British Columbia officials issued an environmental assessment certificate to IDM Mining for its Red Mountain gold mine in the region’s prolific Golden Triangle near Hyder, Alaska.

In addition to the 38 conditions that are part of the Red Mountain EA certificate, design requirements are specified in the certified project description, which are legally binding requirements that IDM must meet to maintain compliance with the certificate. The conditions were developed following consultation and input from Indigenous groups, government agencies, communities and the public. IDM is required to obtain other federal, provincial and local government permits to proceed with construction of the project, the company said in a release.

“Nisga’a Treaty lands are rich with natural resources. We are confident that this decision and conditions will provide significant opportunities for our citizens, with strong protection of the land, water and wildlife,” said Eva Clayton, President of Nisga’a Lisims Government (NLG).

IDM Mining president and chief executive officer Rob McLeod said the 363-acre Red Mountain mine will be a relatively modest operation.
“It’s a fairly short mine life at about five and half years,” McLeod said. “But in 2017, we added another 20 percent of resources and the deposit is wide open for expansion.”

The environmental assessment approved by B.C. authorities envisions downstream monitoring for about 10 years after the mine closes down.

Federal scientists in Juneau are concerned that’s not long enough and said so in comments filed with provincial authorities, KTOO Public Media reported.

NOAA hydrologist Sean Eagan said historic mines nearby have proven it can take decades for sulfides in mine waste to oxidize in a way that generates acid rock drainage.

“They had piles of rock sitting around and it took 20 years for the acid to really develop, the acid leaching to really come out of those piles,” Eagan told CoastAlaska. “So the amount of time they are proposing to monitor does not seem sufficient.”

Alaska regulators have also weighed in. They work with their B.C. counterparts and track transboundary mines because of potential downstream impacts in Alaska.

The post-closure monitoring period isn’t necessarily fixed. If stream samples detect concerning levels of contaminants the monitoring period could be extended by B.C. regulators.

Alaska-based mine watchdogs also have concerns about the proposed tailing facility.

McLeod said his company understands the sensitivity around tailing ponds and that IDM is still finalizing its storage plan.

“We may mix the tailings in with concrete,” he said. “But upon closure it would be sealed with another geomembrane and covered up and will be continued to be monitored at the headwaters.”

The Canadian Environmental Assessment Agency is doing its own separate federal review and taking public comment through Oct. 18.
IDM projects its Red Mountain mine will produce about a half-million ounces of gold – worth nearly $600 million at today’s gold prices.

The company expects to begin construction in 2020.