The property was discovered by prospectors in 1879 with high-grade zinc ore discovered in the Zenith Lake area, which is adjacent to Winston Lake. Development on the site of the Zenith deposit commenced in 1900 and by the end of 1901 some 2,700 tonnes were mined. Between the late 1960s and early 1970s an additional 165,000 tonnes at 16.5% Zn of ore was mined before operations ceased. In 1986 the development of the Winston Lake Mine was commenced by Inmet Mining Limited (subsequently acquired by First Quantum Minerals Limited) with 3.4 million tonnes grading 1.0% copper and 16% zinc processed.
The development of the Winston Lake Mine included a 1,000tpd mill (three-stage crushing circuit followed by a two-stage milling circuit) which produced approximately 900Mlbs of zinc, 53Mlbs of copper and over 50,000 ounces of gold at reported recoveries of 93% zinc and 78% copper. Historical mining methods included mechanised cut and fill, AVOCA and Alimak. Towards the end of the mine operations, a test stope was successfully completed at the Pick deposit using sub-level longhole stoping.
Operations continued for 11 years with production from the Pick deposit adding to the ore feed from 1995 until operations were suspended in December 1998. The operation was finally closed in February 1999 due to a very low zinc price at the time (US$0.42/lb).
Historical zinc concentrate grades were between 52% and 53.5% zinc and copper concentrates ranged from 22% to 25% copper. The historic gold and silver grades in the copper concentrate were around 11g/t gold and 310g/t silver. Concentrates were considered high quality, free of deleterious elements and with low impurities of critical elements such as arsenic, antimony and mercury.
Superior Lake consolidated the Project ownership in 2017 and has since advanced the Project through a positive Bankable Feasibility Study as well as commenced the first exploration program in more than 20 years.