The Environmental Cost of Copper Mining: A Case Study in Butte, Montana

1. The Environmental Cost of Mining : A Case Study Mark Khaimov Thomas Newman Brian Hernandez

2. The Environmental Cost of Mining Copper Mining in Butte, Montana

3. The Anaconda Mine • Montana and other states in area saw a boom in mining activity during late 19th century when rich deposits of ore were discovered. • In 1881, Anaconda Copper Mining Company forms, acquiring land around Butte in hopes of finding deposits of ore on the land. • By 1890 , Butte was largest city west of Mississippi due to mining activity. • 1890 – Population of 24,000

4. Mining in Butte • Butte was nicknamed “The Richest Hill on Earth” due to vast amount of ore found. • 1892 – 1903, Anaconda Mine was largest copper producer in the world. • Advent of electricity increased demand for this metal • By WWII, Butte had a population of 50,000

5. Mining Methods in Butte • Underground Mining • Early miners dug shallow shafts to reach the ore. • Underground shafts were supported with timber and unexcavated rock pillars . • A system of air passages connected to the outside served as ventilation. • Ore was carried up by hand until new steam-powered hoisting technologies were developed. • Early mines were drained with buckets and tunnels until large, steam-powered Cornish pumps became widely used to drain water.

6. Mining in Butte

7. Mining Methods • Open Pit Mining • In 1955, Open-Pit Mining became the primary method used in Butte. Led to creation of the Berkeley Pit. • The Berkeley Pit utilized the existing subterranean infrastructure to mediate groundwater levels beneath the pit. • By the end of the first year of the pit’s operation, it was producing 17,000 tons of ore per day, primarily copper. • Over the course of decades, the pit grew in size and swallowed several communities due to its expansion.

8. Berkeley Pit

9. Basics of Open Pit Mining • Used when deposits of minerals and ore are found near the surface. • Walls of the pit are called benches. Benches are essentially terraces that can range from 4 to 60 meter intervals. • Ore is extracted from the bottom of the pit, where it is carried up with machinery. • The pit is dug deeper and expanded until the ore deposit is exhausted

10. Hazards of Open-Pit Mining • “Environmental hazards are present during every step of the open-pit mining process. Hardrock mining exposes rock that has lain unexposed for geological eras. When crushed, these rocks expose radioactive elements, asbestos-like minerals, and metallic dust. During separation, residual rock slurries, which are mixtures of pulverized rock and liquid, are produced as tailings, toxic and radioactive elements from these liquids can leak into bedrock if not properly contained.” • Taken from web.mit.edu

11. Hazards of Underground Mining • Underground mining can release toxic compounds into the air and water surrounding the mine. • The water in the mine absorbs harmful concentrations of the minerals in the rock, making the water a contaminant. If the water is not treated or contained, it can contaminate the surrounding region’s water.

12. Preventive Measures • Underground Mining • To limit the potential environmental damage, the mines are filled with a concrete slurry. • Landfills with waste materials are fenced off or covered in clay. • The cost to perform “land rehabilitation”, as it is called, for an underground mine is minimal compared to an open-pit mine.

13. Preventive Measures • Open-Pit Mining • Waste dumps are flattened, to stabilize them. • The dump is then covered with a layer of clay to prevent rain and oxygen from oxidizing sulfides within the ore, a process known as Acid Mine Drainage. Soil and vegetation are then used to cover the clay. • The pit is usually fenced and allowed to fill up with rain water

14. The Case of the Berkeley Pit • The pit was fenced off when it was shut down in 1982, however, the underground mines were not filled so that they could mediate the water levels in the open pit when it was in operation. • Over the course of the 27 years the pit was in operation, over a billion tons of ore were extracted, most of it copper. • It is now one mile long by a half-mile wide. • It is 1780 feet deep and occupies 675 acres.

15. The Case of the Berkeley Pit • Pumps used to mediate groundwater were shut off when the pit closed. • Groundwater eventually began to fill the pit at a rate of 1ft per month. • In 2013, the groundwater in the pit was measured to be 5,311.89 ft. above sea level. • The level at which water will overflow from the pit is 5,510 ft.

