Authors: Dunn, MJ; Stacey, TR


Cite As:
Dunn, MJ & Stacey, TR 2008, 'Design of Stable Spans at Tau Lekoa Mine ', in Y Potvin, J Carter, A Dyskin & R Jeffrey (eds), SHIRMS 2008: Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium, Australian Centre for Geomechanics, Perth, pp. 179-192,

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Large hangingwall instabilities have been a problem at Tau Lekoa mine since stoping commenced in 1991. Crush pillars are used to prevent these by limiting spans. Spans between the crush pillars are designed to limit the potential fallout height to a thickness that is controllable by means of internal stope support. The design is based on the empirical relationship between the span and fallout height which is poorly correlated and observed thicknesses often deviate significantly from the design prediction. This paper presents results from a statistical back analysis of 81 large instabilities and includes various geotechnical and mining aspects. Probabilistic keyblock analyses have been conducted to assess the hazard associated with different pillar spans, mining directions and support systems.

Biddulph, M.N. (1999) Implications of the geological model on safety at Tau Lekoa Mine. Internal AngloGold Report.
Daehnke, A., Andersen, L.M., de Beer, D., Esterhuizen, G.S., Glisson, F.J., Grodner, M.W., Hagan, T.O., Jaku, E.P., Kuijpers, J.S., Peake, A.V., Piper, P.S., Quaye, G.B., Reddy, N., Roberts, M.K.C., Schweitzer, J.K., Stewart, D.R. and Wallmach, T.R. (1998) Stope face support systems. Project GAP330 SIMRAC.
Dunn, M.J. (2003) The determination of stable inter-pillar spans at Tau Lekoa Mine. Proceedings of the 10th ISRM Congress, SAIMM, Johannesburg, pp. 261–266.
Dunn, M.J. and Stacey, T.R. (2006) Stable pillar spans at Tau Lekoa Mine. The 41st U.S. Symposium on Rock Mechanics (USRMS): 50 Years of Rock Mechanics – Landmarks and Future Challenges, Golden, Colorado.
Dunn, M.J. (2007) Design of stable inter-pillar spans at Tau Lekoa Mine. MSc. Project report. Unpublished. University of the Witwatersrand.
Esterhuizen, G.S. (1996) JBlock User’s Manual and Technical Reference.
Esterhuizen, G.S. and Streuders, S.B. (1998) Rockfall hazard evaluation using probabilistic keyblock analysis. Jour. S. Afr. Inst. Min. Metall. March/April, pp. 59–63.
Fourie, C. (1999) Implications of variable lava strengths on the hangingwall stability at Tau Lekoa. Internal AngloGold Report.
Frith, I. (1998) Developments to the VCR facies model at Tau Lekoa Mine. Presentation for the AngloGold Senior Geologists Conference.
Goodman, R.E. and Shi, G. (1985) Block theory and its application in rock engineering. Prentice Hall.
Judeel, G. and Laas, J.J. (1999) An empirical method for the determination of the fall out height versus span between crush pillars at AngloGold – Tau Lekoa Mine. 2nd Southern Africa Rock Engineering Symposium, In Implementing Rock Engineering Knowledge, T.O. Hagan (editor), SANIRE, Johannesburg, pp. 28–36.
Lombard, J.J. (1989) Rock Mechanics strategy for 10 shaft. Internal AngloGold Report.
Rosenblatt, M. (1994) Support strategy – Vaal Reefs No. 10 Shaft. Internal AngloGold Report.

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