A study of UG2 pillar strength using a new pillar database
DOI:
https://doi.org/10.17159/Abstract
A recent experimental pillar extraction project at a UG2 bord and pillar mine presented a unique opportunity for the compilation of a new pillar database. Currently, the South African hard rock bord and pillar mines design pillars using the Hedley and Grant strength formula. This empirically derived formula was developed for uranium mines in the Elliot Lake district of Canada. The use of this formula for the design of pillars in South Africa is questionable. Very few pillar failures have nevertheless been observed in the mines and the formula and its current calibration is possibly too conservative. A new South African database of 66 pillars, of which 7 are classified as failed, was compiled by the authors. This enabled a revised calibration of the K-value of the Hedley and Grant formula. A value of K = 70 MPa (approximately 60% of the UCS) was obtained by using this database. Further work is nevertheless required to determine whether the Hedley and Grant formula is an accurate estimate of the pillar strength for UG2 pillars in bord and pillar layouts.Downloads
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Copyright (c) 2024 Daniel Francois Malan
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