Zortman-Landusky Gold Mine, Montana, USA


The Zortman-Landusky mine was one of many heap leach mines located near the Fort Belknap Indian Reservation that was home to the Gros Ventre and Assiniboine Tribes. The heap leach process uses chemicals including cyanide to absorb the precious then re-separate them later. This specific mining operation had over a dozen cyanide spills including one incident that resulted in over 50,000 gallons of cyanide being spilled. The mine was also found to be leaking acids, arsenic and lead. This large and frequent contamination led to extensive surface and groundwater contamination. In 1993, the EPA filed a Clean Water Act suit that required a 32 million dollar clean up. Although the leaks happened in the 1980s, and the mine was eventually shut down in 1998, health problems on the reservation continue to be a problem. The company filed for bankruptcy and left the state of Montana without proper reclamation of the land including leaving toxins like arsenic, hills of waste rock and exposed mountain sides.

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Basic Data
NameZortman-Landusky Gold Mine, Montana, USA
CountryUnited States of America
SitePhilips County - Fort Balknap Indian Reservation
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Mineral Ores and Building Materials Extraction
Type of Conflict (2nd level)Mineral ore exploration
Specific CommoditiesGold
Project Details and Actors
Project DetailsThe two open pit mines on the Zortman-Landusky mines were open from 1979 to 1998. The mines produced 140 million tons of ore and disrupted 1,200 acres of land.
Project Area (in hectares)486
Level of Investment (in USD)56,525,300
Type of PopulationRural
Potential Affected Population5,000-10,000
Company Names or State EnterprisesPegasus Gold Corporation from Canada - Owner
Zortman Mining Inc. (ZMI) from United States of America
Relevant government actorsUnited States Bureau of Land Management

U.S Environmental Protection Agency

Montana’s Department of Environmental Quality

National Wildlife


Montana Environmental Information Center
The Conflict and the Mobilization
Intensity of Conflict (at highest level)LOW (some local organising)
When did the mobilization beginIn REACTION to the implementation (during construction or operation)
Groups MobilizingIndigenous groups or traditional communities
Local government/political parties
Ethnically/racially discriminated groups
Gros Ventre and Assiniboine Tribes
Forms of MobilizationDevelopment of a network/collective action
Lawsuits, court cases, judicial activism
Environmental ImpactsVisible: Soil contamination, Waste overflow, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion, Reduced ecological / hydrological connectivity, Mine tailing spills
Health ImpactsVisible: Accidents, Other environmental related diseases
Otherbreathing difficulties, heart pains, vomiting, blood

changes, headaches, enlargement of the thyroid gland, convulsions, and loss of consciousness, and death
Socio-economic ImpactsVisible: Loss of traditional knowledge/practices/cultures, Violations of human rights, Loss of landscape/sense of place, Other socio-economic impacts
Project StatusIn operation
Pathways for conflict outcome / responseCompensation
Environmental improvements, rehabilitation/restoration of area
Court decision (victory for environmental justice)
Negotiated alternative solution
enduring environmental disaster legacy, orchestrated company bankruptcy
Do you consider this as a success?No
Why? Explain briefly.While there were litigious victories and compensation by Pegasus and the state of Montana, it is believed that this will not be enough to adequately clean up the mining operation. Additionally, there was not adequate involvement with the Indian Nations by the Bureau of Land Management when the large expansions of the mines were developed.
Sources and Materials

Honoring the River by the National Wildlife Federation, April 2013
[click to view]

CYANIDE LEACH MINING PACKET by Mineral Policy Center August 2000
[click to view]


R. David Williams2

ZORTMAN-LANDUSKY: CHALLENGES IN A DECADE OF CLOSURE, by R. David Williams, Joan Gabelman, Shannon Shaw, Wayne Jepson, Chris Gammons,

and John Kill Eagle
[click to view]


Tribes attack BLM for broken trust over mines
[click to view]

Impacts of Resource Development on Native American Lands
[click to view]

Schweitzer signs measure for Fort Belknap water treatment
[click to view]

Earthwork on Canadian mining companies in the US
[click to view]

Media Links

Zortman Landusky Pegasus Heap Leach Cyanide Gold Mine
[click to view]

Other Documents

Source: http://nodirtygold.earthworksaction.org/better_mining#.VIbl_2SsWu8
[click to view]

Meta Information
ContributorSara Orvis, University of Michigan School of Natural Resources and Environment, [email protected]
Last update09/12/2014