Abstract: A mine roof bolt assembly (10) comprises a bolt (20), a bearing plate (30), and a washer (40) situated between a ledge (24) of the bolt (20) and a lower face (33) of the bearing plate (30). The washer (40) includes an elbow (42), a radially inner portion (43) extending upward from the elbow (42), and a radially outer portion (44) sloping upward from the elbow (42). The elbow (42) engages an inboard location of the bolt ledge (24) so as to reduce stress on the flange (23) of the bolt (20).

Abstract: A mine roof bolt assembly (10) comprises a bolt (20), a bearing plate (30), and a washer (40) situated between a ledge (24) of the bolt (20) and a lower face (33) of the bearing plate (30). The washer (40) includes an elbow (42), a radially inner portion (43) extending upward from the elbow (42), and a radially outer portion (44) sloping upward from the elbow (42). The elbow (42) engages an inboard location of the bolt ledge (24) so as to reduce stress on the flange (23) of the bolt (20).

Abstract: A mounting assembly for holding a bolt in a hole or opening drilled in a mine roof includes an expansion anchor assembly which mechanically grips the side surface of the hole and an adhesive anchor section which is bonded to the side surface of the hole by a body of adhesive material. When the mounting assembly is to be installed in a hole drilled in a mine roof, a cartridge of adhesive is inserted into the hole and the mounting assembly is forced upwardly in the hole until the cartridge ruptures. Immediately after the cartridge ruptures, a bolt is tightened to press retainer elements in the expansion anchor assembly against the side surface of the hole. Shortly thereafter, the adhesive sets up around the expansion anchor assembly and the tubular adhesive anchor section. Therefore, the expansion anchor assembly provides a mechanical gripping action with the stratum of rock in which the hole is drilled and adhesive bond is obtained between the tubular adhesive anchor section and the stratum of rock.

Abstract: An improved bearing plate is used to support a portion of a mine roof. The bearing plate is stamped from sheet metal and has elongated ribs which define grooves facing toward a back side of the bearing plate. Reinforcing members are disposed in the grooves and are fixedly connected to the bearing plate. The reinforcing members increase the resistance of the bearing plate to deflection under the influence of loads applied to the bearing plate by the mine roof.