Statement of Critical Regional or State Water Problems:

Great interest has arisen in metallic mining at various locations in Wisconsin. The Flambeau copper mine was operated in northwestern Wisconsin from 1992 to 1997 and a large zinc and copper mine is being proposed for northeastern Wisconsin. Also, exploration is being conducted at several other sites in western Wisconsin for potential mine sites. Concurrently, significant concern has developed regarding the potential for environmental impacts of mining, particularly the pollution of groundwater. Mining’s greatest threat to Wisconsin groundwater is pollution from drainage of mine tailings. Tailings are the residue remaining after benefication of the ore. Drainage from tailings may consist of process water present at the time of disposal (tailings are often disposed in a slurry form) or acidic water caused by percolate passing through tailings undergoing oxidation. Drainage of process water or acidified water can pose a significant threat to groundwater because both liquids usually contain a variety of toxic heavy metals. Statement of Results or Benefits: Mine wastes have significant potential to affect groundwater quality in Wisconsin, the region, and the nation. This is a timely issue because of the major debate taking place in Wisconsin regarding metallic mining and the issues faced by the citizens and the regulatory staff in permit review of mines. There is a need to understand whether the containment systems proposed to contain mine waste will be effective in preventing groundwater pollution. This study will assess a variety of lining system materials exposed to several mine waste liquids. The engineering properties (hydraulic conductivity, strength, and durability) of the materials will be tested after exposure to confirm whether the liquids have had an adverse effect on engineering properties