Cogeneration can be defined as any system that recovers energy that is normally lost, and converts it to useful shaft power. The U.S. Bureau of Mines has undertaken a program to evaluate the practicality of applying cogeneration principles to the incoming cooling and/or service water into deep mine shafts. Cogeneration, although quite commonly practiced in South African mines, has not found wide acceptance in the U.S. mining industry. The Bureau, through its contractor Foster-Miller, Inc., is proceeding with the design, installation, and operation of a demonstration cogeneration system to be operated in the Hecla Mining Company's Lucky Friday Mine, Mullan, Idaho. The objectives of the program are to verify the predicted energy savings resulting from the use of a turbine generator system to recover the available potential energy of the incoming water, to demonstrate the viability of the system hardware, and to promote the use of this technology throughout the U.S. mining industry. The demonstration system consists of an impulse turbine directly coupled to a 300-kw induction generator. The turbine is capable of operation of a range of flow from 16 to 47 l/s at a gross head of 915 m. The electrical power that is generated is fed into the mine power grid for internal use. However, the output is metered and will in essence be "sold" to the local power company at their avoided energy cost.
Paper in Proc. Asme Ind. Power Conf., Philadelphia, PA, Oct. 28-31, 1984, PP. 45-52