Modern Mining January 2022

with a 900 000 t reserve and is estimated to have a life of mine of two-and-a-half years. The material is extracted from three layers and blended to a grade of 36,5% manganese. To achieve this, the material needs to be sent to the plant in the correct batches. Products include 85% lumpy man- ganese ore and 15% fine material. Sitatunga has established a grade-control section on the mine and employed a grade control geolo- gist, along with a supporting team. Additionally, the company has established a fully equipped on-site laboratory to oversee the blending process. “The manganese is fed to the plant and the crushed product is then deposited as cones over a two-hour period. The slewing conveyor is then adjusted to start a separate cone while the first cone is sampled and analysed,” says Rothmann. The laboratory analysis then determines on which stockpile the material is placed to maintain a weighted average grade of 36,5% manganese. The highest quality layers are about 39% manganese and this is blended with a portion of the lower grade ore. Load & haul The pit is accessed using load and haul mining pro- cesses and then overburden material is hauled to the overburden and topsoil stockpiles, which will be used at later stages for mine rehabilitation purposes. The mine’s fleet of mining machines comprises 12 articulated dump trucks (ADTs), four excavators, two dozers, one grader and two front-end loaders. Due to the conical shape of the pit, it took approx- imately eight months to reach first ore, after which steady production has been achieved swiftly. Due to the depth and footprint of the ore, which is situated about 50 m below surface at the bottom of the pit,

minimal impact on the overall development of the mine. The company, reiterates Rothmann, subscribes fully to all the COVID-19 protocols applicable to the mining sector and remains committed to the indus- try’s zero harm target. Three layers East Manganese is an opencast mining operation

Due to the depth and footprint of the ore, which is situated about 50 m below surface at the bottom of the pit, Sitatunga could not apply conventional strip mining, hence the conical shape of the pit with a ramp down to the ore.

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January 2022  MODERN MINING  23