The purpose of this paper is to present a progress report (as of April 1, 1984) of the project to install two modular air-cooled binary cycle power plants at the Casa Diablo Hot Springs near Mammoth, California. The authors have been involved for 10 years in the development of this resource located on 90 acres of fee land owned by Magma Energy, Inc., who drilled and tested 8 wells in the early 60's establishing the existence of a low salinity (1500 ppm) moderate temperature (330 F) resource at shallow depths (400' - 700'). The present status of the project is as follows. Contracts for the lease of the land and the use of the Magmamax process have been executed with Magma Energy, Inc. A contract for the sale of the electricity has been executed with the Southern California Edison Company. Construction of the plant started in August of 1983 with completion planned on August 1, 1984. Four production wells and two injection wells were completed in December, 1983. The total project including wells and plant is estimated to cost about 12.5 million dollars. 5 references.