·The longwall top coal caving LTCC production method applied by forming a face in the horizontal thickness of the seam and also called horizontal section top coal caving especially in studies originating from China is widely used in the production of inclined and thick coal seams In this production method in addition to the top coal
·Learn techniques for creating tonal values textures and expressive effects using charcoal Start making captivating charcoal drawings Free Online Art Lessons at Artvilla Theory HOW TO DRAW DOCTOR STRANGE WITH GRID METHOD ON GRAPHITE AND CHARCOAL PENCIL Realistic Drawing2022
An alternative way for proximate analysis is spectral analysis in combination with various machine learning methods However most previous works analyze individual characteristics and fail to explore the relationship among them The proposed MOA Unet is compared with classical chemometric methods on 670 coal samples from on site test The
·The results show that the MICES of the coal gangue recognition model established based on the TI‐CNN structure and the data input of a single position sensor is the highest while the sensor position has little effect on the recognition results The problems of insufficient recognition accuracy poor real‐time performance and lack of consideration of
Use the subtractive drawing method to remove highlights with an eraser and refine details with a charcoal pencil as the drawing progresses Create a cityscape with contrasting values To create hard lines and precision get a hard charcoal pencil Choose a cityscape that s familiar to you or find a photo reference of a city you ve always
·Evolution Phase In situ stress is the dominant cause of an outburst After the start of the mining operations the load in the mining field is transferred to the coal wall and the in situ stress gradient of the coal wall increases and concentrates raising the gas pressure In addition changes in the ground stress affect the internal structure of the coal seam alter the
·The results show that the MICES of the coal gangue recognition model established based on the TI‐CNN structure and the data input of a single position sensor is the highest while the sensor position has little effect on the recognition results The problems of insufficient recognition accuracy poor real‐time performance and lack of consideration of
·The classification of coal bursting liability CBL is essential for the mitigation and management of coal bursts in mining operations This study establishes an index system for CBL
·The longwall top coal caving LTCC production method applied by forming a face in the horizontal thickness of the seam and also called horizontal section top coal caving especially in studies originating from China is widely used in the production of inclined and thick coal this production method in addition to the top coal losses that occur behind the
·Therefore this paper establishes deep learning based RGB image classification models for the classification tasks of various coal particles with two density level < g/cm 3 & > g/cm 3 in different water gradients and analyzes their classification performance Moreover the model operational process and the change of classification
·Classication of coal bursting liability of some chinese coals using machine learning methods Chao Wang1 Yv Liu1 Yuefeng Li2 Xiaofei Liu3 & Qiwei Wang1
·The easiest way to begin drawing with charcoal is to identify the basic shapes and outline them lightly in your drawing If you are drawing a subject make sure to sketch the entire figure or scene before moving on to individual details For example if you are drawing a face start with a circular or square shaped outline
·In the laboratory top coal drawing experiments the marker method can provide sufficient accuracy in calculating the top coal recovery ratio The results of the marker method supported the field test results using the top coal tracking devices The top coal tracking devices being based on the radio frequency RF technique was designed to
·Using longwall top coal caving LTCC in an extra thick seam many problems appear such as large broken top coal blocks frequent arch formation in the drawing process poor balance of drawing top coal and low top coal recovery which seriously affect safe efficient and green mining In this study the size distribution of top coal blocks was measured in LTCC
·Evolution Phase In situ stress is the dominant cause of an outburst After the start of the mining operations the load in the mining field is transferred to the coal wall and the in situ stress gradient of the coal wall increases and concentrates raising the gas pressure In addition changes in the ground stress affect the internal structure of the coal seam alter the
·In order to investigate top coal drawing regularity and automated top coal caving technology in extra thick coal seams an approach coupling the particle element and the block element is presented based on the continuum discontinuum element method CDEM Then the constitutive model of hydraulic support is introduced into the CDEM to simulate the top coal
·of top coal arches in the drawing process and performed the countermeasures against the arches and technology path of in telligent mining to improve the recovery in extra thick seams In addition Zhang et al 2020 proposed a three round unequal time top coal drawing method and optimized the automated top coal drawing techniques in extra
·Coal pores are the locations of coalbed methane occurrence and enrichment and the main storage space targeted in CO2 sequestration The systematic investigation of the coal pore structure and its
·The size distribution of granular top coal holds great influence on the drawing mechanism in longwall top coal caving LTCC panel In this paper based on the data observed from the Ruilong mine in Shanxi province China the effect of the size distribution of granular top coal on the drawing mechanism was investigated using theoretical analysis 3D physical
·The performance of different methods was benchmarked with a linear signal/noise discriminator which was based on two features extracted from the waveform They used 3 s long waveform snippets to train DCNN and GANRF The results demonstrated that all machine learning methods outperform the linear classifier
·Longwall top coal caving LTCC mining technology is a productive and economical method to extract thick coal seams and thus is widely used in many coal mines in China Wang 2009 Wang et al 2014 Although some hypotheses on top coal drawing process were proposed Wang and Fu 2002 Wang et al 2004 Wang et al 2010 Wang et al
·For a genuine and thorough interpretation of coal mining impacts it is quite important to understand the direct as well as the far reaching environmental and social consequences of coal mining
·A particle element approach based on continuum discontinuum element method CDEM is applied to optimize the automated top coal drawing techniques in extra thick coal seams
·The ML includes a subset of the deep learning DL technique which uses artificial neural networks to learn and analyze data [11] This paper reviews the operation of the ML as a fire safety level analyzer and indicator at the fire formation stages for implementing this method in coal mines of the Russian Federation and China
·A coal mine in the central district of Botswana is experiencing premature failure of conical picks which mine 150 350 tons of coal/ pick rather than 400 tons/pick specification
