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Sulfate-Reducing Bacteria Demonstration
Primary Issue Addressed: Acid Drainage/Water Treatment
Secondary Issues Addressed: Biological Treatment, Passive Treatment, and Remote Location
Project Site: Lilly/Orphan Boy Mine near Elliston, Montana
Collaborating Entities: MSE
Cost Share: None
Project Description
This project focuses on an acid mine drainage biological sulfate reduction technology. Aqueous waste contained in the shaft and flowing through the tunnels of the Lilly Orphan Bay Mine are being treated using the mine as an in situ bioreactor. A substrate composed of cow manure, wood chips, and alfalfa was added in 1994 to promote growth of the sulfate-reducing bacteria (SRB). The mineshaft extends to a depth of 250 feet, and it has been flooded to the 74-foot level for over 50 years. This is the level of the portal tunnel. Figure 5 shows a cross-section of the underground mine with the technology installation detailed.
Figure 5. Mine cross-section.
In 2004, this field demonstration was in its tenth year. The analytical data generally demonstrates a decrease in dissolved metals concentrations within the mine tunnel as shown in Figure 6. Manganese, however, is not removed because
SRBs are not effective in its removal. The plot indicates that there is
a significant increase in dissolved metals concentrations during a spring
runoff; however, the levels decreased when flow
rates returned to normal. Sampling of this project is currently
scheduled to continue through September 2005.
Figure 6. Data from feed, tunnel, and portal monitoring locations.