Abstract: In an acidic in situ leaching system, a short circuit passage through a subterranean formation between a fracture associated with an injection well and a fracture associated with a production well can be plugged by introducing a non-acidic liquid for displacing acidic leach liquid from the short circuit passage, introducing into the injection well a basic composition including a sealing material that gels under acidic conditions, and introducing sufficient liquid into the injection well to displace at least a portion of the basic composition containing sealing material from the injection well into the short circuit passage. Liquid flow between the injection well and the production well is then discontinued for a sufficient time for residual acid in the subterranean formation surrounding the short circuit passage to contact the sealing material and cause gelation of the sealing material in the short circuit passage. The introduction of acidic leach liquid to the formation can then continue.

Abstract: A permeable region adjacent a well bore used in an acidic in situ leaching system can be repaired by introducing a non-acidic liquid for displacing acidic leach liquid from the permeable region, introducing into the well bore a basic composition including a polymeric material that gels under acidic conditions, and applying sufficient pressure to the well bore to displace at least a portion of the basic composition and polymeric material from the well bore into the permeable region adjacent the well bore. Liquid flow in the well bore is then discontinued for a sufficient time for acid remaining in the subterranean formation adjacent the well bore to contact such polymeric material and cause gelation of the polymeric material in the permeable region. The introduction of acidic leach liquid can then continue.