THE DIAVIK DIAMOND MINE sits on an island in the middle of a lake, which itself is surrounded by hundreds of other lakes and the barren lands of the Northwest Territories. From above, three human-made craters look like God Herself started drilling giant, threaded holes into the landscape.

All commercial diamond mining was scheduled to stop in March, marking the beginning of the end of the mine’s life. Joe Blandford, one of the superintendents, remembers when there were only a couple of trailers on site and a small construction crew plotting out the mine’s future.

Once mining stops, it will take another three to four years of remediation work, followed by up to ten years of post-closure monitoring to make sure the site is safe for wildlife and people. Those giant craters will be filled with processed kimberlite and flooded with lake water, eventually getting swallowed up into Lac de Gras. Some of the mine’s materials will be buried in the permafrost under a blanket of rock, while other material will be repurposed: the solar panel farm might be distributed to communities in the NWT. Of course, there are downsides to the mine’s hand-me-downs; hazardous waste, for example, will be trucked to Yellowknife and Alberta for disposal.

This is a massive cleanup project in a part of Canada where mining companies have a dirty track record. Giant Mine, a gold mine outside of Yellowknife, is the most famous example of a company that fled, leaving 237,000 tons of arsenic trioxide waste behind. The federal government is spending around 4.38 billion taxpayer dollars to clean up the mess, which will take until at least 2038 to finish. Indigenous communities have pushed the territorial government to ensure that wouldn’t happen again with the diamond mines.