Bill Harris
May 18, 2007, 01:07 AM
The spectral characteristics of weathering coal mine spoil or coal mine waste can disclose a great deal of information about the potential for acid mine drainage production. This image is from a proof-of-concept study I conducted two years ago at a coal waste reclamation project to demonstrate the use of RC aerial photography for coal mine inspection.
The first photo is an unenhanced image of the reclamation project. The second image shows this image with enhanced red, green and blue channels showing differences in features that could cause environmental problems. The third image is an annotated version of the previous image.
When coal waste weathers, the iron pyrite in it oxidizes to iron and sulfate, both of which are soluble and can enter the hydrologic system with the potential for causing acid mine drainage. The sulfate is expressed at the surface as a light-toned coating called a sulfate bloom and shows in the enhanced imaes as a light blue color. Iron in groundwater can oxidize to a ferric hydroxide on contact with the air, which has a characteristic dark red color when enhanced.
--Bill
The first photo is an unenhanced image of the reclamation project. The second image shows this image with enhanced red, green and blue channels showing differences in features that could cause environmental problems. The third image is an annotated version of the previous image.
When coal waste weathers, the iron pyrite in it oxidizes to iron and sulfate, both of which are soluble and can enter the hydrologic system with the potential for causing acid mine drainage. The sulfate is expressed at the surface as a light-toned coating called a sulfate bloom and shows in the enhanced imaes as a light blue color. Iron in groundwater can oxidize to a ferric hydroxide on contact with the air, which has a characteristic dark red color when enhanced.
--Bill