Mine closure review: Planning for successful rehabilitation

In 1999, as the Giant mine on the outskirts of Yellowknife in Canada’s Northwest Territories was nearing end of mine life, low gold prices forced owner Royal Oak Mines into receivership. Responsibility for the mine’s closure was transferred to Indigenous and Northern Affairs Canada, a department of the federal government.

This was to be no ordinary clean-up job. During a half-century of operations, the Giant mine produced 237,000 tonnes of arsenic trioxide waste. Under the remediation plan approved in 2014, the waste was being frozen underground at a cost of more than C$1 billion (US$710 million) to the Canadian taxpayer.

Around the same time, another historic mine was shutting down 2,000km to the south in Kimberley, British Columbia. This was the Sullivan mine, a zinc-lead-silver mine that operated for more than a century. The Consolidated Mining and Smelting Company of Canada (later Cominco, now Teck Resources) began engaging the local community on mine closure as far back as the 1960s. Today, the 1,100ha former mining area has a privately-owned ski hill and golf course, as well as a 1.05MW solar farm that is owned and operated by Teck. Teck continues to maintain responsibility for water treatment.

By preparing for closure and engaging stakeholders early in the mine life, Sullivan’s operators were ahead of their time. Thanks to tighter regulations and a cultural shift in the industry’s approach to stakeholder engagement, it’s likely more closures will resemble Sullivan in future. But unlike Sullivan’s operators, it appears too many mining companies are still not preparing early enough for closure.