Monitoring and evaluation of disaster risk caused by linkage failure and instability of residual coal pillar and rock strata in multi-coal seam mining

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COMPREHENSIVE MONITORING AREA AND METHOD OF LINKAGE INSTABILITY OF RESIDUAL COAL PILLAR AND ROCK STRATA

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CREDIT: QING MA, ET AL.

A large number of coal pillars were left behind during the mining of multi-coal seams. These pillars, when unstable, pose significant risks during both production and well closure stages in coal mines. Their failure can exert intense dynamic pressure on lower coal seams, resulting in substantial deformation and damage to support structures and mining tunnels. In extreme cases, such instability can trigger disasters like mine earthquakes and widespread collapse of goaf areas, potentially leading to casualties. Therefore, it is necessary to carry out monitoring and evaluation research on the risk of instability and disaster caused by the linkage of residual coal pillars and rock strata.

The challenge of instability linkage between residual coal pillars and rock strata is complex, as it not only involves the interaction between these pillars and strata but also engenders a cascade of linkage disasters. Present research efforts mostly lack a holistic assessment of the instability and disaster risks arising from the interaction between residual coal pillars and rock strata in multi-coal seam mining.

To that end, a group of researchers from China established a comprehensive monitoring and evaluation of disaster risk caused by linkage failure and instability of residual coal pillar and rock strata in multi-coal seam mining. In brief, they reported:

1. The instability of residual coal pillar-rock strata is characterized by shallow burial depths, concentrated beneath overlying coal seams, and manifests through various mine pressure forms, including support bending and roof collapse, sometimes leading to surface damage;
2. Monitoring of residual coal pillar-rock strata instability requires attention to fracture development height in addition to other components. A comprehensive monitoring approach is devised to address diverse monitoring needs;
3. Key evaluation indices such as microseismic energy and crack development height are identified for assessing coal pillar-rock strata linkage instability. A quantitative evaluation method using fuzzy comprehensive evaluation is introduced; and
4. Using fuzzy comprehensive evaluation, the medium-risk level of disaster stemming from coal pillar-rock strata linkage instability in the 307-panel area during multi-seam mining is assessed. Pressure relief techniques like blasting are effective in reducing stress, validating the accuracy of risk assessment.

“Our study serves as a resource for studying and evaluating the disaster risk stemming from the linkage instability of residual coal pillar-rock strata in multi-seam mining,” notes first author Qing Ma. “Furthermore, the findings offer insights that can be applied to assess the stability and risk associated with residual coal pillar-rock formations post-CO2 injection in closed or abandoned mines.”

The team detailed their findings in the KeAi journal Geohazard Mechanics.

“Nevertheless, it is essential to customize the application of these findings to suit the specific production and geological conditions of individual mines, necessitating certain adjustments during implementation,” adds Ma.

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Contact the author: Qing Ma, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, China, qingma819@126.com

The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 100 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).

 

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JOURNAL

Geohazard Mechanics

DOI

10.1016/j.ghm.2023.11.001 

ARTICLE TITLE

Monitoring and evaluation of disaster risk caused by linkage failure and instability of residual coal pillar and rock strata in multi-coal seam mining

Risk assessment of multi-disaster in Mining Area of Guizhou, China

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https://doi.org/10.1016/j.ijdrr.2022.103128Get rights and content

Highlights

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  We propose a method to study risk assessment of multi-disaster in mining areas.

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  Population was concentrated in areas susceptible to multiple hazards.

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  Multi-hazard risk is expected to increase in the Mining Area of Guizhou.

Abstract

Increased slope and soil instability due to rainfall infiltration and artificial exploitation is a significant cause of multi-disaster in mining areas. Many kinds of research have been conducted to evaluate the susceptibility of single geological disaster species such as landslides, collapses, ground subsides, and debris flows. However, due to the coupling effect of different stages, the evaluation system index's construction is often disregarded during mining-induced multi-disaster risk assessments. Hence, we propose a relatively complete evaluation index system to assess the multi-disaster risk that considers the assessment processes of disaster susceptibility, hazard, and vulnerability in mining areas. The procedure for the proposed method includes three main steps. In step 1, we analyze the spatial probability assessment due to topographic, geological, and geomorphic indicators. In step 2, the hazard assessment indexes system and multi-disaster models are established using different rainfall probability periods, considering the annual maximum daily rainfall. In step 3, the vulnerability assessment method of multi-disaster was proposed according to the calamity environment and considering hazard distribution and bearing body characteristics. The risk evaluation system for multi-disaster mining areas is established based on the previous three steps. We validated the proposed model by analyzing mining exploitation in Panguan town, China. Our model classifies the likelihood of multi-disaster occurrence in mining areas according to five risk levels: very high, high, moderate, low, and very low. The multi-phase risk assessment map is drawn with different rainfall frequencies (10%, 5%, 2%, and 1%, respectively), providing reasonably scientific guidance on the mining region's emergency response capacity.

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