scholarly journals Applications of Geophysical Logs to Coal Mining—Some Illustrative Examples

Resources ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 11
Author(s):  
Binzhong Zhou ◽  
Hua Guo
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Financial Risks ◽  
Geotechnical Assessment ◽  
Mining Condition ◽  
Natural Gamma ◽  
Potential Applications ◽  
Geophysical Logs ◽  
Mining Projects ◽  
Conventional Logs

Geophysical logs can be used not only for qualitative interpretation such as strata correlation but also for geotechnical assessment through quantitative data analysis. In an emerging digital mining age, such a use of geophysical logs helps to establish reliable geological and geotechnical models, which reduces safety and financial risks due to geological and geotechnical uncertainty for new and existing coal mining projects. This paper presents some examples of geological and geotechnical characterizations from geophysical logs at various coal mines in Australia and India. The applications include rock strength and coal quality estimations, automated lithological/geotechnical interpretation and geophysical strata rating, all based on geophysical logs. These derived parameters could provide input to modelling, control, even ‘digital twin’ generation in a form of geological and geotechnical models as part of the future digital mining. The outcomes can be visualized in 3D space and used for identifying the key geotechnical strata units that are responsible for caving behaviors during longwall mining. This could assist site geologists and planning and production engineers predict and manage mining conditions on an ongoing basis. Both conventional logs such as density, natural gamma and sonic and less common logging data, such as full waveform sonic, televiewer and SIROLOG spectrometric natural gamma logging data are examined for their potential applications. The geotechnical strata classification and rock strengths predicted from the geophysical logs match the laboratory tests, drill core geotechnical strata classification, core photos and the mining condition/behavior observed. These illustrate the usefulness and effectiveness of using geophysical logs for geological and geotechnical characterizations.

Research on Overlying Strata Movement and Deformation under the Conditions of Shortwall and Longwall Mining

2011 ◽  
Vol 90-93 ◽  
pp. 1299-1302 ◽  
Author(s):  
Kuo Li ◽  
Yong Bo Zhang
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Strata Movement ◽  
Damage Level ◽  
Mining Condition ◽  
Movement And Deformation ◽  
Overlying Strata Movement ◽  
Overlying Strata ◽  
Subsidence Curve

We simulate the rock’s movement and defoemation process in the coal mining, and research the overlying strata movement and deformation under the conditions of shortwall and longwall mining. The conclusion of the experiment indicates: with the method of double deck mining, the rock’s damage level in caving layer is more serious, the final subsidence curve presents a tooth geometry. The subsidence curve of fissure and flexure zone is simily with the longwall mining condition.

Study of Effective Environmental Engineering Impact Assessment on Coal Mining Projects

2020 ◽  
Vol 48 (3) ◽  
pp. 03-04
Author(s):  
Kai Pearce
Keyword(s):  
Coal Mining ◽  
Environmental Issue ◽  
Ecological Effect ◽  
Current Status ◽  
Ecological Security ◽  
Effect Evaluation ◽  
Significant Function ◽  
Mining Projects ◽  
Time Evaluation ◽  
Security Check

The mineral asset abuse assumes a significant function in monetary turn of events, yet it additionally causes numerous natural issues, particularly environmental issue. In coal mining, so as to accomplish feasible utilization of these assets, we should give exceptional consideration to eco-ecological insurance. This article first quickly presented the current status of natural designing effect evaluation and afterward talked about the time viability of appraisal through the investigation of its present status, utilizing ecological security check and acknowledgment in coal mining ventures. The creators consider that one-time evaluation of ecological effect on the coal tasks and "three synchronous" acknowledgment of the coal ventures executed in china as of now isn't sensible.

scholarly journals Calculation of Residual Surface Subsidence Above Abandoned Longwall Coal Mining

