3-D numerical modelling of Domino failure of hard rock pillars in Fetr6 Chromite Mine, Iran, and comparison with empirical methods

Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving works such as roof support and replacing existing pillars with concrete pillars (CP) were carried out. During the construction of the second CP, in the space between the remaining pillars, one of the pillars failed leading to the progressive failure of other pillars until 4 000 m2 of mine had collapsed within a few minutes. In this work, this phenomenon is described by applying both numerical and empirical methods and the respective results are compared. The results of numerical modelling are found to be closer to the actual condition than those of the empirical method. Also, a width-to-height (W/H) ratio less than 1, an inadequate support system and the absence of a detailed program for pillar recovery are shown to be the most important causes of the Domino failure in this mine.

[1]  K. P. Mukherjee,et al.  Application of the yield pillar technique for successful depillaring under stiff strata , 1995 .

[2]  Z. Bieniawski Engineering rock mass classifications , 1989 .

[3]  W. A. Hustrulid,et al.  Underground mining methods handbook , 1982 .

[4]  C. González-Nicieza,et al.  A Comparative Analysis of Pillar Design Methods and its Application to Marble Mines , 2006 .

[5]  D. F. Malan,et al.  The design of stable pillars in the Bushveld Complex mines: a problem solved? , 2011 .

[6]  E. T. Brown,et al.  Rock Mechanics: For Underground Mining , 1985 .

[7]  E. T. Brown Rock characterization, testing & monitoring: ISRM suggested methods , 1981 .

[8]  Paul Smaglik,et al.  Ground control , 2003, Nature.

[9]  B. Whittaker,et al.  Subsidence: occurrence, prediction and control (Developments in Geotechnical Engineering, 56) : Amsterdam: Elsevier, 1989, 528P , 1989 .

[10]  E. T. Brown,et al.  Underground excavations in rock , 1980 .

[11]  Dennis R. Dolinar,et al.  Pillar and roof span design guidelines for underground stone mines , 2011 .

[12]  R. K. Zipf,et al.  Description of a large catastrophic failure in a southwestern Wyoming Trona Mine , 1999 .

[13]  R. Karl Zipf,et al.  Toward Pillar Design to Prevent Collapse of Room-and-Pillar Mines , 1900 .

[14]  Dennis R. Dolinar,et al.  Pillar strength in underground stone mines in the United States , 2011 .

[15]  Z. T. Bieniawski,et al.  The effect of specimen size on compressive strength of coal , 1968 .