Earth Sciences Commons^™

Key Pretreatment Technologies For Coalbed Gas Bioengineering And Review On Their Mechanism Of Action, Bao Yuan, Chang Jianing, Liu Xiangrong, Xia Daping, Wang Yaya

Coal Geology & Exploration

Coalbed gas bioengineering (CGB) is a new technology for the purpose of realizing the clean utilization of coal resources and the enhanced recovery of coalbed gas. To explore the key characteristics of the pretreatment technologies of CGB, hydrocarbon generation potential and its mechanism of action, conclusion and summary was made for various pretreatment technologies herein. Meanwhile, the pretreatment technologies were divided into three types according to the action mode of coal (organic matter) and bacteria (microorganism): microflora optimization and improvement, coal dissolution and oxidation, and biological stimulation and synergy. By comparing the capability of coal to generate methane through microbial …

Occurrence Characteristics And Ecological Risk Assessment Of Heavy Metals In Fly Ash Of Ningdong Energy Chemical Industry Base, Zhang Zhiguo, Tan Yuning, Hu Youbiao, Zheng Yonghong, Chen Denghong, Cai Weiqing, Li Yating, Lu Jiangwei

Coal Geology & Exploration

In order to expand the resource utilization of fly ash, research was conducted based on the fly ash of Yuanyang Lake Power Plant in the Ningdong Energy Chemical Industry Base. Specifically, the physical and chemical properties of fly ash were characterized and analyzed by means of scanning electron microscope, energy spectrum analysis and X-ray diffraction. Besides, the total amount, effective state and content in different forms of Pb, Cr, Ni, Cu, Cd and As in fly ash were determined through acid digestion, DTPA extraction and 5-step Tessier sequential extraction. In addition, the ecological risk of heavy metals in fly ash …

Heat Conduction Performance And Transfer Mechanism Of Sand-Barite Powder Backfill Materials, Jia Hailiang, Zhu Zixian, Zhou Yang, Sun Qiang

Coal Geology & Exploration

The ground source heat pump of buried pipeline is a major form of shallow thermal energy utilization, and the thermophysical properties of backfill materials, especially the thermal conductivity, are the key factors affecting the heat transfer efficiency of the heat pump system. In this paper, the variation law of thermal conductivity of the sand-barite powder samples at different barite powder mixing ratio (volume fraction) and saturation was studied. The mechanism of improving the thermal conductivity of backfill materials with barite powder was revealed based on the macroscopic and microscopic experiments such as stereoscope and nuclear magnetic resonance analysis. In addition, …

Tomography Method For Adjacent Channel Frequency Shift Of Transmitted In-Seam Waves, Tian Han, Wu Rongxin, Hu Ze’An, Yang Qiaonan

Coal Geology & Exploration

In-Seam Seismic is one of the main detection methods for small geological structures in the coal mining working face. In this method, the energy attenuation feature of in-seam waves is mainly utilized. In case of any significant geological anomaly or receivers coupling difference in coal working face, the energy distribution of the in-seam wave at different frequency bands will be significantly affected, and the stability and accuracy of in-seam wave detection results will be decreased. Using the centroid frequency change features of the in-seam wave signals for inversion imaging is an innovative, effective method. However, for this method, there are …

Development Of Rescue Truck-Mounted Drilling Rig In Ground Emergency, Fan Dong, Zou Zujie, Wang Ruize, Lu Feifei, Liu Qi, Wang Hejian

Coal Geology & Exploration

Ground drilling is an effective means to rescue the person trapped underground in case of accident in a mine. The rescue truck-mounted drilling rig is an ideal model for mine accident rescue due to its adaptability to a variety of drilling technologies and the advantages of wide formation adaptability, high mobility and strong accident handling capacity. In view of the shortcomings of domestic truck-mounted drilling rig in the construction of life support hole and large-diameter relief well, ZMK5550TZJF50/120 truck-mounted drilling rig was developed. Specifically, the large capacity power head adaptable to various technologies was developed, adopting the design of installation …

Adaptive Electro-Hydraulic System Of Zmk5550tzjf50/120 Truck-Mounted Drilling Rig With Wob Adaptive Control Function, Chang Jianghua, Zhao Liang, Lu Feifei, Wang Longpeng, Yang Jiangbo

Coal Geology & Exploration

The truck-mounted drilling rig is an ideal model for rescue drilling construction due to its strong mobility and wide process adaptability. The traditional truck-mounted drilling rig adopting the mode of hydraulic control and hydraulic drive has the problems of non-intuitive displaying of control parameters and many pipelines, which is hard to achieve the closed-loop control. In case of drilling into the complex formations, the response speed of the driller is often difficult to adapt to changes in working conditions, which is not conducive to the drilling safety. In order to meet the requirements of safety and high automation of rescue …

