Method and apparatus for supporting a mine roof

Method for supporting a rock formation comprising,

• advancing an elongated reinforcing rod in a hole drilled in the rock formation,
• connecting said reinforcing rod to an elongated bolt membe with the end portion of said bolt member in spaced relation to the adjacent end of said reinforcing rod, said bolt member having a bearing plate secured thereto and positioned adjacent the rock formation externally of the drill hole,
• maintaining said bearing plate in spaced relation to the rock formation to permit rotation of said reinforcing rod and said bolt member as a unit,
• adhesively bonding said reinforcing rod in the drill hole to the rock formation, and
• thereafter rotating said bolt member relative to said reinforcing rod after said reinforcing rod is bonded to the rock formation to move said bolt member end portion toward said adjacent end of said reinforcing rod and said bolt member bearing plate into abutting relation with the rock formation to tension said bolt member.

A coupling for joining together the threaded end portion of a pair of cylindrical members comprising,

• an elongated tubular body portion,
• a longitudinal bore extending axially through said body portion,
• said bore having a first threaded portion operable to threadedly receive one of the cylindrical members,
• said bore having a second threaded portion spaced from said first threaded portion for threadedly receiving the other of the cylindrical members,
• a first stop means to permit rotation of said other cylindrical member with said coupling,
• second stop means extending transversely from said body portion and intersecting said first threaded portion for retaining the end of said one cylindrical member in spaced relation from the end of said other cylindrical member within said body portion and permit rotation of said one cylindrical member.

Apparatus for insertion in a drill hole of a rock formation to support the rock formation comprising,

• an elongated reinforcing rod positioned in the drill hole, said reinforcing rod having one end portion positioned adjacent the end of the drill hole and an opposite threaded end portion,
• means securing said reinforcing rod to said rock formation,
• an elongated bolt member positioned in the drill hole, said bolt member having a threaded end portion positioned oppositely of said reinforcing rod threaded end portion and an opposite end portion extending out of the entrance to the drill hole,
• a bearing plate retained on said bolt member opposite end portion,
• a coupling having an internally threaded bore for receiving said reinforcing rod threaded end portion and said bolt member threaded end portion,
• stop means positioned in said coupling for maintaining said bolt member threaded end portion in a first position within said coupling spaced from said reinforcing rod threaded end portion to permit rotation of said bolt member and said reinforcing rod, and
• said bolt member operable upon rotation to shear said stop means and advance in said coupling to urge said bearing plate into engagement with the rock formation and apply tension on said bolt member with said reinforcing rod secured within said drill hole.

Method for supporting a rock formation comprising,

• advancing an elongated reinforcing rod in a hole drilled in the rock formation,
• connecting said reinforcing rod to an elongated bolt member with the end portion of said bolt member in spaced relation to the adjacent end of said reinforcing rod, said bolt member having a bearing plate secured thereto and positioned adjacent the rock formation externally of the drill hole,
• maintaining said bearing plate in spaced relation to the rock formatin to permit rotation of said reinforcing rod and said bolt member as a unit,
• securing said reinforcing rod in the drill hole to the rock formation, and
• thereafter rotating said bolt member relative to said reinforcing rod after said reinforcing rod is secured to the rock formation to move said bolt member end portion toward said adjacent end of said reinforcing rod and said bolt member bearing plate into abutting relation with the rock formation to tension said bolt member.