Water Resources Research Act Program

Details for Project ID 2007MT152B

Sediment and Heavy Metals Source Determination and Reduction at a Reclaimed Abandoned Mine Site, Alta Mine, Jefferson County, MT

Institute: Montana
Year Established: 2007 Start Date: 2007-03-01 End Date: 2009-02-28
Total Federal Funds: $4,000 Total Non-Federal Funds: $8,750

Principal Investigators: Clayton Marlow

Project Summary: The Alta Mine is located in the Lake Helena Watershed. Specifically, the Alta Mine tributary discharges into Corbin Creek, which is on the 303(d) list for water quality impairments. The Alta Mine was divided into 2 sites, the upper Alta and lower Alta, for the sake of a 1999 reclamation effort. During reclamation, steep slopes adjacent to the mine were terraced and re-vegetated to reduce erosion into the Alta tributary. However, only the lower Alta was reclaimed; and both sites persist as sources of heavy metals and sediment discharge to the stream. The problem addressed by the proposed research project is the lack of baseline information necessary to successfully re-vegetate the reclaimed area. Specifically, an accurate assessment of the amount of sediment and heavy metals from both reclaimed and un-reclaimed portions of the Alta Mine does not exist. The objective of the proposed research is to test the efficacy of re-vegetation treatments at reducing sediment and heavy metals in the Alta tributary. However, before the success of the vegetation treatments can be evaluated, a baseline quantification of the heavy metals and sediment loads from major sources at the abandoned mine site must be made. While the establishment of this baseline is only a preliminary step towards source reduction, it is an imperative one. Thus, direct field sampling of suspected sources for heavy metals (arsenic, lead, and zinc) and sediment is the primary task of the proposed research. Secondly, an attempt will be made to re-vegetate portions of the previously reclaimed slopes that have no vegetative ground cover; and any changes in sediment and metals loads will be measured over the first growing season. Three major sources, the upper Alta waste rock pile, the lower Alta reclaimed hill-slopes, and a leaking mine shaft (#8 shaft) will be investigated. In-situ metals concentrations in the lower Alta slopes will be determined by soil pit sampling and spatial analysis (i.e. kriging or thin plate splines). Metals concentrations taken in a 1993 pre-reclamation sampling effort will be considered representative of the nonreclaimed upper Alta waste rock pile. Bi-weekly water samples will be collected below each source via standard methods and analyzed for suspended sediment, As, Pb, and Zn. Re-vegetation treatments, applied in a block design on the lower Alta, will include lime and compost, lime and erosion fabric, lime alone, compost alone, fabric alone, and seeding with no amendments. Upland sediment traps will be installed below each of the treatments to quantify initial sediment yield.