The first known use of explosives for stimulating a geothermal well was successfully conducted in December 1981 with a process called GEOFRAC. The 260/sup 0/C well was located at the Union Oil Company's Geysers Field in northern California. For the initial test, 364 kg of a new explosive called HITEX II was placed at a depth of 2256 meters and detonated to verify techniques. The explosive was contained in an aluminum canister to separate it from the well fluids. In the second test, 5000 kg of explosive was used representing a column length of approximately 191 meters. The explosive was detonated at a depth of 1697 meters in the same well. The results of these tests show that HITEX II can be safely emplaced and successfully detonated in a hot geothermal well without causing damage to the well bore or casing