Formation Mechanism Of Coalbed Methane In Dafosi Mine Field, Huanglong Coalfield, Liu Kaide, Yao Kaiwen, Chen Nengyuan, Fan Zhangqun, Li Shujia, Zheng Han, Yue Wenping, Li Xiaolong

Coal Geology & Exploration

Dafosi mine field is a typical low-rank coalbed methane (CBM) field in Binchang mining area of Huanglong Jurassic. There are many coalbed methane wells in the field, but few researches are performed on the formation mechanism of coalbed methane. Thus, it is of great guiding significance to clarify the geochemical characteristics and formation mechanism of coalbed methane (CBM) in the mine field, which could provide important basis for the analysis on productivity difference of high- and low-yield CBM Wells. For this reason, the samples of drained gas at the wellhead of six CBM wells, 22 coal samples of No.4 coal …

Application Of Pneumatic Dth Hammer In Drilling Rescue Of Mine Accidents, Zhao Jiangpeng, Hao Shijun

Coal Geology & Exploration

As an efficient percussive rock breaking tool, pneumatic down-the-hole (DTH) hammer has played an important role in drilling rescue of mine accidents at home and abroad. Herein, the technical characteristics of pneumatic DTH hammer were described from the points of rock breaking mechanism, structure type, drilling method and specification, and the reverse circulation type and its characteristics of pneumatic DTH hammer were emphatically analyzed. Besides, the application of forward circulation drilling of pneumatic DTH hammer and the combined deviation correction drilling of pneumatic DTH hammer and mud screw in small diameter drilling, as well as the research progress of pneumatic …

Theory And Experiment Of The Dual-Bit Torque Self-Balancing Drilling System For Rescue Drilling, Gao Ke, Zhang Cong, Zhao Yan, Li Xu, Wen Yumin, Lyu Xiaoshu, Xie Xiaobo

Coal Geology & Exploration

The rapid and safe construction of rescue channel is an effective method to save the trapped person underground after mine accidents. The conventional rescue hole drilling technologies mainly include the downhole hammer percussion drilling technology and the composite drilling technology, which have the disadvantages of large rig structure, complex drilling process, great disturbance to the formation and low target hit rate. In particular, it is easy to have secondary accidents in the fractured strata, and the rescue requirements could not be effectively met. In order to ensure the formation adaptability and wall stability of rescue boreholes, the dual-bit torque self-balancing …

Research And Application Of Multi-Source Information Detection Technology For Drilling Rescue Of Mine, Zheng Xuezhao, Sun Ziyu, Guo Jun, Zhang Duo, Chen Gang, He Qinjian

Coal Geology & Exploration

Drilling rescue of mine is a new type of rescue technology. In order to quickly and accurately obtain the information on drilling channel, the location distance of the trapped person and the characteristics of the gas environment in the disaster area during rescue, as well as to realize the two-way video and audio communication between the trapped person underground and the rescue commander on the ground, theoretical research and technical development were conducted with the technical methods such as multi-source information fusion, dual-stream network video service, edge computing, intrinsically-safe circuit control, and ultra-wideband radar. Meanwhile, two key technologies were proposed: …

Distribution Characteristics Of Trace Elements In Different Density Fractions Of High-Germanium Coal From Wulantuga, Inner Mongolia, China, Duan Piaopiao, Wang Wenfeng, Ma Mengya

Coal Geology & Exploration

The exploitation and utilization of critical metals in coal measures is of great significance to alleviate the shortage of strategic mineral resources in China. In addition to the critical metal germanium (Ge), the low-rank coal from Wulantuga Coal Mine of Shengli Coalfield in Inner Mongolia, China is enriched with the toxic elements Be, F, As, Hg, Sb and W. Considering the extraction and utilization of key metals and environmental protection, the coal in the study area must be washed. As shown in the previous study, flotation is relatively good for the removal of As, Sb and W inWulantuga coal, but …

Research On Key Technology Of Pipe Jacking Drilling Equipment For Large-Diameter Rescue Borehole Of Coal Mine, Wang Lei, Zhu Yuqin, Zhang Weina, Liu Hao, Zhao Wenbo, Yang Chuang, Wang Guanxiong

