Mt. Hope Moly to Expand Mill Throughput

Idaho General Mines announced plans to increase mill throughput capacity at its Mt. Hope molybdenum mine in eastern Nevada from 44,000 t/d to an average of approximately 60,000 t/d, with actual annual throughput dependant on ore characteristics and other factors. The increased throughput capacity is expected to expand average annual molybdenum production during the first 10 years of operations to 37 million lb from the company’s prior estimates of approximately 31 million lb. The expanded throughput rate and associated mine planning, capital and operating cost impacts are being incorporated into an upcoming bankable feasibility study, according to the company.

Commenting on the decision, Idaho General Mines’ CEO Bruce D. Hansen said, “After evaluating recent grindability studies and the robustness of the initial plant design, we have determined that higher throughput capacity at Mt. Hope is both feasible and financially accretive, despite additional capital requirements.

The Mt. Hope mill was initially designed to expand throughput from 44,000 t/d to 55,000 t/d in year 12 through the addition of a third ball mill and further mining equipment. Recent grindability studies, however, indicated that approximately 60,000 t/d could be initially achieved with two incrementally larger ball mills driven by more horsepower. Over the next month, the mine plan will be re-optimized and line balanced to coincide with higher throughput levels. The company said it expects an increase in project NPV from previous estimates of $840 million (calculated at $15/lb molybdenum and a 10% discount rate) despite higher projected capital costs, due in part to the plant expansion, a larger initial truck fleet, and larger pre-stripping and waste segregation requirements.