Earth Sciences Commons^™

Effect Of Cadmium-Free Filler Metal On Mechanical Properties And Microstructure Of Pdc Cutters, Zhang Suhui, Yao Ningping, Liu Qingxiu, Liu Huan, Wang Dechuan

Coal Geology & Exploration

Objective PDC bits are critical components of geological support equipment and play a vital role in advancing technology and improving efficiency in the coal industry. Currently, PDC bits are brazed using silver filler metals containing cadmium, a toxic and polluting element. This study introduces the use of environmentally friendly, cadmium-free filler metals for brazing PDC bits. Methods The study investigates the wetting mechanism between brazing filler metals and base materials, utilizing Ag-Cu-Zn series brazing filler metals containing high silver and Sn, Mn and Ni, and only Ni for flame brazing of PDC cutters and steel. The shear strength of different …

Rock Burst Hazard Evaluation Of Coal Mining Face Based On A Gaussian Mixture Model, Cui Feng, Li Yifei, Jia Chong, Lu Changliang, He Shifeng, Zhang Suilin, Tian Mengqi

Coal Geology & Exploration

Objective Deep insights into the probabilistic information contained in the energy distribution of acoustic emission (AE) or microseismic events are significant for the rock burst hazard evaluation of coal mining face. Methods This study investigated No.40111 mining face of the No.4 coal seam at the Dafosi Coal Mine in Shaanxi Province. Using physical simulation experiments with similar materials, theoretical analysis, and on-site monitoring, this study investigated the evolutionary patterns of AE monitoring data during coal mining and illustrated the physical meaning of fluctuations in the probability distribution of AE energy. Accordingly, this study proposed an index model for the rock …

Advances In Research On The Evolution Of Trans-Scale Discontinuous Structures During The Creeps Of Strongly Disturbed Coals, Zhang Liang, Wang Laigui, Ren Ting, Li Xiangchun, Gao Ke, Li Haitao, Zhao Shankun

Coal Geology & Exploration

Objective and Methods Disasters associated with surrounding rocks in roadways, such as time-dependent deformation failure and creep-induced rock bursts, severely threaten deep mines in China. These disasters, coupled with the impacts of deep mining and structural changes, render it urgent to explore the evolutionary patterns of trans-scale discontinuous structures during the creeps of strongly disturbed coals. This study systematically reviews the scale effects of coals' mechanical properties, the discontinuous structures and multi-physics field effects of coals, and the long-term stability, creep evolutionary patterns, and mechanical models of coals. It highlights the close correlation between discontinuous structures (including their fractures and …

Sedimentary Environments, Mechanical Properties, And Rock Burst Risk Identification Of Overburden In Deep Mines, Qiao Wei, Cheng Xianggang, Dou Linming, He Hu, Meng Xiangsheng, Ren Yangyang, Xiao Chong, Cai Jin

Coal Geology & Exploration

Objective Disaster risk identification and prediction serve as a prerequisite for disaster control. An engineering geological environment is identified as the fundamental condition inducing dynamic disasters like rock bursts in mines. Exploring the sedimentary genetic mechanisms of engineering geological environments holds great significance for predicting rock burst risks. Methods With the Gaojiapu Coal Mine in the Binchang mining area, Shaanxi Province, as a case study, this study analyzed the engineering geological characteristics of rock masses under different sedimentary microfacies. Furthermore, it explored the deformation and failure characteristics of rocks in different sedimentary environments, along with the energy release patterns of …

An Experimental Study Of The Evolutionary Patterns Of Mechanical Properties Of Coals Under Multiple Mining Disturbances, Ouyang Zhenhua, Liu Yang, Li Chunlei, Shi Qingwen, Li Wenshuai, Yi Haiyang, Qin Hongyan, Zhang Ningbo

Coal Geology & Exploration

Objective In the mining process of coal mines, the cyclic loading and unloading effects caused by multiple mining disturbances can alter the mechanical properties of coals, serving as a significant cause of rock bursts. Revealing the response characteristics of crucial mechanical parameters and the damage mechanisms of coals can provide a basis for discriminating the impact-induced instability state, holding great significance for enhancing disaster prediction capabilities. Methods Quasi-static uniaxial cyclic loading and unloading experiments and the dynamic impact loading experiments on large-size coal-like specimens were combined to accurately capture the stress, strain, and acoustic emission responses during the experiments, thoroughly …

Evolutionary Characteristics Of Microcracks In Rocks Under Weak Dynamic Disturbance And Disaster Prevention And Control, Jiang Mingwei, Liang Yuntao, Feng Wenbin, Li Haitao, Zhou Rui, Guo Baolong, Liu Yang, Ma Ju

