sandstone coal mine roof
- صفحه اصلی
- sandstone coal mine roof
Section snippets Rock sample. To make the research more representative and credible, two groups of coal mine roof sandstones in China are selected as the preparation materials of experimental samples; the groups are the −800-m roof rock layer of Zhangshuanglou Coal Mine (Xuzhou City, Jiangsu Province) and −500-m roof rock layer …
به خواندن ادامه دهید
The main water filling sources affecting #7 coal mining in the deep Kongzhuang coal mine are sandstone water at the boundary of the Lower Shihezi Formation and sandstone fissure water at the roof of the Shanxi Formation. #7 coal roof sandstone fissure aquifer has poor and uneven fissure development, the overall water …
به خواندن ادامه دهید
Chimney subsidence can cause surface subsidence (ground settlement) in the form of a pit or sag when there is a mine roof collapse in a mine entry. Surface …
به خواندن ادامه دهید
In Chinese coal mines, roof accidents account for 50 to 55% of injuries each year [1,2,3,4,5]. ... The main roof is 8 m thick and comprised of medium sandstone. The complex roof structure is a typical thin-layered sand-mudstone interbed roadway roof. The immediate floor is 2 m thick and comprised of sandy mudstone, and the main floor is 7 m ...
به خواندن ادامه دهید
200m, but a 30-m thick layer of hard sandstone is present above the roof of the coal seam, resulting in a large periodic pressure step during the mining process. In addition,
به خواندن ادامه دهید
PDF | On Oct 1, 2021, Shankun Zhao and others published Crack Propagation Mechanism of Hydraulic Fracturing in Thick-Bedded Sandstone Coal Mine Roof | Find, read and cite all the research you need ...
به خواندن ادامه دهید
Masabattula (2010) showed that sandstone in the immediate roof was responsible for almost 40% of the total reported roof fall incidents in Indian underground coal mines during 1997–2006, whereas shale (a relatively more unsafe roof type) was responsible for comparatively less (nearly 17%) roof falls incidents (Masabuttula, 2010). …
به خواندن ادامه دهید
Sandstone channels: their influence on roof control in coal mines. Full Record. Related Research. Abstract. The purpose of this report is to familiarize the coal mining industry …
به خواندن ادامه دهید
Another common condition in Fire Clay coal mines is shale roofs with kettlebottoms. Kettlebottoms are isolated, tubular blocks of sandstone or hard shale in mine roofs; …
به خواندن ادامه دهید
The ignition source of gas explosion accident in Babao Coal Mine is not CSC, but seems to be electric sparks generated by the breakage and ionization of premixed gas due to the electricity from the extrusion and collapse of roof sandstone during the periodic weighting, and the location of explosion source might be the goaf of the −4164 …
به خواندن ادامه دهید
The electricity generation and discharge characteristics of the roof sandstone of the Renlou coal mine described in Section 3 comprehensively demonstrate that the electrical effect generated by the roof sandstone can ionise the combustible gas and cause a gas explosion. Fig. 12 shows the electric spark generated during the cracking of the ...
به خواندن ادامه دهید
The roof of coal seams are mostly soft rock with weak cementation. To further study the mechanical characteristics and deformation control scheme of the roadway with weakly cemented siltstone as roof, this paper took Linchang coal mine as the research background and adopted field investigation methods, laboratory experiments, …
به خواندن ادامه دهید
At an underground coal mine in the western U.S., ground control problems and roof falls have occurred in areas where the geological formation in the mine roof consists of a water saturated sandstone unit. This sandstone unit occurs in channels or washouts, due to the depositional environment of the coal and strata beds. It is quite common for the
به خواندن ادامه دهید
In recent years, bed separation water inrush, as a new type of water disaster, has posed serious threat to mining safety in China’s many coal mines. This study focused on periodic water inrush accidents in the No. 7335 working face owned by Xuzhuang Coal Mine, Jiangsu Province, China. Based on the theory of key strata, the …
به خواندن ادامه دهید
The coal mine has an annual output of 20 million tons per year, but its thick and hard roof restricts its development. The buried depth of the C1 coal seam is …
به خواندن ادامه دهید
The roof breaks along dipping weaknesses in the sandstone caused by thin, discontinuous shale laminae. Some sandstone roof falls occur along inclined bedding, such as these examples from the Jellico and Harlan coal beds in eastern Kentucky. Trends: Local falls in sandstone generally occur along bedding weaknesses, which may follow overall bed ...
به خواندن ادامه دهید
2.1 Experiment Design 2.1.1 Specimen Preparation. The sandstone and coal samples in this experiment were taken from the 13 # coal seam of a coal mine in Shanxi Province, China. Coal and rock blocks were removed from a long-wall entry and immediately wrapped with plastic film to ensure freshness and prevent weathering.
به خواندن ادامه دهیدThe triaxial compression test was carried out on the 50 mm × 100 mm standard specimen to explore the characteristics of a coal mine roof sandstone. The triaxial compression curve is shown in Figure 4. The uniaxial compressive strength was 131.7 MPa, the elastic modulus was 29.7 MPa, the Poisson's ratio was 0.228, the …
به خواندن ادامه دهید
The more complex the hydrogeological conditions of a mine, the more likely the coal seam is to experience water inrush during the mining process, and the greater the degree of the water inrush hazard. The scientific and reasonable prediction of water inrush in mines with complex hydrogeological conditions is of great significance to the safe and …
به خواندن ادامه دهید
The Permian sandstone aquifer is a direct water-bearing layer, which greatly threatens the mining safety of No. 1 coal seam, the deepest coal seam in the mine area; therefore, it is necessary to evaluate the risk of water inrush on the roof of …
به خواندن ادامه دهید
duce. Roof falls are also one of the more prominent hazards in underground hard coal mines, which has been confirmed by statistical data from hard coal mines in the USA, India and Poland [1–3]. The longwall mining system is the main system used in Poland's hard coal mines. Retreat longwalls with natural roof caving in the gob are the most ...
