TORONTO (miningweekly.com) – With cold commissioning of its zinc expansion project under way at Bisha base metals mine, in Eritrea, Canadian miner Nevsun Resources on Thursday reported strong customer demand for its future zinc concentrates.

The company said hot commissioning of the zinc plant would be delayed by a month, after it confirmed that the supergene-ore mining phase at Bisha would extend into June.

The zinc expansion would enable Nevsun to process the primary copper/zinc/gold/silver ore at up to 2.4-million tonnes per year, producing both copper and zinc concentrates from the existing copper flotation and new zinc flotation plants. The current reserve life with the completed zinc expansion extended until 2025.

Bisha was one of the few new sources of zinc concentrate hitting the market in 2016.  Its zinc concentrate, which was expected to be of a high quality, was attracting significant interest from buyers. Bisha’s zinc offtake remained completely uncommitted at this time as the zinc market was expected to continue to tighten.

As a result of its processing more supergene ore, Nevsun expected to hit the upper end of its production guidance and the lower end of its C1 cash-cost guidance for supergene copper.

The forecast total capital outlay for the zinc expansion would total about $80-million, significantly under the original budget of $100-million, the company advised.

Based on the current openpit mine plan, Nevsun expected Bisha to produce on average 225-million pounds of zinc and 53-million pounds of copper in concentrate a year until 2025.

The deposit currently held life-of-mine payable metals of 470-million pounds of copper, 1.7-billion pounds of zinc, 240 000 oz of gold and 8.2-million ounces of silver. It had 3.4-billion pounds of zinc contained in compliant resource categories.

Meanwhile, Bisha continued to mine – and had historically stockpiled – a variety of highly variable precious-metal-bearing ores. In 2015, the mine invested in equipment to screen and beneficiate portions of the materials in an effort to create saleable contiguous lots of material.

These efforts had defined 90 000 t varying materials assaying 20 g/t to 30 g/t gold and 800 g/t to 900 g/t silver, which the company would continue to market throughout the year.

Nevsun also reported strong buyer demand generating better-than-planned commercial terms of sale, while low marine shipping rates helped drive lower-than-expected selling costs.

Nevsun shipped about 20 000 t of precious metals concentrates during the first quarter, with ongoing shipments expected through 2016.