2020 ◽  
Vol 12 (4) ◽  
pp. 1528 ◽  
Author(s):  
Ximin Cui ◽  
Yuling Zhao ◽  
Guorui Wang ◽  
Bing Zhang ◽  
Chunyi Li
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Land Reclamation ◽  
Surface Subsidence ◽  
Mining Subsidence ◽  
First Year ◽  
Longwall Coal Mining ◽  
The Stability ◽  
Ecological Reconstruction

Exhausted or abandoned underground longwall mining may lead to long-term residual subsidence on surface land, which can cause some problems when the mined-out land is used for construction, land reclamation and ecological reconstruction. Thus, it is important to assess the stability and suitability of the land with a consideration of residual surface subsidence. Assuming a linear monotonic decrease in the annual residual surface subsidence, the limit of the sum of the annual residual subsidence factor, and continuity between surface subsidence in the last year of the weakening period and the residual surface subsidence in the first year, we establish a model to calculate the duration of residual subsidence and the annual residual surface subsidence factor caused by abandoned longwall coal mining. The duration of residual surface subsidence increases with the increase in mining thickness as well as the factor of extreme residual subsidence. The proposed method can quantitatively calculate the annual residual subsidence, the accumulative residual subsidence, and the potential future accumulative residual subsidence. This approach can be used to reasonably evaluate the stability and suitability of old mining subsidence areas and will be beneficial for the design of mining subsidence land reclamation and ecological reconstruction.

Chapter 11 Coal mining subsidence in the UK

2020 ◽  
Vol 29 (1) ◽  
pp. 291-309 ◽  
Author(s):  
Laurance Donnelly
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Ground Surface ◽  
Mining Subsidence ◽  
Ground Movement ◽  
Working Face ◽  
Mine Roadway ◽  
Coal Mining Subsidence ◽  
The Uk

AbstractOne of the geohazards associated with coal mining is subsidence. Coal was originally extracted where it outcropped, then mining became progressively deeper via shallow workings including bell pits, which later developed into room-and-pillar workings. By the middle of the 1900s, coal was mined in larger open pits and underground by longwall mining methods. The mining of coal can often result in the subsidence of the ground surface. Generally, there are two main types of subsidence associated with coal mining. The first is the generation of crown holes caused by the collapse of mine entries and mine roadway intersections and the consolidation of shallow voids. The second is where longwall mining encourages the roof to fail to relieve the strains on the working face and this generates a subsidence trough. The ground movement migrates upwards and outwards from the seam being mined and ultimately causes the subsidence and deformation of the ground surface. Methods are available to predict mining subsidence so that existing or proposed structures and land developments may be safeguarded. Ground investigative methods and geotechnical engineering options are also available for sites that have been or may be adversely affected by coal mining subsidence.

scholarly journals Surface Subsidence Prediction Method for Coal Mines with Ultrathick and Hard Stratum

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hongkai Han ◽  
Jialin Xu ◽  
Xiaozhen Wang ◽  
Jianlin Xie ◽  
Yantuan Xing
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Prediction Method ◽  
Prediction Equation ◽  
Arbitrary Cross Section ◽  
Surface Subsidence ◽  
Strong Impact ◽  
Subsidence Prediction ◽  
Movement Characteristics ◽  
Mining Condition

Overburden conditions consisting of ultrathick and hard stratum (UTHS) are widespread in China and other countries, but existing surface subsidence prediction methods ignore the strong impact of UTHS on surface subsidence. They are thus not applicable for surface subsidence prediction for coal mining with the presence of UTHS. We conducted actual measurements of surface and UTHS subsidence in the Tingnan Coal Mine. The results showed that under the UTHS mining condition, the required gob dimension is much larger than the empirical value when the surface reaches sufficient mining and that the actual measured maximum value of surface subsidence is much smaller than the empirical value. The UTHS subsidence is approximately equal to the surface subsidence. The movement of UTHS has a strong impact on surface subsidence and has a controlling function for it. It was proposed that surface subsidence could be approximately predicted by calculating the UTHS subsidence. The UTHS movement characteristics were studied using Winkler’s theory of beams on an elastic foundation, the subsidence prediction equation of the main sections in the strike and dip directions was obtained under different mining dimensions, and the subsidence prediction equation of any arbitrary cross section parallel to the two main sections was established. Then, the surface subsidence prediction method for coal mining with the presence of UTHS was developed, and the influences of UTHS thickness, strength, and layer position on the surface subsidence were discussed. The Tingnan Coal Mine was taken as an example, and the subsidence curves of the strike and dip main sections were calculated using different mining dimensions. Subsequently, the surface subsidence after the mining of working faces 204, 205, 206, and 207, respectively, was predicted, and the prediction method was verified by comparing the results with the measured surface subsidence results of working faces 204, 205, and 206.

