Banded iron formation–hosted gold deposits in Nunavut and a new prospectOnline pre-recorded
Nunavut has reached a milestone for the first time ever by surpassing the Northwest Territories’ value of mineral production in 2019-2020. This is largely due to an increase of banded iron formation- (BIF) hosted gold production, mainly by the opening of Agnico Eagle Mines Limited’s Meliadine and Amaruq mines in 2019. Moreover, BIF-hosted gold is projected to become increasingly important for Nunavut with the opening of Sabina Gold and Silver’s Back River soon-to-be mine. To quantify the importance of BIF-hosted gold in Nunavut today, approximately 528,302 ounces of BIF hosted-gold (from Meliadine and Meadowbank complex) were produced in 2020, valued at ~$1.06 billion (at $2,015/oz). Natural Resources Canada estimates this as a 27% increase over 2019, which builds on an increase of 57% from 2018.
Although there are many types of gold deposits, the BIF-hosted gold deposit is arguably one of the most highly sought-after because of its potential for high-grade, high-tonnage, and long lasting mine life. All three regions of Nunavut (i.e., Kivalliq, Kitikmeot and Qikiqtaaluk) contain BIF-hosted gold deposits, some of which are considered world class. Two of Nunavut’s mines and four exploration properties and their geology will be briefly reviewed. The mines include Agnico Eagle’s Meadowbank complex (Portage, Goose and Amaruq deposits) and the Meliadine mine district of the Kivalliq region. Exploration projects include: Fury Gold Mines Limited’s Three Bluffs project, Mandalay Resources Corporation’s Lupin former mine, and Sabina Gold and Silver Corporation’s Back River project (all of the Kitikmeot region), and ValOre Metals Corporation’s Baffin Gold project (Qikiqtaaluk region).
Upon review of the nature of each of these BIF-hosted gold deposits, recurring characteristics emerge that can be useful for future exploration in Nunavut and worldwide. These characteristics include a thick BIF unit (oxide and silicate facies, decametres in thickness); strong deformation and dominant structural controls on ore (faults and folds); greenschist- to amphibolite-facies metamorphism; and a sulphide-mineral assemblage dominated by pyrrhotite, with possible arsenopyrite±loellingite and lesser chalcopyrite and pyrite along quartz-carbonate veins and/or as stratabound replacements.
During the 2019 fieldwork for the Fury and Hecla Geoscience Project led by the Canada-Nunavut Geoscience Office, a previously unknown, deformed BIF unit of significant thickness and lateral extent was discovered on northwest Baffin Island. Here, preliminary field observations, petrography and geochemistry of this BIF unit are presented. Although this work is preliminary, further exploration of this BIF is warranted.