摘要:
An elongated rod fabricated of polymeric material for use in reinforcing an underground passage includes an integral structure of a shaft portion, washer element and torque receiving end portion. The shaft portion is fabricated of a preselected polymeric material as required to meet the strength requirements of the rod in reinforcing the rock formation surrounding the passage. For use in reinforcing the side walls of a passage, the rod is fabricated of plastic material recycled, for example, from plastic beverage containers. The integral construction eliminates the need to thread the end of the rod to receive a nut. The washer element seats against a bearing block compressed against the side wall. When used with a resin system, the rod is anchored in the bore hole to maintain the bearing block compressed against the side wall to support the surrounding rock strata.
摘要:
A mine roof bolt, preferably one inch or less in diameter, having an external coating configured with particles which mix resin as the mine roof bolt is rotated in a mine roof bore hole.
摘要:
A tensionable mine roof cable bolt having a resin grouted upper portion and a mechanically anchored lower portion. The lower portion includes a shaft which is swaged to the cable and accepts a mechanical anchor. The cable bolt is rotated during installation in a mine roof bore hole to mix resin and simultaneously engage the mechanical anchor with the rock. A drivehead press fitted onto the lower end of the cable fails upon tensioning of the bolt to a predetermined load.
摘要:
A steel alloy having 0.44-0.52 wt. % C, 1.1-1.6 wt. % Mn, 0.15-0.35 wt. % Si, a maximum of 0.04 wt. % P, a maximum of 0.05 wt. % S, a maximum of 0.45 wt. % Cu and 0.06-0.09 wt. % V. A No. 5 mine roof bolt formed from the steel alloy has a minimum yield strength of 90,000 psi. A mine roof bolt having a cross-sectional diameter of 7/8 inch or 1 inch and formed from the steel alloy has a minimum yield strength of 100,000 psi.
摘要:
A method for designing and fabricating a mine seal includes determining an initial thickness for a mine seal based on a predetermined underground opening, developing and solving a numerical model for response of the mine seal upon application of a blasting pressure, and determining whether the mine seal meets predetermined design criteria. A mine seal having a minimum seal thickness may be fabricated after determining the mine seal meets the predetermined design criteria.
摘要:
A method for designing and fabricating a mine seal includes determining an initial thickness for a mine seal based on a predetermined underground opening, developing and solving a numerical model for response of the mine seal upon application of a blasting pressure, and determining whether the mine seal meets predetermined design criteria. A mine seal having a minimum seal thickness may be fabricated after determining the mine seal meets the predetermined design criteria.
摘要:
A method of designing supports for an underground mine opening comprising the steps of: receiving mine slope information including at least one of site location, entry length, entry grade, entry orientation, size of opening, surface topology, adjacent borehole data and rock mechanics test data, historical roof fall height, and expected steel set support capacity; conducting stress and geological condition evaluation of the mine opening using a finite element computer modeling program based on the mine opening information; and designing structural supports for the mine opening utilizing the stress and geological condition evaluation of the mine opening.
摘要:
A mine roof bolt expansion anchor is formed from a plurality of identical shell segments. Each shell segment has a first end, a second end, and an end section at the first end. A first finger extends from the end section to the second end of the shell segment. A second finger extends from the end section toward the second end of the shell segment and terminates at a distal edge spaced from the second end of the shell segment. The end section, the first finger and the second finger each include an inner surface and an outer surface. A deformable coupling couples a plurality of shell segments together to form a multi-piece shell. The inside surfaces of the end sections, the first fingers and the second fingers of the multi-piece shell define a central aperture in which a wedge, adapted to coact with the plurality of shell segments, is received in the central aperture. Movement of the wedge from the second end to the first end of the shell segments forces the fingers to move in an outwardly direction.
摘要:
A pair of truss brackets are secured to the roof of an underground passage adjacent to opposing ribs of the passage. The truss brackets each include a roof engaging surface and a truss supporting arm member extending from the roof engaging surface. A pair of U-bolts are supported by the arm members of the truss brackets. Each arm member extends horizontally from the truss bracket to an enlarged end portion of the arm member. The U-bolt is horizontally movable in a vertically hanging position on the arm member and is restrained by the enlarged end portion from disengagement from the arm member. The U-bolts are pivoted on the truss brackets to a horizontal position for connection to truss members which are connected to each other and tensioned to apply an uplifting force to the roof. As the truss members are connected and tensioned, the U-bolts are retained for a range of horizontal movement on the arm members to facilitate adjustments in the position of the U-bolts on the truss brackets.
摘要:
An elongated channel member for supporting the surface of an underground rock formation includes a base portion with a bearing surface for contacting the rock strata and an opposite surface having a longitudinally extending central rib and flanged edges for resisting deflection and bending of the channel member under the load of the rock strata. A plurality of openings spaced a preselected distance apart extend through the central rib. A bearing plate is positioned in overlying abutting relation with each opening in the channel member. The bearing plate includes embossed areas and longitudinally flanged edges that are complementary in shape with the central rib and flanges on the channel to securely engage the bearing plate on the channel member. Thus, the bearing plate engages the channel member to restrain longitudinal and lateral movement of the bearing plate on the channel member and stiffen the channel member to resist bending. An anchor bolt extends through the aligned openings in the bearing plate and channel member into a bore hole drilled in the rock formation. Anchoring the bolt in the bore hole compresses the bearing plate against the channel member to urge the channel member into compressive relation with the surface of the rock formation to support the rock formation.