In several mines at Tonopah anomalous underground temperatures have been reported. In the Ohio Tonopah shaft, temperatures up to 25.6°C were found at 233 m and temperature gradients reportedly vary from 8 to 16 m per 0.56°C in dry rocks at depths less than 244 m (Spurr, 1905, p. 263-265; Darton, 1920). Water temperatures up to 41.1°C were reported by Bastin and Laney (1918, p. 29) from depths of 457 m to 706 m in the central part of the mining district. Large flows of hot water were encountered in the Tonopah Extension Mines (Broderick, 1949, p. 9). In 1926, about 11,000 m3 per day of hot water were pumped from the deeper mines (McCracken, 1990). A swimming pool was supplied with hot mine waters in the 1920s (McCracken, 1990) and during this same period, some of the hot mine water was used in a greenhouse to grow fresh vegetables.