Equipment layout at Griffin Mining’s upgraded Caijiaying zinc-gold recovery plant. (Photo: Griffin Mining)
Recently commissioned processing facilities at Griffin Mining’s Caijiaying zinc-gold mine in China were expected to reach an expanded nameplate capacity throughput rate of 1.5 million metric tons per year (mt/y) of ore by the end of June. This level of output was not possible, explained the London-based company, before delivery of a new ball mill and connection of additional grid power.
The company’s production and financial results for 2014 were significantly impacted by a suspension in processing to allow for the upgrade from August 11 to November 17 and the subsequent re-commissioning of the plant—a process which took six weeks longer to complete than originally expected.
Production in 2014 included 747,775 mt of mined ore, compared with 877,803 mt in 2013, and 572,390 mt of ore processed compared with 838,431 mt in 2013. The mine produced 25,901 mt of zinc metal in concentrate last year, compared with 39,724 mt in 2013; 7,623 oz of gold in concentrate, compared with 11,468 oz in 2013; along with 201,982 oz of silver in concentrate, compared with 323,808 oz, and 857 mt of lead in concentrate, compared with 1,551 mt in 2013.
The average price per mt of zinc metal in concentrate received in 2014 rose by 3.3% to $1,345 ($1,302 in 2013), silver rose 1.8% to $17.1 per oz (2013 – $16.8), gold by 1.5% to $1,251 per oz (2013 – $1,233) and lead fell 2.3% to $1,595 per mt (2013 – $1,633).
With the lower-grade ores processed during re-commissioning of the plant, the base and precious metal grades of the ore were slightly down on 2014, resulting in a minor drop in the recovery of base metals, while improvements were made in gold recoveries.
Griffin’s chairman, Mladen Ninkov, said, “The additional time taken to complete the expansion of the processing facilities at Caijiaying will inevitably cause disappointing financial results in 2014. However, the price has been worth paying to position the company to be a globally significant zinc producer with substantial precious metal credits with the expected and much discussed global shortfall in zinc supply expected in 2015 and beyond.”