CompuServe Messages

Chris- Well, my geothermal courses are some years behind me. However, you have the natural geothermal gradient and when you get down to 300m in mines my experience shows around 34C when non ventilated. You may have read about the SouthAfrican mines where one of the main costs are refrigeration plants for the air which at 2000m would be 40-50C without ventilation. Now for, the alternating hot/cold-if you are in sulphide vein areas you would be having oxidation of the sulphides with heat release-it is exothermic reaction, no? This could be part of it. OR, it may be a result of partial ventilation with "pulses" of new air mixing with old air. I hadn't heard about that old wall method but it makes sense. I will consult a mine ventilation book (yes, there are several books on the topic) to see if they have more profound answers, tommorrow. If my number two scenario is correct, maybe these are spots for further exploration. Steve