Potential Utilization of FGD Gypsum for Reclamation of Abandoned Highwalls
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| Title: | Potential Utilization of FGD Gypsum for Reclamation of Abandoned Highwalls |
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| Authors: | Modi, Deepa |
| Advisors: | Wolfe, William, Butalia, Tarunjit |
| Summary: | In order to reduce air pollution resulting from the combustion of coal in electric utility boilers, utilities that operate coal-fired power plants have installed air pollution control technologies. While airborne pollution has been significantly curtailed, these methodologies have significantly increased the amount of solid byproducts generated, most of which are currently landfilled. In the Appalachian region of the US, a large number of abandoned coal mines exist, many with dangerous highwalls and pits. These abandoned highwalls pose a safety risk and many are sources of acid mine drainage that can compromise the quality of the ground water and nearby streams. In this thesis, the above two issues are addressed and the utilization of coal combustion by-products in mine reclamation work has been studied. This study is focused on the use of FGD (Flue Gas Desulfurization) gypsum in the reclamation of abandoned coal mine highwalls. The main objective of this research is to investigate the potential use of FGD gypsum (in the combination with fly ash and lime) as a backfill material for reclaiming abandoned highwalls. FGD gypsum and a mixture of FGD gypsum, fly ash, and lime are studied as a potential highwall backfill material. Several laboratory tests (e.g. compaction, strength, permeability, and solubility) are performed. The substitution of FGD gypsum with fly ash did not appreciably change the permeability or strength of the FGD gypsum. However, the addition of lime to the mixture of FGD gypsum and fly ash reduced the permeability and increased the strength by an order of magnitude. Solubility of the FGD gypsum mixes studied was found to be low.In order to check the stability of a reclaimed highwall backfill, the factor of safety was evaluated using a commercial analyses program for a demonstration site close to the Conesville power plant. The slope stability analyses indicated that FGD gypsum or a mixture of FGD gypsum and fly ash gives a factor of safety more than 1.5. |
| URL: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1281477085 |
| Database: | OpenDissertations |
| Abstract: | In order to reduce air pollution resulting from the combustion of coal in electric utility boilers, utilities that operate coal-fired power plants have installed air pollution control technologies. While airborne pollution has been significantly curtailed, these methodologies have significantly increased the amount of solid byproducts generated, most of which are currently landfilled. In the Appalachian region of the US, a large number of abandoned coal mines exist, many with dangerous highwalls and pits. These abandoned highwalls pose a safety risk and many are sources of acid mine drainage that can compromise the quality of the ground water and nearby streams. In this thesis, the above two issues are addressed and the utilization of coal combustion by-products in mine reclamation work has been studied. This study is focused on the use of FGD (Flue Gas Desulfurization) gypsum in the reclamation of abandoned coal mine highwalls. The main objective of this research is to investigate the potential use of FGD gypsum (in the combination with fly ash and lime) as a backfill material for reclaiming abandoned highwalls. FGD gypsum and a mixture of FGD gypsum, fly ash, and lime are studied as a potential highwall backfill material. Several laboratory tests (e.g. compaction, strength, permeability, and solubility) are performed. The substitution of FGD gypsum with fly ash did not appreciably change the permeability or strength of the FGD gypsum. However, the addition of lime to the mixture of FGD gypsum and fly ash reduced the permeability and increased the strength by an order of magnitude. Solubility of the FGD gypsum mixes studied was found to be low.In order to check the stability of a reclaimed highwall backfill, the factor of safety was evaluated using a commercial analyses program for a demonstration site close to the Conesville power plant. The slope stability analyses indicated that FGD gypsum or a mixture of FGD gypsum and fly ash gives a factor of safety more than 1.5. |
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