Impedance Measuring Method of and Apparatus for Detecting Escaping Leach Solutions.
U S Pat 4 253 063 1981 Feb; :
In an in situ uranium-leaching process, a method of detecting leach solution escaping from a desired leaching zone involves monitoring the electrical impedance of a zone outside the desired zone. The electrical impedance is detected by locating monitoring wells and positioning pairs of current and voltage probes within the monitoring wells and closest injection wells. A low-frequency current is generated by each pair of current probes to develop a zone impedance-dependent voltage drop that is correlated to ionic concentration and the presence of escaping leach solution.
U.S. Pat. 4,253,063, Feb. 24, 1981; Chem. Abstr. 91:P126,683x