Geotechnical Factors Affecting High- and Low-wall Stability in Opencast Coal Mines
by Grant van Heerden | May 2004
R1500,00
Description
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Demonstrate the efficiency of UAV-GPR for assessment of rehabilitation sites and detection of subsurface cavities
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Field trials at two South African collieries comparing drone mounted ground penetrating radar against ground based surveys, for measuring rehabilitation soil thickness and locating shallow voids. For rehabilitation teams.
What this report foundGround based radar mapped rehabilitation soil profiles well enough to replace much of the auger sampling normally needed, and a 100 MHz system picked out...
R1500,00
Ground based radar mapped rehabilitation soil profiles well enough to replace much of the auger sampling normally needed, and a 100 MHz system picked out anomalies at about 5 to 6 m depth that were likely old mining voids and related subsidence. Penetration below roughly 6 m needs lower frequencies, which cost resolution and require larger antennas.
Dry Screening Tests Conducted With a Bivi-tec Screen
2008
Screening trials at two South African collieries, one on a small test unit and one on a full scale installation, for plant staff handling fine, damp coal.
What this report foundFine coal was screened at small apertures while surface moisture stayed below about 5 per cent.
R1500,00
200820 pages
Fine coal was screened at small apertures while surface moisture stayed below about 5 per cent. Above that, fines adhered to the coarser particles and screening became very difficult. The dual vibrating polyurethane mats stopped blinding and clogging, so screening area stayed available, but the screen action still could not dislodge fines from very damp coal.
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...
R1500,00
Back analysis of 77 collapsed and 245 uncollapsed pillar cases showed that much of the scatter in pillar strength comes from differences between coalfields, so a single national formula is unrealistic. Seam specific formulae were derived for the major coalfields; Free State and KwaZulu Natal data remained too sparse. The lognormal safety factor distribution was retained.
Development of Junior Management and Supervisory Personnel for the Mining Section of the Future
2004
Interviews, questionnaires and on site observation at three South African collieries, with recommended training content and selection criteria for supervisors and junior managers in mining sections.
What this report foundMines already provide substantial training and their junior managers were found motivated and committed, yet development at this level remains problematic.
R1500,00
Mines already provide substantial training and their junior managers were found motivated and committed, yet development at this level remains problematic. Gaps sat in commercial exposure, financial and accounting skills, industrial relations, quality standards, administration and project management. The report sets out the attributes to screen for at appointment and a framework that makes candidates responsible for their own development.