Today MinnPost published a piece by Chris Baldwin, a third generation Iron Ranger and mining engineer with 45 years of experience in mining, on why sulfide-ore copper mining should never be attempted on the border of the Boundary Waters. The Biden administration is currently reviewing Chilean mining conglomerate Antofagasta's Twin Metals project. In 2016 the US Forest determined after a multiyear study that copper mining posed an inherent risk of irreparable harm to the Wilderness and subsequently denied renewal of Twin Metals leases and began the process to ban mining in the Boundary Waters watershed. The Trump administration reversed all of these decisions. Peer reviewed science and economic analysis clearly shows that protecting the Wilderness is the smart public policy choice.
Mr. Baldwin expands on the risks posed by copper mining when he writes:
As a mining engineer and graduate from the Colorado School of Mines, I dedicated my career to extracting minerals to support a modern society. Now my engineering and operating experience in 12 different open pit and underground salt, iron, uranium, and gold mines across the U.S. over the past 45 years, tells me Minnesotans should be deeply concerned about the long-term impacts for the Boundary Waters Canoe Area Wilderness (BWCA) watershed if the sulfide-copper and nickel minerals of the geologic Duluth Complex of northern Minnesota are mined according to the proposed Twin Metals mine plan.
First, the sulfide minerals of the Duluth Complex are significantly different from the low sulfur iron ores of the Mesabi Iron Range. The resulting waste dumps, tailings ponds, and abandoned mines from sulfide minerals all would be potential sources of acid mine drainage, heavy metals and other pollutants, contaminating clean water. If this area is mined, these sulfide wastes would need to be treated differently and isolated in a “geologic sarcophagus” in perpetuity, to try to protect the headwaters of the greatest source of fresh water on the planet.
Second, engineering can reduce but not eliminate risk, especially with sulfide minerals mining. Pipe, valves, pumps, liners and other parts of a mine do wear out and fail, and often the failures are not predicted. And of course all people are fallible, including engineers and miners, so it is impossible to say in advance that there won’t be mine design flaws, operator errors, and missed signs of an impending failure.
Third, and I say this as an experienced mining engineer, you can’t trust the startup mining company or the new mining operator to keep its most important promises. The executives making the promises today probably won’t be in charge when it’s time to keep them, and future mine permit amendments likely would expand the footprint of the mining project, increasing environmental risk. Start-up mining projects (mining juniors) are traded like commodities on the open market and there is no guarantee the new owner has any proven business or mining experience in a water rich place like Minnesota. The new owner could be a shell company, a convenient box into which the real mining company drops all the risk and long-term liabilities, and bankruptcy courts protect the main corporation’s profits. Twin Metals is owned by the Chilean company Antofagasta PLC, meaning the local mine executives might not have the authority to keep their promises made here in Minnesota…
...Even new sulfide mining and processing technology and practices like lime neutralization, cementation, double lined (ponds, tailings basins, and waste dumps), and topographic isolation of tailings, which are currently available and costly, would not take the risk away of a design flaw, or operator error, or failure to supervise for hundreds of years, or future decisions to cut corners because of a lower than expected ore grade or a market downturn. We should want this type of mining to be proven first, in a low environmental risk area. But sulfide copper and nickel mining should never be attempted on the border of the BWCA. The risks are simply too great.
You can read the full piece here.