16. The Case of the Berkeley Pit

17. Acid Mine Drainage in the Berkeley Pit • The walls of the pit, as well as the underground mine shafts, contained minerals that were subject to decay from the oxygen rich pit water • The pyrite and sulfide in the walls of the pit and mines were then exposed to the dissolved oxygen, starting a reaction that creates a highly-acidic liquid known as Acid Mine Drainage. • The pit now holds up to 40 billion gallons of highly-acidic water, which if the pit fills up past the pit rim’s lowest level, will contaminate the surface water and groundwater in and around Butte.

18. EPA Action • Plans in the 1990s were made to divert water from pit to the slow the rise of the water level. Only a temporary solution to a serious problem. • 1994 EPA Record of Decision • Called for a Butte Mine Flooding Operable Unit to utilize cleanup alternatives as a superfund site. • “Actual or threatened releases of hazardous substances at and from this site, if not addressed by implementing the response action selected in this ROD, may present an imminent and substantial endangerment to public health, welfare, or the environment.”

19. The Snow Geese Incident

20. The Snow Geese Incident • Serious national attention was paid to the Berkeley Pit after November 1995, when a flock of snow geese landed in the pit. • They were prevented from leaving the water due to bad weather and heavy fog. • After the weather finally cleared, all 342 geese were found dead. • It was determined by the state that the toxic water had eroded the esophagi of the pit.

21. Horseshoe Bend • The Horseshoe Bend Drainage Water Facility opened in the spring of 1996. • The facility would divert up to 3,000 gallons per minute of water flow into the pit. However, 2,000 gallons per minute still flowed into the pit despite the facility. • Very soon after opening the facility, operations were suspended by Montana due to high energy costs. • A settlement was reached in 2002 where the previous owners of the mine and the Montana Resources group would pay for a $18mm dollar water treatment plant.

22. Horseshoe Bend • The Horseshoe Bend Water Treatment Plant would treat 5,000 gallons per minute. • Used calcium oxide to raise the pH levels and lower the acidity of the water. • As the pH rises, the metals are able to be removed from what is now a sludge. Therefore, copper was still being mined from the pit. • In 2003, the plant was online. Expected to treat pit water until 2023.

23. What Exactly is Being Done? • The water treatment plant is able to treat and capture about 5 million gallons of water a day, water that would otherwise enter the pit. • However, still 491,000 gallons flow into the pit everyday. • So… it’s still filling up? • Yes

24. The Critical Water Level

25. The Critical Water Level? • The Critical Water Level (5,410 feet) represents the lowest level in the Butte basin, the Silver Bow Creek. It was set to prevent contaminated water from moving into surface and groundwater. • The lowest point on the pit rim is 5,510 feet, so it could only overflow if it surpassed that height. • When the water reaches the critical level, expected to be 2023, full-scale pumping and treating will begin to prevent the level from raising any further. • However, collapses of the pit wall have raised the water level in the past, so the plan is not foolproof.

26. Potential Environmental Effects • If the pit were to overflow, acidic water from the pit would flow into Silver Bow Creek, destroying the habitat. • Serious threat to the ecological health of the Butte area because of the damage it could wreak to the water table. • Such water is not hospitable to local flora, insects, plants, or fish because it simply too toxic.

27. Potential Environmental Effects • If the water were to be consumed by an organism, the toxins could enter the food chain through bioaccumulation, putting the local residents at serious risk of being poisoned by the metals. • Being subject to heavy metal toxicity could cause inflammatory diseases, cardiac functional disorders and even potentially cancer.

28. Conclusion • Although so far successfully contained (with the exception of the snow geese incident), the Berkeley Pit represents a potential environmental disaster that could destroy the local habitat and cause serious harms to local residents. • But be sure to visit the gift shop.

29. The Gift Shop

30. The Viewing Platform($2 Admission Fee)

31. South Africa

32. South Africa • South Africa has one of Africa’s richest and largest economies, mainly due to its immense Mining industry. • It has the second largest economy in Africa after Nigeria, which built its wealth from the oil industry.

33. South Africa

34. South Africa • South Africa has more than $2.5 trillion in mineral reserves. • The country is the world’s biggest producer of platinum, and one of the leading producers of gold, diamonds, base metals and coal.

