A News Tribune editorial last week gushed with optimism about research being done in Canada to make mining greener, the trials possibly resulting in heavy extractive industrial operations without such heavy carbon footprints.
“Technology and research being tested now could soon transform and revolutionize mining in Northeastern Minnesota, too,” the editorial concluded.
Unfortunately, “There are major differences between the Canadian examples and the geology of Northeastern Minnesota,” as University of Minnesota Duluth professor of geology John Goodge pointed out to the News Tribune Opinion page.
Turns out our rock here is far different from the rock where “carbon sequestration” is being tried out. Our rock is incompatible for the technology, Goodge said. In British Columbia, researchers are working with the mining industry on a chemical process that introduces carbon dioxide to mine tailings that contain magnesium-rich minerals.
The process has been known for some time, Goodge said. The testing now is to see if it can be effectively “scaled up in order to help decrease atmospheric carbon dioxide by using existing mine tailings. Combining carbon dioxide with what is otherwise considered waste rock provides a viable mechanism for reducing a greenhouse gas linked to atmospheric warming. ...
“To be sure, the rocks (in Northeastern Minnesota) that host sulfide deposits do contain (the) magnesium-rich minerals (that are necessary for the process now being tested),” Goodge said.
“But with few exceptions, these minerals represent only a minor volume of the rocks in question,” he continued.
“In addition, although minerals like olivine from the Duluth Complex gabbros and peridotites are commonly altered to serpentine, it is typically only partial replacement, rendering the total volume of serpentine mineral quite small,” said Goodge. “Therefore, the rocks that may be mined in Northeastern Minnesota are not amenable to the methods being tested elsewhere. ...
“The proposed carbon sequestration being tested in British Columbia can only be scaled up because they have gigatons of serpentinite waste rock to work with,” he said.
And we don’t. “The occurrences in Minnesota are simply different in origin, composition, and volume from the deposits and tailings being considered in Canada, and we should not be optimistic that similar processes could be applied here.”
Disappointing. But let’s not let go of our optimism just yet. If a chemical process was able to be imagined and developed for the unique geology found in British Columbia, perhaps researchers can strike on a process with similar promise for Northeastern Minnesota.
The ultimate goal — mining with lowered greenhouse-gas impacts — remains worthy of gushing over.