For nearly a century, the Bunker Hill Mine, was one of the most productive mines in the highly prolific Silver Valley region of the Coeur d’Alene Mining District. A region that includes many world-renowned silver mines such as the Lucky Friday, Gold Hunter, Sunshine, Galena and Crescent mines, and one that produced over 1.2Bn Oz of Silver in its history.

Primarily focused on the production of zinc and lead concentrates from the mining of over 30 distinct and often-disseminated Sphalerite (zinc-rich) or over 10 distinct narrower and higher-grade Argentiferous-Galena (lead-silver rich) and other hybridised veins, it nonetheless produced 165Moz of silver as a valuable by-product. Significantly, this silver represented over 31% of the mine’s gross metal value, and 40-50% of its Net Smelter Value over that time.

Following the construction of its lead smelter in 1920 and its electrolytic zinc processing plant in 1927 its mining operations were focused on maintaining the maximum possible ore-feed to these expensive downstream components of the business value-chain to ensure optimal profitability. This mining focus of volume over grade, led to extensive use of bulk-mining techniques within the largest zinc ore-bodies from the 1960s and a corresponding significant reduction in head grade by the 1970s. A volume-focused business model that became untenable when metal prices collapsed due the effects of the global recession that followed the 1973 Oil Crisis and the collapse of the Bretton Woods system.

From 1977, as an attempt to improve its long-term profitability, the mine owners conducted the first systematic survey of the mine’s geology in the mine’s history in order to inform an exploration and mine development plan that would focus on generating the highest head-grade for the processing plants as possible. These studies yielded significant new insights and indicated new opportunities for the business as well as highlighting the strategic importance of its silver endowment as a central to the mine’s future profitability. Sadly, the benefit of these new insights was never realised, as the mine was closed in 1981.

Led by Sam Ash, our new CEO, an American mining engineer who is himself the son of a Bunker Hill employee from the 1970s, the company is focused on identifying the optimal development strategy for the mine.

This involves four key activities: