Anaconda Revegetation Treatability Study

Abstract

The Anaconda Revegetation Treatability Study (ARTS) is being conducted to demonstrate inplace treatments of mill tailings, smelter wastes and soils impacted by smelter emissions at the Anaconda Smelter National Priorities List Site in Anaconda, Montana. A study area of approximately 11,000 acres has been divided into the following five subareas: the Opportunity Tailings Ponds, the Anaconda Tailings Ponds, Smelter Hill, Old Works and Adjacent Areas. Acidic mill tailings that contain elevated metal levels are contained in the Opportunity and Anaconda Tailings Ponds systems. The other three areas have been affected by smelting processes and stack emissions. The soils contain elevated metal concentrations and have pH values ranging from acidic to neutral.ARTS is being conducted in four phases. The first completed in 1993, included reviews of reclamation literature and data searches to determine factors controlling the revegetation of acid metalliferous materials at the Anaconda site and other locations with conditions similar to Anaconda. Other Phase I activities included physical and chemical data collection and the selection of demonstration sites within the designated subareas. The second phase included laboratory and greenhouse tests that were used to develop effective amendment/vegetation treatments. Large demonstrations have been implemented in all of the subareas as part of Phase III. On Smelter Hill a five acre site was treated with selected amendments using specialized equipment and seeded with selected vegetation in the Fall of 1993. A one acre demonstration site in the Old Works area was treated with various combinations of amendments and two pieces of heavy equipment were used to incorporate the amendments into these soils. This site was seeded with selected plant species in the Spring of 1994. Another demonstration on a one acre site located on soils which have been primarily surfically impacted is determining the effectiveness of different sources of organic matter (wood wastes, commercial compost, and composted manure) in combination with different lime materials in providing a suitable rootzone. Field demonstrations on tailings ponds were constructed in the Fall of 1994. In Phase IV the effectiveness of the treatments at each site will be monitored. Changes in soil chemistry, rootzone hydrology and vegetation response will be measured.