This recently became obvious when the company announced it had executed a user licence with Bayan Airag Exploration LLC in Mongolia for the world ’ s first application of its proprietary glycine gold leaching process , GlyCat™ , in a commercial heap leaching application . Application of the technology has already commenced to extract gold from ores mined from the Golden Hills and Limestone Ridge pits , with the decision to fully implement the technology following site-based testing and a 1,000-t trial heap leach . This recent trial demonstrated higher recoveries than conventional cyanidation , with 78 % overall gold recovery , Draslovka said , all while achieving a 65 % reduction in cyanide use and high recyclability of the glycine .

Overall , due to high cyanide unit costs , the total reagent costs are projected to fall by over 70 % at the pits , according to the Czech Republicbased company .

Ivor Bryan , Chief Technology Officer of Draslovka Mining Solutions , said the company has several “ advanced demonstration projects ” taking place over the next six or so months , including another large heap leach trial in South America on “ ripios ” ore – spent , previously leached ore where other valuable metals ( gold in the case of this trial ) may still be present and available for reprocessing .

Draslovka views the heap leaching part of the market as an area where waste can be turned into value ; aligning with the core benefits of the

glycine leaching technology Bryan and his team , in conjunction with Curtin University , have developed over the decades .

“ Glycine , the main reagent in our gold ( GlyCat ) and base metal ( Glyleach™ ) solutions , is both selective and recyclable ,” he told IM .

“ Selectivity is important as the solution does not take gangue / waste minerals into solution – unlike the gangue minerals consumed by the majority of acid-based leaching technologies . This provides for a clean and simple system , instead of more complex flowsheets seen in acid leaching projects .

“ Our process is also based on chelation ; it is not a chemical reaction . This means the glycine is not consumed ; once it gets into solution , you can extract the metal and recover and / or reuse the reagent .”

This aids its ability to treat carbonate-hosted deposits that are high acid consumers , low-grade tailings where previous leaching solutions have not provided an economical business case , and environmentally sensitive deposits where cyanide or acid use have previously been ruled out .

While many ‘ alternative ’ leaching solutions have come to the fore in both the gold and base metal space of late ( some of which are discussed in this article ), Bryan thinks GlyCat and GlyLeach have their own unique market proposition .

“ In the gold area , we are able to significantly reduce the amount of cyanide used without typically adding capital expense or complexity – it is effectively a drop-in solution ,” he said , adding that GlyCat provides an over 50 % cyanide consumption reduction in most instances . “ In the copper space with GlyLeach , we provide one of the only alkaline-based leaching solutions for copper oxides that can be applied to ‘ orphan ’ deposits previously deemed as high acid consumers ,” he said . Bryan estimates around

20- 30 % of current world copper production comes from oxide deposits .

While the company ’ s R & D team works on sulphide solutions in the copper space and cyanide-free solutions in gold , it is also trying to prove out the use of GlyLeach on low-grade nickel sulphide deposits .

“ We ’ re only just beginning our first pilot of this process on nickel , but we are confident we can economically recover significant amounts of nickel and cobalt thanks to the aforementioned selectivity and recyclability advantages ,” Bryan said .

“ The other thing about the nickel opportunity is that , as we are very selective when it comes to leaching the metals into solution , we can avoid the smelting process typically required to separate the valuable metals from the gangue minerals , providing battery pre-cursor materials in a low-cost and much truncated value chain ,” he added .

Another potential heap leaching avenue Draslovka is pursuing with a major client in Zambia is the idea of stacking copper tailings by adding low levels of cement as a binding agent and leaching the resultant heap .

“ If you were to try this with an acid-based solution , it would start ‘ eating ’ the material and the whole heap would slump ,” Bryan said . “ With an alkaline leach , we don ’ t see such slumpage , meaning we could treat finer material and material you otherwise would have been unable to treat .” https :// www . draslovka . com