by Greg Klein | March 21, 2017
Aurvista Gold TSXV:AVA declared preliminary metallurgical results for its Douay deposit “in line with the recoveries achieved elsewhere in the Abitibi belt at projects with comparable mineralization styles and similar or lower gold grades.” Ten composite samples totalling 311 kilograms and averaging 1.89 g/t gold from seven zones underwent the tests.
With consistent results, gold recovery averaged 26% from gravity and 66% from flotation, for an average total of 92%. The correlation between gold and sulphur recovery suggested the metal’s association with sulphide minerals.
Cyanidation leaching of a gravity and flotation concentrate averaged 85% recovery. The process improved recovery of samples from the project’s North West zone, characterized by a felsic volcanic host rock, but other composites did better. Excluding the North West samples, recovery averaged 88.9% for material from mafic volcanic and porphyry host rocks.
Results suggest capex and opex advantages to gravity-flotation-leach over an entirely leach process. The company has further tests planned later this year to optimize results and lower costs.
Earlier this month Aurvista issued a clarifying news release with an amended resource estimate. Using a 0.5 g/t cutoff within a conceptual pit shell, Douay’s eight zones total:
- inferred: 83.3 million tonnes averaging 1.05 g/t for 2.81 million gold ounces
Last month Aurvista released assays up to 2.2 g/t over 23.1 metres. Backed by $7.5 million raised in 2016, the company has about 30,000 metres of additional drilling planned this year.
Douay consists of 14,520 hectares along a 20-kilometre segment of the Casa Berardi deformation zone in Quebec’s Abitibi region. Aurvista holds a 100% interest in 13,310 hectares, a 90% interest in 20 hectares and a 75% interest in the 1,190-hectare North West zone, a JV with 25% partner SOQUEM, the mineral exploration branch of the provincial government’s Investissement Québec.