Coal Geology & Exploration

Objective High stress with superimposed weak dynamic disturbance serves as a critical factor including rock bursts. However, the microcrack propagation characteristics and energy dissipation pattern of rocks under different disturbance amplitude, frequencies, and unloading ranges remain unclear, leading to a lack of technical support for rock burst prevention and control.Methods Based on the true triaxial unloading dynamic disturbance tests, this study analyzed the instability failure patterns of deep surrounding rocks under different disturbance amplitude (5, 10 MPa), frequencies (4, 10 Hz), and triaxial stress unloading (0, 12 MPa). Moreover, this study examined the characteristics of microcracks in rocks using …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Rock Bursts Induced By Thick-Hard Roof With Compound Key Strata: Mechanisms And Technical Modes For Prevention, Zheng Kaige, Yuan Liang, Zhang Pingsong, Wang Lintao

Coal Geology & Exploration

Objective Thick-hard roofs serve as the key factor inducing disasters such as rock bursts and mining-induced earthquakes in coal mines. These disasters are especially serious in the case of coal seam roofs with compound key strata. Hence, there is an urgent need to reveal the mechanisms behind the rock bursts induced by thick-hard roofs with compound key strata and to develop technical modes for the prevention and control of these rock bursts. Methods Using methods including physical simulation experiments on similar materials and mechanical analysis, this study developed methods for identifying roofs with compound key strata and for non-synergistic breaking …

Mechanisms Behind Mine Earthquake-Induced Dynamic Instability Of Thick Top Coals In High-Stresses Roadways, Zhou Kunyou, Dou Linming, Cao Anye, Ma Yankun, Kan Jiliang, Li Jiazhuo, Ma Xiaotao

Coal Geology & Exploration

Objective Thick top coals are common in roadways excavated along the bottom of thick coal seams. Mine earthquakes along the mining face can exert dynamic loading on thick top coals in roadways, prone to induce the dynamic instability of thick top coals and even roof fall-rock burst compound disasters. Therefore, there is an urgent need to explore the mechanisms behind the dynamic instability of thick top coals in roadways under dynamic loading induced by mine earthquakes. Methods This study investigated a roadway of deep thick top coals in the Binchang mining area, Shaanxi. Specifically, this study analyzed the dynamic instability …

Fracturing Characteristics Of Significantly Thick Overburden Inducing Mine Earthquakes And The Stress-Triggering Mechanisms Of The Mine Earthquakes, Dou Linming, Cao Anye, Yang Yao, He Hu, Yang Yaoxin, Bai Xianxi, Gu Qianyue, Li Songhui, Fu Xiangchao, Gu Yingshi, Wu Zhen, Zhang Di

Coal Geology & Exploration

Objective Frequent mine earthquakes that cause surface seismaesthesia, induced by the fracturing of significantly thick overburden in deep coal mining, are identified as the most severe challenge to the efficient production of mining areas. There is an urgent need to overcome the current difficulty caused by mine earthquakes induced by significantly thick overburden, which feature high frequency and challenging prevention and control. Methods Using such mine earthquakes occurring in a certain fully mechanized mining face adjacent to goaves in the Khujirt mining area in Ordos, Inner Mongolia Autonomous Region, as an example, this study (1) analyzed the evolutionary patterns of …

Mechanism Of Thrust Fault Slip Under The Disturbance Of Stress Waves Induced By Coal Mining, Zhang Ningbo, Xu Qianhai, Ouyang Zhenhua, Li Yizhe, Shi Qingwen, Qin Hongyan, Yi Haiyang

Coal Geology & Exploration

Objective The seismic sources, such as roof collapse and artificial blasting, in coal mining may induce stress waves, which will cause the surrounding faults lose its stability and thus cause the dynamic disasters such as rockbursts etc. Methods The propagation law of stress waves in the fracture structure and the evolution characteristics of friction energy under the action of stress waves were studied through dynamic photoelastic experiment, numerical simulation and theoretical analysis based on the thrust fault F16 in Henan Yima mining area. Meanwhile, the disturbance law of the location of seismic source and energy to the slip of thrust …

Influencing Analysis Of Bedding Plane Location On The Dynamic Failure Characteristics Of Coal-Rock Combinations, Zheng Jianwei, Zhang Xiufeng, Ju Wenjun, Wang Cunwen, Han Yueyong, Li Guoying, Chen Yang, Li Haitao, Hao Jinwei, Liu Biao

