Luminant is a Texas-based electric utility. It is a wholly owned subsidiary of Energy Future Holdings Corporation. Luminant's operations include electricity generation and wholesaling, mining, construction, and development. The company has capacity for the generation of 18,300 megawatts (MW) of electricity in 20 power plants spread across Texas, of which 2,300 MW come from nuclear power generated at the company's Comanche Peak Nuclear Power Plant, 5,800 MW from coal-fired power plants, and the remainder from natural gas-fired plants. Luminant is also a major purchaser of wind power.Luminant also owns and operates three of the five largest coal mines (by production) in Texas: the Beckville Strip, the Three Oaks Mine, and the Oak Hill Strip. The Beckville Mine was mined out in the fall of 2015 and the three drag lines were moved to other mines. The Oak Hill Mine will cease operation in December 2016. In December 2016, 77 miners were laid-off due to the closures. The company extracted over fourteen million short tons of coal from those three mines in 2007. The company also operates a private rail line known as the Martin Lake Rail Line that carries coal from mines around Texas and the Powder River Basin via BNSF to the Martin Lake Power Plant.