Mining Returns: Finding Uses for Coal Combustion Byproducts
By Jenelle Cooper
Tarunjit Butalia, a research scientist, leads a team that already has determined how the byproducts can be used in highway and other infrastructure rehabilitation applications. Now the civil and environmental engineering and geodetic sciences experts aim to expand the beneficial use of Ohio coal combustion byproducts from 3 million tons per year in 2008 to about 5.6 million tons by 2012. The work is funded by
$1.7 million from the Ohio Coal Development Office as a part of the Ohio Advanced Energy Job Stimulus Fund.
Federal and state regulations require coal-fired power plants to remove particulate matter (fly ash) from the flue gases and scrub the gases for sulfur-dioxide, Butalia explains. The forced oxidation desulfurization process generates a solid flue gas desulfurization (FGD) material called FGD gypsum. In the absence of oxidation, the FGD material generated is called sulfite FGD, and when it is stabilized with the addition of fly ash, it is referred to as stabilized FGD material.
“By 2012, Ohio is expected to generate more than 16 million tons per year of coal combustion byproducts, including
10 million tons of FGD materials,” says Butalia, coordinator of the statewide Coal Combustion Products Program at the university.
To prevent the excess FGD gypsum from being sent to landfills, Butalia and his team are using it to reclaim old abandoned surface coal mines that have dangerous highwalls, spoil and acid mine drainage.
Butalia’s colleagues on the project are Professors William Wolfe and Harold Walker and research associate Jason Cheng; Bob Baker, president of Baker Environmental Services and Testing and an Ohio State natural resources alumnus; and James Kirch, a civil engineering master’s degree fellowship student. They collaborate with program co-sponsors American Electric Power, Ohio American Energy, Ohio Department of Natural Resources’ Division of Mineral Resource Management, U.S. EPA, U.S. Department of Interior’s Office of Surface Mining, Electric Power Research Institute, American Coal Ash Association, Midwest Coal Ash Association and Ohio Mineland Partnership.
The mine reclamation demonstration project consists of three field construction and monitoring sites:
a large use of FGD gypsum (about 1 million tons) to backfill an abandoned highwall near American Electric Power’s Conesville plant. Stabilized FGD material generated at the plant is used as a liner under and cap over the gypsum fill. Trees will be planted to improve the site’s appearance and produce environmental carbon credits.
about 0.2 million tons of FGD gypsum combined with onsite spoil to reclaim a site where Ohio American Energy is recovering coal near AEP’s Cardinal plant
a small field trial expected to be near Cardinal or Conesville where auger holes from previous mining will be filled — with a coal combustion byproduct grout (including FGD gypsum) being developed by Kirch — so miners can drill additional holes to retrieve coal without losing the site’s stability. Using this method, highwall miners could re-mine an abandoned site, recover significantly more coal reserves and then reclaim the site during the re-mining process, enabling the coal industry to clean up abandoned coal mine sites created before modern mining laws were implemented, says Butalia.
Widespread use of such methods would promote Ohio coal, reduce environmental and safety hazards, prevent landfill expansion, and reclaim land for recreation and economic development. The program saves money by reclaiming the sites with a no-cost material and reducing landfill costs.