Abstract: A method and apparatus for drilling a hole in a body of ice and for destroying a body of ice. The method comprises the steps of providing a source of reactant gas of a type which will react chemically with ice to form solid compounds which are unstable and which break down rapidly to water and a dissolved gas. The reaction product which is formed is removed quickly in order to avoid a secondary and initially undesirable exothermic reaction of gas dissolution into the water so formed. The reactant gas is directed through a nozzle to generate a stream of reactant gas. The nozzle is located in close proximity to a body of ice, and the stream of reactant gas is directed against a localized area of the surface of said body of ice at a velocity and flow rate to obtain an optimum phase change reaction with the ice and to quickly remove water formed from the ice in the localized area.

Abstract: A method for controlling stress and increasing the load-bearing strength of support members, the support members comprising coal, of a coal mine wherein the method consists essentially of injecting ammonia or hydrochloric acid into the interior portions of the support members.