Minerals and Mining - Abandoned Mined Lands

 

Updated as of 1/24/01

The South Dakota Department of Environment and Natural Resources (DENR) completed an inventory of known inactive and abandoned mine lands (IAMs) in the Black Hills. The inventory, conducted by the South Dakota School of Mines and Technology as a contractor for DENR, includes information on old, historic mines operated by the "old time" miners many years before environmental laws required reclamation. It identifies approximately 900 hardrock IAM sites within a specified area of Meade, Lawrence, Pennington, and Custer counties. An inventory of IAM sites on U.S. Forest Service lands (discussed in more detail below) was incorporated into the state's inventory.

 

Important: Abandoned mines are dangerous and should not be visited in the field. The abandoned mine inventory is not intended to encourage or facilitate people to visit these sites in the field. This is particularly important due to hazards that can be present. Children should never be brought onto these sites. Most of the sites are on private land and access without permission would constitute illegal trespassing.

It is also important to recognize that abandoned mines can have negative impacts outside of the boundaries of the site where mining activities took place. For example, eroding tailings and/or contaminated water can be present and have toxic effects downstream (downgradient) from the site where mining, mineral processing and waste disposal occurred.

 

Of the approximately 900 inventoried sites, about 200 are located on U.S. Forest Service land and about 700 on private land. A fee imposed on active large scale gold mining in the state funded the inventory. The inventory includes information on the locations of known abandoned mine sites (mainly from conducting a literature search on available information on abandoned mines), the results of random field verification conducted at about 10 percent of the sites identified in the literature on private land, and a bibliography of existing abandoned mine related data. These items were part of the requirements of the state law that mandated the inventory.

 

An inventory of IAM sites on U.S. Forest Service (USFS) lands was conducted by the USFS and was incorporated into the state's database. In an effort to prioritize the mines on National Forest lands, those sites (about 200) were subjected to a hazard screening for physical and environmental hazards.

About 65 inactive and abandoned mine sites, mostly on private land, have been voluntarily reclaimed by the active mining industry on properties that they own or control. Some of those sites have become part of an active mining operation. A few sites on federal land have been reclaimed by the USFS.

 

Acid Mine Drainage at the Minnesota Ridge Mine, North-Central Black Hills

Many abandoned mine sites pose physical safety, human health and/or environmental hazards, and are in need of cleanup. However, with regard to the total number of sites identified in the inventory, the number of sites that pose these various kinds of hazards is not known. Based on the limited information collected in the inventory on environmental and physical hazards at sites on US Forest Service land and the few sites on private land that were visited in the field, the DENR believes that the majority of the 900 sites do not pose a significant environmental threat. However, significant physical safety hazards exist at many of the sites. This conclusion is qualified by the recognition that the assessment of environmental and physical hazards was limited in scope (i.e., a "screening" process) and was confined only to the sites on US Forest Service land (about 200 sites). Only 10 percent of the approximately 700 sites on private land were visited in the field to verify locational information, estimate the total area affected by mining, and note any obvious physical or chemical hazards. Human health hazards were not accounted for in assessing any of the sites that were looked at for hazards.

                                                                                Acid Mine Drainage at the Minnesota Ridge Mine,
North-Central Black Hills

 

It is important to point out that, in most cases of abandoned mines in the Black Hills, risks to human health, safety, and the environment have not been assessed. Thus, in most instances, the specific risks and the severity of associated problems posed by individual abandoned mine sites are unknown. Because of this, the DENR is evaluating what it may be able to do to better assess these sites and take remedial steps that are appropriate.

 

The DENR is currently engaged with the U.S. Forest Service and the EPA in assessment work and planned cleanup at the Minnesota Ridge Mine. Likewise, the DENR is working with the U.S. Bureau of Land Management to assess and reclaim the Belle Eldridge Mine. Lessons learned from these two abandoned mine cleanup projects will be evaluated for their potential application to other sites. Although it is currently not certain what might be done at the remaining abandoned mine sites that are in need of assessment and cleanup, the inventory of IAM sites in the Black Hills is a starting point for South Dakota to identify potential problem sites. Opportunities for assessment and cleanup work will continue to be evaluated as they arise and pursued as deemed appropriate. The inventory of IAM sites helps put South Dakota in a position to identify sites that need cleanup and to work with the appropriate landowners, if and when funding and authority to do further assessment work and/or reclamation become available.

 

The DENR regulates the active mining industry, but does not have an abandoned mine reclamation program or adequate funds to reclaim the remaining unreclaimed IAM sites that warrant further cleanup attention. Several efforts are underway on the national level to secure the r?sources needed to cleanup priority IAM sites and to provide incentives to do so. DENR is actively involved with some of these national efforts in hopes of increasing our ability to reclaim sites that are in need of it.

 

The Western Governors' Association has entered into partnerships with the National Mining Association and several federal agencies. These partnerships are currently seeking solutions to the IAM cleanup problem. As part of this national effort, DENR has identified three IAM sites in Lawrence County as sites that the state wants to see reclaimed -- the Minnesota Ridge Mine (see picture above), the Belle Eldridge Mine, and the Eagle Bird Mine. They are small to medium sized abandoned mines typified by draining mine tunnels, acid mine drainage consisting of elevated heavy metals and other contaminants, sulfide waste rock piles, eroding streamside tailings, dilapidated structures and open shafts. As previously mentioned, work is now underway at the Minnesota Ridge and Belle Eldridge mines through cooperative efforts with three federal agencies.

Congress continues to debate the reform of the 1872 Mining Law, which could provide an IAM reclamation fund. Liability remains a major disincentive for cleanup at IAM sites. A "Good Samaritan" amendment to the Clean Water Act has been suggested to provide an incentive for voluntary cleanup of water quality impacts at IAM sites. Under the suggested amendment, a remediating agency would be protected from the liability of any continuing discharges from the reclaimed site provided that the remediating agency -- or "Good Samaritan"-- does not otherwise have liability for the site and attempts to improve the conditions at the site.

 

Papers:

Focusing on the problem of mining wastes: An introduction to acid mine drainage. This is a paper written by Tom Durkin, DENR and J.G. Herman discussing acid mine drainage problems from abandoned metal mine sites.

 

For more information on inactive and abandoned mines, contact Eric Holm or call (605) 773-4201.

 

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