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Boulder-White Clouds Council |
Acid mine drainage
is the toxic gift that
never stops giving.
Pure
water is more
precious than gold
(or moly).
Keep the Salmon
River
Clean
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LEARN |
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Thompson Creek Molybdenum Mine JUMP AHEAD: General Info Acid Mine Drainage Fact Sheets References Letters Updates
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General Information
Thompson
Creek Molybdenum Mine (TCM) is located between Stanley and Challis and
is Idaho’s largest mine at 3,000 acres. This immense mine is a serious
concern for Idahoans who care for Salmon River country -- it’s just
five miles from and 2,000 feet above the Salmon River. Low moly prices have caused the mine’s work force to drop from 195 people in 1998 to 60 in 2002. Once touted as being a 50-year project, TCM may only operate another 10 years, or close sooner if prices continue to drop. The mine’s gigantic tailings dam, the mile-long, 1500-foot deep open pit, and massive waste rock dumps will need monitoring and maintenance forever. The mine finalized a revised operating plan in 1999.
Facts
about Thompson Creek Mine
The
Mine's Setting There are five key concerns at Thompson Creek:
The
"Acid EIS"… The acid problem was first identified in 1987 (see Fact Sheet #1). But only in 1997, a decade later, did the Salmon-Challis National Forest release a draft environmental impact statement (DEIS). That document analyzed options for containing acid mine drainage, and picked a preferred alternative. Conservation groups worked for years trying to convince the Forest to choose a plan that put keeping the Salmon River clean, first. Such a plan would stop the mine from burying acid-generating material in the Bruno Creek tailings facility. Boulder-White Clouds Council and other groups advocated storing pyrite in a separate, lined facility, or hauled off-site for disposal. Pyrite when mixed with air and water produces sulfuric acid (see Fact Sheet #3 below).
Unfortunately,
the adopted plan continues to allow pyrite to be dumped into the Bruno
Creek tailings impoundment. While it’s true that as long as the pyrite
is under water or otherwise not exposed to air, it will not "go acid"
– but many things can go wrong. Once acid mine drainage starts, it’s
extremely difficult and expensive to stop.
Thompson Creek
Mine Fact Sheets 1989 -- Captions on Forest Service File Photos: In the pit, "brownish pyrite crystals ... are evident throughout the pit area. Pyrite is an acid producer. Snow and rain water and future pit water coming in contact with the sulfides in the pit walls will likely be acidic", (Captions - Photos 5 and 6). In the tailings dam "New material is continually being placed over the lower (acidic) material causing the potential acid producing material to be buried throughout the entire embankment (Photo 9). "Material that has been in place about 18 months is very yellow and has a pH of 3.3 (Photo 12). [A pH of 3.0 will kill all aquatic life.] "The spring water above the upper paddock that runs through tailings had a pH of 3.5 (Photo 15). Forest Service File Photos, 1989.
October
1989
-- "Considering both the sand and rock ... and water sample
results as well as the field indicators we saw last May, it[s] important
that Cyprus obtain a full characterization of the existing and future
potential acid mine drainage situation... On the assumption that this
mine is developing an acid mine drainage condition, there are still alternatives
for mitigation and control. But time is not on our side and if a full
blown AMD problem develops at this mine, there will be few alternatives
for control, if we can control it all." (Forest Service Region IV
letter to Challis NF Supervisor, Oct. 27, 1989, West-Wide Reclamation
Specialist).
