scholarly journals Behaviors and Overlying Strata Failure Law for Underground Filling of a Gently Inclined Medium-Thick Phosphate Deposit

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Xiaoshuang Li ◽  
Jiabo Geng ◽  
Qihang Li ◽  
Weijun Tian ◽  
Tao Zhou
Keyword(s):  
Distinct Element ◽  
Mining Area ◽  
Surface Subsidence ◽  
Experimental Results ◽  
Support Pressure ◽  
Rock Layer ◽  
Deformation And Failure ◽  
Sublevel Caving ◽  
Similar Simulation ◽  
Overlying Strata

In this study, the No. 6 pit in the eastern mining area of the Jinning phosphate mine in China was taken as the research background. In order to reduce the cost of filling, an improved pillarless sublevel caving method is proposed. This method greatly improves the ore recovery rate by adding a recovery route. In addition, the combination of similar material simulation experiments and numerical simulations (discrete element and universal distinct element code) revealed the deformation and failure laws of the surrounding roof rock and the characteristics of the surface subsidence. The results indicate the following. (1) The similar simulation experimental results indicate that the deformation of the overlying rock layer originated from the direct roof of the goaf and gradually developed into the deep part of the rock layer. An irregular stepped caving zone formed in the goaf. The maximum surface subsidence was located above the phosphorus orebody, and it gradually decreased toward both sides. As the stope approached propulsion, the location of the maximum subsidence gradually moved toward the propulsion direction. (2) The numerical results revealed that the displacement of the overlying strata was nonlinear, and it decreased with increasing roof height. A support pressure concentration area was formed within a certain range of the stope roof. The numerical simulation results are basically consistent with the similar simulation experimental results.

New Technology of Surface Subsidence Control and Environmental Protection Research in Coal Mining Region

2014 ◽  
Vol 675-677 ◽  
pp. 1385-1394
Author(s):  
Cheng Rong Jiang ◽  
Liu Yang ◽  
Hao Xie ◽  
Hua Yi Huang ◽  
De Ke Sun
Keyword(s):  
Coal Mining ◽  
New Technology ◽  
Mining Area ◽  
Industrial Test ◽  
Surface Subsidence ◽  
High Concentration ◽  
Geological Conditions ◽  
Surface Subsidence Control ◽  
Fissure Water ◽  
Overlying Strata

In combination with the geological conditions of Tie'er mining area in Tangshan coal mining, this paper not only analyzes the evolution of overlying strata structure in stope and the development law of overlying strata separation, also proposes a new continuous grouting technology with large flow and high concentration slurry. The industrial test showed that, when the grout-mining ratio of the whole mining area is 25.3%, the reducing subsidence ratio is 51.5%, the effect of reducing the surface subsidence is good. According to the chemical analysis of water quality ingredients of slurry, the test result showed, heavy metals contents in fly-ash slurry water do not exceed the standard, which has no bad effect on the fissure water in the bedrock.

scholarly journals Research on the Evolution Characteristics of Rock Mass Response from Open-Pit to Underground Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiabo Geng ◽  
Qihang Li ◽  
Xiaoshuang Li ◽  
Tao Zhou ◽  
Zhifang Liu ◽  
...  
Keyword(s):  
Underground Mining ◽  
Vertical Direction ◽  
Mining Area ◽  
Open Pit ◽  
Measuring Point ◽  
Deformation And Failure ◽  
Ore Body ◽  
Evolution Characteristics ◽  
The Impact ◽  
Overlying Strata

This study is based on the engineering background of pit no. 2 in Jinning Phosphate Mine, China. In order to systematically analyze the movement, deformation, and failure laws of surrounding rocks in underground stopes. The room and pillar method is used to excavate and stop the ore bodies in the mining area. Combined with the similar physical model experiments and discrete element MatDEM numerical simulations, it reveals the deformation and failure laws and evolution characteristics of the surrounding rock of the stope in the process of converting from open-pit to underground mining. The results show the following: (1) Along the inclination of the ore body, the farther the horizontal and vertical displacements are from the underground stope, the less the impact of mining stress. On the other hand, along the inclined vertical direction of the ore body, the farther the measuring point is from the stope, the smaller the range of mining influence will be. (2) In the process of ore body recovery, the rupture of the overlying strata of the stope has an obvious layered structure, with collapse zones, fissure penetrating zones, and microfracture loosen zones appearing from the bottom to top. In addition, the movement and destruction of the overlying strata of the entire stope is an “elliptical arch.” Therefore, the results of similar simulation experiments and numerical simulation are basically consistent.

