Thousands of abandoned hard-rock

metal mines (such as gold, copper,

lead, and zinc) have left a dual legacy

across the Western United States.

They reflect the historic development

of the West, yet at the same time

represent a possible threat to human

health and local ecosystems. 

Abandoned Mine Lands (AML) are

areas adjacent to or affected by

abandoned mines. AML’s often

contain unmined mineral deposits,

mine dumps (the ore and rock

removed to get to the ore deposits),

and tailings (the material left over

from the ore processing) that contaminate the surrounding watershed and

ecosystem. For example, streams

near AML’s can contain metals and

(or) be so acidic that fish and

aquatic insects cannot live in them.

Many of these abandoned hard-rock

mines are located on or adjacent to

public lands administered by the

Bureau of Land Management,

National Park Service, and U.S.

Forest Service. These Federal land

management agencies and the USGS

are committed to mitigating the

adverse effects that AML’s can have

on water quality and stream habitats. 

The USGS AML Initiative began in

1997 and will continue through 2001

in two pilot watersheds - the Boulder 

River basin in southwestern Montana

and the upper Animas River basin in 

southwestern Colorado. The USGS is

providing a wide range of scientific

expertise to help land managers

minimize and, where possible,

eliminate the adverse environmental

effects of AML’s. USGS ecologists,

geologists, water quality experts,

hydrologists, geochemists, and

mapping and digital data collection

experts are collaborating to provide

the scientific knowledge needed for an

effective cleanup of AML’s.

Goals of the USGS AML Initiative: 

• Develop a watershed-based

approach to provide scientific information needed for cost effective

cleanup of AML’s.

The USGS Abandoned Mine Lands Initiative

Protecting and Restoring the Environment Near Abandoned Mine Lands

U.S. Department of the Interior

U.S. Geological Survey

USGSFact Sheets 095-99

January 1999

The Abandoned Mine Lands

Initiative is part of a larger

strategy of the U.S. Department

of the Interior and the U.S.

Department of Agriculture to

clean up Federal lands contaminated by abandoned mines.

Silverton Colo., at the mouth of the Upper Animas River, surrounded in the background by the headwaters of the Animas

watershed where over 1,500 abandoned mines may be affecting downstream water and ecosystem quality.

Tailings filling the High Ore Creek valley, Boulder River 

watershed southwestern Montana in 1997. The creek eroded

a channel through the tailings, washing them down to the

Boulder River and enriching the water with metals.
• Determine the physical, biological

and chemical processes that control

the environmental effects of AML’s. 

• Provide scientific information for

the design and implementation of

AML cleanup methods.

• Transfer scientific methods developed in the two pilot watershed

studies to other AML’s nationwide.

• Demonstrate the ability of science

to solve an important national environmental problem in a timely

fashion.

• Develop effective working relationships with stakeholders, land management age n c i e s , and reg u l at o ry age n c i e s .

USGS Research Is Making A

Difference

• Tracer tests, in which a harmless

tracer, such as dye, is put into a stream

and its downstream movement measured and modeled, are successfully

identifying the largest sources of

AML contamination and enabling

efficient targeting of cleanup

activities.

• Measurements of water quality and

quantity in both pilot watersheds have

made possible the study of seasonal

and other temporal variations in the

movement of contaminants. For

example, these studies showed that

on approximately 354 days a year

zinc levels in the upper Animas

River exceeded the standards

proposed by the Colorado Water

Quality Control Division.

• Metal concentrations in fish and

invertebrates in the two pilot

watersheds were found to be higher

than in the surrounding water and

bottom sediments. These measurements show that metals (some of

which are toxic) are accumulating

in the local food chain. Researchers

have also determined how these

metals (such as cadmium, copper,

lead, and zinc) move downstream to

settle and accumulate in the bottom

sediment of rivers and streams.

• In some cases, water quality near

AML’s was affected by the natural

weathering of mineral deposits before

mining occurred. Because of this,

scientists are working to determine

the environmental conditions that

existed before mining began in

order to establish realistic cleanup

goals for an area.

• Mapping of the two pilot AML sites

has identified those areas where land

surfaces and stream channels have

been affected by historic mining

activities.

The Future of AML Initiative

Research

USGS AML Initiative activities will

conclude in the year 2001 with a

summary of lessons learned for

successful implementation of a

watershed approach to characterize

contamination from AML. Land

managers will then be able to apply

these lessons to remediate AML sites

in other watersheds. One lesson

already learned by the USGS is that

the success of this initiative depends

upon an interdisciplinary team of

scientists working together with

Federal land managers to provide

science-based solutions to AML

reclamation.

Information

For more information on Abandoned

Mine Lands research at the USGS,

please visit our Web sites at

http://amli.usgs.gov/amli/ and

http://www.usgs.gov.

A natural spring in Prospect Gulch, upper Animas

watershed in southwestern Colorado. Its red iron coloring

and metals enrichment are caused by ground water coming

in contact with naturally occurring minerals present as a

result of ancient volcanic activity in the area.

Biologists collecting samples of aquatic insects from a site impacted by mining activity.