Environmental Impacts at Fort Belknap from Gold Mining

This page was written by Erin Klauk as part of the DLESE Community Services Project: Integrating Research in Education.

Ruby Gulch flowing through Zortman, MT. Details

The Zortman-Landusky gold mine is a case study of the environmental risks of cyanide heap-leach gold mining and the impacts that these operations can have on communities, water and cultural resources. The Zortman-Landusky mine illustrates how modern mine operations continue to impact landscapes and leave behind massive environmental problems and liabilities. The mine experienced many problems, such as cyanide spills, and surface and groundwater contamination from acid mine drainage. This was one of the first massive cyanide heap-leach operations to open, as well as one of the first to close, leaving behind significant pollution and cleanup problems (Case Studies - The Effects of Mining ( This site may be offline. ) ).

In 1982, 2,953 liters of cyanide-tainted solution leaked from a containment pond and a section of piping used in the mine's cyanide sprinkling system ruptured and released 196, 841 liters of cyanide solution onto lands and creeks. The tap water revealed cyanide concentration levels above drinking water standards and the community's local water system was shutdown. Over the next two years, eight separate cyanide spills occurred. Without a permit, in September 1986, 75 million liters of treated cyanide solution was released onto 7 hectares of land when a solution pond was at risk of overflowing after a heavy rainstorm. Following one of the major spills, cyanide appeared in tap water in a mineworker's housing unit, just south of the mine, animals were found dead, and acid mine drainage contaminates nearly every stream drainage that emanates from the mine (Case Studies - The Effects of Mining ( This site may be offline. ) ).

Even though there were major environmental problems from the mining, the mining company, Pegasus, received only one fine for $15,000 in its first 16 years of operation. After years of unsuccessfully trying to address the environmental problems at Zortman-Landusky, local citizens and environmental groups sued Pegasus under the Clean Water Act, resulting in a 36 million settlement in 1996. Even with this settlement, cleanup funds for the mine were inadequate and citizens in the state were left with cleanup liability of tens of millions of dollars. In 1998, Pegasus went bankrupt (Case Studies - The Effects of Mining ( This site may be offline. ) ).

Although the mines are no longer in operation, tribal water resources continue to be threatened by acid mine drainage that occurs when sulfide rocks uncovered by the mining process produce sulfuric acid after exposure to rain and snow, and the mine sites contain vast quantities of sulfide rock (Final Report of the State - Tribal Relations Committee). The severe acidity of the water will require water treatment, but there is currently only enough funding for treatment until the year 2028 (Final Report of the State - Tribal Relations Committee).

Landusky Mine as viewed from the south. Details

To further investigate environmental impacts from gold mining on the Fort Belknap Indian Reservation, follow the links below.

Investigate the Environmental Impacts on the Fort Belknap Indian Reservation

Resources containing information about the environmental impacts of the Fort Belknap Indian Reservation.

