scholarly journals Complete methodology to resist in mechanism longwall mine 6# at Nam Mau Coal Company

2019 ◽  
Vol 61 (1) ◽  
pp. 116-123
Author(s):  
Nguyen Phi Hung ◽  
Nguyen Cao Khai ◽  
Bui Manh Tung ◽  
Lai Quang Trung ◽  
Tran Van Thang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mines ◽  
Field Measurements ◽  
Longwall Face ◽  
Support Pressure ◽  
Geological Condition ◽  
Hydraulic Support ◽  
Working Face ◽  
Calculation Results ◽  
Longwall Mine

Geological condition of 6# at Nam Mau coal mines is very complicated for mechanism longwall method, specialy was cause of is the cause of difficulties in moving hydraulic support, so it is necessary to have appropriate reform solutions for the support equipment to operate effectively. The result of dynamic field measurements at the site shows that the maximum support pressure is from 5 to 10 m in front of the mechanism longwall. The coal seam area is located close to the working face due to the influence of the support pressure and beyond the durable limit which was in an unconsolidated state, so it is possible to cause the mirror landslide and topping out. Calculation results show that the distance of 15 m against advance reinforcement at the junction of the furnace head and foot furnace as designed. The results of the study of the distribution of surrounding longwall face pressure, length of longwall need longer 40 meters.

scholarly journals A Gas Seepage Modeling Study for Mitigating Gas Accumulation Risk in Upper Protective Coal Seam Mining Process

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Cun Zhang ◽  
Lei Zhang ◽  
Mingxue Li ◽  
Chen Wang
Keyword(s):  
Coal Seam ◽  
Field Measurements ◽  
Interlayer Spacing ◽  
Mitigation Measures ◽  
Plastic State ◽  
Geological Condition ◽  
Gas Emission ◽  
Working Face ◽  
Gas Seepage ◽  
Seam Mining

Protective coal seam mining (PCSM) is one of the most significant mitigation measures of regional outburst in the process of deep coal seam mining, which has high outburst risk in China. During the PCSM process, the phenomenon of methane concentration exceeding the limit usually occurs in the working face. It is vital to understand factors affecting gas emission from the protective seam working face (PSWF) and to obtain an equation for determining the quantity of gas emission. A gas seepage model (GSM) was developed to simulate the gas emission during the process of upper PCSM. In this study, an equation was formulated to determine the quantity of gas desorbed from the protected seam into PSWF. These equations have been developed by using Fick’s second law of diffusion and Darcy’s flow law. The relationship between permeability and stress was described in an elastic-plastic state, and the mechanics of surrounding rock were investigated. It can be concluded from GSM that the initial gas pressure of protected seam, the characteristics of interlayer rocks, and the ventilation pressure of PSWF were the main factors that influenced the desorption of gas emission from the protected seam into PSWF. The developed GSM was tested for calculating gas emission quantity from the PCSM process by utilizing the actual geological condition data of a coal mine, which is located in Hancheng, China. The results have shown great agreement with obtained field measurements, which is done by combining the fitting curve of ventilation air methane quantity for PSWF with an interlayer spacing. A loss coefficient (δ) of 1.012 × 10−3 was obtained in this study.

The Adaptation Analysis of the Fully Mechanized Coal Mining Face of Huopu Mine’s Third Soft Coal Seam

2014 ◽  
Vol 1049-1050 ◽  
pp. 335-338 ◽  
Author(s):  
Fa Quan Liu ◽  
Xue Wen Geng ◽  
Yong Che ◽  
Xiang Cui
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Geological Condition ◽  
Soft Coal ◽  
Working Face ◽  
Mining Face ◽  
Soft Coal Seam ◽  
Working Resistance

To get the maximum coal in front of the working face of the 17# coal seam, we installed a longer beam which is 1.2m in length in the leading end of the original working face supports ZF3000/17/28, and know that working face supports’ setting load and working resistance are lower .We changed the original supports with shield supports ZY3800/15/33 that are adaptable in the geological condition and got the favorable affection.

scholarly journals Stress Distribution Around Mechanized Longwall Face at Deep Mining in Quang Ninh Underground Coal Mine

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Manh Tung BUI ◽  
Tien Dung LE ◽  
Trong Hung VO
Keyword(s):  
Stress Distribution ◽  
Sea Level ◽  
Coal Mine ◽  
Coal Mines ◽  
Longwall Face ◽  
Geological Condition ◽  
Deep Mining ◽  
Roof Fall ◽  
The Impact ◽  
Quang Ninh

