High Grades Support Cerro Blanco Gold Project

Bluestone Resources has reported the results of an independent, NI 43-101-compliant feasibility study of its 100% owned Cerro Blanco underground gold project in southeast Guatemala. The study is based on proven and probable mineral reserves of 940,000 ounces (oz) of gold and 3.6 million oz of silver in 3.4 million metric tons (mt) at grades of 8.5 grams (g) per mt gold and 32.2 g/mt silver. Total gold production is estimated at approximately 902,000 oz over an eight-year mine life, including an average of 146,000 oz/y gold during the first three years of production. Initial capital to develop the project is estimated at $196 million, with an after-tax payback period of 2.1 years. Average life-of-mine all-in sustaining costs are estimated at $579/oz, net of credits.

The Cerro Blanco project is located approximately 160 km by road from Guatemala City, nine km west of the border with El Salvador. Bluestone acquired the project from Goldcorp in January 2017. The current project benefits from an existing underground access decline, a fully functional water treatment plant, maintenance shops, a warehouse and office facilities, and results from more than 128,000 m of drilling. The current decline will serve as the primary access to the mine for personnel, materials, and haulage of mineralized material to the plant site. Annual ore production of up to 460,000 mt is planned from a combination of long-hole stoping and cut-and-fill mining methods.

Processing is based on a plant with throughput capacity of 1,250 mt/d. The comminution circuit includes three-stage crushing and two-stage ball mill grinding to produce a target grind size of 80% passing 50 microns. Based on recent test work, the optimized flowsheet includes pre-oxidation and a 48-hour leach circuit followed by a 6-hour carbon-in-pulp adsorption circuit, with expected recoveries of 96% gold and 85% silver.

A drilling program is ongoing, and results will be incorporated into an updated resource estimate in the third quarter of 2019, followed by an updated feasibility study. The Cerro Blanco feasibility study was led by JDS Energy & Mining, with participation by Capuano Engineering, Hatch Ltd., Kirkham Geosystems, and Stantec.

As featured in Womp 2019 Vol 03 - www.womp-int.com