Coal Geology & Exploration

In order to solve the rescue problem of collapsed roadways in coal mines and improve the drilling speed of large-diameter rescue boreholes, the construction method of large-diameter borehole with pipe jacking technology was proposed. Specifically, the collapsed rock mass was crushed and the slag was removed by pushing the connectable pipe joints and cutter heads with the main jacking equipment arranged in the chamber, so as to form a rescue channel composed of jacked pipes at last. A composite cutter head with large opening under the condition of collapsed rock mass was developed, which is composed of 10 cutters, 10 …

Quantitative Experimental Study On Time-Varying Characteristics Of Bleeding Of Cement-Based Grouting Materials, Zhang Runqi, Xu Bin, Yin Shangxian, Li Shuxia, Chang Yongwang, Lian Huiqing, Cao Min

Coal Geology & Exploration

Cement-based cementitious materials are the most common grouting materials for grouting engineering. This type of material has obvious water separation effect, and obtaining the quantitative formula of water separation thickness will be helpful to improve the calculation accuracy of slurry diffusion radius. By observing the water separation process of three admixtures, namely pyrophyllite powder (0%-35%), polyvinyl alcohol (0%-8%) and fly ash (0%-90%) in cement-based slurry, the water separating rate, stone formation rate, final water separation time and water separation thickness of the three admixtures were obtained. It is found that the water separation thickness of the slurry varies regularly with …

Digital Twin Technology Of Geological Information In Mining And Excavation Working Face, Li Peng, Cheng Jianyuan

Coal Geology & Exploration

The mine geology transparency is the basis for the intelligent coal mine construction. 3D geological modeling is an important measure for realizing the mine geology transparency. In the geological modeling of the previous working face, there are problems including the discrepancy between the interpolation algorithm and the geological law, the low fusion level of the multi-source heterogeneous geological data, and the seldom coupling between the coal mine production equipment and the geological information. The concept of the digital twin of the geological information about coal mine working face was proposed, the discrete smooth interpolation (DSI) algorithm was adopted, and the …

Subgrade Subsurface Anomalous Body Full-Waveform Inversion Based On Ground-Penetrating Radar, Hu Leilei, Chen Kang, Huang Dejun, Yang Rong

Coal Geology & Exploration

The hidden dangers of road collapse and underground voids are usually difficult to notice and easy to occur in sudden. They have caused huge losses in people's lives and properties. Therefore, the detection and analysis of road collapse and underground voids are crucial. The ground-penetrating radar (GPR) is the main method for detecting the hidden dangers of urban road collapse currently by virtue of its high accuracy, high efficiency, continuous non-destructiveness and real-time imaging. A convolution type objective function FWI algorithm was proposed to solve the problem of the lower inversion accuracy and practicability caused by the inaccurate estimation of …

Table Of Contents, The Editors

Coal Geology & Exploration

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A 1.8 Million Year History Of Amazon Vegetation, Andrea K. Kern, Thomas Kenji Akabane, Jaqueline Q. Ferreira, Cristiano M. Chiessi, Debra A. Willard, Fabricio Ferreira, Allan Oliveira Sanders, Cleverson G. Silva, Catherine Rigsby, Francisco W. Cruz, Gary S. Dwyer, Sherilyn C. Fritz, Paul A. Baker

Department of Earth and Atmospheric Sciences: Faculty Publications

During the Pleistocene, long-term trends in global climate were controlled by orbital cycles leading to high amplitude glacial-interglacial variability. The history of Amazonian vegetation during this period is largely unknown since no continuous record from the lowland basin extends significantly beyond the last glacial stage. Here we present a paleoenvironmental record spanning the last 1800 kyr based on palynological data, biome reconstructions, and biodiversity metrics from a marine sediment core that preserves a continuous archive of sediments from the Amazon River.

Tropical rainforests dominated the Amazonian lowlands during the last 1800 ka interchanging with surrounding warm-temperate rainforests and tropical seasonal …

Drought‑Stricken U.S. States Have More Comprehensive Water‑Related Hazard Planning, Theresa Jedd, Kelly Smith

National Drought Mitigation Center: Faculty Publications

Despite the devastating impacts of droughts, the United States lacks a national drought plan. This leaves states to address droughts in water, hazard, and stand-alone plans which are designed to reduce drought vulnerability and to prepare government, industry, and society to cope with the impacts. Yet, there is limited empirical research that evaluates the comprehensiveness of these plans, specifically in terms of whether they include preparedness and mitigation measures or triggers for action and response. To fill this gap, this study’s first aim was to establish an evaluation framework based on principles from the drought mitigation literature. The study then …

Emplacement Of The Franklin Large Igneous Province And Initiation Of The Sturtian Snowball Earth, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth’s thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. …

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