SciELO - Scientific Electronic Library Online

 
vol.108 número7Ground support strategies to control large deformations in mining excavationsSeismic monitoring of the Northparkes Lift 2 block cave - Part 2 production caving índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados

Artigo

Indicadores

Links relacionados

  • Em processo de indexaçãoCitado por Google
  • Em processo de indexaçãoSimilares em Google

Compartilhar


Journal of the Southern African Institute of Mining and Metallurgy

versão On-line ISSN 2411-9717

J. S. Afr. Inst. Min. Metall. vol.108 no.7 Johannesburg Jul. 2008

 

TRANSACTION PAPER

 

Seismic monitoring of the Northparkes Lift 2 block cave - Part I undercutting

 

 

M. HudymaI; Y. PotvinII; D. AllisonIII

IItasca Consulting Canada Inc
IIAustralian Centre for Geomechanics
IIIRio Tinto

 

 


SYNOPSIS

Caving of the second lift of the E26 orebody at Northparkes Mines was monitored with a comprehensive package of instrumentation, including an ISS seismic monitoring system. Seismicity was collected by an array of 19 triaxial accelerometers and 9 uniaxial geophones, giving a high quality seismic data set. The seismic response to block caving at Northparkes has been divided into two papers. The first paper focuses on the seismicity during undercutting. The second paper deals primarily with the seismicity during cave propagation during initial cave production.
In this paper, traditional seismic monitoring concepts are applied to seismicity during cave mining. More than 40 000 seismic events were recorded during cave undercutting between February and January 2004. Events up to local magnitude +1.3 were recorded near the mine during undercutting, with event rates of up to 500 per day. Analysis of frequency-magnitude distributions, S-wave to Pwave energy, and temporal variations in event magnitude all gave insight into the seismicity recorded. In addition, a new technique, called apparent stress time history, was shown to be sensitive to stress change from undercut blasting, and useful to identify significant periods during cave development.
A significant difference was identified between the cave back location and the halo of seismic events above the cave. Throughout the undercutting, the aseismic zone of loosening was typically 50 to 70 metres in vertical thickness. Based on the seismicity, a stress driven rock mass failure model is proposed. Early in the undercutting, seismicity and movements in the seismogenic zone were directly triggered by stress change from undercutting. Towards the end of undercutting, seismicity was virtually uncorrelated with undercut blasting, and likely due to the onset of cave initiation.


 

 

“Full text available only in PDF format”

 

 

References

1. DUFFIELD, S. Design of the second block cave at Northparkes E26 mine. Proceedings MassMin 2000, G. Chitombo (ed.), Australian Institute of Mining and Metallurgy: Melbourne, 2000, p. 334-346.         [ Links ]

2. HOUSE, M., VAN AS, A., and DUDLEY, J. Block Caving Lift 1 of the Northparkes E26 Mine, Underground Mining Methods: Engineering Fundamentals and International Case Studies, SME, Colorado, 2001. pp. 411-416.         [ Links ]

3. GLAZER, S.N., LURKA, A., MUTKE, G., DUBINSKI, J., and MOSS, A. Application of seismic tomography to block cave operations. Technical report to Rio Tinto.2005.         [ Links ]

4. CHEN, D. Geotechnical assessment of block cave mining in Northparkes Mines, NSW Australia, Proc. 2nd North Am. Rock Mech. Symp. M. Aubertin, F. Hassani and H.S.Mitri (eds.), Int. Soc. Rock Mech. 1996. p. 261.         [ Links ]

5. ITASCA. FLAC3D Modelling of the Lift 2 Undercut and Extraction-Level Development at Northparkes Mines, E26 Mine. Technical Report for Northparkes Mines. 2005.         [ Links ]

6. DOOLAN, J. An analysis of microseismic activity at Northparkes mines during undercutting of the Lift 2 block cave project. Unpublished undergraduate thesis. RMIT. 2004. 77 pp.         [ Links ]

7. DUPLANCIC, P. Characterisation of caving mechanisms through analysis of stress and seismicity. Unpublished PhD thesis, Department of Civil and Resource Engineering, University of Western Australia. 2001. 227 pp.         [ Links ]

8. BUTCHER, R. Caving Geomechanics. Proceedings of ACG Seminar 0309, 2003, Perth.         [ Links ]

9. WHITE, H., DE BEER, W., VAN AS, A., and ALLISON, D. Design and implementation of seismic monitoring systems in a block-cave environment. Proceedings of Massmin 2004, Santiago, Karzulowicz K. and Alfaro, M.A. (eds.) Chile, 2004. pp. 559-564.         [ Links ]

10. GUTENBERG, B. and RICHTER, C.F. Frequency of earthquakes in California, Bulletin of the Seismological Society of America, vol. 34, 1944, pp. 185-188.         [ Links ]