35. South Africa • From July 2011 to September 2011, over 1.1 million ounces of gold and gold uranium were produced. • Gold accounts for more than a third of exports from the country. • Mining contributions contribute to almost 60 percent of exports. • Coal is also a plentiful resource in the country. In 2010, South Africa had about 32 billion tons of coal reserves, ranking it as the world’s fifth largest producer.

36. Mining According to the Chamber of Mines, a mining-industry employer organization, mining: • Creates one million jobs • Accounts for about 18 percent of South Africa’s GDP • Contributes to roughly 94 percent of electricity generation through coal power plants • Requires about 15 percent of the country's electricity demand.

37. Mining • Among the gold mines in South Africa are two of the deepest mines in the world, going as deep as 11,762 feet. • Plans exist to bring the depths to roughly 12,800 feet, as most of the ores are buried deep underground • At such depths, the temperatures of the rocks reach 140 degrees Fahrenheit.

38. Gold farms of Witwatersrand • This area of South Africa is immensely rich in gold ores. • The area’s gold reserves were discovered accidentally over 100 years ago; the discovery would lead to the Witwatersrand gold rush, and the creation of a major city in South Africa.

39. The Witwatersrand Gold Rush • The gold rush occurred in the year 1886. Up until this point, the massive supply of gold in the area was untouched by humans. • Elsewhere in South Africa, mines followed a general trend: when gold was discovered, small mining towns were established around the reserve. When the gold ran out, the towns would close down and people would disperse

40. The Witwatersrand Gold Rush • This area was different. The gold ran for miles underground. It became known as “an endless treasure of gold” • Over the course of ten years, the Province containing the land, Gauteng, went from a poor struggling Republic to the richest gold mining area of the world. • As word about the area spread, eager men made their way to the area. • They came by walking, riding horseback, slow ox-wagons, or on rafts from places as far as Europe. • All were hoping to find the riches of their dreams

41. The Witwatersrand Gold Rush

42. The Witwatersrand Gold Rush

43. The Witwatersrand Gold Rush • The mining camps soon became towns. The area near the reserves became part of a large mining camp called Johannesburg. • Soon, the camp became the biggest town in the Transvaal (land north of the Vaal River in South Africa) • As time passed, tents in the town disappeared and were replaced by more permanent structures like houses and buildings.

44. Johannesburg Today • The largest city in South Africa, and also the largest city in the world not situated on a river, lake or coastline. • Mining no longer occurs within the city, but major mining companies have their headquarters in Johannesburg.

45. Methods of Mining • Gold Mining in South Africa typically involves: • Panning - essentially sifting through soil with a pan • sluicing - separating gold from gravel using a device called a “sliuce box” • hard rock mining - underground mining • by-product mining - mining where gold is not the primary product, but it is still retrieved. • Ex: The largest producing gold mine in the world, the Grasberg Mine located in Papua, Indonesia, is primarily a copper mine.

46. Methods of Mining • Most mines in South Africa partake in hard rock mining, as most of the ores are fully encased in rock deep underground • This method is complemented by chemical beneficiation, a method where chemicals are used to extract the gold from the ore • Modern beneficiation methods can yield gold with up to 99.999 percent purity • A common chemical used in the process is cyanide, a potentially deadly chemical if inhaled 4 Au + 8(NaCN) +O2 + 2 H2O –> 4 NaAu(CN)2 + 4 NaOH

47. Environmental Impact • Gold mines result in a multitude of environmental issues, including groundwater and surface water pollution, soil damage and pollution, and air pollution caused by dust particles

48. Environmental Impact on Water • Water pollution is primarily caused by chemical contamination associated with mine operations. • Acid Mine Drainage is a particularly notable issue: Oxidized pyrite, which forms sulfuric acid, seeps into groundwater. • The pollution of water continues more than 10 kilometers from the source.

49. Environmental Impact on Water • Depending on the area, the water is contaminated with different levels of salts, sulphate, iron, aluminium, toxic heavy metals like cadmium and cobalt, lead and radioactive elements such as uranium. • The contamination causes the pH of the water to reach such acidic levels that animals can no longer survive.

50. Environmental Impact on Water • Mercury, which occurs naturally in gold ores, gets released into the environment when the ores are processed. This also contributes to polluted waters and soil. • It was reported that the Mercury emissions in South Africa are second only to China in 2005.