Quang Ninh underground coal mines are currently in the phase of finishing up the mineralreserves located near the surface. Also, in this phase, a number of coal mines have opened and preparednew mine sites for the extraction of the reserves at greater depth. Several mines have mined at -350 mdepth and are driving opening excavations at -500 m depth below sea level. The mining at greater depthfaces many difficulties, such as a significant increase in support and excavation pressures. The longwallface pressure is mostly manifested in great magnitude that causes support overloaded and jumped andface spall/roof fall. This paper, based on the geological condition of the Seam 11 Ha Lam coal mine,uses the numerical program UDEC for studying the impact of mining depth on stress distribution aroundthe longwall face. The results show that the deeper the mining is, the greater the plastic deformationzone is. The peak front abutment stress moves closer to the coal wall, mainly concentrating on theimmediate roof and top coal. The top coal is greatly broken, and its bearing capacity is decreased. Somesolutions to the stability of roof strata are proposed, and a proper working resistance of support isdetermined. Additionally, the paper suggests that the starting depth for deep mining in Quang Ninhunderground coal mines should be -350 m below sea level.

scholarly journals Reasonable Scope of Kilometer Drilling in Lower Layer of Extrathick Coal Seam: A Case Study of Tingnan Coal Mine, China

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Delong Zou ◽  
Xiang Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Lower Layer ◽  
Maximum Depth ◽  
Support Pressure ◽  
Directional Drilling ◽  
Pressure Relief ◽  
Gas Drainage ◽  
Working Face ◽  
Fracture Development

When stratified mining is adopted in high-gas and extrathick coal seam, a large amount of pressure-relief gas of the lower layer flows into the upper layer goaf along the cracks in the layer, resulting in upper layer working face to frequently exceed the gas limit. And ordinary drilling can no longer meet the requirements of the pressure-relief gas drainage of the lower layer. The 205 working face of Tingnan Coal Mine is taken as the test background in this paper, and based on the “pressure-relief and flow-increase” effect of the lower layer under the action of mining stress during the upper layer mining, the gas drainage of kilometer directional drilling in lower layer is studied. According to the distribution characteristics of support pressure before and after the working face, the pressure-relief principle, fracture development characteristics, and gas migration law of the lower layered coal body are analyzed in the process of advancing the upper layered working face in the extrathick coal seam with high gas. The maximum depth of goaf damage is calculated theoretically, and the Flac3D numerical simulation of the failure deformation of the 205 working face floor is carried out. It is found that the maximum depth of plastic failure of the lower layer is about 13 m. According to the plastic deformation of the lower layer under different vertical depths and the movement of coal and rock mass, it is determined that the reasonable range of kilometer directional drilling in the lower layer is 6–9 m below the floor vertical depth. From 15 m to 45 m in the two parallel grooves, there is no fracture failure with a sharp increase or decrease in the displacement in the local range. Meanwhile, in this part, the roof falling behind is not easy to compaction, and the displacement of the floor is large, which does not cause plastic damage. The degree of pressure relief is more sufficient, and the permeability of the lower layer is good. Therefore, drilling should be arranged as much as possible along the working face in this tendency range. The determination of reasonable arrangement range of kilometer directional drilling in extrathick coal seam provides reference index and theoretical guidance for industrial test of working face and also provides new ideas for gas control of stratified mining face in high-gas and extrathick coal seam.

Study on the Relationship between Hydraulic Support on the Working Face with Large Mining Height and Surrounding Rock

2011 ◽  
Vol 328-330 ◽  
pp. 1671-1674
Author(s):  
Ying Ma ◽  
Sheng Zhong
Keyword(s):  
Coal Seam ◽  
Surrounding Rock ◽  
Hydraulic Support ◽  
Working Face ◽  
Safety Work ◽  
Immediate Roof ◽  
The Face ◽  
Large Mining Height ◽  
The Relationship ◽  
Mining Height

Using unified model and theory of rock pressure, the problems, such as caving of stope roof with large mining height and destruction of support, strata movement and surface subsidence, are unified analyzed and researched. The results show that: pressure shell is dynamic shell, which moves forward with the propulsion of working face; with the increase of mining height on the face, the height of fracture zone in coal seam increases, not continuously, but jumpily; with the increase of mining height, support load rises, but the degree of this rise decreases gradually, increased degree of immediate roof weight should be greater than that of given deformation pressure. The results provide necessary basis for reliability of hydraulic support on the working face with large mining height and safety work in the underground.

The Application of Similar Material in the Simulation of Overlying Strata Movement in High Inclined Seam in Dongbaowei Mine

2012 ◽  
Vol 600 ◽  
pp. 194-198 ◽  
Author(s):  
Ming Ming Wen
Keyword(s):  
Coal Seam ◽  
Reference Value ◽  
Geological Condition ◽  
Similar Material ◽  
Strata Movement ◽  
Support Measures ◽  
Working Face ◽  
Overlying Strata Movement ◽  
Similar Material Simulation ◽  
Overlying Strata

Studying on the characteristics of the overlying strata movement in high inclined coal seam, the similar material is applied in the simulation model which was built based on the similar material simulation theory and high inclined seam geological condition of Dongbaowei coal mine. The picture and displacement of overlying strata were obtained from the similar material simulation. As a result, the characteristics of the fracture and movement of overlying strata above the full mechanized working face in high inclined seam. This paper proposes some support measures to improve the safety of the working face. These provide significance theoretical guidance and reference value for other working face in high inclined seam.

