Mining optimization in Lift 410 m of Tongkuangyu copper mine

Authors: Wen, L; Changnian, X; Yuming, L; Xin, W; Yan, W; Haohao, W Download Paper

Cite As:
Wen, L, Changnian, X, Yuming, L, Xin, W, Yan, W & Haohao, W 2024, 'Mining optimization in Lift 410 m of Tongkuangyu copper mine', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 307-318.



Abstract:
Tongkuangyu copper mine was the first block caving mine in China and has produced for nearly 40 years. It is currently entering a transition period from Lift 530 m to 410 m in the Phase II project. The Lift 410 m has a block height of 120 m, and extraction and undercutting levels are located at the 434 m and 447 m, respectively. Post undercut strategy is adopted for mining. In order to reduce damaging effects of ground pressure on bottom infrastructures, the height and support type of bottom infrastructures in Lift 410 m were optimized. The height of major apex was increased by 3 m, and a combined support measure of spraying anchor mesh, anchor rod and cable, concrete steel arch was adopted. In order to ensure stable production capacity of Tongkuangyu copper mine during the transition period, rock mass pre-conditioning by hydraulic fracturing was implemented at the start mining area of No. 5 and 4 orebodies in Lift 410 m. Six vertical boreholes were drilled for hydraulic fracturing preconditioning at each start mining area of two orebodies, and segmented fracturing operations by high pressure water injection were conducted for about 30 minutes. The results show that orebody cavability at the start of a mining area was effectively improved, and an increase of about 3 times in caving rate was achieved, and a decrease of about 20.4 percentage in large block rate, which effectively ensure the production target of 9 million tons of ore per year at Tongkuangyu copper mine.