Study on Similar Simulation of the Roof Strata Movement Laws of the Large Mining Height Workface in Shallow Coal Seam

2012 ◽  
Vol 450-451 ◽  
pp. 1318-1322 ◽  
Author(s):  
Ping Wei Xing ◽  
Xuan Min Song ◽  
Yu Ping Fu
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Supporting Pressure ◽  
Immediate Roof ◽  
Large Mining Height ◽  
Roof Strata ◽  
Basic Roof ◽  
Mining Height ◽  
Similar Simulation ◽  
Overlying Strata

Based on the condition of No.1-2 coal seam of Shang Wan Coal Mine Shendong mining area, the movement of the overlying strata of the 7.0m large mining height workface have been studied by similar simulation test, which geometric similarity ratio is 1:50.The results show that: the immediate roof strata caves stratified to loose blocks, and the goaf can’t be filled with these loose blocks; the basic roof strata caves stratified too, the lower slice caves to loose blocks, it evolves into the immediate roof and widen the immediate roof; there is the periodic weighting phenomenon of size alternating in the large mining height workface of No.1-2 coal seam ; the immediate roof and the basic roof and the overlying strata of basic roof have different characteristics of caving; the large mining height workface has a greater sphere of supporting pressure than the traditional small height workface, the peak supporting pressure of the large mining height workface is more depth to the coalwall than the average mining height workface, and this led to workface roof strata fracture further ahead.

Change Properties of Water Conductivity Height in Coal Roof Induced by Mining in Extra Thick Coal Seams under Influence of Complex Fissures Zone

2012 ◽  
Vol 446-449 ◽  
pp. 59-63
Author(s):  
Shi Guo Sun ◽  
Guo Hong Li ◽  
Jing Xin Wang ◽  
Hong Ying Zhao ◽  
Shao Jie Feng
Keyword(s):  
Underground Mining ◽  
Water Inrush ◽  
Technical Problem ◽  
Mining Area ◽  
Water Conductivity ◽  
Deformation And Failure ◽  
Mining Areas ◽  
Mining Safety ◽  
Strata Deformation ◽  
Overlying Strata

It’s a technical problem of underground mining safety to determine the water conductivity height in coal roof induced by mining under the condition of fully mechanized caving. With a number of mining engineering cases, we studied complex fault zone overlying rock mass damage characteristics under the compound effect of many mining area. The results show that overlying strata deformation and failure is the results of accumulation in mining of each mining area. Therefore, whether the overlying strata water inrush in mining process will happen or not, needs to take account of water in overlying strata in old mining area. Based on the change characteristics of water conductivity height induced by mining in seven mining areas, we built regression forecasting model, and achieved the prediction of water conductivity height induced by mining in lower coal seam, so as to provide a basis for decision-making for the safety of follow-up exploration.

Slow surface subsidence and its impact on shallow loess landslides in a coal mining area

CATENA ◽  
2022 ◽  
Vol 209 ◽  
pp. 105830
Author(s):  
Dongdong Yang ◽  
Haijun Qiu ◽  
Shuyue Ma ◽  
Zijing Liu ◽  
Chi Du ◽  
...  
Keyword(s):  
Coal Mining ◽  
Mining Area ◽  
Surface Subsidence ◽  
Coal Mining Area ◽  
Slow Surface ◽  
Loess Landslides

scholarly journals Movement Laws of Overlying Strata above a Fully Mechanized Coal Mining Face Backfilled with Gangue: A Case Study in Jiulishan Coal Mine in Henan Province, China

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Zhengkai Yang ◽  
Zhiheng Cheng ◽  
Zhenhua Li ◽  
Chunyuan Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Main Roof ◽  
Surrounding Rock ◽  
Surface Subsidence ◽  
Key Strata ◽  
Key Stratum ◽  
Mining Face ◽  
Failure Depth ◽  
Gangue Backfilling ◽  
Overlying Strata

The aim of this study is to obtain movement laws of overlying strata above a fully mechanized coal mining face backfilled with gangue and solve the problem of surface subsidence during coal mining. This study was carried out based on gangue backfilling mining of Jiulishan Coal Mine (Jiaozuo City, Henan Province, China) from the perspectives of deformation of backfilled gangue under compaction, surrounding rock of a stope, and activities of key strata. The method combining with rock mechanics, viscoelastic mechanics, control theory of rock mass under mining, and numerical simulation was used based on physical and mechanical characteristics of backfilled gangue. On this basis, the research analyzed the temporal-spatial relationships of activities of surrounding rock of the stope, compressive deformation of backfilling body, failure depth of the floor, deformation characteristics of the main roof with laws of surface subsidence. The movement characteristics of overlying strata above the fully mechanized coal mining face backfilled with gangue and the traditional fully mechanized mining face were compared. It is found that, under the same conditions of overlying strata, movement laws of overlying strata are mainly determined by the mining height of coal seams and the heights of a caving zone and a fracture zone are nearly linearly correlated with the mining height. Through analysis based on thin-plate theory and key stratum theory, the location of the main roof of the fully mechanized coal mining face backfilled with gangue in coal seams first bending and sinking due to load of overlying strata was ascertained. Then, it was determined that there are two key strata and the main roof belongs to the inferior key stratum. By using the established mechanical model for the main roof of the fully mechanized coal mining face backfilled with gangue and the calculation formula for the maximum deflection of the main roof, this research presented the conditions for breaking of the main roof. In addition, based on the theoretical analysis, it is concluded that the main roof of the fully mechanized coal mining face backfilled with gangue does not break, but bends. The numerical simulation results demonstrate that, with the continuous increase of strength of backfilled gangue, the stress concentration degree of surrounding rock reduces constantly, so does its decrease amplitude. Moreover, the compressive deformation of backfilling, failure depth of the floor, and bending and subsidence of the main roof continuously decrease and tend to be stable. The mechanical properties of backfilling materials determine effects of gangue backfilling in controlling surface subsidence. Gangue backfilling can effectively control movement of overlying strata and surface subsidence tends to be stable with the increase of elastic modulus of gangue.