Coal Geology & Exploration

Objective The bedding plane location significantly impacts the dynamic failure processes and mechanical properties of coal-rock composites, but the specific influence patterns remain unclear. Methods Dynamic mechanical tests were conducted on coal-rock composite specimens with bedding planes located at the top, middle, and bottom using the split Hopkinson pressure bar (SHPB). The investigation focused on the dynamic stress-strain behavior, failure process, energy distribution, and fragmentation characteristics under impact loading conditions. Results and Conclusions The findings indicate that: (1) The dynamic stress-strain behavior of coal-rock composites can be segmented into five distinct stages: near-linear stage, nonlinear dynamic stress-strain stage, elastic modulus …

Exploring The Evolutionary Patterns Of Stress Field In Coal Seams During Water Drainage In Overburden Confined Aquifers Based On Charge Monitoring, Wang Gang, Yu Xiaojie, Wang Aiwen, Xiao Xiaochun, Wang Yong, Ding Xin, Wang Weibin, Xu Zengjun, Du Lulu

Coal Geology & Exploration

Objective Deep coal mining areas in regions such as Inner Mongolia, Shaanxi, Shandong, and Gansu in China feature intricate hydrogeological conditions, which lead to substantial water drainage from roofs and increasingly prominent rock bursts induced by water drainage in overburden confined aquifers. This study investigated the evolutionary patterns of the stress field in coal seams during the water drainage of overburden confined aquifers. Methods By combining the laboratory charge induction experiments of coals under graded loading with charge monitoring pre- and post-water drainage from a roof in a coal mine, this study systematically examined the variations of induced charge in …

Spatiotemporal Evolutionary Characteristics Of Asymmetric Stress Transfer In Overburden Of Steeply Dipping Coal Seams, Zhu Kaipeng, Li Zhilin, Luo Shenghu, Xie Panshi, Fan Juan, Wang Tong, Tian Chengyang, Yan Zhuangzhuang

Coal Geology & Exploration

Objective The key to the safe and efficient mining of steeply dipping coal seams is the effective control of the stability of surrounding rocks, while the effective control is underpinned by identifying and revealing the spatiotemporal evolutionary characteristics of the stress transfer path of the overburden. Methods This study investigated mining face 25221 of a coal mine in Xinjiang through field measurement, physical simulations using similar materials, and numerical computation. This study determined the rock pressure behavior of the mining face, along with the deformation and failure patterns of the overburden, through a comprehensive analysis. Accordingly, it established stress characteristic …

Evolutionary Pattern And Control Technology Of Mine Pressure When Mining Face For Coal Pillars In Main Roadways Passing Through Abandoned Roadways, Li Zhenhua, Ren Ziyuan, Du Feng, Ren Hao, Wang Wenqiang

Coal Geology & Exploration

Objective With the adjustment of the mining face layout in mines, the overburden roof of the mining face for coal pillar recovery is frequently difficult to control when the mining face passes through abandoned roadways. Methods To address this challenge, this study investigated the coal pillar mining face outside the No.2 panel in the Zhaogu No.2 Coal Mine in Henan Province, which passes through abandoned roadways. Using methods like theoretical analysis, numerical simulation, and in-situ tests, this study examined the composite structure of the mining face and the broken overburden of abandoned roadways, followed by simulation of the full-cycle evolutionary …

Spatial Surveying Characteristics And Reconstruction Method Of Millimetre Wave Radar In Complex Environment Of Coal Mine Roadway, Xue Xusheng, Yang Xingyun, Yue Jianing, Wang Chuanwei, Mao Qinghua, Ma Hongwei, Wang Rongquan

Coal Geology & Exploration

Objective Underground spatial surveying of coal mine is an important part of transparent geological modelling for coal mine. However, the complex environment of coal mine roadway, incomplete information acquisition, insufficient accuracy of sensed data and other difficulties need to be urgently solved. Methods First, the signal characteristics of millimeter wave radar under the complex environmental factors such as dust, water mist, surrounding rock structure, etc. were studied in depth, the millimeter wave signal attenuation model was established for the surrounding rock of coal mine roadway, and the influence mechanism of complex environmental factors for millimeter wave radar was comparatively analyzed. …

Advances In Research On Stratigraphic Characteristic Parameter Modeling And Safety Early Warning For Deep Geological Drilling Processes, Yang Yulong, Cao Weihua, Gan Chao, Li Yupeng, Wu Min

Coal Geology & Exploration

Significance As the new round of national exploration & development planning continues, resource exploration is advancing toward the deep Earth. However, deep strata exhibit diverse rock types, which complicate the measurement of rock mechanical parameters. Furthermore, the harsh environments of these strata, characterized by high temperatures, high pressures, and high in-situ stress, are prone to induce downhole accidents like drilling tool failure, wellbore collapse, loss of circulation, and well kicks, posing challenges to geological drilling. Advances Aiming at the perception and modeling of complex geological environments, this study reviews the existing studies on the modeling of stratigraphic characteristic parameters from …

