San Miguel Lignite Mine - Christine, Texas
On January 1, 2011, Kiewit was awarded a contract to provide management services to mine and deliver lignite from the San Miguel Mine. Approximately 3.3 million tons of lignite coal is delivered to the adjacent 400-MW San Miguel Electric Cooperative, Inc. power plant, which is the owner of the mine. San Miguel Electric Cooperative, Inc. furnishes power and energy to Brazos Electric Cooperative, Inc. and the South Texas Electric Cooperative, Inc.
The mining process consists of clear and grub, topsoil salvage, overburden removal, lignite mining, regrade and final reclamation. The overburden removal is achieved using two draglines, a 76-cubic-yard machine and a 30-cubic-yard dragline. The 76-cubic-yard dragline moves nearly 21 million yards per year of overburden, while the 30-cubic-yard dragline moves about 7.7 million yards per year. Assisting the overburden operation is a 19-cubic-yard mass excavator with a fleet of 100 ton end dump trucks. The lignite is mined using a specialized mining tool called an Easy Miner. These machines resemble milling machines used to remove and recover asphalt and concrete highway surfaces and provides tight depth control to selectively mine the lignite or remove the parting, as well. Unique to the operation is the daily removal ash from the power plant which is hauled to specified dump locations in prior mined pits. Nearly 2 million tons of ashed is hauled annually from the power plant.