MAMATWAN, an open-pit manganese mine, is part of BHP Billiton's subsidiary, Samancor Manganese. With benches varying from 5 to 45 m, the company was encountering serious overhang and highwall stability problems on the high lime' horizon as well as the manganese benches. There are four main rock layers: El Sandstone (referred to as top lime). D Limestone (mid-lime). C Waste manganese (top-cut). D Manganese (middle-cut). The height of the three layers of waste on the manganese is 50-90+ m and is removed in three benches of +/-10 m of sandstone, +/-45 m of limestone and 2-40 m of waste manganese.
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