The Obed Mountain coal mine spill was a

mining disaster A mining accident is an accident that occurs during the process of mining minerals or metals. Thousands of miners die from mining accidents each year, especially from underground mining (hard rock), underground coal mining, although accidents al ...

that occurred on October 31, 2013, when a waste pit at the Obed Mountain Mine failed near the town of Hinton in

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

, Canada. Following the collapse of a

tailings dam A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and potent ...

, up to one billion litres () of wastewater flooded into the nearby Athabasca River in what may be the largest coal slurry spill in Canadian history. The river's waters experienced immediate spikes in

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...

, metals, and carcinogenic polycyclic aromatic hydrocarbons (PAHs). Although the Athabasca was deemed safe for drinking and wildlife by the end of the year, the extent of the environment's recovery remains in doubt.

Spill

Located about east of Hinton, the Obed Mountain Mine was a thermal coal mine with the capacity to produce about 3.2 million tonnes () of

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

per year; 2.6 million tonnes () are proven to exist, and up to 84.7 million more tonnes () were posited. Tailings ponds were constructed to contain water used to wash coal; besides wastewater, the pools also contained fine rock and clay particles, unrecovered coal, and flocculents. Operations were suspended in 2012 because of economic pressures, and around of the mine has been reclaimed. On October31, 2013, one of the mine's tailings dams failed, and from between 600 million to one billion litres () of slurry poured into the Plante and Apetowun Creeks. The plume of waste products then joined the Athabasca River, travelling downstream for a month before settling in Lake Athabasca near Fort Chipewyan, over away.

Environmental impact

In the first month after the spill, water quality tests revealed the presence of metals and chemicals such as

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

, arsenic,

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

, and

PAHs A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...

in excess of limits for consumption or life along the first of the Athabasca River. Mercury, for instance, was found to be nine times higher than normal, while PAHs were at levels four times higher than the Canadian standard for potable water. As a result, residents were discouraged from both drinking any of the Athabasca as well as watering any livestock or pets. By December 2013, as the plume reached Fort McMurray, government officials reported that water from the Athabasca was once again below safety thresholds for both wildlife and drinking water. Monitoring continued for at least two years, although First Nations representatives disputed the rigour of the sampling program, its exclusion of data from sediment, and the lack of information made available to the public.

Aftermath

In October 2015, the Alberta Energy Regulator corporation filed charges against the mine's operators, Sheritt Coal and Coal Valley Resources Inc., on several counts of violations of the ''Environmental Protection and Enhancement Act'', the ''Water Act'', and the ''Public Lands Act'' which could have amounted up to a $2.2 million fine. Proceedings began on January20, 2016. In June 2017, Prairie Mines & Royalty, formerly known as Coal Valley Resources, a subsidiary of Sheritt Coal, was fined $4.5 million after the company pled guilty to two violations of federal law under the ''Fisheries Act'' and one violation of Alberta's ''Environmental Protection and Enhancement Act''.

References

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