Opencast to underground iron ore mining method

Abstract

At the end of the open-pit mining process in large metal mines, the mining model must change from open-pit mining to underground mining, but the mutual interference between the two mining models leads to poor production safety conditions and difficulties in production convergence during the transition period. To solve these technical problems of poor production safety conditions and difficulties in production convergence during the transition period, in this study, based on the case of the Dagu Mountain Mine, a new transition mode of wedge switching for collaborative mining is proposed and established, which is suitable for collaborative mining. This new mining process completely eliminates the boundary pillar and the artificial covering layer, combining the technology of the mining-induced caving method and the technology of deep mining at the bottom of the open-pit. The results show that 1) the optimization of the open-pit boundary reduces the amount of rock stripping, and 2) it achieves a stable transition of collaborative mining capacity. The study shows that the proposed method uses the technologies of the mining-induced caving method in underground mining and deep mining at the bottom of the open pit in open-pit mining, and the method then optimizes the open-pit mining in detail by comparing the advantages of open-pit mining and underground mining. This study provides true and accurate technical support for the transition from open-pit mining to underground mining.

Keywords

opencast-to-underground mining / transition mode / wedge-shaped transition mode

References

[1] BakhtavarE, ShahriarK, OraeeK. Mining method selection and optimization of transition from open pit to underground in combined mining [J]. Archives of Mining Sciences, 200954

[2] HanX M, LiZ J, GanD Q. Numerical simulation and sensitivity analysis of slope stability in mine transferred from open pit to underground mining [J]. Metal Mine, 2007, 6: 8-12

[3] SongW D, WangZ C, GongD F. Numerical simulation on the slope stability when transferring open-pit mining to underground mining in Zimudang gold mine [J]. Gold, 2008, 29: 20-23

[4] SafariM, AtaeiM, KhalokakaieR, KaramozianM. Mineral processing plant location using the analytic hierarchy process–A case study: The Sangan iron ore mine [J]. Mining Science and Technology, 2010, 20: 0691-0695

[5] SunS G, GuoW C, LiuW B, GuoP, DongY F. Study on high slope sliding deformation mechanism induced by transiting from opencast into underground mining [J]. Metal Mine, 2015, 15(5): 162-165

[6] WangS Y, SloanS W, ShengD C, TangC A. Numerical analysis of the failure process around a circular opening in rock [J]. Computers & Geotechnics, 2012, 39: 8-16

[7] WangS Y, LamK C, AuS K, TangC A, ZhuW C. Analytical and numerical study on the pillar rockbursts mechanism [J]. Rock Mechanics & Rock Engineering, 2006, 39: 445-467

[8] WangS Y, SloanS W, HuangM L, TangC A. Numerical study of failure mechanism of serial and parallel rock pillars [J]. Rock Mechanics & Rock Engineering, 2011, 44: 179-198

[9] MaT H, TangC A, YangT H. Analysis on stability of top pillar when coming into underground mining from open-pit [J]. Journal of Northeastern University (Natural Science), 2006, 27: 450-453

[10] ZhaoX D, LiL C, TangC A, ZhangH X. Stability of boundary pillars in transition from open pit to underground mining [J]. Journal of Central South University, 2012, 19: 3256-3265

[11] RaoZ B, CaiS J. The blasting test and blasting vibration monitoring of vertical crater retreat mining method in the Luohe iron mine [J]. Geotechnical and Geological Engineering, 2015, 34: 1047-1056

[12] XuH L, YangT H, ZhuL K. The studying on reasonable thickness of the boundary pillar during transferring open-pit into underground mining in III slope of Sijiaying mine [J]. China Mining Magazine, 2007, 16: 74-76

[13] HeP X, WuZ J. Order researching of transferred from opencast mining to underground mining in Guangxi Daxin MengKuang [J]. China’s Manganese Industry, 2008, 26: 35-38

[14] JASON PHILLIPS.. The application of a mathematical model of sustainability to the results of a semi-quantitative environmental impact assessment of two iron ore opencast mines in Iran [J]. Applied Mathematical Modelling, 2013, 37: 7839-7854

[15] SainsburyD P, SainsburyB L, LorigL J. Investigation of caving induced subsidence at the abandoned Grace Mine [J]. Transactions of the Institution of Mining and Metallurgy, 2013, 119: 151-161

[16] HanF, XieF, WangJ N. 3-D numerical simulation on the stability of rocks in transferred underground mining from open-pit [J]. Journal of University of Science and Technology Beijing, 2006, 28: 509-514

[17] WangY F, CuiF. Study on stability and failure characteristics of the slope in transition from open-pit to underground mining by structural geology [J]. Applied Mechanics and Materials, 2012, 170: 932-936

[18] YanS S. Study on feasibility of transfer from open-pit mining to underground mining in Washan pit of Nanshan mining Co [J]. Metal Mine, 2006, 9: 34-36

[19] VyazmenskyA, SteadD, ElmoD, MossA. Numerical analysis of block caving-induced instability in large open pit slopes: A finite element/discrete element approach [J]. Rock Mech Rock Eng, 2010, 43(1): 21-39

[20] HouJin. Study on feasibility of underground mining turned to surface mining in Yuanjin mine [J]. Coal Engineering, 2013, 3: 17-19

[21] BakhtavarE, ShahriarK, MirhasaniA. Optimization of transition from open-pit to underground in combined mining using (0–1) integer programming [J]. Journal of SAIMM, 2012, 112: 1059-1064

[22] ZhangL, WangW P. Reviews on the developing status of combining mining with underground and open-pit [J]. Metal Mine, 2007, 28(8): 118-122