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A platform for research: civil engineering, architecture and urbanism
A Limit Equilibrium Model to Simulate Time-Dependent Pillar Scaling in Hard Rock Bord and Pillar Mines
https://orcid.org/0000-0002-9861-8735
Abstract This study investigated the use of a limit equilibrium model to simulate the time-dependent scaling of hard rock pillars. In the manganese bord and pillar mines in South Africa, extensive scaling is observed for pillars characterised by a high joint density. It appears that the scaling occurs in a time-dependent fashion. Evidence for this is the ongoing deterioration of pillars in old areas, even after the pillars are reinforced with thin spray-on liners. Monitoring of selected pillars were conducted in an attempt to quantify the rate of time-dependent scaling. Contrary to expectations, almost no additional scaling was recorded for the pillars during a 3-month monitoring period. The scaling distance for pillars of different ages could be measured and it seems as if most of the scaling occurred soon after the pillars are formed. Only a limited amount of additional time-dependent scaling seems to occur after this. Numerical simulations of the time-dependent scaling were conducted using a displacement discontinuity code and a limit equilibrium constitutive model. The postulated exponential decay of the failed rock mass strength at the edges of the pillars resulted in simulated behaviour that is qualitatively similar to the underground observations. The results from this study are encouraging and the method can be used to investigate the long-term stability of bord and pillar excavations. Further work is required to improve on the calibration of the model and to better quantify the rate of scaling of the underground pillars.
Highlights Time-dependent scaling gradually reduces the strength of pillars. This paper presents a study of this behaviour in a hard rock bord and pillar mine.A numerical modelling approach to simulate time-dependent pillar failure, on a mine-wide scale, is described in the paper. It consists of a displacement discontinuity boundary element method with a time-dependent limit equilibrium model.The behaviour of the hard rock pillars in the manganese mines in South Africa is used to test the proposed model. It provides valuable data for researchers interested in case studies of time-dependent pillar strength.The proposed modelling methodology seems valuable to design layouts where long-term stability is a requirement. Although the focus in this paper is on hard rock mines, it can also be used for coal pillars.
A Limit Equilibrium Model to Simulate Time-Dependent Pillar Scaling in Hard Rock Bord and Pillar Mines
https://orcid.org/0000-0002-9861-8735
Abstract This study investigated the use of a limit equilibrium model to simulate the time-dependent scaling of hard rock pillars. In the manganese bord and pillar mines in South Africa, extensive scaling is observed for pillars characterised by a high joint density. It appears that the scaling occurs in a time-dependent fashion. Evidence for this is the ongoing deterioration of pillars in old areas, even after the pillars are reinforced with thin spray-on liners. Monitoring of selected pillars were conducted in an attempt to quantify the rate of time-dependent scaling. Contrary to expectations, almost no additional scaling was recorded for the pillars during a 3-month monitoring period. The scaling distance for pillars of different ages could be measured and it seems as if most of the scaling occurred soon after the pillars are formed. Only a limited amount of additional time-dependent scaling seems to occur after this. Numerical simulations of the time-dependent scaling were conducted using a displacement discontinuity code and a limit equilibrium constitutive model. The postulated exponential decay of the failed rock mass strength at the edges of the pillars resulted in simulated behaviour that is qualitatively similar to the underground observations. The results from this study are encouraging and the method can be used to investigate the long-term stability of bord and pillar excavations. Further work is required to improve on the calibration of the model and to better quantify the rate of scaling of the underground pillars.
Highlights Time-dependent scaling gradually reduces the strength of pillars. This paper presents a study of this behaviour in a hard rock bord and pillar mine.A numerical modelling approach to simulate time-dependent pillar failure, on a mine-wide scale, is described in the paper. It consists of a displacement discontinuity boundary element method with a time-dependent limit equilibrium model.The behaviour of the hard rock pillars in the manganese mines in South Africa is used to test the proposed model. It provides valuable data for researchers interested in case studies of time-dependent pillar strength.The proposed modelling methodology seems valuable to design layouts where long-term stability is a requirement. Although the focus in this paper is on hard rock mines, it can also be used for coal pillars.
A Limit Equilibrium Model to Simulate Time-Dependent Pillar Scaling in Hard Rock Bord and Pillar Mines
https://orcid.org/0000-0002-9861-8735
Abstract This study investigated the use of a limit equilibrium model to simulate the time-dependent scaling of hard rock pillars. In the manganese bord and pillar mines in South Africa, extensive scaling is observed for pillars characterised by a high joint density. It appears that the scaling occurs in a time-dependent fashion. Evidence for this is the ongoing deterioration of pillars in old areas, even after the pillars are reinforced with thin spray-on liners. Monitoring of selected pillars were conducted in an attempt to quantify the rate of time-dependent scaling. Contrary to expectations, almost no additional scaling was recorded for the pillars during a 3-month monitoring period. The scaling distance for pillars of different ages could be measured and it seems as if most of the scaling occurred soon after the pillars are formed. Only a limited amount of additional time-dependent scaling seems to occur after this. Numerical simulations of the time-dependent scaling were conducted using a displacement discontinuity code and a limit equilibrium constitutive model. The postulated exponential decay of the failed rock mass strength at the edges of the pillars resulted in simulated behaviour that is qualitatively similar to the underground observations. The results from this study are encouraging and the method can be used to investigate the long-term stability of bord and pillar excavations. Further work is required to improve on the calibration of the model and to better quantify the rate of scaling of the underground pillars.
Highlights Time-dependent scaling gradually reduces the strength of pillars. This paper presents a study of this behaviour in a hard rock bord and pillar mine.A numerical modelling approach to simulate time-dependent pillar failure, on a mine-wide scale, is described in the paper. It consists of a displacement discontinuity boundary element method with a time-dependent limit equilibrium model.The behaviour of the hard rock pillars in the manganese mines in South Africa is used to test the proposed model. It provides valuable data for researchers interested in case studies of time-dependent pillar strength.The proposed modelling methodology seems valuable to design layouts where long-term stability is a requirement. Although the focus in this paper is on hard rock mines, it can also be used for coal pillars.
A Limit Equilibrium Model to Simulate Time-Dependent Pillar Scaling in Hard Rock Bord and Pillar Mines
Wessels, D. G. (author) / Malan, D. F. (author)
2023
Article (Journal)
Electronic Resource
English
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
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