STANDARD UPLAND REVEGETATION SPECIFICATIONS FOR THE BUTTE PRIORITY SOILS OPERABLE UNIT SILVER BOW CREEK/BUTTE AREA SUPERFUND SITE BUTTE, MONTANA

Abstract

This paper will describe the development and implementation of standards for the revegetation of lands disturbed by mining activities in Butte, Montana. The Butte area has served as a globally important mining, milling, and smelting district since the time gold was discovered in the area in 1864. Metal-sulfide deposits rich in copper and zinc were discovered a short time later and became the primary ores in Butte. Over a century of mining resulted in the development of more than 500 underground mines with roughly 3,000 miles of underground workings and numerous waste rock dumps. The operation of mines, mills, concentrators, and smelters generated a variety of waste materials containing elevated concentrations of arsenic, lead, and other metals. In the early 1980s, the Butte area was designated as a Superfund site by the U.S. Environmental Protection Agency (EPA). Land reclamation involving vegetated soil caps has been a vital component of cleanup actions taken to address mine-impacted lands within the largely urban area known as the Butte Priority Soils Operable Unit (BPSOU). Several parties, including EPA, the state abandoned mine lands bureau, the local county government, and members of the responsible party group, have implemented reclamation activities that include the use of vegetated soil caps placed over mining-related wastes. The results of early reclamation efforts were mixed, with both successes and failures. Successful reclamation using soil caps is a critical component of the long-term cleanup plan for the BPSOU. In the late 1990s, EPA, in conjunction with the responsible party group and other stakeholders, agreed upon a standard set of site-specific revegetation construction specifications for upland areas in the BPSOU to ensure consistency in the reclamation work. Criteria were established for pH testing of the subgrade, limestone application, cover soil quality and texture, organic amendment application, seed mixtures, fertilizer, mulch, and seed application. The specifications were derived from a variety of sources including existing abandoned mine reclamation specifications, previous reclamation practices established by EPA and by the local county government, and technical standards developed by the Reclamation Research Unit at Montana State University, as well as negotiation with the responsible party group and input from other stakeholders at the site. The specifications have strengths and weaknesses, but have served the site well in establishing the standards, expectations, and quality of revegetation work conducted at the BPSOU. Additional