Tailings hit the highwayIndustrial Construction Consulting of Coleraine has announced plans for national distribution of coarse taconite tailings for use on highways and construction projects.
By: News-Chronicle, Lake County News Chronicle
Industrial Construction Consulting of Coleraine has announced plans for national distribution of coarse taconite tailings for use on highways and construction projects.
Regarded as a super aggregate, taconite is the byproduct of iron mining on the Iron Range. Recognizing a depletion of high grade aggregates in many parts of the country, “the timing is right for introduction of this product,” said project manager Scott Quick.
Taconite has been used by contractors working on Lake County roads, said highway engineer Al Goodman. Ulland Brother and Northland Construction have blended it into bituminous mixtures, he said.
Up to 60 percent of the ore produced in Minnesota is waste product, said Ed Shaughnessy, Industrial Consulting’s vice president. For decades, taconite has been stockpiled with some used on Minnesota road projects as a sub base layer and asphalt aggregate.
Goodman said Northshore Mining could have a part in the road business if not for the past environmental history of Reserve Mining, the original Silver Bay and Babbitt plant operator.
“The real tragedy is that we cannot utilize the materials from Northshore Mining due to the old Reserve Mining court case,” Goodman said.
It was determined that the tailings in Silver Bay from the eastern part of the Iron Range had asbestos-like fiber in it. In the past few years, Northshore owner Cliffs Natural Resources had tried to amend rulings on air pollution measures it is forced to comply with from the Reserve rulings.
District Judge Kenneth Sandvik ruled in January that the state should not require Northshore to conduct a full environmental impact statement before applying for a change in the permit to drop the air testing standard.
The PCA must now decide how to formally consider the company’s request to drop the air monitoring requirement from the permit, along with dropping a requirement that fiber levels in Silver Bay be compared to fiber levels in St. Paul.
Goodman said the taconite in Silver Bay is recognized by experts as OK to use in something like road projects. “If you talk to the Minnesota Minerals division of the DNR, their feeling is that tailings from North Shore Mining could be utilized in a safe fashion.”
The Minnesota Department of Transportation has said taconite tailings from western parts of the Iron Range is safe and has been used for decades on projects.
In the past few years, taconite has also been used in concrete projects involving bridge reconstruction.
The Mesabi hardrock that Industrial Construction will use is processed to size or specifications for use as an aggregate. “Because of its inherent mineral properties, taconite provides the hardness and angular shape desirable for use as a replacement for commonly used materials in wear course surfaces,” Quick said. “We recognize the long term success with this material.”
For several years, the University of Minnesota National Resources Research Institute in Duluth has worked to perfect the use of taconite. The institute conducted a three-year study ending in 2008 that suggested taconite could be marketed to regions where gravel pits are being converted to housing use in metropolitan areas. The institute studied tailings from the five west Range mines for signs of asbestos or asbestos-like fibers and issued a report concluding the rock is a good alternative to current materials.
“Over the years, the research has shown that, if properly integrated into highway mix designs, by-products of the mining industry could decrease the life-cycle cost of highway and railway construction, as well as reduce the need for new stone and gravel quarries throughout the United States,” the NRRI wrote in its newsletter last year.
The studies have “paved the way for our introduction of taconite material nationally,” Quick said.
The hangup for companies trying to utilize tailings has been transportation of the heavy material from the Iron Range, Industrial Construction officials said. “We intend to educate more end users throughout the nation that our more than abundant supply of material is available and cost competitive,” Quick said.
The density of taconite tailings means less wear and tear over the course of time, Quick said, justifying some of the extra cost of the material.
One option is using Lake Superior for transportation, potentially increasing traffic for ports along the North Shore and in the Twin Ports.
The company is attempting to introduce the material in the Gulf Coast region and is in discussions with potential users, Quick said. The company intends to offer some trials in selective markets.
Goodman hopes that Lake County and its tailings near Silver Bay will someday be cleared for use as well. “Perhaps the ongoing health study being done by the University of Minnesota will clear this up,” he said.
Extra for roads
- According to the University of Minnesota National Resources Research Institute in Duluth, every year, Minnesota uses about 55 million tons of sand and gravel and crushed rock, or aggregate, for construction projects, including roads.
- Nearly one ton of fine Mesabi Hard Rock is generated for every ton of finished taconite pellets produced, adding up to millions of tons a year. Tens of millions of tons of coarse Mesabi Hard Rock are also generated every year. Taconite waste rock has long been used on roads near the taconite mines on the Iron Range. Mine roads made of coarse taconite rock withstand regular use by 250-ton trucks.
Information about demo projects, meetings, mix designs and more can be found at www.nrri.umn. edu/egg/TACAGG.