De Graaf, Wolter Willem(University of Pretoria, 2018)
Conventional drill-and-blast practice in deep-level hard rock mining impacts negatively on
the immediate environment and alternatives are frequently sought for efficient, continuous,
automated and safe rock breaking. The ...
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 ...
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 ...
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 ...
