RE: PREM Zim meeting this afternoon19 Feb 2019 10:21
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The viability and economics of RHA when its ramp up is complete and operating in a steady state in say two years time is slightly complex but I don’t think this rough and simplified appraisal I've set out will be too difficult to understand.
From a restart brea-keven should be achievable in less than two months and if the first notional milestone is still 16,000t’s of ore delivered to the ROM pad within six months a quick calculation at that point indicates the mine should be producing 4,500 to 5,000 mtu’s APT/month and making roughly $400 monthly net profit.
To get to an optimised and steady state we’re now told the intention is to construct a semi-mechanised decline to extract the ore from newly cut stopes at depth in the underground mine where the grades are expected to be higher at 0.70% WO3 or more.
As a consequence the pit is sure be redesigned to give access th the higher grade ore blocks not just at depth but also those nearer to the old underground shaft when it becomes redundant and safe to do so. The grades there are subject to further analysis but conservatively are known to be not less than 0.35% WO3.
The intention also is to re-process the economic material from the old tailings. For the purpose here I’ll going to assume the grade equivalent is going to be 0.25% WO3.
The ROM is designed to be 40kt’s/month. The bottleneck being the XRT sorter I believe. For ease of maths then let's assume then 500kt’s of economic ore are delivered annually to the ROM pad in the mix of 150kt’s from the underground mine, 300kt’s from the pit and 50kt’s from the tailings. I don’t think that’s unreasonable.
Workin the maths through the average grade will therefore be 0.45% (150 kt's x 0.70% + 300kt’s x 0.35% and 50kt’s x 0.25% = 0.45%) and the product will be 2.25kt’s WO3. From there assuming a Metallurgical Recovery rate of near 80% we get to an annual production 177.5k mtu’s APT at the point of sale.