Coal Extraction Process Research Articles

Landuse change detection in a surface coal mine area using multi-temporal high-resolution satellite images

Surface mining activities, exploitation of ore, and stripping and dumping of the overburden cause changes in the land cover and land use of a mine area. The area of land disturbance can be very large in the case of surface coal mining, due to the nature of the coal extraction process. Sustainable mining requires continuous monitoring of changes in land cover and land use induced by the mining activities. This is essentially important for identifying the long-term impacts of mining on theenvironment and on land cover in order to provide necessary mine closure andreclamation measures. In this sense, digital image classification provides apowerful tool for obtaining rigorous data, and reduces the cost of field measurements in time and money, particularly when dealing with large areas. Various remote sense data records and image classification techniques serve different features for numerous purposes. The selection of a suitable data and image classification method is significant for ensuring the effective use of information extracted from the satellite images, e.g. land-use classes. This paper proposes a methodology for identifying land-use change in surface coal mines using multi-temporal high-resolution satellite images. The methodology has been implemented for identifying, quantifying and analysing the spatial response of landscape to surface mining activities in the Goynuk, Bolu surface mine in Turkey, from 2004 to 2008. The methodology essentially entails (i) acquiring data, (ii) preprocessing the data, (iii)image classification using the maximum likelihood classification algorithm (iv) accuracy assessment and (v) change detection analysis depending on class-based approaches. The results show that the methodology can be utilised effectively in monitoring land-use change in surface coal mining areas. It also provides essential input for planning mine reclamation and closure activities.

No.58 高性能粘結材(HPC)抽出溶剤の平衡組成(2)(改質・処理・クリーン化(1))

No.58 高性能粘結材(HPC)抽出溶剤の平衡組成(2)(改質・処理・クリーン化(1))

Mercury separation from fuel constituents in an ash-free coal manufacturing process

A novel process to produce ash-free coal, called Hyper-Coal (HPC), has been developed based on the coal liquefaction with organic solvent extraction. Seventy wt% of combustible contents can be extracted from raw coal via the dissolution in 1-methylnaphthalen at 633K, reducing the ash and alkali contents to less than 1000 and 0.5ppm, respectively. This process is also a promising approach to separate toxic trace elements from fuel constituent in coal before its combustion. Mercury is one of the toxic trace elements of growing concern, because mercury emission from a coal combustion process to the atmosphere has been becoming a serious problem in the coal use all over the world. Therefore, in this study, various intermediate products such as coal–organic solvent slurry were sampled from the HPC manufacturing process, and analyzed for mercury contents to investigate the mass balance and the distribution behavior of mercury in the process. As a result, it was found that a large portion of the mercury was separated from fuel constituents and recovered as a dissolved matter in the solvent. This dissolved mercury, however, built up in the total distribution behavior of mercury in the HPC manufacturing process again because the solvent was recycled for the coal extraction process without any cleanup treatment this time. Nevertheless, the mercury distributed into the HPC was lowered to be 20% or less of the total found in raw coal.

Partitioning of Boron during the Generation of Ultraclean Fuel (HyperCoal) by Solvent Extraction of Coal

Extraction of coal by organic solvent is an effective strategy for producing clean fuel and thereby minimizing the ash-related problems and improving coal power generation efficiency. Up to date, most elements in coal extracts have been investigated, but little attention has been given to boron. In this paper, the partitioning behavior of boron has been investigated in one coal extraction process, named HyperCoal (HPC) generation, developed in Japan. Five coals were extracted by both 1-methynaphthalene and its mixture with 20 wt % polar indole for 1 h at 360 °C. Boron in coal extract (HPC), coal residues, and raw coals has been examined by inductively coupled plasma−optical emission spectroscopy and solid-state 11B magic angle spinning−nuclear magnetic resonance spectroscopy. The results indicate that, regardless of the coal rank, boron has a lower concentration in HPC than in the corresponding raw coal and coal residue. Up to 20% of the original boron could be eluted. The eluted boron is an organoboron complex associated chemically within the coal matrix which has the following characteristics: resonates from −5.88 to −7.00 ppm in 11B NMR spectra, completely decomposes when coal is ashed by plasma at 150−200 °C, and is insoluble in acetic acid while preferentially extracted by organic solvents. No boron-bearing mineral particles have been detected in HPCs. Regarding the elution amount of boron, it is a function of the fraction of organoboron in raw coal and HPC yield. For raw coal having more organoboron as well as a higher HPC yield, a larger fraction of its original boron could be extracted accordingly. The eluted boron could also in part undergo chemical reactions with coal radicals and/or polar indole to form new coordination states in HPCs.