The 1998 Forest Service draft plan states that approximately 106 million tons of waste rock remains to be moved to the Pat Hughes and the mine’s other dump in Buckskin Creek. Approximately 33.4 million tons of this waste rock is classified as potentially acid generating. The plan relies on limiting the amount of air and water available to the potentially acid rock for perpetuity in order to prevent acid mine drainage from occurring. The total amount of waste rock to be stored in Pat Hughes and Buckskin dumps is 600 million tons. Pat Hughes steams and melts snow -- Forest Service ignores. Active steam vents of 70 degrees and hot spots which melted snow were observed at the Pat Hughes dump in January 1996, an indication of a chemical reaction taking place. This event has never been documented or reported by the Forest Service. Nor by the mine. However, others were noticeably concerned. "Pat Hughes dump is smoking or steaming. Showing high oxidation and smell sulfur." (Idaho Department of Lands note, after attending Interagency site visit at Thompson Creek on Jan. 18, 1996.) "It appears that Thompson Creek Mine will have a major Acid Rock Drainage (ARD) problem with the Pat Hughes waste dump...This assumption is based on the observation of active steam vents (70 deg. F) and hot spots (melting snow) on parts of the Pat Hughes dump. Steam vents and hot spots, on waste dumps, are indicative of sulfide oxidation in waste material and if left untreated will result in ARD. The Pat Hughes dump is composed mostly of intrusive, sulfide-bearing waste rock (rock type with high potential for ARD). (Idaho Dept. of Environmental Quality (IDEQ) Memo on 1/18/96 Interagency Task Force Meeting at Thompson Creek Mine , Jan. 29, 1996) " Temperature probes buried (10’ bgs) in the Pat Hughes Waste Rock Dump show elevated temperatures, indicating that the dump is starting to go acid. (Ibid.)"[The] site tour consisted of reviewing the Pat Hughes and Buckskin Waste Rock Dumps ... it was very obvious that the sulfides contained in the Pat Hughes and, to a lesser extent, the Buckskin dump are starting to oxidize and give off heat in the form of steam vents and or hot spots on the sides or tops of dumps." (Ibid.) The Idaho Department of Lands Shows Concerns, Seeks Answers Concern in 1996 over the Pat Hughes dump, led the Idaho Department of Lands (IDL) to ask Eugene Farmer, retired Forest Service minerals specialist and expert in acid mine drainage to address the issue: IDL Question: "What do you think is happening with Pat Hughes Dump when snow is melting in patches on the surface of the dump and steam is rising from these patches? Farmer’s Reply: "A chemical reaction is taking place between pyrite ore, FeO2 and H20. This reaction is a form of oxidation that generates sulfuric acid, H2SO4. Heat in the magnitude of 200 degrees Fahrenheit is generated from the reaction that melts snow and that adds more water to the pyrite oxidation process. Mines in Europe that are 1700 years old are still generating acid. Depending upon the availability of water and percentage of sulfur, it would take three to five thousand years to completely oxidize." "The mine dumps at Cyprus Thompson Creek contain 30 to 40 percent void spaces. This porosity allows for tremendous storage capacity and it could take years before we would be able to evidence acid rock drainage from beneath the dumps." "As the surface of the ground warms, convection currents flow up the canyons. The porosity of the dump allows air to float through the dump fanning the oxidation process. It will be almost impossible to control this process unless the dumps are designed to eliminate infiltration of water and air by covering with impervious material." IDL’s Summary: "Mr. Farmer stated that the company should be thinking in terms of water treatment facility or facilities. The cost of water treatment facilities are dependent upon concentration of materials to be treated and volume of water to be treated. His experience has been that the capital investment for a single treatment plan could cost between 3-4 million dollars and 1 million dollars to operate annually." ("Cyprus Thompson Creek Mine Status Report--Comments of Expert ARD Resource People", Idaho Dept. of Lands, Boise, ID, Undated (1996 or 1997). For information: Boulder-White Clouds Council, Box 6313, Ketchum, ID 83340
Fact Sheet #3. Thompson Creek Mine Watch ACID MINE DRAINAGE = THE PERPETUAL POLLUTION MACHINE In June 1998 The Forest Service released a draft plan to address acid mine drainage at the Thompson Creek Mine. Acid mine drainage (AMD) occurs when mining activity exposes natural sulfides in rock, usually iron pyrite, to air and water, and forms sulfuric acid. This acid drainage can leach out metals from mine waste dumps, tailing deposits, and from open pit or tunnel surfaces. Metals dissolved from host rock may include aluminum, arsenic, cadmium, copper, iron, lead, manganese, selenium, silver, zinc, and others, intensifying harmful impacts as the acidic water enters surface and ground water. Acid rock drainage (ARD) is another term used to describe acid generation. ARD occurs when there is natural exposure of sulfide rocks combining with water and oxygen. ARD can be observed in non-mined areas as a yellow-orange coloring or slime on rocks, vegetation or sediments. Whether caused by mining or naturally, this visible form of acid generation, is called yellowboy. Yellowboy is composed primarily of iron (or ferric) hydroxides and sulfates. pH - The pH (hydrogen ion concentration) scale measures relative acidity or alkalinity and runs from 0 to 14. A pH of 7 is neutral. Liquids with a pH value below 7.0 are acidic; above 7.0 is alkaline. As water acidity increases, so does its leaching ability. Nature may adjust for small changes in acidity, and buffers in the soil may neutralize runoff. But AMD may exceed natural buffers and carry dissolved heavy metals into surface and ground water, lowering pH to levels, which cannot support life. Acid mine drainage harms fish. Few fish can survive in water more acidic than pH 4.0. A pH of 3.0 will kill all aquatic life. Optimum pH levels for fish range between 6.5 and 8.7 or nearly neutral to slightly alkaline (US EPA 1976). Toxic affects of low pH on fish include death, reduced growth rate, reproductive failure, and skeletal deformities. Low pH also causes elimination of sensitive species and proliferation of tolerant species; reductions in density, biomass and diversity in aquatic systems; and reproductive, emergence and rearing failure (R.L. Nelson et al, 1991). Large-scale mining does what once took centuries for nature to erode and expose sulfide-bearing rock. Today’s enormous mines like Thompson Creek have compressed such exposure into a few years. Natural weathering could never duplicate the tremendous scale of the Thompson Creek open pit (currently one-mile long and over 600 feet deep), or its 450-acre tailings impoundment which will hold 200 million tons of potential acid-generating material. The mine’s two waste dumps will contain 600-million tons (3.5 million truck loads) of discarded rock.
