Tinka Resources has announced positive results from a preliminary economic assessment (PEA) of its 100% owned Ayawilca Zinc Zone underground mine project in central Peru. The PEA assumes development of a 5,000-metric-ton-per-day (mt/d) processing plant producing an average of approximately 101,000 mt per year (mt/y) of zinc in zinc concentrates and 906,000 ounces (oz) per year of silver in silver-lead concentrates over a 21-year mine life.
Initial capex is estimated at $262 million. The project is based on mining 8.4 million mt of indicated resources grading 6.95% zinc, 0.18% lead, and 15.8 grams (g)/mt silver, plus 29.8 million mt of inferred resources grading 5.79% zinc, 0.27% lead, and 19 g/mt silver.
Mining will be based on room-and-pillar and post-pillar mining methods. Zinc-rich mill feed will be trucked to the surface via a one-way-traffic ramp system connecting the two mine portals to the underground infrastructure and accessing production areas.
Ore will be processed through a standard crushing and grinding circuit followed by froth flotation, concentrate thickening, and filtration. The plant will produce zinc concentrates that are anticipated to assay 50% zinc and lead concentrates that are anticipated to assay 50% lead and between 2,750 and 5,930 g/mt silver. The zinc concentrates are expected to be readily marketable, with no deleterious elements other than an iron penalty.
About half of the tailings will be thickened and sent to a surface tailings storage facility, while the remainder will be mixed with cement and used as structural backfill in the underground operations (additional information is presented on p. 76 in our digital edition http://bit.ly/2NyA2Ea).