Duluth News Tribune - July 16, 2002
By Peter Passi
News Tribune Staff Writer

Taconite Plant has new use for ash
Nothshore Mining waste may replace come cement used in concrete roads

Much of the ash that Northshore Mining Co. once trucked to a landfill will wind up in Minnesota highways.
Recent state certification of the ash as an approved ingredient in concrete roads could remove about 18,000 tons of material annually from the Silver Bay taconite plant’s waste stream.
Bob Berglund, Northshore’s general manager, said his company has invested about $500,000 in truck-loading machinery plus equipment to separate valuable fly ash from unsuitable by products.
Fly ash produced by coal-burning generators that power the taconite plant could be used to replace up to 25 percent of the Portland cement used in concrete roads, said Doug Schwartz, a concrete engineer for the Minnesota Department of Transportation.
The ash is an attractive additive because it is less expensive than cement and has some advantageous properties. Concrete that contains fly ash is generally more resistant to damage from freezing and thawing, Schwartz said.
Mike Osmundson, Northshore’s manager of special projects, says the taconite plant will be able to sell almost all of the fly ash it produces during construction season, which can run from March through November. But for now, ash that Northshore produces during the off-season will still need to be discarded in a landfill. That’s because Northshore is equipped to store no more than about 200 tons of ash at a time, making it likely that just 50 percent to 75 percent of fly ash it produces annually will be sold.
Osmundson said the landfill Northshore uses was expected to run out of space in 10 years. If the taconite plant can sell half of the ash it produces, Osmundson said, the landfill could remain viable for 30 years.
Should the market for fly ash prove strong enough, Osmundson said, the plant will build, additional storage units that could enable it to sell 80 percent to 90 percent of the ash it produces in a year. Such a move could stretch the life of Northshore’s landfill out to 40 or 50 years, Osmundson said.
Larry Nelson, president of Enduracon Technologies, a Twin Cities firm that helped Northshore become the first facility in the Northland to certify its ash as an acceptable material for state highway construction, is in charge of marketing it, too. His confidence in the future of the product is so strong that he has trademarked the ash, calling it Poz NS.