Shaped charges with plastic liner, concave recess and detonator means
AssigneeDyno Nobel Asia Pacific Limited
InventorAnthony Leonard Ey
Life of this patent
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Abstract
A shaped charge is provided which includes an elongate container or housing having a concave recess in an upper end thereof. Explosive is located or provided within the container and at least below the concave recess. Detonator means are provided within the container at or adjacent a lower end thereof and spaced apart from and below the concave recess and explosive located therebelow.
Claims8
A shaped charge for use in blasting, whereby the charge when detonated releases energy focussed broadly upwardly of the charge, said charge including an elongate container having a substantially transverse base closure at a lower end and a plastics liner in an upper end thereof, said plastics liner spaced inwardly from said container and comprising an upwardly facing generally concave recess which is sealably closed, detonator means being provided on a longitudinal axis of the container within said container and spaced apart from said concave recess;
- and explosive being provided within said container in a space not occupied by the liner and extending about and below said recess, said explosive regularly decreasing in radial thickness as the explosive extends away from the longitudinal axis of the container towards a peripheral edge of the liner and being thinnest adjacent the peripheral edge of the recess.
A method of blasting to remove or diminish overburden for mineral strata or stratum, including:
- (a) forming one or more bore holes in said overburden;
- (b) placing a plurality of shaped charges together with explosive within said one or more bore holes.
- (c) said shaped charges including an elongate container having a substantially transverse base closure at a lower end and a plastics liner in an upper end thereof, said plastics liner spaced inwardly from said container and comprising an upwardly facing generally concave recess which is sealably closed, detonator means being provided on a longitudinal axis of the container within said container and spaced apart from said concave recess;
- and explosive being provided within said container in a space not occupied by the liner and extending about and below said recess, said explosive regularly decreasing in radial thickness as the explosive extends away from the longitudinal axis of the container towards a peripheral edge of the liner and being thinnest adjacent the peripheral edge of the recess.
- (d) wherein said plurality of shaped charges are located in said one or more bore holes, one above the other;
- and
- (e) detonating said charges such that energy released from each charge is focussed broadly upwardly within said bore hole, so as to substantially remove or diminish overburden thereabouts.
Dependencies are inferred from the claim text.