Timok and Better Gold RecoveriesCopper gold ores often have complex mineralogical and chemical characteristics, demanding innovative and complex processing solutions. Obtaining full value for the gold contained is a problem at Timok. Direct sale (i.e. DSO) of the concentrate results in significant treatment charges and delays in payment; and often results in relatively low gold recovery as seen in the PEA (i.e. ~44% for Au) and is typical for sulphide associated ores. The economic incentive to investigate better processes to recover the gold could be significant despite the additional cost of treating the ore.
Ores containing difficult to recover gold/copper minerals should be given a thorough review which Peter K. is entertaining by delaying the PFS study to Q1 2018.
Roughly speaking, using cyanidation in the concentration process could/will increase gold recoveries to the 60-70% range. The size of the prize is as follows for the Upper Zone at Timok:
- Run-Of-Mine contained ounces ==> 1,875,000 oz.
- Base Case Recovered ounces ==> 649,000 (Year 1 to Year 4) and 184,000 (Year 4 to 12).
- At 65% recovery an additional 386,000 total ounces is realized resulting in an additional $482,500,000 of revenue.
Another interesting scenario brought up by Seeking Alpha is the combination of DPM with NSU and processing the ore (I would imagine the DSO) at Dundee's Tsumeb smelter in Namibia to deal with the high arsenic content.
At any rate, the need to delay the PFS makes perfect sense, and will flush out the right base case to persue in the PFS.