Other

Mining Services International

Lex L Udy

John T Day

Robert B Clay

A method and apparatus for delivering an explosive to the bottom of a borehole containing water without allowing a detrimental amount of mixing between the explosive and the water. More particularly, the present invention allows an ammonium nitrate rich bulk explosive to be placed in a borehole without allowing the explosive composition to change significantly through dissolution of its constituents. The apparatus of the present invention includes a length of collapsible tubing having a plurality of apertures near its base and a weight attached to its base. The tubing is then lowered into a borehole. The weight causes the tubing to extend through any water layer within the borehole and the collapsible nature of the tubing serves to keep any significant amount of water from entering the tube. An explosive can then be flowed into the mouth of the tubing and down through the length of the tubing to the bottom of the borehole. At the bottom of the borehole, the explosive exits the tubing through the plurality of apertures.

Methods and apparatus for loading a borehole with explosives

A dry explosive seismic composition which can be initiated by low grain detonating cord so as to minimize the fire hazards typically associated with seismic testing. Preferred compositions within the scope of the present invention include a sensitizer of Hexamine or a derivative thereof, such as Hexamethylenetetramine Mononitrate. The compositions of the present invention not only reduce the fire hazards associated with using such compositions, but they also resist vaporization of the sensitizer, thereby minimizing the problems associated with handling the compositions.

Seismic explosive composition

A cylindrical primer cup having a top end which may be sealed so as to safely contain granular or liquid explosive matter is disclosed. A cylindrical conduit extends in a straight path through the cup, providing an opening at either end permitting through-passage of detonating cord or blasting caps. The cylindrical conduit additionally has a fixed diameter throughout, facilitating its travel along a detonating cord. A frustoconical conduit extends well within the primer cup for the placement and frictional retention of blasting caps therein. The sidewalls of the two conduits are relatively thin to provide for easier primer detonation. Symmetrically placed columnar-shaped ribs provide longitudinal structural support for the cylindrical conduit.

Primer cup

A simple dewatering system comprises hollow expandable bore-plugging body which can be set in place and locked there in the borehole, at any desired level, by simply pumping compressed air into it. An orifice of calculated size in the bottom of the body allows compressed air to escape and build up pressure below to raise the water in the lower part of the hole to the ground surface through a conduit which extends from the borehole bottom to a level above the ground. The orifice, which may be adjustable, maintains a predetermined minimum pressure differential inside the body which pressure is enough higher than the water-expelling pressure below to keep the body tightly inflated so it cannot slide upwardly. Compressed air escapes continuously through the orifice so that outflow of water from the borehole bottom is continuous until the water level reaches the bottom of the outflow conduit, when the conduit is blown clear, preventing run-back of the water in the conduit. The body and the outflow conduit may be enclosed in a sleeve or liner of impervious flexible sheet material which lines the inner borehole surface and prevents loss of compressed air through fissures or other pores or openings in the rock formation where the hole is located. To withstand high pressures, a protective shroud of metal mesh is used to limit stretching of the expandable body.

Growing community of inventors

Holladay, UT, United States of America

Lex L Udy