به خواندن ادامه دهید
The roof of coal seam in Xin'an Coal Mine is composed of mudstone and sandstone. Each rock stratum possesses a "mudstone-sandstone" composite structure comprising a lower layer of hard sandstone and an upper layer of soft mudstone. ... The second is roof and floor sandstone aquifers in No. 3 coal seam. The roof and floor …
به خواندن ادامه دهید
The stability of the composite structures formed by coal pillar and roof rock is of great significance to safe production and sustainable development of coal mines. In …
به خواندن ادامه دهید
Panel - A coal mining block that generally comprises one operating unit. Panic bar - A switch, in the shape of a bar, used to cut off power at the machine in case of an emergency. Parting - (1) A small joint in coal or rock; (2) a layer of rock in a coal seam; (3) a side track or turnout in a haulage road.
به خواندن ادامه دهید
Combined with the comprehensive analysis of the electrical generation and discharge and spark characteristics of the coal mine roof sandstone in Section 3, it can …
به خواندن ادامه دهید
With the continuous exploitation of coal resources, the reserves of coal resources in the eastern region are decreasing. Now the exploitation of coal resources is gradually transferring to the western region. The hydrogeologic types in the western mining region are quite different from those in the eastern region. The main types of water hazards are …
به خواندن ادامه دهید
The water-bearing aquifers in the study area are sandstone aquifer in the roof of the 3 –1 coal seam in the third member of the Yan'an Formation and sandstone aquifer in the roof of the 2 –2 ...
به خواندن ادامه دهید
The increase in the water-flowing fractured zone and roof caving height caused by coal seam mining had an clear influence on the seepage characteristics of the roof, and the fracturing grouting of ...
به خواندن ادامه دهید
The roof of the mining seam consisted of four mudstone layers and two thin coal seams (see Fig. 1). This combined roof mudstone-coal formation had a total thickness of approximately 9 m and was generally very weak, with an uniaxial compressive strength (UCS) of 10–20 MPa. Above this formation was a thick and more competent sandstone …
به خواندن ادامه دهید
explore the characteristics of a coal mine roof sandstone. The triaxial compression curve is. shown in Figure 4. The uniaxial compressive strength was 131.7 MPa, the elastic modulus.
به خواندن ادامه دهید
PDF | On Oct 1, 2021, Shankun Zhao and others published Crack Propagation Mechanism of Hydraulic Fracturing in Thick-Bedded Sandstone Coal Mine Roof | Find, read and …
به خواندن ادامه دهیدWeak sandstone can cause roof falls in underground coal mines (from Greb and Cobb, 1987). Potential roof-fall hazards: Roof quality is usually good in sandstone, but local …
به خواندن ادامه دهید
3.1 Sample preparation. The sandstone samples were collected from the No. 4 coal seam roof of the Panbei Coal Mine in Huainan and Huaibei Mining Area, China. Unweathered sandstone samples with good integrity and uniform texture were sealed in wax at the collection site and transported to the laboratory.
به خواندن ادامه دهیدThe mechanical properties and acoustic emission characteristics of thick hard roof sandstone were investigated. Samples were taken from the 30.87-m thick sandstone roof in a mine in the Shengdong coal field, China. Firstly, the composition and microscopic characteristics were analyzed by XRD and FE-SEM, respectively. Moreover, the indirect …
به خواندن ادامه دهید
The "rock-gangue" structure refers to the semi-arch structure formed by extruding no caved rock and caved gangue. This structure form is the most common structure form in top coal caving stope, especially when the upper direct roof is sandstone with larger thickness and higher strength, the collapse of which is easy to form bulk …
به خواندن ادامه دهید
roof instability. Therefore, for these mines, studies of roof instability were a natural consequence, although not the original objective. ... sandstone, coal, and some fresh-water limestone lenses found in the upper third of this group. Flint (8) states that the Johnstown limestone is persistent and is used as a stratigraphic guide in Somerset ...
به خواندن ادامه دهید
Mining disturbances may cause fissure water in the sandstones of a coal seam roof to link up with the coal seam, further causing changes in the moisture conditions of coal–rock systems such as ...
به خواندن ادامه دهید
where OD y is the mine depth in ft. before the sandstone roof yields, i.e., yielding overburden depth. This relationship shows that when L/H is below about 6 (or h = 3.33 ft for L = 20 ft) there is a considerable increase in span capacity as the sandstone thickens. ... Studies of roof movement in coal mines, Crucible Mine of the Crucible Fuel ...
به خواندن ادامه دهید
interaction is the immediate roof rock competency (4). The shale unit shown in figure 2 directly above the Eagle Coalbed varies in thickness from 0 to 10 ft. In areas of Harris, this shale unit can either be laminated, sandy, or nonexistent (replaced by a sandstone scour). These fluctuations explain the range in Coal Mine Roof
به خواندن ادامه دهید
Usually composed of interbedded siltstone, fossiliferous shale, and thin layers of sandstone, Coal Mine Roof Rating (CMRR) values typically range between 40 and 60, with typical UCS values of 50–80 MPa (Maleki et al. 2006; Stewart et al. 2006). The immediate floor usually contains a considerable thickness of coal.
به خواندن ادامه دهیدچه بخواهید با ما کار کنید و چه علاقه مند به کسب اطلاعات بیشتر در مورد محصولات ما هستید، مایلیم از شما بشنویم.