How is coal mined and extracted?
— At each level where coal is present, the shafts connect to a grid of huge galleries (10- to 20-square-meter sections) that can extend over dozens of kilometers. The longwall method involves using a …
Plugging methods for underground gas extraction boreholes in coal …
— Coalbed methane (CBM) extraction is an important method for coal mine gas disaster management, natural gas utilization and environmental protection (Kurlenya et al., 2014; Tao et al., 2019; Liu et al., 2020a; Wang et al., 2015; Xi et al., 2023).Surface well extraction and underground borehole extraction are two synergistic methods of CBM …
Frontiers | A New Repeated Mining Method With …
— A New Repeated Mining Method With Preexisting Damage Zones Filled for Ultra-Thick Coal Seam Extraction – Case Study. Liang Chen 1,2,3 Dongsheng Zhang 1,2 Gangwei Fan 1,2 Shizhong Zhang …
Coal Mining –The 2 Most Basic Techniques Of Extraction
— They are two most basic methods that miners use to quarry coal. While. ... The machines used for this type of coal extraction can excavate at depths of more than thousand feet. The coal itself is cut out from rocks using machinery. ... The brand new techniques to make mining sustainable in 2020 January 28, 2020.
The new liquid–liquid extraction method for separation of …
— DOI: 10.1016/J.CEJ.2014.12.071 Corpus ID: 98004951; The new liquid–liquid extraction method for separation of phenolic compounds from coal tar @article{Jiao2015TheNL, title={The new liquid–liquid extraction method for separation of phenolic compounds from coal tar}, author={Tiantian Jiao and Chunshan Li and Xulei …
Characteristics and Evolution of Water-Occurrence in Coal
— The presence of water in coal and its interaction plays pivotal roles in the storage and migration of coalbed methane (CBM), making it imperative to understand the water-occurrence across different coal ranks to guide CBM exploitation effectively. Here, a novel method for categorizing water into condensed and adsorbed forms based on their …
Improvement of Continuous Lateral Surface Mining Method for Coal
— The presented paper deals with a continuous lateral method of closed mines' coal pillars surface mining and its advantages in land intensity, dust emissions, maximizing coal extraction, and overburden transporting costs. While inclined and steep coal seam strata in the pillars are widely exploited with land-and-cost intensive …
Preparation of Medicinal Plants: Basic Extraction and …
— The extraction solvent hot or cold is then poured on top of the drug material, soaked, and kept for a short period of time.[1,2,3,11] This method is suitable for extraction bioactive constituents that are readily soluble. In addition, it is an appropriate method for preparation of fresh extract before use.
The new liquid–liquid extraction method for separation of …
— In this research, imidazole and its homolog compounds were designed as new extraction agents for the separation of phenols from coal tar, which can form deep eutectic solvent with phenols with the removal efficiencies more than 90%. The influence of the extraction agent structure was explored, and different substitutes were investigated.
New, environmentally friendly method to extract and …
— A new method improves the extraction and separation of rare earth elements—a group of 17 elements critical for technologies such as smart phones and electric car batteries—from unconventional sources. ... The research team separated yttrium (Y) from neodymium (Nd)—both abundant in primary rare earth deposits and …
Frontiers | A New Repeated Mining Method With …
— The results show that 1) filling material with low strength and good cuttability is suitable for LCL, while material with high strength and robust bearing capacity is suitable for UKBL; 2) with increasing the …
Coal mining to move to more sustainable practices
Increased automationis one of them. Knights points to the benefits to be gained from a greater adoption of autonomous equipment and remote technologies. "These are aimed at removing personnel from hazardous locations, and performing unit operations in a repeatable, consistent fashion so as to reduce process losse…
A new method to extract coal-covered area in open-pit …
— ABSTRACT. Coal is a prominent energy resource in China. Therefore, it is crucial to accurately extract the coal-covered areas. Taking Xinjiang's Zhundong mining region as the study area, Landsat 8 OLI data were employed to assess the spectral curves of four typical ground objects, including vegetation, bare land, water body and bare coal.
A new coal pillars design method in order to enhance safety …
— Highlights The paper presents a new method for pillar design in room and pillar coal mines. The method can estimate the magnitudes of various loads on pillars. The method uses tributary area theory and abutment angle concept to estimate loads. The main advantage of the method is pillar failure risk reduction in retreat mining. The outcome of …
Coal mining to move to more sustainable practices
— The ongoing shift from traditional coal mining to sustainably mined coal in 2024 and beyond will "witness remarkable advancements" in new coal mining methods, driven by innovative technologies ...
