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Aiming at the problem that the gear failure of the cutting part of the shearer reduced the working efficiency of coal mining production and brought hidden dangers to production safety, taking the MG1000/2500-WD shearer as the research object, the gears of the cutting part of the shearer were analyzed, and the failure mechanism research, simulation analysis and experimental test research were carried out. Firstly, the overall structure of shearer was analyzed, and the common causes and mechanism of gear failure of shearer cutting part were analyzed. Then, the expression formulas of convolution layer, pooling layer and full connection layer of convolution neural network were summarized. The gear fault model of cutting section was constructed based on deep convolution neural network (D-CNN), and the algorithm flow of the model was studied. Finally, by selecting the training data set, the model was trained, and the gear faults of the cutting part were predicted and classified; combining with the performance evaluation index, the experimental results of different models were compared. The experimental results show that the prediction model based on deep learning method can effectively predict the gear fault of shearer cutting part. The gear fault recognition rate is about 98.71%. Under the same conditions, the D-CNN model achieves an accuracy rate of 98.78% and a recall rate of 98.88% for the normal state and fault state of the gear. The model has a more accurate identification rate of gear faults. It has high fault prediction and classification performance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Operators of opencast heavy earthmoving machinery (HEMM), during their 8-hour shift duration, are regularly succumbed to the high level of whole body vibration (WBV) amplitudes. Due to long and continuous working in the field, the operators of HEMM may yield to adverse health effects and results in hazardous conditions if the magnitudes repeatedly exceed the permissible limits. Based on extensive literature review, the authors of the paper put forward the recognized harmful adverse health effect of short and longterm WBV exposure of HEMM operators in surface mining and also with the same view with the findings of various researchers in this field and feels that for the safety of operators, long-term understanding of WBV should be carried out instead of short term vibration monitoring. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on the application of recycled tyre rubber, in the form of rubber dust, in mixtures bound with a hydraulic binder, to improve the physical and mechanical parameters of unburnt coalmining slates. In particular, the parameters related to resistance to water and susceptibility of bound mixtures. The research was carried out on mixtures containing unburnt coal-mining slate, rubber dust, fly ash and cement, as well as on reference mixtures with no rubber dust in their composition. The observations were aimed at checking how the varied content of rubber dust affects the physical and mechanical parameters of the samples. [ABSTRACT FROM AUTHOR]

Taking the MG2∗55/250-BWD shearer as the research object and considering the influence of the rock on the working performance of the shearer, the shearer-coal-rock coupled discrete element model was established and its dynamic working process has been studied. The single-factor analysis method was used to study the variation law of the cutting depth, traction speed, and the drum's rotational speed on the three-way force acting on the drum, the coal loading rate, and the trajectory of the coal particles. The simulation showed that the coal loading rate fluctuated during the start-up phase of the shearer, and it was then constant as the time increased. The value of the cutting resistance was the largest, the traction resistance was the second largest, the axial force was the smallest, and the fluctuation coefficient of the axial force was the largest of all of them. The research showed that the coal loading rate of the drum decreased with the increase of the cutting depth, increased with the increase of the rotating speed of the drum, and decreased with the increase of the traction speed. The three-way force of the drum increased with the increase of the traction speed, decreased with the increase of the drum's rotational speed, and increased with the increase of the cutting depth. According to the analysis of the coal cutting force and the coal loading rate, the drum could achieve high-efficiency cutting if the cutting depth, rotational speed, and traction speed of the dynamic were matched. [ABSTRACT FROM AUTHOR]

Coal seam that is thinner than a certain value is defined as thin coal seams (TCS). It commonly occurs in China as it covers 84.2% of the mining area. This situation is even severe in China’s large surface coal mines, in which TCS accounts for 10-50% of the total reserve. Most TCS cannot be feasibly mined due to the working conditions of commonly used mining equipment. A tremendous of resource is wasted due to the abandon of TCS as overburden waste. It also causes environmental problems. This paper investigated the current status of TCS mining in China, and compared different approaches to feasibly recovery this resource. The surface miner method has the potential and advantages to be applied to the mining of TCS, and a method to optimize its working condition is proposed. A case study was conducted, which shows, if correctly planned, a surface miner can recover most of the TCS reserve without delaying the main coal seam production. [ABSTRACT FROM AUTHOR]

This paper presents improvements to parts of the excavatorERc1470/30/7, resulting in: increasing the volume of annual mines by improving the time of intensive and extensive use, lower production costs, increased operational safety, improving the quality of the delivered production, reducing the excavator's weight by replacing some subassemblies having lower weight, low power consumption, optimization of excavation capacity, ensuring the ergonomic comfort of the excavator and protection of electrical and mechanical circuits. [ABSTRACT FROM AUTHOR]

The machine has expired lifetime and current physical condition is characterized by the existence of significant structural degradation which in turn can affect the functionality and safety of personnel working in this. It is estimated that an increase of about 8-9%, or a maximum of 10% of the torque moment, to be sustained by the current drive group, is necessary. It remains only the change of the belt drive group on the porthole wheel arm and / or the change of the drive drum, the cups, the frontloading transmission bunk. [ABSTRACT FROM AUTHOR]

