Interaction between block caving and rock slope deformation kinematics as a function of cave position and orientation of discontinuities

Abstract

Several operations are considering the transition from surface mining to underground block caving to access deeper resources. Depending on the geometry of the orebody, the undercut may be positioned beneath the foot of a large open pit slope, or behind its crest. The latter scenario also arises where a natural rock slope is present. Results are reported here from a numerical modelling study investigating the mechanics of deep-seated slope displacements in response to caving. Different failure models are investigated as a function of the orientation of the jointing pattern relative to the location and progressive development of the block cave. A 2-D discontinuum modelling approach is utilised based on the distinct-element method. The results show that the cave location and the resultant strain field, plays a significant role in the rock mass interactions that develop and the subsequent kinematic response of the slope with respect to translational, rotational and toppling behaviour.

Keywords

Distinct-element method Block caving Pit slope interaction Numerical modelling Slope deformation kinematics Rock slope instability

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References

Bailey

2003. Findings and recommendations: inquest into the deaths of R Bodkin; M House; S Osman; and C Lloyd-Jones; on the 24th November, 1999 at the E26 Lift 1 Mine, Northparkes Mines, Parkes, New South Wales. NSW Coroners Court, 18 March, 2003.

Beck

, Arndt

, Thin

, Stone

and Butcher

2006. A conceptual sequence for a block cave in an extreme stress and deformation environment, Proc. 3rd Int. Seminar on ‘Deep and high stress mining’, Universite’ Laval, Section 11 (eds. Hadjigeorgiou

and Grenon

), Quebec City, QC, Canada.

Brown

. 2012. Progress and challenges in some areas of deep mining, Min. Technol., 121, (4), 177–191.

Brummer

, Li

and Moss

2006. The transition from open pit to underground mining: an unusual slope failure mechanism at Palabora, in Stability of rock slopes in open pit mining and civil engineering situations, 411–420, Johannesburg, The South African Institute of Mining and Metallurgy (SAIMM).

Du Plessis

and Martin

. 1991. Numerical modeling studies for design of high rock slopes at Palabora Copper Mine, Proc., 7th Int. Cong. Int. Soc. Rock Mech., vol. 1, 799–804, Balkema, Aachen.

Elmo

, Vyazmensky

, Stead

and Rance Jr . 2007. A hybrid FEM/DEM approach to model the interaction between open-pit and underground block-caving mining, Rock mechanics: meeting society's challenges and demands: proceedings of the 1st Canada-US Rock Mechanics Symposium, (eds. Eberhardt

et al.), 1287–1294, London, Taylor & Francis.

Goodman

and Bray

. 1976. Toppling of rock slopes, Geotechnical engineering division conference: specialty conference on ‘Rock engineering for foundations and slopes’, Vol. 2, 201–234, Boulder, CO, ASCE.

Halim

, Trueman

and Castro

2008. Quantifying effect of concurrent draw on extraction zones in block caving mines using large scale 3D physical model, Min. Technol., 117, (3), 128–135.

Itasca. 2004. UDEC4·0: command reference (version 4·0), Minneapolis, MN, Itasca Consulting Group Ltd. Available: http://www.itascacg.com

10.

Manske

and Paul

. 2002. Geology of a major new porphyry copper center in the Superior (Pioneer) district, Arizona, Econ. Geol., 97, (2), 197–220.

11.

Moss

, Diachenko

and Townsend

2006. Interaction between the block cave and the pit slopes at Palabora mine, in Stability of rock slopes in open pit mining and civil engineering situations, 479–484, Johannesburg, The South African Institute of Mining and Metallurgy (SAIMM).

12.

Palabora Mining Company Limited Mine Geological and Mineralogical Staff. 1976. The geology and the economic deposits of copper, iron, and vermiculite in the Palabora igneous complex: a brief review, Econ. Geol., 71, 177–192.

13.

Pretorius

and Ngidi

2008. Cave management ensuring optimal life of mine at Palabora, 5th International conference and exhibition on mass mining, 63–71, Luleå University of Technology Press, Luleå, Sweden.

14.

Resolution Copper Mining. 2006. Sustainable development report. Available: www.resolutioncopper.com (accessed on 1 April 2008).

15.

Rio Tinto . 2008. Resolution copper mining LLC reports an inferred resource of over 1 billion tonnes at its property in Arizona, USA, 1–5, Melbourne, VIC, Australia, Rio Tinto Press. (Rio Tinto Press Release).

16.

Van As

, Davison

and Moss

2003. Subsidence definitions for block caving mines. Rio Tinto Technical Services. (unpublished).

17.

Vyazmensky

, Stead

, Elmo

and Moss

2010. Numerical analysis of block caving-induced instability in large open pit slopes: a finite element/discrete element approach, Rock Mech. Rock Eng., 43, 21–39.

18.

Woo

K.-S

, Eberhardt

, Elmo

and Stead

2013. Empirical investigation and characterization of surface subsidence related to block cave mining, Int. J. Rock Mech. Min. Sci., 61, 31–42.

19.

Woo

K.-S

, Eberhardt

, Rabus

, Stead

and Vyazmensky

2012. Integration of field characterization, mine production and InSAR monitoring data to constrain and calibrate 3-D numerical modelling of block caving-induced subsidence, Int. J. Rock Mech. Min. Sci., 53, 166–178.