Minnesota state lawmakers are proposing new rules for tailings basins and dams that could could add another hurdle before the state’s first copper-nickel mines could go into production.
Minnesota has many years of experience in iron ore mining, but not with the mining and storage of waste from copper-nickel mine. The Star Tribune reported that the state’s administrative rules on metal mining have not been updated since they were written in 1993.
The new rules under consideration by legislators would require metal mining storage structures to be designed to Canadian safety guidelines, with an independent panel of engineers approving the design. Companies would have to create an operations manual for managing the tailings dams and submit to annual safety inspections.
It's too late in the 2019 Legislature for action on the bills, but they have bipartisan support from eight members of the House and Senate and will be taken up in the fall.
Sen. Paul Anderson, R-Plymouth, chief author of the proposal in the Senate, called the proposal a conversation starter but the states Department of Natural Resources (DNR), which oversees mine permitting in Minnesota, is cool to the proposal in its current form.
DNR Assistant Commissioner Jess Richards said the bill lacks definition in many areas "and includes language that would conflict with existing mining and dam safety laws."
"The DNR would be available to discuss dam safety in Minnesota," Richards said. "However, this sweeping proposal begins with a single solution, rather than a broad and inclusive conversation that involves the full range affected stakeholders."
Frank Ongaro, executive director of the industry coalition Mining Minnesota, called the proposed rules unnecessary. The state's existing rules are "thorough and comprehensive," he said. "From an industry perspective, I believe the DNR is doing a good job of ensuring public confidence in the safety of Minnesota tailings basins," he said. "We all care about dam safety."
Concern about Minnesota's regulations for tailing dams comes as the state debates two copper-nickel mines proposed for northeast Minnesota, near the Boundary Waters Canoe Area Wilderness (BWCA).
PolyMet Mining, backed by Swiss mining and minerals trading giant Glencore, has proposed an open pit mine near Babbitt. It has cleared most state regulatory hurdles and would be Minnesota's first copper-nickel mine, but faces several legal challenges (see page 12). The other proposal is for an underground copper-nickel mine near Ely, planned by Twin Metals Minnesota, a subsidiary of Chilean mining company Antofagasta. It's still in the early stages of regulatory approvals.
Tailing dam safety has been in the headlines since the collapse of the Brumadinho tailings dam at the Córrego do Feijão iron ore mine in January. Brazil's National Mining Agency has banned construction of new "upstream" tailings dams following the collapse that killed at least 200 people.
Upstream tailings dams are the most common type of dam — and the type planned by PolyMet Mining in its proposed mine.
The International Council of Mining & Metals in London reacted to the Brazilian catastrophe by launching an independent review of standards for managing tailings dams.
The proposed rule changes are modeled on similar reforms Montana lawmakers passed in 2015. That industry-led effort was a response to the disastrous collapse of the Mount Polley tailings dam in British Columbia in 2014, which spilled more than 20 million tons of mining waste into streams and lakes.