Solution mining, the extraction of metals, minerals and materials from the earth through leaching and fluid recovery, is still a relatively new but rapidly growing field. The annual economic value of solution mined metals in the United States now exceeds that of metals extracted by underground mining. Originally published in 1992, this second edition of an introductory text for students and professional engineers expands information on the science of fluid flow in heaps, nonsteady state "in situ" fluid flow and nonsteady state well hydraulics. Information on bioheap pretreatment of refractory gold ores and the environmental stabilization of contaminated earth materials has been added.