|
MMS was commissioned, by Anglo Americans Western Deep Limited and Elandsrand Gold Mining Company to develop a headboard that would enhance the efficiency of the hydraulic props used in deep level mines. The hydraulic props have to exert a force of 40 tons or more to prevent the hanging wall from crushing down on the stopes. This force causes the hydraulic props to bore into the hanging wall, resulting in a weakened hanging wall and an increased risk of a rock fall. A headboard with a larger capacity had to be developed.Because of the working depth the stope face is cramped, making it difficult for workers to manhandle a heavier headboard onto position, creating a mass restriction.The last problem that had to be overcome was that of durability. The props and headboards are used as close as 1.5 meters from the blasting.After extensive material tests and detailed theoretical analyses a fibre reinforced composite laminate was chosen for its high strength to mass ratio and good economy.The product was fully designed, analyzed and manufactured by MMS. A special resin infusion technique was developed to produce the units. Advantages of the composite headboard:The composite headboard is much lighter than a steel headboard of the same 60 ton capacity.Load capability upwards of 60 tons.Large coverage.Corrosion resistant only deforms elastically and displays ballistic resilience to superficial blasts.Versatile to requirements.Zero resale value as “scrap”. Therefore seldom if ever lost through pilfering.Cost effective.
|
