Reproducible shot hole apparatus

Claim 2

In apparatus for making a reproducible shot hole in the earth, the combination comprising a string of casing which includes a length of shot hole liner to be positioned at the depth at which shots are to be fired; a coupling having means to mount an end of said casing string and an end of said liner therein, a tapered sleeve surrounding the end portion of said liner and having its thickest end at said coupling; and means to join said thick end of said sleeve, the end of said liner, and said coupling together; whereby said liner at said coupling is highly resistant to expansion and decreasingly less resistant to expansion at points on said liner spaced along said sleeve moving away from said coupling.

Claim 3

The combination of claim 1, said liner consisting of aluminum.

Claim 4

In apparatus for a reproducible shot hole the improvement comprising a string of casing cemented in the shot hole to a depth below the weathered zone at which the shot is to be fired, said string of casing having a cylindrical liner of ductile material through the interval of the hole at which the shot is to be fired, a steel sleeve at each end of the liner surrounding and spaced slightly from the liner and extending from the end of the liner toward the center thereof for a distance to support the ends of the liner and leave the liner unsupported in the interval at which the shot is to be fired.

Claim 5

In apparatus for a reproducible shot hole the improvement comprising a string of casing cemented in the shot hole to a depth below the weathered zone at which the shot is to be fired, said string of casing having a cylindrical liner of ductile material through the interval of the hole at which the shot is to be fired, a steel sleeve at each end of the liner surrounding and spaced slightly from the liner and extending from the end of the liner toward the center thereof for a distance to support the ends of the liner and leave the liner unsupported in the interval at which the shot is to be fired.

Claim 6

The apparatus of claim 3 in which each of the sleeves is of greatest thickness at the end of the liner and tapers to a reduced thickness at the end of the sleeve nearest the midpoint of the liner.

Claim 7

The apparatus of claim 3 in which the liner is in the borehole within a sheath of a cement-sand mixture set under an elevated pressure to fill voids and reinforce weak formations surrounding the liner.

Claim 8

Apparatus as set forth in claim 3 in which the liner is aluminum.

Claim 9

Apparatus as set forth in claim 3 in which the ratio of the thickness of the liner to its diameter is approximately 3:100.

Claim 10

Apparatus for a reproducible shot hole comprising an upper section of steel casing and a lower section of steel casing, an upper coupling at the lower end of the upper section and a lower coupling at the upper end of the lower section, an aluminum liner extending between the upper section and lower section of casing and having its upper end mounted in the upper coupling and its lower end mounted in the lower coupling, an upper sleeve surrounding and secured to the upper coupling and extending therefrom downwardly part of the distance to the lower end of the liner, a lower sleeve surrounding and secured to the lower coupling and extending upwardly therefrom a part of the distance to the lower end of the upper sleeve to leave a central portion of the liner unsurrounded by the sleeve.

Claim 11

Apparatus for a reproducible shot hole comprising an upper section of steel casing and a lower section of steel casing, an upper coupling at the lower end of the upper section and a lower coupling at the upper end of the lower section, an aluminum liner extending between the upper section and lower section of casing and having its upper end mounted in the upper coupling and its lower end mounted in the lower coupling, an upper sleeve surrounding and secured to the upper coupling and extending therefrom downwardly part of the distance to the lower end of the liner, a lower sleeve surrounding and secured to the lower coupling and extending upwardly therefrom a part of the distance to the lower end of the upper sleeve to leave a central portion of the liner unsurrounded by the sleeve.

Claim 12

Apparatus as set forth in claim 8 in which the sleeves taper from a section of maximum thickness at the ends secured to the couplings.