ACTION OF A NATURAL BATERIAL CONSORTIA ON ACID MINE DRAINAGE FROM THE KEMPTON MINE COMPLEX: A SMALL COMPONENT OF UNDERSTANDING OF ONE OF THE LARGE COAL MINES IN MARYLAND

The Kempton Mine operated in western Maryland and northern West Virginia between 1914 and 1950 and primary extraction of the ~60 inch thick Upper Freeport coal bed. Closure of the mine was followed by rapid filling of the complex with groundwater. For over 50 years, water has been flowing primarily from the man shaft and bore hole edifices of the mine, into Laurel Run at the headwaters of the Potomac River. Effluent is being released into the environment at a rate of ~6 million gallons per day, and a pH of ~ 3.45, with a relatively constant ion load. A variety of remediation efforts have been attempted to rectify the problem with variable success.

In this study, we have attempted to investigate the influence of microorganisms on acid mine drainage (AMD) generation. To this end, water and sediment samples were collected aseptically from Kempton effluent vents, in addition to a sample from a coal seam. The following information was also collected at the sample sites: temperature, total dissolved solids, dissolved oxygen, pH, sulfate, ferric and ferrous iron.. Water and sediment samples were examined in the laboratory using a microscope and found to contain a variety of motile organisms. These samples were used as an inoculum for nineteen experiments containing a defined base media, 15 mg of crushed pyrite, and addition of ~1 cm pyrite cubes. Products of the experiments were then analyzed for pH, and bacteria-mineral relationships using a FE-SEM. The following results were obtained: 1) well developed biofilms on mineral surfaces that appear to be dominated by polysaccharide polymers, 2) bacterial consortia exhibiting three common morphological forms (cocci, rods, and spirillum), and 3) pH values ranging from 1.0 to 1.5. These observations provide evidence that natural bacterial species from the mine are able to form prolific biofilms in association with sulfide minerals, and that the bacteria play a role in the kinetics and extent to which pyrite is reduced in the production of AMD in the system.