Duluth News Tribune - September 23, 2003
By Peter Passi
News Tribune Staff Writer

Success on the fly
RECYCLING: Profitable experiment teaches Duluth Steam Cooperative
that fly ash can be a valuable byproduct, instead of trash.

After more than two years of trial, Duluth Steam Cooperative manager Jerry Pelofske is ready to call his plant’s experiment selling fly ash an unqualified success.
In the past year, Duluth Steam has sold more than 1,600 tons of the fine ash from its coal-burning boilers to a company that markets the material as a concrete additive.
The fly ash hasn’t generated a large revenue stream for the cooperative by any stretch. Pelofske said it generates just a few hundred dollars per year.
However, ash sales have cut the steam plant’s expenses substantially. Formerly, the plant paid to truck all of its ash to a landfill near Eau Claire, Pelofske figures the cooperative saves about $45,000 annually by not trashing 1,600 tons of ash.
Those numbers made it easy for the cooperative to decide last week to renew its contract with Enduracon Technologies, the St. Paul firm that buys and distributes its ash. When added to cement in proper proportions, the fly ash can slow the curing of concrete, resulting in a stronger, harder finished product.
During the winter, when Northland construction crawls to a near-halt, demand drops. So the steam cooperative invested about $75,000 into a storage silo in 2001, allowing it to stash away ash during periods of low sales.
Pelofske said the silo investment paid for itself in less than two years.
Larry Nelson, Enduracon’s president, said that only low-carbon ash produced by a very hot-burning fire is suitable for use as a concrete additive. His company has supplied tools and training to the operators of Duluth Steam, enabling them to constantly monitor the quality of ash being produced.
Pelofske said that about two-thirds of all fly ash generated by the steam plan is deemed suitable for sale. The cooperative also is studying whether there might be a market for lower-grade ash and ground up boiler slag as a backfill material.
Today, Enduracon also buys fly ash from another Northland coal burner – Northshore Steel Mining Co., a Silver Bay taconite producer. But Nelson said, “It all started with Duluth Steam.”
This year, Nelson expects his company will sell 11,000 tons of ash from Northshore. During 2004, he hopes to increase that total to 15,000 to 16,000 tons.
Nelson sees room for more growth, as well. He said he’s in preliminary discussions with Minnesota Power about the possibility of buying fly ash from its power plant in Taconite Harbor.