California Gulch NRDAR Dinero Tunnel Acid-Mine Drainage Pathway Elimination Restoration

Background information. The Dinero Tunnel, which extends approximately 3,000 feet from the surface to the Dinero Shaft, was used in the late 1800s to mine primarily for silver. In more recent years, the tunnel, located approximately five miles west of Leadville, Colorado, began to discharge acid mine drainage into Sugarloaf Gulch, a tributary to the Lake Fork River which ultimately drains into the upper Arkansas River. Consequently, acid mine drainage from the Dinero Tunnel has significantly affected downstream waters, including a wet meadow and beaver pond complex. Occasionally, the Dinero Tunnel experienced blowouts that developed when temporary pressure would build up behind a blockage in the tunnel, which would then expel sludge ... Show More

Background information. The Dinero Tunnel, which extends approximately 3,000 feet from the surface to the Dinero Shaft, was used in the late 1800s to mine primarily for silver. In more recent years, the tunnel, located approximately five miles west of Leadville, Colorado, began to discharge acid mine drainage into Sugarloaf Gulch, a tributary to the Lake Fork River which ultimately drains into the upper Arkansas River. Consequently, acid mine drainage from the Dinero Tunnel has significantly affected downstream waters, including a wet meadow and beaver pond complex. Occasionally, the Dinero Tunnel experienced blowouts that developed when temporary pressure would build up behind a blockage in the tunnel, which would then expel sludge and rocks and increase the risk of acid mine drainage further downstream.

In response to these conditions, settlement funds from the California Gulch Superfund site have been utilized to support the Dinero Tunnel Acid Mine Drainage Pathway Elimination Project. For this project, the U.S. Fish and Wildlife Service partnered with the Bureau of Land Management (BLM) and the Colorado Division of Reclamation, Mining and Safety. Although the tunnel is located on private land, the BLM led the cleanup because of identified impacts on adjacent and downstream land managed by that agency.

The Dinero Tunnel Acid Mine Drainage Pathway Elimination Project addressed problematic acid mine drainage through the installation of a concrete bulkhead deep inside the tunnel. The idea behind the bulkhead was to reduce the volume of acid mine drainage and the risk of blowout events from the tunnel. The steel reinforced concrete bulkhead, which was installed 1,250 feet from the opening of the Dinero Tunnel, is equipped with a valve to allow for adjustments of water level within the tunnel. Following installation of the bulkhead, there exists the possibility that water from the tunnel may surface uphill of the tunnel opening. However, it is expected that the water will be of good quality because the metals that are generated in the upper portion of the mine pool tend to stratify to the bottom and movement of water within the mine pool is expected to occur above the sulfide ore zones (Stratus Consulting Inc., 2009).

Background information on the Dinero Tunnel Acid Mine Drainage Pathway Elimination Project was obtained from Laura Archuleta, U.S. Fish and Wildlife Service, and Craig Bissonnette, Colorado Division of Reclamation, Mining, and Safety, written commun., 2015; and from California Gulch Superfund site Natural Resource Damage Assessment and Restoration case documents at http://www.cerc.usgs.gov/orda_docs/CaseDetails?ID=37.

References Cited
Stratus Consulting Inc., 2009, Final restoration plan and environmental assessment for the Tiger and Dinero Tunnels restoration: Stratus Consulting Inc., 36 p., accessed June 1, 2015, at  http://www.cerc.usgs.gov/orda_docs/DocHandler.ashx?ID=151. Show Less

Contact(s): Catherine M Cullinane Thomas, Christopher C Huber.

