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MEI Online: Sizing, Classification & Sorting: Latest News: October 6th 2017


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:: Ore Sorting Increases Grade of a Bulk Sample by 55% at Dalradian's Curraghinalt Project


Dalradian Resources Inc. has announced positive ore sorting test results based on a bulk sample of mineralized development material from several of the veins at the Curraghinalt Gold Project in Northern Ireland. Testing was carried out by Outotec at their TOMRA sorting test facility in Wedel, Germanyon approximately 5 tonnes of material grading 9.52 g/t Au. Using x-ray and laser technology, plus additional screening prior to processing, the amount of non-mineralized (waste) material that would be sent to the mill in an operating mine was reduced by 35.8% and the grade increased by 54.6% to 14.72 g/t Au with a gold recovery of 99.3%. Similar results would be expected if implemented into a mine scale situation.

Ore sorting technology has been used in diamond processing operations for many years and is now used with a variety of other commodities including tungsten and gold. The ore sorting process has become increasingly efficient with advancements in x-ray, laser and computer technology. It was anticipated that ore sorting would be a good fit at Curraghinalt because of the large contrast in density and colour between the high-grade quartz-sulphide veins and the surrounding country rock.

Throughout the testing, the ability to effectively sort the ore from Curraghinalt was clearly demonstrated. Using only x-ray technology with rougher stage material, waste removal of 50.5% with a gold recovery of 97.8% was achieved. When the laser scavenger step was added, which is used to recover additional mineralized material from the x-ray waste material, total gold recovery increased to 99.3% at the expense of a decrease in total waste removal to 35.8%. Optimisation of the proposed process, including a cost benefit analysis of the secondary scavenger circuit, will be needed prior to implementation of the technology.

Eric Tremblay, Dalradian's Chief Operating Officer commented: "These are very good results. Independent testing proves our high-grade gold is easily sorted from waste. We can now show that a modest capital investment in this technology will improve Curraghinalt's already robust grades and project economics. We plan to investigate it further by visiting operations using the technology prior to designing our own ore sorting infrastructure for inclusion in an updated feasibility study."




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