Distribution of Abandoned and Inactive Mines on
National Forest System Lands

A supporting technical document for the 1993 Update of the RPA Assessment

Before the 1970s, reclamation of mine sites was not required, and was not performed for most sites. Unreclaimed sites often detract aesthetically from the landscape and pose physical hazards that could cause personal injury. Both surface and underground mines, as well as mill tailing and smelter waste dumps, can discharge toxic materials and sediments that degrade water quality.

This report characterizes the distribution of abandoned and inactive mines throughout the United States. The goal of the report is to provide a general understanding of the extent to which abandoned mines are likely to be found throughout the millions of acres of National Forest System (NFS) lands. This assessment is based on the nonconfidential, nonproprietary portions of the Minerals Availability System/Mineral Industry Location System (MAS/MIL) database that has been compiled by the U.S. Department of the Interior. The data provide a reasonable basis for characterizing a lower limit on the number of abandoned and inactive mines on and near national forests throughout the United States. Although great detail is not provided by National Forest, this report indicates where among NFS lands concerns regarding abandoned mines are the greatest.

Mining has taken place in virtually every part of the United States, so there are past producers everywhere as well. A significant portion of the Nation=s mining has occurred on or near NFS lands. The MAS/MIL database lists more than 13,500 past producing mines within the administrative boundaries of the NFS alone. Many of them currently, or have the potential, to degrade surface or ground water, and impact natural ecosystems. In addition, 1,500 of the past produces within NFS boundaries already have been identified as having significant mine drainage problems.

Shields, Deborah J., Douglas D. Brown and Thomas C. Brown. 1995. Distribution of abandoned and inactive mines on National Forest System lands. General Technical Report RM-260. Fort Collins, CO: U.S Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 195 p.