Prediction of Surface Subsidence Extension due to Underground Caving: A Case Study of Hemushan Iron Mine in China

Abstract

Underground caving can potentially lead to large-scale surface destruction. To test the safety conditions of the surface construction projects near the circular surface subsidence zone in the Hemushan Iron Mine, this paper proposes an analytical model to analyze the stability of the cylindrical caved space by employing the long-term strength of the surrounding rock mass, the in situ stress, and the impact of caved materials as inputs. The proposed model is valid for predicting the orientation and depth where rock failure occurs and for calculating the maximum depth of the undercut, above which the surrounding rock mass of the caved space can remain stable for a long duration of time. The prediction for the Hemushan Iron Mine from the proposed model reveals that the construction projects can maintain safe working conditions, and such prediction is also demonstrated by the records from Google Earth satellite images. This means that the proposed model is valid for conducting such analysis. Additionally, to prevent rock failure above the free surface of caved materials, backfilling the subsidence zone with waste rocks is suggested, and such a measure is implemented in the Hemushan Iron Mine. The monitoring results show that this measure contributes to protecting the surrounding wall of the caved space from large-scale slip failure. The contribution of this work not only provides a robust analytical model for predicting the stability of rock around a cylindrical caved space but also introduces employable measures for mitigating the subsequent extension of surface subsidence after vertical caving.

Climate Impact of China’s Promotion of the Filling Mining Method: Bottom-Up Estimation of Greenhouse Gas Emissions in Underground Metal Mines

“…For example, backfilling of the subsidence pit is suggested for caving-based cases, so as to prevent the subsequent extension of surface subsidence after vertical caving. Such prevention has been validated in the Hemushan and Gongchanling iron mines [56]. Moreover, three approaches, i.e., using industrial wastes (such as fly ash or alkali-activated slag [57,58]) as cementing materials to reduce the consumption of cement in the backfilling stage, employing energy-efficient pumps, and further developing hauling systems, especially LHDs, are recommended for filling-based projects to mitigate their GHG emissions.…”

Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

“…e overlying rock mass appears to move and destroy caused by the underground mining method, such as the room and pillar mining method [1,2] and the caving mining method [3,4]. Gradually, this deformation expands upward to the surface with the development of new cracks and the expansion of primary cracks [5]. e mine area for underground mining may be forced to be closed when the surface strata movement seriously threatens the safety of surface structures, such as roads, bridges, and open pits.…”

Optimization of Stope Structure Parameters Based on the Mined Orebody at the Meishan Iron Mine

“…Castro et al [24][25][26][27][28][29] proposed a mining theory of high sublevel and large drift spacing based on the ore drawing theory, adjusted the sublevel height and drift spacing in different mines accordingly, and implemented it. In addition, extensive literature indicated that the decreased ore loss and dilution rate depended on the reasonable stope structure parameters [30][31][32][33][34][35][36]. Tan et al [37] proved that the optimization of stope structural parameters based on ellipsoid arrangement theory was not rigorous and perfect, which did not follow the consistent principle of the blasted ores and IEZ's shape in essence.…”