Mining Engineering Commons^™

Characteristics And Formation Mechanisms Of Microstructures In Coal Treated With Co2 Phase Transition Fracturing, Cao Yunxing, Zhang Xinsheng, Zhang Junsheng, Guo Shuaifang, Meng Bingbing

Coal Geology & Exploration

CO₂ phase transition fracturing (CPTF) is a newly developed technique for coal mine gas control and is characterized by high efficiency, high coal seam permeability, a high gas drainage rate, and outburst elimination. The core of CPTF is reinforced fracturing and the pressure-relief and permeability-enhancement effects of coal seams under high-pressure dynamic loading. Nevertheless, there is a lack of studies on the morphological characteristics and formation mechanisms of newly formed fractures. Current observation and description of the underground fractures on a centimeter-meter scale primarily aim to reveal the fracturing and permeability-enhancement mechanisms of low-permeability coal seams. However, the study …

Occurrence Modes And Stepwise Chemical Extraction Experiment Of Lithium In No.20 Coal Seam In Pu’An Mining Area, Guizhou Province, Cheng Chen, Song Yang, Zang Jingkun, Cheng Wei

Coal Geology & Exploration

Lithium (Li) is an important energy metal, and the global demand for Li has grown rapidly in recent years. The discovery of coal-associated Li deposits in China proves that coal mines may serve as a potential alternative of Li resources. No.20 coal seam in Pu’an mining area in Guizhou province of China was selected as the study object. The basic properties, mineral composition, elemental composition, and occurrence modes of Li of the raw coal and six density-graded samples (obtained through a float-sink test) were determined by using coal proximate analysis, optical microscope, X-Ray fluorescence spectroscopy (XRF), inductively coupled plasma mass …

Spatial Distribution Of Harmful Trace Elements In Chinese Coals, Cao Qingyi, Ren Wenying, Liang Chaoming, Zhang Yufei, Yang Liu

Coal Geology & Exploration

The potential impact of harmful trace elements in coal on the ecological environment and human health is one of the hot topics in the fields of geochemistry and energy environment. Geochemical mapping plays an important role in the deep understanding of geochemical processes and their changing laws. However, previous studies have not provided the national geochemical maps of harmful trace elements in Chinese coals. In this study, the content data of 1 167 Be, 1 315 Co, 1 406 Cu, 1 191 Mo, 1 247 Th, and 1 390 Zn in Chinese coal samples are analyzed, and their average contents …

Gravity Field Changes During Deep Exploitation Of The Coal Longwall And Their Relation To Stress Distribution And Seismic Activity, Łukasz Kortas

Journal of Sustainable Mining

Mining operations cause volumetric deformations within the rock mass and changes in its density, to which the gravimetric method is sensitive. These changes are particularly well seen in periodic measurements of the local gravity field. The paper analyses the relationship between the movement of a longwall in a coal seam and the change in the distribution of the gravity field in time and space observed on the ground surface. Relative gravimetric measurements were carried out in six series between 2018 and 2020; before the start of coal extraction, with the progress of the longwall and after the cessation of mining. …

Slippage Effect And The Seepage Mechanism Considering The Compaction And Embedding Action Of Proppant, Cheng Qiaoyun, Li Bobo, Li Jianhua, Gao Zheng, Wang Bin

Coal Geology & Exploration

Hydraulic fracturing technology is an effective method to improve the efficiency of coalbed methane drainage, but the universal embedding of proppant under stress will change the width of the fractures, which will affect the gas slippage effect and the permeability mechanism. In order to explore the gas slippage effect and coal seepage law under the background of hydraulic fracturing, the Hertzian contact theory is used to quantify the embedding depth of proppant, and the gas slippage coefficient calculation equation and permeability model of the combined effect of proppant and effective stress are constructed. The results show that under different gas …

Rare Earth-Bearing Particles In Fly Ash Carbons: Examples From The Combustion Of Eastern Kentucky Coals, James C. Hower, John G. Groppo Jr.

Center for Applied Energy Research Faculty and Staff Publications

Graphitic carbons from the combustion of bituminous coals and, perhaps, other coal ranks, tend to capture iron and a number of hazardous elements, including As, Hg, and Se. Rare earth elements in fly ashes occur in minerals, such as monazite, xenotime, and davidite. They also occur in sub-nm particles, probably in a mineral form, within the Al–Si glass on the investigated fly ashes. Just as graphitic carbons can capture Fe and hazardous elements, the carbons surrounding the fly ash glass and magnetic particles captures or encapsulates a broad suite of rare earth elements.

Characterization Of Rare Earth Elements In The Illinois Basin Coals, Alireza Valian

Theses and Dissertations--Mining Engineering

The purpose of this study is to characterize the distribution and occurrence of rare earth elements (REEs) in the coal and coal-related material from the Illinois Basin. For characterizing the distribution of REEs, 17 core samples were investigated from various parts in the basin. Also, several individual samples from coal preparation plants and isolated geological occurrences were included in the study. In result, the average REE concentrations were calculated on a bed-to-bed basis, although the distribution of REEs in the coal beds was found laterally and vertically heterogeneous. A number of trends were found that describe the variations. Most importantly, …

An Improved Method For Characterizing Coal Metamorphism By Xrd, Wang Chao, Zhao Younan, Wang Zhenwei, Lu Zhaolin

Coal Geology & Exploration

At present, the X-ray measurement method of coal metamorphism has the problem that the γ band is not well divided, the δ peak information is not used, and the background of the bottom is unreasonable. The X-ray diffraction pattern of coal with different metamorphosed degrees is compared and studied. It is proposed to correct the metamorphic coefficient formula by using the information of the slope of the 002 peak, the extended half-height width and the δ peak without deducting the so-called background information. The calculation of the XRD patterns of coal samples with different degrees of metamorphism is verified. The …

Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation, Dong Zhiwei, Guo Hongyu, Xia Daping, Liu Xile, Bai Yang, Zhao Guojun

Coal Geology & Exploration

To explore the bio-permeability enhancing effect via methanogen treatment on different rank coals after anaerobic fermentation, micro-CT was used to analyze the change characteristics of pore structure of coal before and after biodegradation. At the same time, the adsorption characteristics of methanogens on the coal surface after anaerobic biodegradation were observed by scanning electron microscopy to analyze the reasons for the effect difference of biological transformation of different rank coals. The results show that the porosity and total throat length of the coal samples biodegraded increase and the connectivity of the pores is enhanced, it is indicated that coal samples …

Occurrence Of Antimony In Magmatic Intrusive Coal Seam: A Case Study From The Wolonghu Coal Mine, Huaibei Coalfield, China, Ou Jinping, Zheng Liugen, Wei Xiangping, Liu Sikui, Li Liyuan, Liu Meng, Huang Xiaoyu

Coal Geology & Exploration

In order to investigate the influence of magmatic alteration on the occurrence characteristics of antimony in coal seam, 12 samples of magmatic magma and coal were collected from Wolonghu coal mine in Huaibei coalfield, Anhui Province, and the content of Sb was determined by atomic fluorescence spectrometry(AFS). The coal quality parameters are analyzed. The results are as follows:the coal in Wolonghu magmatic intrusion area has the characteristics of ultra-low volatile matter, medium ash content and ultra-low sulfur content. And the main forms of sulfur in coal are organic sulfur and pyrite sulfur. Under the influence of magmatic hydrothermal solution, ash …

Technology And Method Of Cbm Concurrent Exploration During Coal Resources Exploration, Lin Yabing, Qin Yong, Duan Zhonghui, Ma Dongmin

Coal Geology & Exploration

The coal seam serves as a geological carrier for CBM, and exploration of CBM and coal resources is a man-datory requirement for the management of national mineral resources. Based on the practice of project exploration in recent years, it analyzed the evaluation criteria of CBM resources in the process of coal resources exploration. On this basis, the exploration ideas, exploration methods, tasks, report preparations have proposed a method system for CBM in the ex-ploration of coal resources. According to the particularity of CBM exploration work methods, CBM seismic, well logging, drilling, well log, gas drainage, and engineering quality acceptance methods …

Analysis On The Development Characteristics And Influencing Factors Of Gas Pores In Coal, Zhang Hui, Wu Jing, Yuan Liying, Song Xiaozhong, Lin Bowei

Coal Geology & Exploration

Based on the study of coalfield geology and coal petrology, using field emission scanning electron microscopy(FESEM) as the main observation method, nanoscale pore research on coals was carried out for different regions, different geological ages and different metamorphic degrees. The results show that gas pores in coal are the pores left by coalbed methane(gas) generation, accumulation and escape during coal metamorphism, are secondary porosity. The pore diameter is mainly at nanometer size and round shape, with uneven density and distribution. The gas pore is intensive, often forms gas pore group, gas pore zone and gas pore nest. The gas pore …

Day 3. Wednesday, August 13, 2003: Travel To Grand Junction, University Of Colorado Boulder. Natural Resources Law Center

Energy Field Tour 2003 (August 11-16)

5 pages (includes color illustration and map).

Contains references.

Knowledge Organization And Inference Engine For The Wvu Face Decision Support System, S. Carrow, R. S. Nutter Jr., R. S. Raman, N. A. Reddy, Y. V. Reddy, R. Larry Grayson

Mining Engineering Faculty Research & Creative Works

The knowledge-based organization for the West Virginia University Face Decision Support System is given, along with the initial development of the associated inference engine. The knowledge base contains generic knowledge about underground coal mines that utilize continuous miners. A typical knowledge entry is given, and the inference engine methodology is explained. The engine utilizes this knowledge with data from monitoring systems and from interaction with the section foreman, to assist in making section management decisions and plans.

Leases For Other Minerals: Recent Developments, Thomas F. Cope

Public Lands Mineral Leasing: Issues and Directions (Summer Conference, June 10-11)

14 pages.

Contains references.

Agenda: Public Lands Mineral Leasing: Issues And Directions, University Of Colorado Boulder. Natural Resources Law Center

Public Lands Mineral Leasing: Issues and Directions (Summer Conference, June 10-11)

University of Colorado School of Law professor Lawrence J. MacDonnell served as the conference organizer and as a member of the faculty.

Federal leasing programs, especially for oil and gas and coal, have been undergoing important changes in recent years. This conference will provide an overview and an update for those involved in public lands mineral development. Significant new issues also will be addressed.

Agenda: Federal Lands, Laws And Policies And The Development Of Natural Resources: A Short Course, University Of Colorado. School Of Law, University Of Colorado Boulder. Natural Resources Law Center

Federal Lands, Laws and Policies and the Development of Natural Resources: A Short Course (Summer Conference, July 28-August 1)

Even before the [Natural Resources Law] Center was established [in the fall of 1981], the [University of Colorado] School of Law was organizing annual natural resources law summer short courses. To date four programs have been presented:

- July 1980: "Federal Lands, Laws and Policies and the Development of Natural Resources"

- June 1981: "Water Resources Allocation: Laws and Emerging Issues"

- June 1982: "New Sources of Water for Energy Development and Growth: lnterbasin Transfers"

- June 1983: "Groundwater: Allocation, Development and Pollution"

(Reprinted from Resource Law Notes, no. 1, Jan. 1984, at 1.)

Instructors for this conference included University …