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Journal of the Southern African Institute of Mining and Metallurgy

On-line version ISSN 2411-9717

J. S. Afr. Inst. Min. Metall. vol.108 n.7 Johannesburg Jul. 2008

 

TRANSACTION PAPER

 

Seismic monitoring of the Northparkes Lift 2 block cave - Part 2 production caving

 

 

M. HudymaI; Y. PotvinII; D. AllisonIII

IItasca Consulting Canada Inc
IIAustralian Centre for Geomechanics
IIIRio Tinto

 

 


SYNOPSIS

Production caving started for Lift 2 at Northparkes in August 2004. In a period of less than 3 months, more than 10 000 seismic events were recorded. Events up to local magnitude +2.9 were induced near the mine during caving, with event rates of up to 500 per day.
This paper documents the seismicity related to cave initiation and cave propagation during the initial production of Lift 2. The seismogenic zone of events initially moved at a rate of about 0.5 metres per day, accelerating to 2 to 3 metres per day after a few months of cave production. Seismic data analysis infers that the crown pillar between Lift 1 and Lift 2 was destressed over a vertical height of about 100 metres. As the seismogenic zone approached the crown pillar, a macroseismic episode occurred, with more than 20 events of at least local magnitude +1 occurring in a two-week period.
Based on the seismicity recorded for Lift 2 at Northparkes Mines, a caving mechanics model is proposed. Comments and suggestions are made for seismic data analysis and design of seismic monitoring systems in block caving mines.


 

 

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References

1. BUTCHER, R. Caving Geomechanics. ACG Seminar, Australian Centre for Geomechanics, Perth, 2003.         [ Links ]

2. 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 ]

3. 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 Unpublished PhD Thesis, Department of Civil and Resource Engineering, University of Western Australia, 2001, 227 pp.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 ]

4. GLAZER, S.N. and HEPWORTH, N. Seismicity induced by cave mining, Palabora experience. Proceedings 6th International Symposium on Rockburst and Seismicity in Mines. Potvin, Y. and Hudyma, M.R. (eds.) Perth, Australia. Australian Centre for Geomechanics, 2005, pp: 281-289.         [ Links ]

5. 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 ]

6. HUDYMA, M.R. and MILNE, D. Analysis of caving induced mine seismicity at Ridgeway Gold Mine. Technical Research Report-Australian Centre for Geomechanics-Mine Seismicity and Rockburst Risk Management Project, 2004, 67 pp.         [ Links ]

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