New coupling technology of phenols extraction in coal tar …
— Some new methods of extracting phenolic compounds from coal tar without alkalization have been reported, such as ionic liquid method [11], [12], deep eutectic crystallization method [13] and solvent extraction method, etc [14], [15]. The main difference between these methods and the alkaline washing method is that they extract phenolic ...
Al and other critical metals co-extraction from coal gangue …
— Coal gangue is an underused resource and there is a lack of its utilization in the green economy. This work aims at the clean recovery of critical metals in coal gangue, with the development of a recycling extraction process through repeated utilization of ammonia and ammonium salts, and development of delamination pretreatment methods …
Recognition Method of Coal–Rock Reflection Spectrum …
— Based on the feature extraction and classification of other waveform signals, a new coal–rock recognition method was proposed herein based on the characteristics of coal–rock reflection spectrum. Compared with other coal–rock recognition technologies, this method can classify and recognize coal–rock according to the absorption ...
Review of underground coal gasification …
— A new type of coal extraction method, known as underground coal gasification (UCG), that addresses most of the problems of coal mining is being investigated and implemented globally. UCG is a …
ADAMS Simulation and HHT Feature Extraction Method for …
— Aiming at the problem of difficult fault diagnosis work caused by the difficulty of data acquisition of the bearing in the traction part of a coal mining machine, a method of ADAMS simulation and HHT feature extraction of the bearing fault of a coal mining machine is proposed. First of all, take the traction section bearing as the research object, use the …
Coal mining | Definition, History, Types, & Facts
— Coal mining, extraction of coal deposits from the surface of Earth from underground. Coal has been used since the Bronze Age, 3,000 to 4,000 years ago, and was the basic energy source that fueled the …
UNDERGROUND COAL MINING: FACTORS, COST, AND …
underground coal mining methods and production, planning and timing, and capital and operating cost ... New Mexico (22%), Oklahoma (25%), and Utah ... • A high extraction method of mining along the face of a predefined block of coal, referred to as a panel, while allowing the immediate roof to ...
Advances in coal mining technology and sustainable mining …
— However, that has pushed the coal mining industry to modernize and develop sustainable, low environmental impact, yet economic mining techniques. This chapter …
A new method for the extraction of tailing ponds from very …
1. Introduction. Tailing ponds are the essential facilities in metal and non-metal mines. It mainly stores tailings waste and industrial waste water from mineral processing (J. Liu et al. Citation 2019; Werner et al. Citation 2020).Tailing ponds contain a variety of contaminants, such as heavy metal contaminants and chemicals, which may seriously impact the …
Mass Production Technologies for Underground Coal …
— The longwall technology is time tested method to coal extract deep-seated coal deposits. This technology can be customised to extract coal deposits of varying geological conditions. On the other hand, conventional CM technology in Bord and Pillar mining may not be economical to extract coal deposits below 500 m depth.
Plugging methods for underground gas extraction boreholes …
— Gas extraction is an important method to solve coal mine gas disasters, utilize coalbed methane (CBM) resources and reduce greenhouse gas emissions. Construction …
New coupling technology of phenols extraction in coal tar …
— Section snippets Procedure and analysis method. For convenient illustration and analysis, a model coal tar consisting of phenol (11.14 wt%), o-cresol (5.56 wt%), m-cresol (5.57 wt%), and n-hexane (77.73 wt%) was used to represent coal tar as the raw material.The MEA solution with C MEA = 20 wt% was used to extract phenols from the …
Coal explained Mining and transportation of coal
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 one hour than in …
Hydrometallurgical Recovery of Germanium from Coal …
— This article is concerned with a simple hydrometallurgical method for the selective recovery of germanium from fly ash (FA) generated in an integrated gasification with combined cycle (IGCC) process. The method is based on the leaching of FA with water and a subsequent concentration and selective separation of germanium by a solvent …
Coal explained Coal and the environment
— This type of coal extraction involves removing the tops of mountains with explosives. ... and particulate matter can also be used to reduce mercury emissions from some types of coal. Scientists are also working on new ways to reduce mercury emissions from coal-burning power plants. Research is underway to address emissions of CO 2 …
South African Coal Mining Techniques | Methods, …
— South Africa's coal mining industry dates back to the late 19th century when commercial mining operations began in the Witbank coalfield. Over the years, the industry has evolved, adopting various …