Browsing Research Articles (Mining Engineering) by Author "De Graaf, Wolter Willem"

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Factors and challenges affecting coal recovery by opencast pillar mining in the Witbank coalfield

Ngwenyama, Philani Larrance; De Graaf, Wolter Willem; Preis, Eugene Pieter (Southern African Institute of Mining and Metallurgy, 2017-03)

The depletion of coal reserves in the Witbank coalfield in Mpumalanga Province has resulted in mining companies exploring the possibilities of extracting coal pillars. These are pillars that were left behind for hangingwall ...
A preliminary qualitative evaluation of a hydraulic splitting cylinder for breaking rock in deep-level mining

De Graaf, Wolter Willem; Spiteri, William (Southern African Institute of Mining and Metallurgy, 2018-08)

Hydraulic rock-splitting cylinders have proved successful in numerous civil and construction applications. The purpose of this study was to conduct a preliminary qualitative evaluation of the applicability of the ...
Risks and challenges affecting opencast pillar mining in previously mined underground bord and pillar workings

Ngwenyama, Philani Larrance; De Graaf, Wolter Willem (Southern African Institute of Mining and Metallurgy, 2021-12)

South Africa is one of the leading producers and exporters of coal globally. A significant amount of the country’s production is obtained from previously mined underground bord and pillar workings. This coal is in the ...

Now showing items 1-3 of 3

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