Factors Influencing The Faunal Recolonization Of Restored Thornscrub Forest Habitats, Audrey J. Hicks, Jerald T. Garrett, Christopher A. Gabler

School of Earth, Environmental, & Marine Sciences Faculty Publications

Tamaulipan thornscrub forests (thornforests) have high ecological and economic values, yet over 90% of these forests have been lost, and they remain threatened, making them a conservation hotspot. For decades, federal, state, NGO, and corporate entities have been acquiring land and actively or passively restoring these forests, but results have been mixed and seldom monitored. This study characterized and quantified faunal communities of restored thornforest habitats in south Texas and examined the relationships between restored faunal communities and key site characteristics and environmental factors. We surveyed and analyzed mammal, bird, Lepidoptera, and herptile communities within 12 restored sites in the …

Liming Acidic Soils Creates Profits, Land Use Options But Often More Emissions, Sud Kharel, Christophe D'Abbadie, Amir Abadi Ghadim, Chris Gazey, Ross Kingwell

Natural Resources Research Articles

Context

Soil acidity constrains crop production in Australia. The practice of liming can reduce soil acidity but produces greenhouse gas emissions.

Aims

By examining land use sequences over three decades at a range of locations in Western Australia, this study aims to identify firstly where and when liming might boost farm profits and secondly, what emissions and land use management flexibilities are generated by liming.

Methods

Bioeconomic simulation modelling is used to identify the gross margins and emissions associated with liming in land use sequences at 14 locations in Western Australia. Three intensities of cropping and three different rotational sequences …

A Multivariate Approach To Assessing Landscape Structure Effects On Wildlife Crossing Structure Use, Thomas J. Yamashita, Humberto L. Perotto-Baldivieso, David B. Wester, Kevin W. Ryer, Richard J. Kline, Michael E. Tewes, John H. Young Jr., Jason V. Lombardi

School of Earth, Environmental, & Marine Sciences Faculty Publications

Background

Complexity in landscape structure is often assessed using individual metrics related to ecological processes. However, this rarely incorporates important relationships among metrics and may miss landscape structure effects. Multivariate statistics provide techniques for assessing overall landscape structure effects. We assessed how multivariate statistics could be used to connect landscape structure with an ecological process [bobcat (Lynx rufus) wildlife crossing structure (WCS) use]. We tested how landscape structure at WCS sites compared to the surrounding landscape and how structure affected detections at WCS sites. Our study was conducted in Cameron County, Texas, USA where WCSs are in various …

A Comparative Study Of Cave System Calcium Isotope Ratios: Implications For Quantitative Reconstruction Of Paleorainfall From Speleothems, Cameron B. De Wet, Elizabeth M. Griffith, Andrea Erhardt, Jessica L. Oster

Earth and Environmental Sciences Faculty Publications

Variations in speleothem calcium isotope ratios (δ44Ca) are thought to be uniquely controlled by prior carbonate precipitation (PCP) above a drip site and, when calibrated with modern data, show promise as a semi‐quantitative proxy for paleorainfall. However, few monitoring studies have focused on δ44Ca in modern cave systems. We present a multi‐year comparative study of δ44Ca, carbon isotopes (δ13C), and trace elemental ratios from cave drip waters, modern calcite, and host rocks from two cave systems in California—White Moon Cave (WMC) and Lake Shasta Caverns (LSC). Drip water and calcite δ44Ca from both caves indicate PCP‐ driven enrichment, and we …

Comprehensive Lead Exposure Vulnerability For New Jersey: Insights From A Multi-Criteria Risk Assessment And Community Impact Analysis Framework, Gift Fabolude, Charles Knoble, Anvy Vu, Danlin Yu

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Lead contamination remains a persistent and insidious threat, particularly affecting young children and vulnerable communities. This study aims to develop a comprehensive sources-based lead exposure index map for New Jersey municipalities by integrating diverse lead contamination data, including lead-based paint, lead service lines, proximity to superfund and brownfield sites, road density, and gas stations, analyzing how municipality socioeconomic and land use factors impact lead exposure. The research employs Principal Component Analysis (PCA) and Analytical Hierarchy Process (AHP) to create two distinct multi-criteria lead exposure indices. The indices are mapped to understand the spatial distribution and magnitude of lead exposure risks …

Festival Of Research Abstracts, Fall 2024, College Of Science And Mathematics, Wright State University

Festival of Research

The collection of abstracts accepted for the Fall 2024 Festival of Research hosted by the Wright State University College of Science and Mathematics.

