Dynamic Coal-Rock Interface Identification Based on Infrared Thermal Image Characteristics

2019 ◽  
Author(s):  
Haijian Wang ◽  
Xiaoxuan Huang ◽  
Xuemei Zhao ◽  
Zhishen Liang ◽  
Alla ALdeen Housein ◽  
...  
Keyword(s):  
Thermal Image ◽  
Image Characteristics ◽  
Rock Interface ◽  
Coal Rock

Application of Improved Canny Edge Detection Algorithm in Coal-Rock Interface Recognition

2012 ◽  
Vol 220-223 ◽  
pp. 1279-1283 ◽  
Author(s):  
Li Hong Dong ◽  
Peng Bing Zhao
Keyword(s):  
Edge Detection ◽  
Detection Algorithm ◽  
Canny Edge Detection ◽  
Edge Detection Algorithm ◽  
Canny Edge ◽  
Rock Interface ◽  
Coal Rock ◽  
Image Edge ◽  
Canny Algorithm ◽  
Canny Edge Detection Algorithm

The coal-rock interface recognition is one of the critical automated technologies in the fully mechanized mining face. The poor working conditions underground result in the seriously polluted edge information of the coal-rock interface, which affects the positioning precision of the shearer drum. The Gaussian filter parameters and the high-low thresholds are difficult to select in the traditional Canny algorithm, which causes the information loss of gradual edge and the phenomenon of false edge. Consequently, this paper presents an improved Canny edge detection algorithm, which adopts the adaptive median filtering algorithm to calculate the thresholds of Canny algorithm according to the grayscale mean and variance mean. This algorithm can protect the image edge details better and can restrain the blurred image edge. Experimental results show that this algorithm has improved the edge extraction effect under the case of noise interference and improved the detection precision and accuracy of the coal-rock image effectively.

scholarly journals Cutting Mechanical Study of Pick Cutting Coal Seams with Coal and Rock Interface

2021 ◽  
Author(s):  
Chenxu Luo ◽  
Junbei Qaio
Keyword(s):  
Compressive Strength ◽  
Coal Seam ◽  
Mechanical Model ◽  
Impact Load ◽  
Strength Analysis ◽  
Strength Condition ◽  
Rock Interface ◽  
Coal Rock ◽  
Rotary Cutting ◽  
Mining Coal

Abstract Shearer provide an effect solution for mining coal, and the cutting performance of pick largely accouts for the ability of a shearer and mining performance. We conducted pick cutting coal experiments in different seam forms on the coal and rock cutting teasted. According to the rotary cutting mechanical model of single pick cutting coal seam, combined with the strength condition of coal seam and coal-rock interface, the rotary cutting mechanical model of pick cutting coal seam with coal-rock interface is established. The stress strain and strength condition of the area in and around the interface are analyzed based on the coal-rock interface crushing theory, which provides basis for further research on the cutting mechanical model of single pick crossing the coal-rock interface. According to the analysis on the ampulitude domain, the phenomenon that force increment between the pick cutting rock and uniform coal seam linearly increases with the increase of compressive strength difference between coal seam and coal-rock interface, and the load fluctuation keep a positive correlation with the compressive strength. Analysis on the signals of the pick cutting coal seam with coal and rock interface at different conditions shows that some basic properties of the cutting load changes over times. In addition, the coal seam with coal-rock interface appears larger impact load and other time-domain characteristics.

Acoustic Signals Analysis Based on Empirical Mode Decomposition and Spectrum Analysis Technique

2010 ◽  
Vol 40-41 ◽  
pp. 91-95 ◽  
Author(s):  
Yan Li Zhang
Keyword(s):  
Empirical Mode Decomposition ◽  
High Frequency ◽  
Acoustic Signals ◽  
Intrinsic Mode Functions ◽  
Mode Decomposition ◽  
Analysis Technique ◽  
Marginal Spectrum ◽  
Rock Interface ◽  
Coal Rock ◽  
Instantaneous Energy

A method to analyze the acoustic signals collected in fully-mechanized caving face is presented in this paper. Through analyzing the marginal spectrum and frequency spectrum of intrinsic mode functions obtained by empirical mode decomposition, acoustic signals’ frequency and amplitude characteristics are gotten, that is, high frequency signals about 1000Hz ~2800Hz are produced when the top coal is combined with gangue. Furthermore, the acoustic signals’ instantaneous energy spectrums in the frequency range of 1000Hz ~2800Hz can be used to identify the coal-rock interface.

Application of Hilbert Marginal Spectrum to Coal-Rock Interface Recognition

2012 ◽  
Vol 569 ◽  
pp. 70-73 ◽  
Author(s):  
Bao Ping Wang ◽  
Zeng Cai Wang ◽  
Yong Juan Wang
Keyword(s):  
Waste Rock ◽  
New Method ◽  
Hydraulic Support ◽  
Marginal Spectrum ◽  
Rock Interface ◽  
Coal Rock ◽  
The Impact

In this paper, a new method based on Hilbert marginal spectrum is presented to solve the problem of coal-rock interface recognition in the top caving process. Coal or waste rock impinges against the tail beam of the hydraulic support. The impact causes the vibration of the tail beam. Because of different intrinsic characteristics, dissimilarities will exist between the two cases. The coal-rock interface is recognized by comparing the Hilbert marginal spectrum. The results show that the proposed method is a promising approach to identifying the coal-rock interface.

scholarly journals Theoretical Study and Numerical Simulation Research on the Effect of Coal-Rock Interface on Multistaged Fracturing in the Roof of Outburst Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Fan Zhang ◽  
Yang Tang
Keyword(s):  
Elastic Modulus ◽  
Coal Seam ◽  
Hydraulic Fracture ◽  
Mechanical Parameters ◽  
Multiple Fractures ◽  
Rock Stratum ◽  
Gas Drainage ◽  
Rock Interface ◽  
Coal Rock ◽  
Outburst Coal Seam

Multistaged fracturing in the roof of outburst coal seam is an efficient and creative technology for coalbed methane (CBM) drainage, which can effectively improve the permeability of coal seam. To reveal its mechanism of permeability enhancement, the effect of coal-rock interface on multistaged fracturing in the roof of outburst coal seam was simulated and discussed in this paper. Firstly, the lithological difference between outburst coal seam and roof was compared, and the concept and significance of multistaged fracturing in the roof of outburst coal seam were explained. Then, the mechanical conditions of multiple fractures in the roof traversing coal-rock interface were analyzed. The effects of mechanical parameters on multiple fractures were numerically simulated. The results indicated that fracturing borehole in adjacent rocks of outburst coal seam is much easier to drill and maintain gas drainage. Considering gas drainage efficiency and avoiding being blocked by coal fines, multistaged fracturing borehole is generally drilled in the stable rock stratum of roof. Whether the multiple fractures in the roof can traverse coal-rock interface is related to mechanical parameters of coal and rock, friction factor of coal-rock interface, angle between horizontal profile and coal-rock interface, cementing strength of coal-rock interface, minimum horizontal stress, and other factors. Higher fracturing fluid pressure contributes to propagating from the reservoir with low elastic modulus to the one with high elastic modulus for hydraulic fracture. Hydraulic fracture is more likely to propagate in the rock stratum with high brittleness index. The research results can improve multistaged fracturing theory and provide technological support for field test.

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