TORONTO (miningweekly.com) – Project developer Marathon Gold will receive research and development (R&D) funding under the GeoEXPLORE programme of the Research & Development Corporation of Newfoundland and Labrador (RDC) for metallurgical testing on mineralised material from the Leprechaun and Marathon deposits, at the company’s flagship Valentine Gold Camp, the company announced on Wednesday.

The estimated cost of the project, which was being done in collaboration with consulting engineering firm Thibault & Associates, would total about C$165 000, of which about C$124 000 would be contributed by RDC.

The RDC had previously part-funded Marathon research and development work, which had successfully identified a preliminary process for treating the Leprechaun deposit, including pre-concentration to significantly reduce the size and cost of downstream processing facilities. The total potential gold recoveries ranged from 92.8% to 95% and were yet to be fully optimised.

PROCESS DEVELOPMENT
This year’s metallurgical testing was currently under way and was expected to be completed in the third quarter. One of the objectives was to test a low-cost heap leach process for treating a portion of the lower-grade resources from both Leprechaun and Marathon deposits, by directly leaching the crushed mineralised material.

If successful, the potential advantage would be a simple, low-cost extraction process that, in many cases, allowed for processing of even lower gold cutoff grades from the resource, thereby increasing the extractable gold from the deposit.

Marathon advised that the initial technology development for this project was based on developing the leaching chemistry at different crush sizes to determine the leaching kinetics, ultimate gold recoveries and reagent consumption rates.

The second part of the project entailed developing a metallurgical process for mineralised material from the Marathon deposit. Development of the process would build on the technology developed in 2014 for the Leprechaun deposit. Process flow sheet options included gravity recovery, flotation and cyanidation of the flotation concentrate and, optionally, the flotation tailings.

Management expected that the successful development of a gold recovery process from the higher-grade Marathon resource and the heap leaching of lower grade Marathon/Leprechaun resources would help reduce overall capital and operating costs at the project.

"Marathon Gold appreciates the continuing support that RDC has provided for the metallurgical testing. This support has helped us to significantly advance the technical merits of the project in these challenging times. We also appreciate the support we continue to receive through the Junior Exploration Programme funded by the Government of Newfoundland and Labrador, which has added C$100 000 a year to our exploration budgets for the last five years. It is really good to be operating in a province that is so supportive," commented Marathon president Phillip Walford.

He noted that, should heap leaching be viable, it would have the potential to dramatically change the economics of the project by reducing capital costs and operational costs, as well as lowering the cutoff grade, potentially resulting in more gold from the same-sized pit. This programme would also confirm the viability of the Marathon gold mineralisation for conventional gold extraction.

The Valentine Gold Camp currently hosted four near-surface, mainly pit-shell-constrained, gold resources totalling 1.06-million ounces of gold grading 2.2 g/t classified in the measured and indicated categories and 200 000 oz gold at 2.85 g/t inferred.

These resources, open along strike and to depth, covered less than 6% of the total length of the highly prospective Valentine Lake Thrust Fault and associated splay faults, which hosted the majority of the gold mineralisation within the property.