Other
Acid Mine Drainage Indicators
AMD
Prevention/Control Even when sulfide rock is buried or covered to prevent exposure to air and water, natural occurrences like erosion, slumping, storm events and earthquakes can trigger AMD. If the pH falls below about 4.0, organisms naturally occurring in the rock can greatly accelerate the sulfide decomposition process, and AMD production.
The
Perpetual Pollution Machine
Back to the Top
"A Review of Procedures for Surface Mining & Reclamation in Areas
with Acid-Producing Materials", J.G. Skousen et al, West Virginia
University, April 1987. p. 14.
April
3, 2000
SUBJECT:
SERIOUS CONCERNS DEAR EDITOR: On March 12, 2000, the Idaho Falls Post Register ran a mining story by Candace Burns which failed to address the serious, documented environmental problems at Beartrack near Salmon, and the Thompson Creek molybdenum mine near Clayton. In response to Burn’s article, Thompson Creek manager Kent Watson wrote to the Recorder-Herald (March 23). We would like to respond to his comments on Thompson Creek. Anyone that lives near or cares about the Salmon River should be deeply concerned over Thompson Creek Mine’s enormous 450-acre tailings dam. One of the world’ largest tailings facilities, the dam embankment is over 700 feet high and the dam impoundment contains over 100 million tons of mine tailings. If Thompson Creek, a Colorado company, mines out the ore body, the impoundment’s volume will double in size over the next dozen years. This structure sprawls across Bruno Creek, a tributary to Squaw Creek, just five miles and 2,000 feet above the Salmon River. The Environmental Protection Agency (EPA) in Seattle has raised serious issues over the tailings facility. In 1998 EPA gave the mine’s new operating plan a failing grade, citing environmental objections. Now, because of Burn’s article, Manager Watson attacks EPA for its "non-collaborative" position with other regulating agencies. In August 1999, EPA reviewed geotechnical reports, which resulted in specific concerns over stability, seismic hazard, and acid-generation from the dam. In response, the Forest Service and Idaho Department of Water Quality (IDWR) brushed aside EPA. IDWR response includes the statement that there’s no worry because every five years IDWR performs a "hazard assessment" on the dam (IDWR letter on Oct. 13, 1999 to Tom Buchta, USFS, Ogden). The USFS and IDWR also tout that the Thompson Creek tailings dam withstood the Mt Borah Earthquake back in 1983. They fail to mention that the mine was new and the tailings dam was much smaller, only 165 feet high, not 700 feet like now. We commend EPA’s courage to ask hard questions about the Thompson Creek sand dam. We have lost count of the times that agencies other than EPA have told us that their role is to let mining proceed, and that regulators must go along and get along because these mines are economically important [in the short term] to rural towns and to Idaho’s pro-mining politicians. Besides the mine’s sand dam, there are other concerns. Back in 1980, "experts" said this project would never have acid mine drainage threatening the Salmon River and its tributaries. They were wrong. The threat of acid mine pollution was why the mine was forced into devising a new operating plan, a process that took five years and still isn’t final. (We have a fact sheet available documenting the mine’s acid history.)
In
1996 at the Pat Hughes waste rock dump, there were active steam vents
of 70 degrees and hot spots melting snow which indicated chemical reactions
within the dump. Despite numerous requests and file inspection visits,
Now water quality problems are showing up at Pat Hughes. The Forest Service reported 1999 water quality tests in Pat Hughes Creek, a Salmon River tributary, which detected exceedances of zinc, cadmium, and suspended solids plus low pH and elevated conductivity. The Forest Service also offered excuses: a pipeline ruptured by an avalanche and breaches in the pit dewatering line. Thompson Creek is a mine, which will require monitoring and maintenance into perpetuity. Forever. We and many others are greatly concerned about this gigantic mine, Idaho’s largest, and what legacy it will bequeath to the Salmon River. We welcome calls and information about Thompson Creek and other mines. Thank you.
Lynne
Stone Update April 2003: According to an April 10, 2003 article in the Challis Messenger by reporter Todd Adams, Thompson Creek Mine has responded to higher moly prices and has begun to remove more overburden from its open pit. In April moly was $5.00 a pound versus $3.00 on November 2002. An additional 50-60 workers have returned to the project, joining a current 100 at the site. Adams quotes mine manager Kent Watson as saying that this latest phase will allow Thompson Creek to operate another two to five years. Watson said "mine life….depend(s) on the economics of mining and market demand…."
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