Overview

Project Period: 2006-2014

Location: Colorado

Restoration Type: Acid mine drainage abatement

Lead Agency: Bureau of Land Management

Economic Impacts
National Economic Impacts (2014 dollars):

Total Project Expenditures: $1,294,000


Job-Years: 24.3 (18.8 per $1M)

Labor Income: $1,472,000 ($1.1M per $1M)

Value Added: $1,988,000 ($1.5M per $1M)

Economic Output: $3,767,000 ($2.9M per $1M)

Local Economic Impacts (2014 dollars):

Local Project Expenditures: $118,000

Percent of Project Expenditures Spent Locally: 9%

Local Job-Years: 2.0

Local Labor Income: $117,000

Local Value Added: $127,000

Local Economic Output: $206,000

Big Picture
Main Project: California Gulch NRDAR Restoration

Leadville, located in the mountains of Colorado approximately 100 miles west of Denver, was historically a rich mining district. Silver, gold, copper, zinc, manganese, and lead were all mined in the area beginning in the mid-1800s, but mining has since subsided as the main economic driver for the district. Because of environmental contamination from mining activities, the area known as the California Gulch Superfund site was placed on the U.S. Environmental Protection Agency’s (EPA’s) National Priorities List in September 1983. The site covers approximately 18 square miles in and around Leadville, Colorado, and contains thousands of piles of mine waste and drainage sites that discharge into the California Gulch from underground abandoned ... Show More

Leadville, located in the mountains of Colorado approximately 100 miles west of Denver, was historically a rich mining district. Silver, gold, copper, zinc, manganese, and lead were all mined in the area beginning in the mid-1800s, but mining has since subsided as the main economic driver for the district. Because of environmental contamination from mining activities, the area known as the California Gulch Superfund site was placed on the U.S. Environmental Protection Agency’s (EPA’s) National Priorities List in September 1983. The site covers approximately 18 square miles in and around Leadville, Colorado, and contains thousands of piles of mine waste and drainage sites that discharge into the California Gulch from underground abandoned mines. The EPA began emergency remediation at the site in 1986 and remediation continues to this day. In 2006, on behalf of the public, the Natural Resource Trustees (Trustees), which include U.S. Department of the Interior agencies and the State of Colorado, estimated damages to natural resources at the California Gulch Superfund site. The Trustees determined that the release of hazardous substances from the site, including heavy metals and acid, have resulted in injuries to groundwater and aquatic and terrestrial resources. Injured terrestrial resources include upland areas associated with mine waste deposits and floodplain areas with contaminated riparian zones, irrigated meadows, and fluvial deposits. Surface water in California Gulch has been observed to exceed the adverse effects thresholds for aquatic biota for zinc, cadmium, and other metals, and these high metal concentrations have resulted in nearly a complete loss of some biological communities (Stratus Consulting Inc., 2010).

A 2008 Natural Resource Damage Assessment settlement agreement requires the Resurrection Mining Company and Newmont USA Limited to pay $10.5 million in damages for injured natural resources resulting from the discharge of hazardous substances from the California Gulch Superfund site. Additionally, the 2009 ASARCO LLC bankruptcy resulted in a $10 million, plus interest, settlement to the Trustees. These settlement funds were used for many restoration projects in and around Leadville, Colorado, including the Arkansas Instream Habitat Restoration Project, the Canterbury Tunnel Project, and the Dinero Tunnel Project. A great deal of progress has been made as a result of these and other restoration projects in the area and, as of 2014, 70 percent of the site had been delisted from the EPA’s National Priority List. The U.S. Geological Survey collected data on restoration activities and expenditures to estimate the economic activity supported by these restoration projects.
Background information on the Arkansas River instream habitat restoration was obtained from Laura Archuleta, U.S. Fish and Wildlife Service, written commun., 2015; and from California Gulch Superfund site Natural Resource Damage Assessment and Restoration case documents at http://www.cerc.usgs.gov/orda_docs/CaseDetails?ID=37.

References Cited

Stratus Consulting Inc., 2010, Restoration plan and environmental assessment for the Upper Arkansas River Watershed: Stratus Consulting Inc., 111 p., accessed June 1, 2015, at http://www.cerc.usgs.gov/orda_docs/DocHandler.ashx?ID=152.

 

 

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