Verification of the New Coal Pillar Strength Formula and Investigations Into the Prediction of Pillar Life in Witbank and Highveld Coalfields
Covers pillar load and strength estimation, the limits of tributary area theory, and the extraction gains available from revised strength formulae, for rock engineers designing bord and pillar workings.
by I Canbulat | February 2004
Laboratory testing showed coal specimen strength rising linearly with width to height ratio and falling exponentially with specimen size, the size effect becoming insignificant beyond about 2 m diameter. The slope of that relationship was the same for coals from different mines, while the intercept varied with specimen size.
R1500,00
Description
Related Products
Agricultural Research on Rehabilitated Coal Mined Land (1994-2001) Conducted in Terms of the Kraai Van Niekerk Report
2001
Consolidated review of six field studies on highveld opencast rehabilitation, covering soil profiles, pasture performance, crop potential and soil water, for mine environmental staff and regulators.
What this report foundRehabilitated opencast soils carried pastures and cash crops, but compaction and cover soil depth set the ceiling on what they could produce.
R1500,00
Rehabilitated opencast soils carried pastures and cash crops, but compaction and cover soil depth set the ceiling on what they could produce. Only land with deep cover soils suited maize and sunflower, and deep ripping with regular tillage was needed. Bulk density standards were not met at the trial sites, which the review judged enough to have changed the results.
FGX Dry Processing Tests Conducted at Exxaro R&D
2009
Pilot tests of a waterless de-stoning unit on raw coals from four South African collieries at a Pretoria research site, for plant metallurgists weighing dry beneficiation.
What this report foundA compound dry cleaning machine de-stoned low grade raw coal without using water, but separation efficiency was low, with high relative density cut points and...
R1500,00
200931 pages
A compound dry cleaning machine de-stoned low grade raw coal without using water, but separation efficiency was low, with high relative density cut points and EPM values in the order of 0.3. Misplaced material was heavy and coal below 6 mm reported to product almost indiscriminately. The unit is cheap to buy and run, needs only crushing to 50 mm, and gives high throughput.
The Estimation of Greenhouse Gas Emissions from South African Surface and Abandoned Coal Mines
2012
Direct sampling across burning, burnt out and rehabilitated dumps at surface mines covering just over half of national surface production, scaled to a national emissions estimate.
What this report foundGas sampling on coal mine dumps found rehabilitation very effective at cutting emissions.
R1500,00
Gas sampling on coal mine dumps found rehabilitation very effective at cutting emissions. Even incomplete rehabilitation held carbon dioxide below about 1 kg per square metre a year, against over 100 on unrehabilitated ground and as much as 7 000 where combustion was active, though burning areas were small. Sulphur oxides, nitrogen oxides, ammonia and methane were low.