Feral Goat, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

The goat (Capra hircus) was one of the first animals to be domesticated, 8 to 10 thousand years ago. Archaeological work indicates the earliest attempts at domestication were in dry hills surrounding the Mediterranean basin. The ability of goats to utilise the coarse browse of mountainous areas made them suitable for domestication, in preference to sheep. With large-scale domestication of goats throughout the world, goats escaped and established feral goat herds on most continents. Overgrazing by goats has caused severe environmental damage, worldwide.

Goats arrived in Australia with the first fleet. They were introduced to many areas by early settlers …

Detection Of Seismic Microwave Radiation Anomalies In Snow-Covered Mountainous Terrain: Insights From Two Recent Earthquakes In The Pamir–Tien Shan Region, Feng Jing, Meng Jiang, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

When earthquakes occur in high-mountain areas during the winter season, the epicentral region is often covered by a snow layer, which can be either thin or thick. The presence of snow and/or ice layers affects the detection of thermal anomalies associated with seismic signals. Taking into account the penetration capabilities of microwaves, microwave brightness temperature data were analyzed by using the index of microwave radiation anomaly to study the response of the epicentral region associated with two recent strong earthquakes in Central Asia, which occurred in snow-covered mountainous areas. Increased microwave radiation was observed within one week prior to the …

Challenges Of Using More Precise Temporal And Spatial Resolution Of Remote Sensing Data For Surface Water Quality Monitoring, Ivan Rykin

Dartmouth College Master’s Theses

Monitoring river suspended sediment concentration (SSC) is critical for environmental challenges such as understanding the fate of thawed permafrost sediment and its impact on global carbon cycling. However, traditional SSC monitoring using Landsat imagery is limited by spatial and temporal constraints, particularly for narrow rivers in cloudy and/or snowy regions.

This study investigates the use of higher spatial (3 m) and temporal (daily) resolution satellite imagery from the PlanetScope constellation to estimate SSC in remote rivers such as those in the Arctic. I compare the performance of PlanetScope’s spectral resolution (4 and 8 bands) with Landsat 7. Merging data from …

Stable Isotope Analysis Of Antipatharian Diets From The Northwestern Gulf Of Mexico, Keir J. Macartney, Victoria Salinas, Zachary Rivera, David Hicks

School of Earth, Environmental, & Marine Sciences Faculty Publications

Antipatharians, or black corals, form a key component of the benthic fauna found throughout the Gulf of Mexico (GOM). In the northwestern GOM, they are a common member of the communities found on the natural relic coral—algal banks known as the South Texas Banks as well as on artificial reefs. They are known to provide important habitat for many ecologically and economically important species in the area but are relatively understudied. Here we present a study on their trophic ecology using stable isotope analysis of carbon and nitrogen from 2 species, Antipathes atlantica and Stichopathes luetkeni from a mesophotic artificial …

Geological Support Technology Framework System For Mining Induced Hazards And Damage Reduction Mining Of Geological Conditions In Western Mining Area, Wang Shuangming, Sun Qiang, Geng Jishi, Yuan Shihao, Gu Chao, Yang Duoxing, Niu Chao, Lu Tuo, Guo Chen, Zhang Huanlan, Huang Haiyu, Shi Qingmin

Coal Geology & Exploration

Objective Coals, as the main energy in China for the long term, secure the basic needs for energy development in China. However, large-scale, intense coal mining damages the geologic environment of coal mining areas, as well as inducing hazards such as water inrushes and rock bursts. Methods To overcome the challenges in geological security through the prediction and early warning of damage to geologic environments and damage-reducing mining faced by safe, efficient coal mining, this study, based on the interdisciplinary characteristics of the geological security, highlighted the hazard control mechanisms and mining-inducing hazard patterns of geological conditions, underscored the whole-space-time …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Pillar Wall Angles Of Karst Collapse Pillars In The Xishan Coalfield: Characteristics And Implications, Zhao Jingui, Wang Jiangwei, Yang Gaofeng, Guo Mintai

Coal Geology & Exploration

Significance As coal mining expands into deep parts, karst collapse pillars have become one of the most concealed disaster-causing geological factors in coal mining from mines in North China. The pillar wall angle of a collapse pillar serves as an important index used to describe the morphology of the collapse pillar. Methods and Results With 265 karst collapse pillars cut by the fully mechanized mining of the upper and lower coal seams in the Xishan coalfield as the data source, this study extracted the geological information contained in the pillar wall angles of karst collapse pillars in the Xishan coalfield …