Exploration History and Mineral Potential of the Central Arctic Zn-Pb District, Nunavut

Abstract

Exploration in the central Arctic Zn-Pb District took place in five phases: 1) an initial exploration period (1960–70), during which most surface showings on Cornwallis and Little Cornwallis islands were found; 2) a discovery period (1971–79), during which the buried Polaris ore body was discovered and its feasibility and viability established, new showings were found farther afield, and many showings received limited drill testing; 3) the production period (1980–88), dominated by drilling at Polaris Mine; 4) an ore-replacement exploration period (1989–2001), during which showings close to Polaris were extensively drilled, showings on Cornwallis Island drill tested, and new showings found and drilled farther away; and 5) a reclamation period (2002–05), during which the infrastructure was removed and the mine site restored. Factors affecting the timing and rate of exploration were generally intrinsic to the region: 1) discovery of showings in 1960, 2) discovery of the Polaris ore body in 1971, 3) declining reserves between 1989 and 2002, 4) closure of the mine in 2002, 5) the short exploration season and difficult logistics, and 6) lack of competition. The external drivers of exploration were 1) oil-related exploration that led to the discovery of the Polaris showings, 2) the onset of regional exploration coinciding with spikes in the price of zinc, and 3) the surge in scientific interest in carbonate-hosted Zn-Pb deposits in 1967. Probabilistic, discovery-time curve analysis indicates that over 50 showings remain undiscovered. Because logistics controlled the target selection, the standard assumption of a logical discovery process (from largest target to smallest target) is likely invalid. This means that large, untested targets may still exist in the district.