On October 31, 2013, one of Obed Mountain coal mine's pits failed, and from between 600 million to a billion liters of slurry poured into the Plante and Apetowun Creeks.[11] 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.[11]