex time was the insistence of the then MD to empty BIOX tanks to find the gold locked in there (which didn't exist).
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Why would he do this?