Mining
Development of Design Procedures for Long Slender Pillars
2005
Design guidance for rib pillars, built from back analysed in situ coal tests and two dimensional modelling rather than empirical data, for rock engineers laying out high extraction panels.
What this report foundNumerical modelling produced upper and lower bound strength formulae for rib pillars, the lower bound covering weak roof and floor contacts.
Development of Seam-Specific Strength Formulae for South African Collieries
2006
Statistical back analysis of an expanded collapse database, testing power, linear and non-linear strength models, for rock engineers setting pillar safety factors.
What this report foundBack analysis of 77 collapsed and 245 uncollapsed pillar cases showed that much of the scatter in pillar strength comes from differences between coalfields, so...
Economic Coal Resources of the Highveld, Ermelo, South Rand and Sasolburg-vereeniging Coalfields
2004
Comparative ranking of coalfields inside and outside South Africa on exploration level, resource size and infrastructure, for companies deciding where to explore next.
What this report foundA rating and ranking system was applied to South African coalfields and, separately, to the coal bearing countries elsewhere in the Southern African...
Evaluate the Remaining Resources of Low Phosphorus Coal in Mpumalanga Province
2004
Assessment of remaining metallurgical grade coal in the Witbank, Highveld and Ermelo coalfields from national borehole records, for resource planners and buyers of reductant coal.
What this report foundTonnage estimates for the remaining low phosphorus resource could not be produced, because the phosphorus analyses supplied by mining companies did not state...
Evaluation of Ground Geophysical Techniques on the Waterberg Coal Fields
2008
Interim account of trial ground surveys along a profile in the Waterberg coalfield, for exploration geologists weighing survey cost against the structural detail mine planning needs.
What this report foundElectrical and electromagnetic ground surveys were run over a Waterberg profile with borehole logs and three dimensional seismic data as control, to test...
Geotechnical Factors Associated With Previously Mined Areas of Coal and Their Impact on Subsequent Extraction
2002
Masters research on pillar extraction in the Witbank Coalfield, ranking the ground conditions that decide method choice and safety, for rock engineers and mine planners.
What this report foundGeotechnical factors affecting secondary extraction were identified from interviews with collieries already re-mining pillars and with people experienced in...
Identify Remnant Coal Deposits for Potential Exploitation by Small Business Developments
2002
Screening of near surface remnant coal for small scale miners in Mpumalanga, with a map of candidate areas and of ground already worked out.
What this report foundShallow coal suitable for small scale opencast working was mapped in the northern Witbank and Highveld coalfields, using a limit of 30 m from surface to the...
Improved Utilization of Underground Coal Reserves
2016
Working reference on high extraction methods, from stooping and rib pillar extraction to auger, punch, longwall and backfilling, drawn from South African colliery experience for mine planners.
What this report foundAbout 3.19 billion tons of coal now sits underground in pillars, growing by roughly 110 million tons a year under current bord and pillar practice.
Intra-seam Sedimentological Controls on Coal Quality: 2 Seam, Witbank Coalfield
2003
Sub-seam mapping at an opencast colliery in the Witbank area, setting out a method geologists and resource estimators can apply to other seams.
What this report foundSub-seams within the No 2 Seam were characterised at a single test site using lithology, seam thickness, proximate analysis, petrography and geophysical logs...