Abstract: An electronic system and method are disclosed for controlling a measured temperature during a sequence of time intervals, in accordance with a sequence of selected reference temperatures, each corresponding to one of the intervals. The values of the reference temperatures are programmable and changeable by the user. The system and method can be used to establish thermostatic control in conformity with a referenced temperature that varies throughout the day, for example, hour by hour. The system also provides for using different sequences of reference temperatures on different days.

Abstract: In a leaching process to recover a selected element or mineral from a gangue, an AC current is applied to the mixture to accelerate the rate at which chemical reactions occur. If the treated material is located in a subsurface earth formation, the AC current may further generate gases in situ to assist in moving and circulating the leaching solution in the formation and to bring the dissolved mineral value to the surface through a borehole or the like. This acceleration of the chemical reactions can shorten the effective leaching time from weeks or months to a matter of hours or days, thereby greatly affecting the rate of recovery of the mineral value and making such leach mining economical on a commercial basis.