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The Obed Mountain coal mine spill was a mining disaster that occurred on October 31, 2013, when a waste pit at the Obed Mountain Mine failed near the town of Hinton in Alberta, Canada. Following the collapse of a tailings dam, up to 1 billion liters of wastewater flooded into the nearby Athabasca River – what may be the largest coal slurry spill in Canadian history. The river's waters experienced immediate spikes in arsenic, 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.
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Spill
Located about 30 km (19 mi) east of Hinton, the Obed Mountain Mine was a 7,460 ha (18,400 acres) thermal coal mine with the capacity to produce about 3.2 million tonnes of coal 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 624 ha (1,540 acres) of the mine has been reclaimed.
On October 31, 2013, one of the mine's pits failed, and from between 600 million to a billion liters 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 500 km (310 mi) away.
Environmental impact
In the first month after the spill, water quality tests revealed the presence of metals and chemicals such as cadmium, arsenic, manganese, lead, mercury, and PAHs in excess of limits for consumption or life along the first 40 km (25 mi) 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 has continued in the years since, although First Nations representatives have continued to dispute the rigor 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, Water, and Public Lands Acts which could amount to up to a $2.2 million fine. Proceedings began on January 20, 2016.