Abstract: A horizontal bore cryogenic drilling method includes in a first embodiment forming a pilot hole of a first select diameter along a desired path of the horizontal bore. A grindable casing is inserted into the guide bore. A cryogenic fluid is flowed through the grindable casing to form a freeze zone of frozen moisture adjacent the grindable casing having a second select diameter. A primary bore is formed having a third select diameter greater than the first diameter and less than the second select diameter within the freeze zone along the desired path of the horizontal bore with the grindable casing in place. The second diameter is selected to be sufficiently greater than the third select diameter to prevent collapse of the freeze zone. Another embodiment of the invention is a method of forming a horizontal bore in an earth formation including providing a drill string having a conduit communicating with a cutting tool for engaging the earth formation.

Abstract: The natural ability of an aquifer formation to remove radionuclides from ground water is recharged by injecting a leaching solution a well. The leaching solution replaces the radionuclides at natural sorption sites in the aquifer formation with ions that can be displaced subsequently by other radionuclides in the ground water. The leaching solution remains in the aquifer formation for a given period of time after which it is pumped out through the well. Thereafter, as water is pumped from the well, other radionuclides become lodged at the sorption sites in the aquifer formation thus being removed from the water.