The measurement of temperature at the bottom of the two deepest mines in Australia - both at Bendigo - indicates an increasing warmth, but less than that due to added depth; the difference being explained by the good effect of ventilation. The deep mines at Bendigo are close together, so as to be easily connected by levels, says "Mining and Scientific Press." The Government Inspector of Mines found the temperature at the 3856 ft. plat of the New Chum Railway mine to-be 86° F., while at the bottom, at 4069 ft., the thermometer registered 88°. The water at the west end of the shaft was 94° and at the east end 96°.

In the Victoria Quartz mine, also near the New Chum reef, the temperature at the plate on the 3824 ft. level was 86°, while in the shaft at 4046 ft. it was 88°. The water was six degrees warmer. The New Chum Railway is warmer than the Victoria Quartz mine because it has an up-cast shaft, and receives air from an adjoining mine, while the Victoria Quartz receives fresh air through its down-cast shaft. As the mean annual temperature at Bendigo is 90° F, the increase at 4000 ft. is not excessive.