December 11, 2018

Cost of asbestos controls at mine won't be known for a while

The discovery of asbestos-like fibers at the proposed Gogebic Taconite mine site could add to the cost of the operation, but the amount of added expense won’t be known for many months.

If the substance is widespread, it’s possible that controlling it during mining and rock-crushing could drive expenses so high that the mine would not be built, but there’s no indication that will be the case, said company spokesman Bob Seitz.

“I guess that would be possible,” Seitz said. “Is it affecting the decisions we’re making about doing the testing and moving forward? No. There’s nothing right now to show it will be too expensive.”

State Department of Natural Resources officials agree that it’s too early to know how much of the cancer-causing material lies in the rock of the Penokee Hills in northern Wisconsin where the company wants to dig for iron.

It’s not clear if the test drilling already done in eight spots and five more that are planned will be sufficient to determine the extent of any hazardous fibrous material with characteristics of asbestos, but Gogebic Taconite almost certainly will be able to engineer solutions to any problem — possibly simply using water to keep dust down — just like mine companies have done in other states, Seitz said.

Six active iron mines currently being studied in Minnesota appear to meet federal standards — with some exceptions — for protecting workers from tiny airborne fibers that break loose from rock, but the workers had higher-than-expected rates of mesothelioma, the uncurable lung cancer caused by asbestos, according to a five-year University of Minnesota study.

The next stage of the study will determine if the toxic particles caused the disease, or if some outside factor such as exposure to commercial asbestos contributed, said Jeffrey Mandel, a University of Minnesota School of Public Health professor and principal investigator for the research effort.

The iron mines keep most workers in enclosed cabs of heavy equipment outfitted with high-efficiency air filtration systems, said Peter Raynor, who led a study of workplace pollution controls.

In rock-crushing plants, new air-filtering technology captures airborne particles better than older scrubbers that collect dust in water, Raynor said.

“In most of these operations, the crushers are enclosed and they have belts that carry the ore that are also enclosed,” Raynor said. “You can still get dust emerging from that if you don’t pull enough air through the enclosure.”

The study found instances of inadequate air flows, but workers doing maintenance or other special jobs were most likely to appear to be exposed, Raynor said.

“You would see miners who would show evidence of contamination on their clothing, or the skin on their face,” Raynor said.

Scientists also monitored air in five mining communities, and collected very few fibrous particles in three places and none in the others, said Larry Zanko, a senior research fellow at the university’s Center for Applied Research and Technology Development in Duluth.

Gogebic Taconite will need to control dust of all kinds, and if the cancer-causing fibers are present, extra air monitoring may be required, said Larry Lynch, a Wisconsin Department of Natural Resources hydrologist who is coordinating the agency’s response as the company seeks permits to conduct bulk sampling, and eventually to mine.

The company insisted in a July 28 letter to the DNR that it didn’t expect to find toxic fibers because the type likely to occur in Wisconsin — in a certain form of a mineral called grunerite — had only been found in one portion of the Mesabi Iron Range in Minnesota.

The letter also asserted that the DNR couldn’t regulate asbestos emissions, but last week company spokesman Bob Seitz acknowledged that the independent laboratories that analyze core samples from the site will look microscopically for toxic fibers under a provision of the state mining law.

The DNR disclosed on Oct. 8 that a rock containing such fibers was found at the mine site in May.

Seitz has questioned the finding, saying that it was possible someone tampered with the sample, although he acknowledged he had no evidence. Mine opponents said the DNR’s confirmation that the material is present should spark tougher scrutiny of laboratory tests that are being conducted on core samples the company collected from the mine site.

“There’s a lot of money at risk for (the company) based on the testing for this material,” said Dave Blouin, who works on mining issues for the Sierra Club in Wisconsin.

Mike Wiggins Jr., chairman of the Bad River Band of Lake Superior Chippewa, whose reservation is downstream of the mine site, said local geologists have observed additional quantities of fibrous minerals. The tribe is also concerned about sulphide in waste rock releasing sulfuric acid into streams.

“They are going to keep the asbestos wet and the sulfide mineral dry?” Wiggins said. “This is a sham. Nobody’s drinking the Kool-Aid up here.”

The federal Mine Safety and Health Administration sets exposure limits for toxic fibers that can break away from certain minerals, including grunerite, which has been documented by the U.S. Geologic Survey in large quantities near the western end of the mine site.

Not all grunerite is of the dangerous “asbestiform” type, but that form of the mineral was documented as early as the 1920s near the Tyler Forks River not far from the east edge of the mine site, Lynch said.

An in-depth USGS survey described fibrous bundles and “needles” that match the description of the asbestiform type of grunerite, Lynch said.

A more recent USGS publication noted that grunerite “is abundant in the iron-formation at Penokee Gap near Mellen” near the west side of the mine site.

Some activists have expressed concern that blasting would spread the toxic particles, but Lynch said that properly executed explosions break the rock without spewing large plumes into the air.

Typically, a blasting site can be wetted down on the surface and containers of additional water are dropped into holes drilled into the rock before each explosion, Lynch said.

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Cost of asbestos controls at mine won't be known for a while

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