1. Introduction. Coal mining can cause surface subsidence and damage to surface structures, which is why it has been intensively investigated in the past several decades. 1, 2 The concept of ground subsidence caused by mining dates back to the 1850s in Belgium. Other countries with significant coal industries, like Germany, Poland …
For instance, some mines in South Africa and Canada have reached a depth of 3000-4000 m (Counter, 2014;Lippmann-Pipke et al., 2011). However, in China, the mining depth is mostly below 800-1100 m ...
When the peak stress was lower, the bearing capacity was smaller, and so the coal was destroyed easily. Therefore, the original cracks number could be viewed as an index that reflected the size of mechanical parameters [50]. In coal seam mining, the stability of coal and rock stratum could be determined by observing macroscopic …
Coal obtained in different places is not the same and varies widely depending on the nature of the soil and geographic conditions. There are two major types of coal mining: underground mining and surface mining. Coal mining satiates roughly 1/4 of our global energy demands, and it is coal that has powered America's power needs for …
There are different methods for estimating coal strength and hardness: compressive strength, fracture toughness, or grindability, all of which show a trend …
There were three kinds of rock samples (sandy conglomerate, siltstone and medium sandstone) and one kind of coal sample: the sandy conglomerate and siltstone samples were taken from the roof of no. 3–5 coal seam, Tongxin Mine, Shanxi Province, China; the coal and medium sandstone samples were respectively taken from no. 2–2 …
During the mining process of impact-prone coal seams, drilling pressure relief can reduce the impact propensity of the coal seam, but it also reduces the integrity and strength of the coal mass at the side of the roadway. Therefore, studying the mechanical properties and energy evolution rules of coal samples containing holes and …
Understanding the mechanical properties of coal after gas and coal interaction can better guide the mining technology of gas-bearing coal seams and drainage technology of coalbed methane. In this study, triaxial compression tests of coal mass under different gas adsorption pressures are carried out to evaluate the mechanical properties, impact …
UCG has a large potential for providing a clean energy source through carbon capture and storage techniques and offers a unique option for CO2 storage. This …
During the underground coal mining process, a variety of mechanical forces act collectively upon coal. These forces encompass the impacts, friction, and shearing forces generated by the coal-cutting machine, explosive shockwaves, and mining-induced stress, among others. The resulting broken coal has a complex grading …
This paper reviews the major achievements in terms of mechanical behaviors of coal measures, mining stress distribution characteristics and ground …
Mining coal. Coal miners use large machines to remove coal from the earth. Many U.S. coal deposits, called coal beds or seams, are near the earth's surface, but others are deep underground.Modern mining methods allow U.S. coal miners to easily reach most of the nation's coal reserves and to produce about three times more coal in …
Canary in the Coal Mine How to Talk to a Science Denier: Conversations with Flat Earthers, Climate Deniers, and Others Who Defy Reason Environmental Aspects of Coal Mining
Coal mining - Underground, Surface, & Drilling: The various methods of mining a coal seam can be classified under two headings, surface mining and underground mining. Surface and underground coal mining are …
In order to study the mechanism of confined water inrush from coal seam floor, the main influences on permeability in the process of triaxial seepage experiments were analyzed with methods such as laboratory experiments, theoretical analysis and mechanical model calculation. The crack extension rule and the ultimate destruction …
The Xinjing Open-Pit Coal Mine landslide is situated in the southern region of Helan Mountain (Fig. 1a). This region under experienced aulacogen deposition from the middle-late Proterozoic and to early Paleozoic periods, with the reactivation of ancient faults and rift development in the late Paleozoic, and reverse thrusting and folding uplift since …
For systematic explorations of the mechanical properties and damage evolution law of coal samples under cyclic loading, natural coal samples of No. 3 coal seam in a mine located in Shaanxi Province were considered as the research object. The RMT-150B rock mechanics test system was used to perform uniaxial compression and …
Fig. 2 illustrates the workface layout of proposed new fully mechanical mining method in extremely thick coal seam, which combines with large mining height and top-coal caving mining methods, named LHTCM. In the extremely thick coal seam, it can be divided into three layers with A, B and C.Firstly, pressure-relief mining (stage Ⅰ) …
Studying the mechanical behavior of coal body is of great significance to understand the mechanism of coal and gas outburst, rock burst and coal roadway deformation (Du and Wang 2019; Cheng et al. 2020; Song et al. 2020; Wang et al. 2020; Khan et al. 2022).However, the instability failure of coal is affected not only by its own …
Coal is a black or brownish-black sedimentary rock that can be burned for fuel and used to generate electricity.It is composed mostly of carbon and hydrocarbons, which contain energy that can be released through combustion (burning). Coal is the largest source of energy for generating electricity in the world, and the most abundant fossil fuel …
Surface coal mining generally involves the following sequence of unit operations: (1) clearing the land of trees and vegetation, (2) removing and storing the top layers of the …
For instance, some mines in South Africa and Canada have reached a depth of 3000-4000 m (Counter, 2014;Lippmann-Pipke et al., 2011). However, in China, the mining depth is mostly below 800-1100 m ...
1 INTRODUCTION. Coal and gas outbursts occur in most coal-producing countries and often result in large-scale casualties and economic losses. 1-3 Coal is China's main energy source. More than 85% of it comes from underground coal mines, and one-third of the world's outbursts have occurred in China. 4-7 On the other hand, the …
In order to achieve safe and efficient mining for extremely thick coal seam more than 20 m, a new fully mechanized top-coal caving mining method with first extracting the middle layer was proposed in this study. In this study, physical model with a similarity ratio of 60:1 and the corresponding numerical simulation were performed to …
Mining industries worldwide have inevitably resorted to exploiting resources from the deep underground. However, traditional mining methods can cause various problems, e.g., considerable mining difficulty, environmental degradations, and frequent disastrous accidents. To exploit deep resources in the future, the concept of mining …
The rock mass around an excavation is generally traversed by different geological discontinuities such as faults, folds, slips, joints, etc. Fault is one of the major geological discontinuities which creates lot of difficulties during underground winning of coal. Entire stress regime and ground conditions in the formation are altered in and …
Coal and rock mass bear loads together in underground engineering such as coal mining and roadway support, resulting in different mechanical properties from …
Rock strata in a coal-mining environment are essentially bedded in nature and this has a large impact on load-deformation characteristics. Mining may induce shearing as well as separation along the bedding planes, which may result in bending and subsequent fracturing of the rock layer causing substantial change in in situ fluid flow …
As shallow coal resources are gradually depleted, resource exploitation extends from the shallow into the deep, where the mechanical properties of the coal rocks change significantly. To study the mechanical properties and mining-induced response characteristics of deep coal rocks. On a laboratory scale, laboratory tests and mining …
Based on geological and mining characteristics, coal mine roadways under complex conditions were divided into five types, for each type the deformation and damage characteristics of rocks surrounding roadways were analyzed. The recent developments of roadway support technologies were introduced abroad, based on the experiences of …
Mechanical mining is a widely used method of separating materials from the face to obtain a useful mineral (e.g., coal, metal ores, salts, and diamonds), to make underground workings (e.g., mine ...
Study on the Mechanical Properties and Mechanical Response of Coal Mining at 1000 m or Deeper 1477 1 3 rocks on an engineering scale. Deep coal mining has been used as an example to reveal the mechanical processes in three typical mining methods (top coal caving, pillarless mining and protective layer mining), namely, the complete
In order to achieve safe and efficient mining for extremely thick coal seam more than 20 m, a new fully mechanized top-coal caving mining method with first …