A life cycle method for assessment of a colliery’s eco-indicator

Global Scope and Background The study was aimed at presenting the methodology of the process eco-indicator, in relation to hard coal mines, and thereby making evaluation of the impact of the mine’s coal extraction process on the environment. The life cycle of a mine is made up of three phases: opening and developing the mine’s deposit, extraction of the mine’s deposit, closing the mine.

98/02122 Preparation and evaluation of coal extracts as precursors for carbon and graphite products

A coal extraction process coupled with coal hydrotreatment has been shown capable of producing suitable precursors for a variety of commercially important carbon and graphite products. The N-methylpyrolidone (NMP) extracts of hydrotreated coals have been analytically and chemically characterized and shown to have properties acceptable for use as binder and impregnation pitch. Mesophase formation studies have demonstrated their capability for producing both needle and anode grade coke as well as precursors for mesophase pitch fibers. A graphite artifact has been produced using a coal extract as a binder and coke derived from the extract as a filler. Further evaluation of the extract materials is being carried out by industrial members of the Carbon Products Consortium.

Analysis of Quartz Exposure Data Obtained from Underground and Surface Coal Mining Operations

Abstract The Mine Safety and Health Administration (MSHA) yearly performs quartz analysis on approximately 9000 respirable coal mine dust samples collected for various occupations in U.S. coal mines. All occupational quartz exposure data gathered by MSHA since 1985 have been compiled and analyzed to characterize current occupational exposures to quartz; to determine if the quartz percentages of samples collected for different occupations have changed during the period 1985 through 1992; and to study the intramine variability associated with quartz sample percentages of selected occupations. Analysis of the occupational data shows that regardless of the type of coal extraction process used, there are a substantial number of occupational samples that contain greater than 5 percent quartz and show quartz exposures that exceed 100 μg/m3. In underground mining operations, approximately 30 percent of the samples collected at the continuous-miner operator and continuous-miner helper occupations on continuous-min...

Effect of temperature and solvent on coal extraction under mild conditions

A western Kentucky coal was extracted with a series of eighteen organic solvents of varying base strength under mild temperature and pressure conditions. Solvents ranged from strongly basic, such as ethylenediamine to nonpolar nonbasic solvents, such as benzene. The relationships between the coal dissolution and the solvent properties show that extractability seems related more to solvent basicity (represented by its electron donor number) than to its acidity (acceptor number). Ethylenediamine was found to be a superior solvent for extracting coals under mild conditions. The coal extraction processes performed at different temperatures, for coal samples of different rank in ethylenediamine and N-methyl-2-pyrrolidinone have produced some interesting results: (1) up to ca. 80 wt.% of a western Kentucky coal could be extracted with ethylenediamine at 225°C within 1 h; (2) significant incorporation of (ca. 10%) strongly basic solvent molecules into the structural network of coal derived materials was observed for extraction over a temperature range of ca. 150°C to 300°C; and (3) the difference between coal extractability and extract yield varies depending upon the extracting temperature and the basicity of the solvent used.

Management analysis in coal mining: Giving authority back to the supervisor

The continuous mining method of underground coal production is the most popular system of mining in use today. It has evolved from early designs with numerous technical and system improvements all aimed at improving the coal extraction process. What has not kept pace with the technical improvements of continuous mining is the understanding and effective utilization of the supervisor as a manager of the production unit. New research suggests that new skills are needed to upgrade the supervisor's ability to deal with both “people” and “word” problems while maintaining high levels of production. Better influence in the form of more persuasion and cooperation skills are needed by the supervisor to effectively direct workers and manage the continuous mining unit activities. This paper discusses this situation by (1) exploring the development background of mining management, (2) discussing how management perceptions about the continuous mining unit influences performance, and (3) suggesting constructive actions a section foreman can apply to improve his management skills on the section.