TriStar Gold Inc. (the "Company" or "TriStar") reports that McClelland Laboratories ("McClelland") in Sparks, Nevada has completed the initial metallurgical test-work that will be used in the Preliminary Economic Assessment of the Castelo de Sonhos gold project due for completion in the third quarter of 2017. Nick Appleyard, TriStar's President and CEO commented: "We're very pleased with these results as they confirm the ability to achieve high recoveries by both cyanidation and gravity under realistic operating conditions. Over the coming months, we will complete additional test-work and assess the economics and timelines of various options to identify the most appropriate process flowsheet for project development."
The metallurgical test-work was performed on a bulk sample created from drill core in the Esperança South region of Castelo de Sonhos with a head grade of approximately 1.5 g/t gold. McClelland assessed the gold recoveries using gravity concentration and cyanidation, with both sets of tests being done at a range of commercially reasonable grind sizes.
The gravity recoverable gold (GRG) tests were performed in triplicate on three 15 kg sub-samples from the bulk sample, at grind sizes that reflect coarse, medium and fine options: 80% passing (P80) 850, 250 and 75 microns. The results, presented in Table 1, demonstrate that most of the gold can be recovered to a rougher concentrate using gravity methods.
Table 1. Gravity recoverable gold test results
Gold recovery by cyanidation was assessed through bottle roll tests on four 2 kg sub-samples from the bulk sample, also at a range of grind sizes typical for a cyanidation process flowsheet. The results, presented in Table 2, show very high recoveries. Consumption of cyanide and lime were both low, an additional benefit as this reduces operating costs.
Table 2. Cyanidation test results
Based on these positive results, TriStar will continue to assess the metallurgical characteristics of the Castelo de Sonhos deposit. Additional test-work will be aimed at establishing standard operating procedures for crushing and grinding, gold recovery and tailings disposal.
Tony Brown, MIMMM, C.Eng, TriStar's Manager of Metallurgical Engineering, is the QP for this press release and has prepared or supervised the preparation of the scientific or technical information in this press release and approves its publication.