SciELO - Scientific Electronic Library Online

vol.116 issue3Breakage mechanisms and an encouraging correlation between the Bond parameters and the friability value author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand



Related links

  • On index processCited by Google
  • On index processSimilars in Google


Journal of the Southern African Institute of Mining and Metallurgy

On-line version ISSN 2411-9717
Print version ISSN 2225-6253


MATHEY, M.  and  VAN DER MERWE, J.N.. Critique of the South African squat coal pillar strength formula. J. S. Afr. Inst. Min. Metall. [online]. 2016, vol.116, n.3, pp.291-299. ISSN 2411-9717.

The South African squat coal pillar strength formula, developed by researchers from the Chamber of Mines Research Organization in the 1980s, predicts an exponential increase in coal pillar strength once a critical width-to-height ratio of 5 is exceeded. The arguments that have been proposed in favour of this formula are discussed critically in this paper. Field experience with squat pillars in the USA and evidence from published physical, analytical, and numerical model pillar studies corroborate the fact that a squat effect is unlikely to occur in coal pillars at width-to-height ratios less than 10. Furthermore, an exponential increase in peak strength of coal pillars does not exist. An alternative design criterion for squat pillars in South Africa is therefore suggested.

Keywords : squat pillars; coal pillar strength; bord-and-pillar mining.

        · text in English     · English ( pdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License