Optimization of Height Prediction of Water Fractured Zone Based on ANN

2015 ◽  
Vol 737 ◽  
pp. 422-427
Author(s):  
Zhong Ming Zhao ◽  
Yong Liang Liu ◽  
Yi Li
Keyword(s):  
Coal Seam ◽  
Prediction Method ◽  
Geological Condition ◽  
Fractured Zone ◽  
Working Face ◽  
Face Length ◽  
Height Prediction ◽  
Bp Neural Network Model ◽  
Bp Model ◽  
Technical Guidance

This paper discussed the factors that affect the height of water fractured zone, and they were divided into primary and secondary factors, in order to construct a system that included factors that affect the height of water fractured zone. By using the BP neural network model, this paper chose the thickness of coal seam, roof lithology, tilt angle of coal seam, overburden hardness, working face length, advance speed and rock bulking to be the primary factors in order to simplify the model and accelerate speed. If the mining geological condition was clear, we could ignore the secondary factors. Prediction results showed that the simplified BP model could meet the accuracy of the height prediction of water fractured zone and the prediction method could provide technical guidance and a certain safety for coal mining under water.

scholarly journals Study on Pressure Relief Technology of High-Pressure Water Jet of Residual Coal Pillar in Overlying Goaf in Close Seam Mining

2022 ◽  
Vol 2022 ◽  
pp. 1-19
Author(s):  
Shang Yang ◽  
Xuehui Li ◽  
Jun Wang ◽  
Shuhao Yang ◽  
Zhen Shen ◽  
...  
Keyword(s):  
High Pressure ◽  
Coal Seam ◽  
Coal Pillar ◽  
Water Jet ◽  
Hydraulic Support ◽  
Working Face ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Residual Coal ◽  
Close Distance

To solve the problem of strong ground pressure behaviour under a residual coal pillar in the overlying goaf of a close-distance coal seam, this paper proposes the technology of weakening and relieving the residual coal pillar in the overlying goaf by a high-pressure water jet. Based on the geological occurrence of the No. 3 coal seam and mountain No. 4 coal seam in the Yanzishan coal mine, the high-pressure water jet pressure relief technology of residual coal pillars in the overlying goaf of close-distance coal seams was studied by theoretical analysis and field industrial tests. First, the elastic-plastic zone of the residual coal pillar and the stress distribution law of the floor are obtained by theoretical analysis, and the influence degree of the residual coal pillar on the support of the lower coal seam working face is revealed. Then, a high-pressure water jet combined with mine pressure is proposed to weaken the residual coal pillar. Finally, through the residual coal pillar hydraulic cutting mechanical model and “double-drilling double-slot” model, the high-pressure water jet drilling layout parameters are determined, and an industrial field test is carried out. The single knife cutting coal output and 38216 working face hydraulic support monitoring data show that high-pressure hydraulic slotting can weaken the strength of the coal body to a certain extent, destroy the integrity of the residual coal pillar, cut off the load transmission path of the overlying strata, and reduce the working resistance of the hydraulic support under the residual coal pillar to a certain extent, which is beneficial to the safe mining of the working face.

scholarly journals Migration Law of the Roof of a Composited Backfilling Longwall Face in a Steeply Dipping Coal Seam

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 188 ◽  
Author(s):  
Wenyu Lv ◽  
Yongping Wu ◽  
Liu Ming ◽  
Jianhui Yin
Keyword(s):  
Coal Seam ◽  
Inclination Angle ◽  
Mechanical Model ◽  
Surrounding Rock ◽  
Longwall Face ◽  
Mining Operations ◽  
Mining Depth ◽  
Working Face ◽  
Face Length ◽  
Migration Law

The artificial-caved rock composited backfilling approach can effectively restrain the dynamic phenomena in the coal seam and the associated roof and floor during mining operations, and can also improve the stability of the system of support and surrounding rock. In this study, based on the analysis of influencing factors affecting the surrounding rock movement and deformation of the composited backfilling longwall face in a steeply dipping coal seam, the roof mechanical model is developed, and the deflection differential equation is derived, to obtain the roof damage structure and the location of the roof fracture for the area without backfilling. The migration law of the roof under different inclination angles, mining depths, working face lengths, and backfilling ratios are analyzed. Finally, mine pressure is detected in the tested working face. Results show that the roof deflection, bending moment, and rotation drop with the increase of the inclination angle and backfilling ratio, whereas these parameters increase with greater mining depth and working face length. The roof failure location moves toward the upper area of the working face as the inclination angle and working face length increases, while it moves toward the center of the non-backfilling area with greater mining depth and backfilling ratio. Results from the proposed mechanical model agree well with the field test results, demonstrating the validity of the model, which can provide theoretical basis for a safe and efficient mining operation in steeply dipping coal seams.

Sign in / Sign up

Export Citation Format

Share Document