Abstract: According to this invention there is provided an aqueous oxidizer solution containing a mixture of dissolved oxidizing salts, for use in the preparation of explosives formulations, which a crystallization point as low as below 0° C. The solution has a water content of 25% by mass or less and contains ammonium nitrate and calcium nitrate wherein the ratio of the molar concentration of ammonium nitrate to calcium nitrate is preferably approximately 1. When the water content of the solution is 24% by mass or less, the solution further contains monomethylammonium nitrate. This solution can be used for manufacturing watergel explosives, or emulsion explosives or ANE's (ammonium nitrate emulsion suspension or gel explosives). It can be easily transported underground in deep level mines through relatively small diameter pipelines, using existing access ways and shafts, to the working places at which point it can then be converted into a watergel or emulsion explosive or an ANE.

Abstract: One aspect of the invention concerns a method of charging an upwardly oriented hole with a pumpable material, typically a pumpable explosive material such as an ANE. In the method of the invention a laterally expandable retainer is provided. This is of smaller length than the hole and has an inlet at a lower end thereof and an outlet at an upper end thereof. In an unexpanded state the retainer has a smaller lateral dimension than the hole. The retainer is inserted upwardly into the hole in an unexpanded state, whereafter material with which the hole is to be charged is pumped upwardly into the retainer through the inlet such that the retainer fills up and expands laterally into engagement with a wall of the hole. Excess pumped material is allowed to upwardly out of the retainer into the hole through the outlet. After the retainer has been filled with material and the hole above the retainer has been at least partially filled with any excess material, the pumping operation is stopped and the inlet is closed.

Abstract: One aspect of the invention concerns a method of charging an upwardly oriented hole with a pumpable material, typically a pumpable explosive material such as an ANE. In the method of the invention a laterally expandable retainer is provided. This is of smaller length than the hole and has an inlet at a lower end thereof and an outlet at an upper end thereof. In an unexpanded state the retainer has a smaller lateral dimension than the hole. The retainer is inserted upwardly into the hole in an unexpanded state, whereafter material with which the hole is to be charged is pumped upwardly into the retainer through the inlet such that the retainer fills up and expands laterally into engagement with a wall of the hole. Excess pumped material is allowed to upwardly out of the retainer into the hole through the outlet. After the retainer has been filled with material and the hole above the retainer has been at least partially filled with any excess material, the pumping operation is stopped and the inlet is closed.

Abstract: A watergel explosive composition is described which contains an oxidiser salt, a sensitiser, a thickener, a crosslinking agent, a fuel and less than 8%, by mass, of the composition of water. The explosive composition is cap sensitive in packages or cartridges having a diameter of about 26 mm or less at temperatures below about 5.degree. C. when detonated with a standard number 6 strength detonator. The explosive composition does not require a supplementary sensitisor or a perchlorate salt to achieve this cap sensitivity. A method of producing the explosive composition by separately preparing a thickened aqueous phase and a dry phase, and allowing the thickened phase to stand for a period of time before the mixing of the two phases, as well as explosive paper cartridge containing the watergel explosive composition, are also described.