scholarly journals Experimental Test on Nonuniform Deformation in the Tilted Strata of a Deep Coal Mine

2021 ◽  
Vol 13 (23) ◽  
pp. 13280
Author(s):  
Hai Wu ◽  
Qian Jia ◽  
Weijun Wang ◽  
Nong Zhong ◽  
Yiming Zhao
Keyword(s):  
High Stress ◽  
Stability Control ◽  
Surrounding Rock ◽  
Experimental Results ◽  
Lower Side ◽  
Reinforcement Scheme ◽  
Deformation And Failure ◽  
True Triaxial ◽  
Deep Mine ◽  
Deep Coal Mine

Taking a deep-mine horizontal roadway in inclined strata as our research object, the true triaxial simulation technique was used to establish a model of the inclined strata and carry out high-stress triaxial loading experiments. The experimental results show that the deformation of surrounding rock in the roadway presents heterogeneous deformation characteristics in time and space: the deformation of the surrounding rock at different positions of the roadway occurs at different times. In the process of deformation of the surrounding rock, deformation and failure occur at the floor of the roadway first, followed by the lower shoulder-angle of the roadway, and finally the rest of the roadway. The deformation amount in the various areas is different. The floor heave deformation of the roadway floor is the greatest and shows obvious left-right asymmetry. The deformation of the higher side is greater than that of the lower side. The model disassembly shows that the development of cracks in the surrounding rock is characterized by more cracks on the higher side and fewer cracks on the lower side but shows larger cracks across the width. The experimental results of high-stress deformation of the surrounding rock are helpful in the design of supports, the reinforcement scheme, and the parameter optimization of roadways in high-stress-inclined rock, and to improve the stability control of deep high-stress roadways.

Study and Practice on the Technology of Filling Mining in Xin Wen Mining Area

2011 ◽  
Vol 121-126 ◽  
pp. 2892-2896
Author(s):  
Ming Tao Gao ◽  
Ming Zhang ◽  
Ming Zhou
Keyword(s):  
Mining Area ◽  
Scientific Basis ◽  
Surface Subsidence ◽  
Open Pit ◽  
Coal Waste ◽  
Coordinated Development ◽  
Underground Disposal ◽  
Rock Movement ◽  
The Stability ◽  
Technology Processes

Because of mine production, the open-pit enission of coal gangue solid waste and surface subsidence are one of important causes to failure the mining area land and environment, so the key technology, processes and equipment of filling mining to replace coal have been developed, which convergences the existing system of mining technology, And the stability theory of the control of filling mining rock movement and the method of surface subsidence prediction have been established, which provides a scientific basis for equipment Selection and the design of subsidence control; the key technologies of filling mining to replace coal is successfully applicated, which significantly improves the recovery rate of coal resources in China and constructs the new coordinated development model that is combined by the underground disposal of coal waste, mining subsidence control and the “under three”safe coal mining, through the above, the target of green mining and the coordinated development of mining social, economic and environmental will be achieved.

scholarly journals Mechanism of Secondary Breakage in the Overlying Strata during Repetitious Mining of an Ultrathick Coal Seam in Design Stage

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hui Li ◽  
Dongsheng Zhang ◽  
Shuyin Jiang ◽  
Gangwei Fan ◽  
Mengtang Xu
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Design Stage ◽  
Mining Method ◽  
Joint Stability ◽  
Mechanical Models ◽  
Physical Simulations ◽  
Research Findings ◽  
New Feature ◽  
Overlying Strata

When designing the mining of an ultrathick coal seam, the laws governing movement in the overlying strata during mining are a fundamental issue based on which several problems are addressed, including determining the mining method and the roadway arrangement, controlling the surrounding strata, and selecting the devices. The present paper considers possible problems related to strata overlying a large mining space subjected to repeated disturbances during the mining of an ultrathick coal seam, including repeatedly broken strata and the existence or inexistence of the structure. The BM coal seam in the No. 2 coal mine of the Dajing mining area in the East Junggar coalfield is studied. Physical simulations are performed on the movements of the overlying strata during slicing mining of the ultrathick coal seam, revealing the new feature of “break-joint stability-instability-secondary breakage” in the overlying strata. Mechanical models are constructed of the secondary breakage of the overlying strata blocks under both static and impact loading, and mechanical criteria are proposed for such breakage. Based on the research findings, methods for controlling the surrounding strata during slicing mining of an ultrathick coal seam are proposed, including increasing the mining rate and designing reasonable heights for the slicing mining.

Sign in / Sign up

Export Citation Format

Share Document