  • A Mountain of Unanswered Questions: Are Health Problems of Reservation Residents Related to the Mines? . This article from Native News addresses the possibility of why health and environmental concerns on the Fort Belknap Indian Reservation may be related to water pollution from cyanide heap leach gold mining. (more info)
  • Au-Ag-Te Vein Deposits. This resource is a part of the USGS document entitled "Preliminary Compilation of Descriptive Geoenvironmental Mineral Deposit Models". This chapter of the document describes gold, silver and tellurium vein deposits. Topics include a summary of relevant geologic, environmental, and geophysical information, geologic factors that influence potential environmental effects, and environmental signatures. (more info)
  • Case Studies - The Effects of Mining. This report consists of a series of ten case studies that represent a diverse cross-section of communities affected by mining and a diverse set of issues about mining. The case studies demonstrate the urgent need for mining companies to formally recognize the rights of communities to free, informed consent as a precondition of mining; to be held accountable to communities during mining; and adhere to the highest environmental, human and social rights, standards and practices. ( This site may be offline. )
  • Cyanide Leach Mining Packet. This information packet provides a variety of resources about the use of cyanide in mining. Included are a fact sheet about cyanide from the Mineral Policy Center, an introduction from the paper 'Cyanide Uncertainties: Observations on the Chemistry, Toxicity, and Analysis of Cyanide in Mining-Related Waters,' a diagram of the heap-leach process, a Washington Post article about the cyanide spill in Romania, a cyanide fact sheet from The Agency for Toxic Substances and Disease Registry, and excerpts from 'Poisoned Profits: Cyanide Heap Leach Mining and its Impacts on the Environment.' Also included is the Environmental Protection Agency´┐Żs Toxic Release Inventory which shows the 1998 releases of cyanide compounds and hydrogen cyanide, and a list of suggested readings. (more info)
  • Cyanide Uncertainties: Observations on the Chemistry, Toxicity, and Analysis of Cyanide in Mining-Related Waters. This article discusses the use of cyanide compounds by mining industries. The article includes information about the chemistry and toxicity of cyanide, monitoring and analysis of cyanide at mine sites, and a case study about a cyanide spill in Kyrgyzstan. Examples of recent cyanide related mine accidents, and factors affecting cyanide toxicity to freshwater fish are also included in this article. (more info)
  • Final Supplemental Environmental Impact Statement for Reclamation of the Zortman and Landusky Mines.. This is the Final Supplemental Environmental Impact Statement for reclamation of the Zortman and Landusky Mines in north central Montana. The purpose of this document is to present several alternatives for the reclamation of the mine complex. The report includes the history of the site, the site geology and hydrology, a description of contamination issues, and 12 alternative plans for reclamation of the mines. Also included are four detailed appendices, an extensive list of tables and figures, and a collection of photos from the mines. (more info)
  • Fort Belknap Tribes File New Lawsuit Over Mining Pollution. This February 2004 article in Indian Country Today discusses a lawsuit over mining pollution at the Zortman-Landusky mine complex on the Fort Belknap Indian Reservation. The Assiniboine and Gros Ventre tribes allege that pollution from mine tailings and open-pit excavation in the Little Rocky Mountains continues to pollute streams and groundwater, the tribes say, and the contamination is impacting the adjacent reservation and its residents. They also argue that the quantity of water flowing from the mine areas has been diminished. (more info)
  • Geochemical Characterization and Water Quality Predictions for the Zortman/Landusky Reclamation Project.. This 16 page PDF provides information about the reclamation of the Zortman and Landusky gold mines in the Little Rocky Mountains of north-central Montana. (more info)
  • Material Characterization and Prioritization of Remediation Measures at the Zortman/Landusky Mine Sites.. This 13-page PDF provides information about the reclamation of the Zortman and Landusky gold mines in the Little Rocky Mountains of north-central Montana. (more info)
  • Modeling of Alternative Cover Scenarios for Mine Rock Piles at the Zortman and Landusky Mine Sites. This paper provides information about the reclamation of the Zortman and Landusky gold and silver mines in the little Rocky Mountains of north-central Montana that is currently on-going under the direction of the Montana Department of Environmental Quality and the U.S. BLM. (more info)
  • More Cyanide Uncertainties: Lessons from the Baia Mare, Romania Spill-Water Quality and Politics. This paper describes the risks associated with the use of cyanide in modern mining and asserts that governments and mining companies have not adequately addressed this growing environmental problem. The paper provides recommendations that should be followed at mines in order to provide more environmental protection. A cyanide leach mining spill at the Baia Mare mining operation in Romania is used as a case study for improvements that need to be considered. The paper also states that a report by the United Nations Environment Programme does not go far enough in providing adequate protection from cyanide spills. ( This site may be offline. )
  • Petitioned Public Health Assessment. This document summarizes environmental and health data for two large, open-pit, cyanide heap leaching, gold mines located adjacent to the Fort Belknap Reservation in Montana. This public health assessment is a review of information about hazardous substances at the Zortman-Landusky mine and it evaluates whether exposure to these substances might cause any harm to people. Topics that are discussed include the history and background of the Zortman-Landusky mine, environmental contamination data illustrated with detailed tables, and public health information. (more info)
  • Review of the Multiple Accounts Analysis Alternatives Evaluation Process Completed for the Reclamation of the Zortman and Landusky Mine Sites. This 17-page PDF describes the MAA process and the rationale developed to prioritize the remediation measures and evaluate the various reclamation alternatives that could be used in the project that is currently on-going at the Zortman and Landusky gold mines in the Little Rocky Mountains of north-central Montana. (more info)
  • Technical Resource Document: Extraction and Beneficiation of Ores and Minerals Volume 2: Gold. This EPA document provides detailed information about the gold mining industry in terms of the wastes associated with gold mining and processing. The report briefly characterizes the geology of gold ores and the economics of the industry. Specific information from EPA site visits is included for the Brewer Mine, Colosseum Mine, Nerco Minerals Cripple Creek, and the Newmont Gold Company in Nevada. (more info)
  • Toxicological Profile for Cyanide . This is a summary of the toxicological and health effects of cyanide. This site is authored by the Agency for Toxic Substances and Disease Registry and begins with a public health statement that summarizes in non-technical language, cyanide's relevant properties. Other topics include human health, chemical and physical information, production, import, use and disposal, potential for human exposure, analytical methods, and regulations and advisories. (more info)
  • Cyanide Hazards to Plants and Animals from Gold Mining and Related Water Issues. [Eisler and Weimeyer, 2004] This article from Reviews of Environmental Contamination and Toxicology discusses cyanide extraction of gold through milling of high-grade ores and heap leaching of low-grade ores. The article describes the procedure of extraction, as well as environmental problems that may occur from cyanide extraction. A variety of exclusion/cyanide reduction techniques are presented and discussed, and additional research is recommended. (citation and description)
  • Progress toward Pollution Prevention and Waste Minimization in the North American Gold Mining Industry. [Hilson and Murck, 2001] This paper addresses the two most environmentally problematic areas in the gold mine industry, which are the use of cyanide and acid mine drainage. The authors outline the environmental options available, the progress made towards pollution prevention, and areas in need of further improvement. The paper points out that most of the gold mines operated by the larger mining companies have implemented the state-of-the-art measures that help to prevent environmental problems; but that the small- and medium- sized companies are only doing what is necessary to comply with environmental regulations. It is concluded that the North American gold mining industry should form research partnerships with governments and academic institutions in order to explore new environmental aspects of the industry, in particular, biological oxidation. (Full Text Online)
  • Characterization and Availability of Cyanide in Solid Mine Tailings from Gold Extraction Plants.. [Zagury, Oudjehani and Deschenes, 2004] This article from Science of the Total Environment investigates the availability and fate of cyanide in gold mill solid tailings. To do this, tailings that were 6 to 9 years old and tailings that were 3 months old were sampled at various depths from two gold mining sites in Quebec, Canada. The study revealed a difference in physicochemical properties, cyanide concentration and speciation, viable bacterial populations and cyanide leaching behavior between aged and fresh solid mine tailings. (citation and description)

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