Acid mine drainage with its associated dissolved metals is a major pollution problem in the United States and around the world. There are thousands of abandoned coal and metal mines that currently are polluting our streams and rivers with metal-laden acid runoff. Passive treatment systems are the most promising because there is no associated recurring cost. One passive system, the Limestone Drain, produces alkalinity in an anoxic or open environment that neutralizes acidity, raises pH, and increases the effectiveness of other wetland systems. The advantage to constructing a limestone drain inside a mine is that the acid drainage is treated while it still is contained inside the mine and has not dispersed to a creek or through the soil, where it is difficult to capture and treat. Conventional construction equipment cannot build a drain longer than 20 to 30 feet without forcing personnel to work inside the portal, a situation not allowed due to the extreme danger.The Phase I project will design and build an in situ limestone drain in a mine portal. The drain will be constructed by pneumatically stowing 2 x 0 limestone rock 100 feet into a mine portal from the outside of the mine, from the portal face, and through a borehole.The project will demonstrate two pneumatic devices that will build limestone drains in underground mines without the necessity for personnel to enter the mine. It is expected that this project will demonstrate that the pneumatically placed in situ limestone drain will raise the pH of the mine outflow to almost 7.0 and reduce the acidity to almost 0. The project will demonstrate that 2 x 0 clean limestone, even if armored, will continue to treat the outflow. The in situ limestone drain will eliminate the need for a large percentage of the chemical treatment systems that can cost $300,000 per year for operation and maintenance.It is estimated that all in situ limestone drain consisting of 300 tons of limestone can be installed in 2 days or less for approximately $10,000. Every mine, abandoned and active, that has the potential for or has acid mine drainage is a potential site for applying the technology. Users will be the government agencies responsible for mine cleanup, both federal and state where abandoned mines are found, the Rural Abandoned Mine Program, the EPA, mine closure specialists, milling companies, and the State and Federal Abandoned Mine Land Programs.Supplemental
Keywords:small business, SBIR, wastewater treatment, pollution prevention, engineering
