The resource is based on 127 drill holes for 54,893m, with the company stating that it is a large low-grade deposit, with a smaller high-grade core which lends itself to conventional large-scale open pit mining. The resource does not include the Merlin zone, 2km south of Central-Silicon, and on the same structural trend.
The company said it evaluated three broad flowsheets in a conceptual study to potentially produce 300,000 ounces a year from North Bullfrog and Silicon including heap leaching, conventional milling and leaching and milling with a float-fine-grind leach circuit. It said a crushed leach with a P100 of 12.5mm achieved the best economic result and was selected as the preferred case for the study.
A prefeasibility study is underway to be delivered in late 2022 or early 2023.
AngloGold interprets Silicon as an epithermal high-level expression of a magmatic-derived advanced argillic alteration system with the mineralisation exhibiting a strong vertical control, strongly associated with the emplacement of hydrothermal breccias, with the gold associated with pyrite.
The completion of the acquisition of Corvus Gold in January will add the nearby North Bullfrog and Mother Lode projects to the resources at Silicon, providing, "the opportunity to develop a world-class operational cluster within the Beatty district," the company said.
Silicon has an underlying net smelter returns royalty of 2.5% divided between RenGold (1%) and Altius Minerals (1.5%), with no buyback provisions.