11. LEGGE, N.B. and SPOTTISWOODE, S.M. Fracturing and microseismicity ahead of a deep gold mine stope in the pre-remnant stages of mining. Proceeding of the 6th Int. Congress on Rock Mech., Montreal, September 1987, 1987, pp. 1071-1078.         [ Links ]

12. GIBOWICZ, S.J. and KIJKO, A. An introduction to mining seismology. 1st edition San Diego: Academic Press. 1994.         [ Links ]

13. FINNIE, G.J. Some statistical aspects of mining induced seismic events. Proceedings of SARES99, 2nd South African Rock Engineering Symposium, Johannesburg, 13-15 September 1999. T.O. Hagan(ed.), Johannesburg, 1999. pp. 132-139.         [ Links ]

14. AMIDZIC, D. Energy-moment relation and its application. Proceedings of Rockbursts and Seismicity in Mines-RaSiM 5, Johannesburg, September 2001. G. van Aswegen et al. (eds.), Johannesburg: South African Institute of Mining and Metallurgy, 2001. pp. 509-513.         [ Links ]

15. GIBOWICZ, S.J., YOUNG, R.P., TALEBI, S., and RAWLENCE, D.J. Source parameters of seismic events at the underground research laboratory in Manitoba, Canada: scaling relations for events with moment magnitude smaller than -2. Bull. Seismol. Soc. Am. vol. 81, 1992. pp. 1157-1182.         [ Links ]

16. BOATWRIGHT, J. and FLETCHER, J.B. The partition of radiated energy between P and S waves. Bull. Seismol. Soc. Am. vol. 74, 1984. pp. 361-376.         [ Links ]

17. CICHOWICZ, A., GREEN, R.W.E., BRINK, A.V.Z, GROBLER, P., and MOUNTFORT, P.I. The space and time variation of micro-event parameters occurring in front of an active stope. Proceedings of Rockbursts and Seismicity in Mines. Minneapolis. C. Fairhurst (ed.). Rotterdam: A.A.Balkema, 1990, pp. 171-175.         [ Links ]

18. URBANCIC, T.I., YOUNG, R.P., BIRD, S., and BAWDEN, W. Microseismic source parameters and their use in characterizing rock mass behaviour: considerations from Strathcona mine. Proceedings of 94th Annual General Meeting of the CIM: Rock Mechanics and Strata Control Sessions, Montreal, 26-30 April 1992, 1992, pp. 36-47.         [ Links ]

19. SATO, T. A note on body wave radiation from expanding tension crack. Sci. Rep. Tohoku University, Geophysics, 1978, pp. 1-10.         [ Links ]

20. VAN ASWEGEN, G. and BUTLER, A.G. Applications of quantitative seismology in South African gold mines. Proceedings 3rd International Symposium on Rockburst and Seismicity in Mines. R.P. Young (ed.). Kingston, A.A. Balkema, 1993, pp. 261-266.         [ Links ]

21. SIMSER, B.P., FALMAGNE, V., GAUDREAU, D., and MACDONALD, T. Seismic Response to Mining at the Brunswick Mine. CIM Annual General Meeting. Montreal. 2003. 12 pp.         [ Links ]

22. MENDECKI, A.J., VAN ASWEGEN, G., and MOUNTFORT, P. A guide to routine seismic monitoring in mines. Chapter 9. A Handbook on Rock Engineering Practice for Tabular Hard Rock Mines. A.J. Jager and J.A. Ryder (eds.), Creda Communications, Cape Town, 1999.         [ Links ]

23. MENDECKI, A.J. and VAN ASWEGEN, G. Seismic monitoring in mines: selected terms and definitions. Proceedings of Rockbursts and Seismicity in Mines-RaSiM 5, Johannesburg, September 2001. G. van Aswegen, R. Durrheim, and W.D.Ortlepp (eds.), South African Institute of Mining and Metallurgy, 2001, Johannesburg. pp 563-570.         [ Links ]

24. WYSS, M. and BRUNE, J.N. Seismic moment, stress and source dimensions for earthquakes in the California-Nevada region. Journal of Geophysical Research, vol. 73, 1968, pp. 4681-4694.         [ Links ]

25. GlAZER, S.N. and HEPWORTH, N. Crown pillar failure mechanism-case study based on seismic data from Palabora Mine. IMM Transactions-Mining Technology. vol. 115. no. 2. 2006. pp. 75-84.         [ Links ]

26. CHEN, D. Application of a microseismic system in monitoring at E26 block cave at Northparkes Mines, Australia, Proc. Int. Conf. on Geomech. N.I. Aziz and B. Indraranta (eds.), 2, Wollongong, Australia., 1998, pp. 1067-1078.         [ Links ]

27. HUDYMA, M.R. Self-similar clustering of seismic events in mines. PhD in progress, University of Western Australia, 2007.         [ Links ]

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