Abstract: An apparatus for the controlled refining of an emulsion explosive composition is shown. The apparatus includes a pump for pumping the pumpable explosive composition, a conduit for transporting the explosive composition away from the pump, and a refining or shear valve located in the conduit. Also provided is control instrumentation which allows the amount of refining to be monitored. The preferred control instrumentation comprises a first pressure indicator located on an upstream side of said valve, the second pressure indicator located on the downstream side of said valve, and an adjustor associated with the valve to allow the valve to be adjusted to produce a predetermined pressure difference between the first and second pressure indicators.

Abstract: A blasting agent is disclosed for use in a borehole having a pressure resistant closure. The blasting agent is used in combination with a primary initiating system comprised of a detonator and an initiator for the detonator. The blasting agent is preferably a semi-fluid explosive material having a predetermined sensitivity. The sensitivity is related to the borehole diameter and the initiating system's strength, wherein the blasting agent upon initiation is transformed into explosive products by means of reaction front which consumes substantially all the blasting agent as the reaction front passes through the blasting agent. The reaction front has an average velocity of propagation of between 200 meters/second and 1,000 meters/second for at least 30% of the total length of blasting agent located in the borehole. Another aspect of the invention is a method of blasting wherein the average velocity of propagation of the explosive front in the blasting agent is in a range of between 200 m/sec and 1,000 m/sec.

Abstract: A blasting explosive having improved water resistance comprises a particulate blend of from about 5 to about 27 wt. % of a slurry explosive and from about 73 to about 95 wt. % of a mixture of ammonium nitrate particles and a liquid hydrocarbon fuel based on the weight of the slurry, the ammonium nitrate particles and the fuel. The mixture of ammonium nitrate particles and a liquid hydrocarbon fuel contain from about 3.0 to about 6.0 wt. % hydrocarbon fuel based on the weight of the ammonium nitrate/fuel mixture. The blend is first coated with a gelling agent and subsequently coated with an anticaking agent.