BRITISH COLUMBIA – Additional metallurgical tests done on material from the Harper Creek copper-gold-silver project owned by Yellowhead Mining of Vancouver indicate that a coarser grind can result in a 4% rise in copper recovery and a 13% savings in grinding circuit power requirements. The improved recovery allows the pebble mill, originally proposed in the preliminary economic assessment, to be eliminated from the flowsheet.
Based on the recent tests, the comminution circuits will likely include a 1,500 x 2,260 mm, 600 kW crusher, a 11.5 x 6.7 metre, 20,000 kW semi-autogenous grinding mill and two 7.3 x 12.8 metre ball mills. A target grind of 80% passing 180 μm appears to be optimum.
The Harper Creek project is a copper-gold-silver volcanogenic sulphide deposit with a measured and indicated resource of 563.2 million tonnes grading 0.31% Cu (3.6 billion lb of copper) plus 0.032 g/t Au and 1.08 g/t Ag. The inferred resource is 117 million tonnes grading 0.29% Cu (0.7 billion lb of copper). The project is located in south-central British Columbia, approximately 150 km by highway north of Kamloops.
Visit www.YellowheadMining.com for maps, photos and technical reports from the Harper Creek project.