scholarly journals AVAILABILITY SIMULATION AND ANALYSIS OF ARMORED FACE CONVEYOR MACHINE IN LONGWALL MINING

2021 ◽  
Vol 36 (2) ◽  
pp. 69-82
Author(s):  
Raziye Norouzi Masir ◽  
Mohammad Ataei ◽  
Farhang Sereshki ◽  
Ali Nouri Qarahasanlou
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Production Systems ◽  
Operating Time ◽  
Mining Industry ◽  
Production Costs ◽  
Machine Failure ◽  
Tabas Coal Mine ◽  
The Mean ◽  
Criticality Index

Since coal mining production systems are very complex, repairing equipment is expensive. If a system failure occurs, it will cause disturbances such as inoperable equipment, reduced operating time, increased production costs, and reduced equipment performance. Therefore, it is necessary to consider the availability of the coal mining industry more than ever. For this purpose, the Armored Face Conveyor (AFC) machine failure data was gathered over a period of 29 months from the Tabas Coal Mine. Descriptive statistics, trends, and serial correlation tests of the data were calculated. Then, the system’s mean and point availability were simulated. Based on the results, the mean availability (all events) and point availability (all events) at 360000 h are 96% and 95%, respectively. The mean time to first failure (MTTFF) of the AFC machine was about 23.61 h. The ReliaSoft Failure Criticality Index, ReliaSoft Downing Event Criticality Index, and ReliaSoft Downtime Criticality Index electrical equipping have the largest effect, whereas the main drive subsystem is the least important. Analysis showed that availability has a direct correlation to activity management and improvements in the quality, efficiency, and the product extraction.

scholarly journals Abnormal open-hole natural gamma ray (GR) log in Baikouquan Formation of Xiazijie Fan-delta, Mahu Depression, Junggar Basin, China

2018 ◽  
Vol 10 (1) ◽  
pp. 844-854 ◽  
Author(s):  
Rui Yuan ◽  
Rui Zhu ◽  
Jianhua Qu ◽  
Xincai You ◽  
Jun Wu ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Junggar Basin ◽  
Fine Grained ◽  
Fan Delta ◽  
Natural Gamma ◽  
Primary Mineral ◽  
Open Hole ◽  
Mineral Components ◽  
Components Analysis ◽  
Conventional Logs

Abstract Based on large amounts of cores, open-hole conventional logs and mineral components analysis, abnormal natural gamma ray (GR) log showing high values in conglomerates and low values in fine-grained sediments, are described and explained in Baikouquan Formation of Xiazijie Fan-delta, Mahu Depression, Junggar Basin. After observing cores, normalizing the GR log and correcting depth errors between both, the GR log values of individual grain-sized lithology are extracted and counted. When grain-size decreases, the average GR values of different sized grains increase generally. The GR values of conglomerates are mostly between 50 and 80 API, while the values of fine-grains are mainly between 70 and 100 API. However, abnormal GR log features exist in the cores and wells of Baikouquan Formation prevalently. A great deal of high radioactive intermediate-acid volcanic minerals, such as volcanic tuff, felsite, andesite, granite, rhyolite, et al., distribute widely in the conglomerates, which results in abnormal high GR values in conglomeratic intervals. Low radioactive quartz components exit widely in high percentage in mudstones, which is the primary mineral explanation for the abnormal low GR values in reddish-brown siltstones and sandstones intervals.

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