ROCBOLT Technologies and ROCBOLT Resins

JMM Cable Truss System

  1. A borehole is drilled into the mine roof strata at an angle of approximately 45 degrees. Be sure to allow enough room away from the rib for the shoe and plate. Spacing of the boreholes holes is determined by mine personnel based on entry width, mining conditions, and/or the approved roof control plan. Borehole depth should be 1"-2" longer than the length of the angle bolt.

  2. With the proper amount of resin inserted into the hole first, the angle bolt with truss plate and shoe on the bolt is then put into the hole, pushed through the resin, and installed. Follow the appropriate installation instructions for type of bolt used (instal or cable). This step is repeated for the other angle bolt.

  3. Hang the U-Bolts on each truss shoe. Slightly lift the U-Bolt upward and insert one end of the cable through the U-Bolt bearing block from the center entry direction. Once the end of the cable is through the U-Bolt bearing block, slip the cable housing and wedge assembly on the end of the cable. Repeat this step for the other U-Bolt. Note: Make sure to leave at least six inches of cable protruding beyond the cable housing and wedge assembly on the side that you will tension from.

    Alternative method: lay the u-bolts on the mine floor or across bolting machine (make sure bolting machine is turned off) and insert cable through the u-bolts and assemble horizontal member components as described above. With helper, the entire horizontal cable assembly is then lifted and the u-bolts are hooked onto the truss shoes. If working alone, lift one side first and hook it onto the truss shoe. Go to the other side and while pulling slightly on the cable, lift and hook u-bolt onto the other truss shoe.

  4. With the complete horizontal member now hanging from the truss shoe, the cable can be adjusted by lifting upward on the cable and moving the housing and wedge assemblies towards the center of the entry as much as possible by hand. be careful when lifting and adjusting housing and wedge assemblies not to push u-bolt off truss shoe.

  5. Insert the cable tensioning unit (CTU) onto the end of cable that has at least six inches of cable protruding beyond the u-bolt bearing block. Make sure the wedge/housing assembly opposite the side being tensioned is seated properly. Engage the hydraulic circuit to tighten the cable. if necessary, repeat the tensioning cycle several times until the cable is tight. Make sure full hydraulic pressure is applied to the cable and the cylinders are not "bottomed out". Do not place hands or fingers on or near nose piece end of CTU. Do not alter or remove components of CTU except to change griping wedges in nose piece. Keep hands away from any rotating parts.

  6. The installation is complete.