Hudbay publishes first estimate for Copper World near Rosemont, Arizona


The mineralization consists of both skarn and porphyry copper sulfides with a significant oxidized component along a regional fault along the west side of the Rosemont, Bolsa and Broad Top Butte deposits known as the backbone fault.

Resource numbers are based on a copper price of $ 3.45 per pound, a molybdenum price of $ 11 per pound, and a silver price of $ 20 per ounce. They are divided according to whether the metals can be obtained by flotation or leaching.

The indicated proportion that could be recovered by flotation is 180 million tonnes grading 0.37% copper, 136 g / t molybdenum and 2.7 g / t silver. The buoyant inferred fraction is 91 million tonnes grading 0.36% copper, 129 g / t molybdenum and 3.8 g / t silver.

The Indicated Proportion suitable for leaching is 92 million tonnes grading 0.34% copper, 74 g / t molybdenum and 3.4 g / t silver. The Leachable Inferred Resource is 51 million tonnes grading 0.35% copper, 61 g / t molybdenum and 2.5 g / t silver.

The resources contain a high grade fraction that begins at or near the surface. The Indicated High Grade Resource is 96 million tonnes grading 0.57% copper, 97 g / t molybdenum and 4.1 g / t silver. The indicated proportion is 31 million tonnes grading 0.71% copper, 86 g / t molybdenum and 3.7 g / t silver. These categories include both types of ore.

The mining and processing of the Copper World mineralization could be a boon to Rosemont. The resources at the Bolsa deposit were considered wasted in the 2017 feasibility study. Converting Bolsa resources into reserves would result in less waste, reducing costs and energy consumption per tonne of ore mined. The oxide mineralization at the Rosemont deposit has previously been considered waste but can potentially be treated with Copper World’s oxide ore, further reducing costs.

Hudbay plans to release a preliminary economic assessment for Copper World in the first half of 2022. The study will cover potential synergies between Copper World and Rosemont. A new Rosemont resource model is also in the works.

The Rosemont project was slowed down by permit issues. Hudbay appealed to the U.S. Ninth District Court of Appeals in June 2020 to apply to Rosemont.

(This article first appeared in the Canadian Mining Journal)


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