Mansour Mining Technologies Inc.

Sunday, 21 Jul 2019
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MCB Modified Cone Bolt

In response to a growing demand for a yielding support system in rockburst prone ground conditions, engineers at the Noranda Technology Centre designed and patented the MCB (modified cone bolt). A bolt testing apparatus was designed and built at NTC to dynamically test the MCB. Mansour Mining Technologies Inc. developed the unique steel forging techniques to manufacture the bolt and Dupont provided the resin cartridge expertise with the introduction of the Coneloc resin. Mansour Mining Technologies Inc. was licensed to manufacture and market this new ground support technology.

Principles of Operation

Seismic events or rockburst often exceed the dynamic load capacity of existing ground support. The MCB is a smooth bar threaded at its outer end, with a forged cone and mixing blade at the other end. The specially formulated Dupont Coneloc Resin is effectively mixed by this patented cone bolt design. The smooth bar has a special coating to reduce the friction and bonding effect of the resin. Under Dynamic loading conditions, the MCB will yield or plough through the Dupont Coneloc resin, thus absorbing the energy through controlled deformation.

The dynamic energy of a rockburst needs to be transferred from the converging ground to the MCB. The use of a high strength 0/0 gauge "Mine Mesh Strap" is an effective way of linking or lacing all the MCB bolts together to effectively transfer the seismic energy. The strapping is installed over top of the existing welded mine mesh, fence link or reinforced shotcrete.

In a static loading condition, the cone functions as a wedge-style mechanical anchor similar to standard mechanical rockbolts. The MCB is tensionable, thus capable of being installed on a single pass and/or used as either a primary or secondary support. Normal load carrying capacity of 3/4" C1055 steel applies. The cone bolt can be installed using conventional equipment such as jacklegs, stopers or mechanized bolters with a minimal amount of additional training.

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