This paper presents the technical state of the mechanism of translation of the coalmining machine after the technical expertise. The rehabilitation to which the translation mechanism will be subjected will be carried out by performing the intervention works that will bring back into the normal operating parameters both the structural part and the functional part. The paper presents: the proposed solutions for repair after verification of the translation mechanism and the way of repairing the mechanism. [ABSTRACT FROM AUTHOR]

This paper presents the technical state of the device for the alignment of a coal-mining machine after the technical expertise. The rehabilitation to which the control cabinet will be subjected will be carried out by performing the intervention works that will restore the normal operating parameters of both the structural part and the functional part. In the paper are presented: the means of verification of the device and the proposed technical solutions for the repair of the device. [ABSTRACT FROM AUTHOR]

In this paper we continue to present the technical state of the mast of a coal-mining machine, following technical expertise. The rehabilitation to which the mast will be subjected will be done by carrying out the intervention works which will restore in the normal operating parameters both the structural part and the functional part. [ABSTRACT FROM AUTHOR]

This paper presents the technical state of the mast of a coalmining machine, following technical expertise. The rehabilitation to which the mast will be subjected will be done by carrying out the intervention works which will restore in the normal operating parameters both the structural part and the functional part. [ABSTRACT FROM AUTHOR]

In this paper presents the technical state of the platform of uplift-descent the mechanism of the coal-mining machine, n following technical expertise. The rehabilitation to which will be subjected of the platform of uplift-descent the mechanism will be done by performing the intervention works which will restore in the normal operating parameters both the structural part and functional part. Also, in the paper are presented: the verification methods of the mechanism as well as the proposed technical solutions for the repair of the mechanism. [ABSTRACT FROM AUTHOR]

In this paper presents the technical state in which it is found in which is the mechanism of lifting ladder from the coal extraction machine, following technical expertise. Rehabilitation to which the lifting mechanism will be subjected of the ladder will be done through the execution of the intervention works which will return to normal operating parameters both the structural part and the functional part. In the work paper are presented: verification procedures of the mechanism as well as the technical solutions proposed to repair the mechanism. [ABSTRACT FROM AUTHOR]

This article establishes a causal effect of product market competition on vertical integration. I exploit a hitherto unexplored natural experiment in the U.S. coal mining industry and a unique mine-level organizational data set. Following an exogenous increase in product market competition, the incidence of vertical integration fell by 33% within the treatment group relative to the counterfactual. I find novel evidence that transition to the lower degree of vertical integration is driven by competition's reducing market prices by 32% which decreased the incentive to conduct vertical mergers. I discuss several possible interpretations of these changes. [ABSTRACT FROM AUTHOR]

Top-coal caving technology is a productive and efficient method in modern mechanized coal mining, the study of coal-rock recognition is key to realizing automation in comprehensive mechanized coal mining. In this paper we propose a new discriminant analysis framework for coal-rock recognition. In the framework, a data acquisition model with vibration and acoustic signals is designed and the caving dataset with 10 feature variables and three classes is got. And the perfect combination of feature variables can be automatically decided by using the multi-class F-score (MF-Score) feature selection. In terms of nonlinear mapping in real-world optimization problem, an effective minimum enclosing ball (MEB) algorithm plus Support vector machine (SVM) is proposed for rapid detection of coal-rock in the caving process. In particular, we illustrate how to construct MEB-SVM classifier in coal-rock recognition which exhibit inherently complex distribution data. The proposed method is examined on UCI data sets and the caving dataset, and compared with some new excellent SVM classifiers. We conduct experiments with accuracy and Friedman test for comparison of more classifiers over multiple on the UCI data sets. Experimental results demonstrate that the proposed algorithm has good robustness and generalization ability. The results of experiments on the caving dataset show the better performance which leads to a promising feature selection and multi-class recognition in coal-rock recognition. [ABSTRACT FROM AUTHOR]

A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate. [ABSTRACT FROM AUTHOR]

The application of cable bolts as a secondary support system is an increasing trend in underground coal mines worldwide. The performances of cable bolts have been evaluated under both axial and shear loading conditions. Two methods of testing cables for shear, single and double shear, have been recognised. This paper examines the shear behaviour of a variety of cable bolts under different pre-tension loads by double shear testing. Plain, spiral and the combination of both cable types were used in this study. The initial axial load and the type of cable bolts are the main factors affecting their shear strength. By increasing the axial pre-tension load, the peak shear load occurs at lower shear displacement. The failure angle due to cable bending across the joint at different pre-tension loads varied between 41° and 49°. This demonstrates that the ratio of axial and perpendicular displacements is almost constant and on average the failure occurs at about 45°. A novel analytical model is proposed to evaluate the shear behaviour of pre-tensioned fully grouted cable bolts subjected to double shearing. Energy and Fourier Series methods were incorporated in the model to simulate the shear behaviour of cable bolts. The comparison of the experimental results with the proposed model shows a good agreement. [ABSTRACT FROM AUTHOR]

Underground extraction of coal is characterized by high variability of mining and geological conditions in which it is conducted. Despite ever more effective methods and tools, used to identify the factors influencing this process, mining machinery, used in mining underground, work in difficult and not always foreseeable conditions, which means that these machines should be very universal and reliable. Additionally, a big competition, occurring on the coal market, causes that it is necessary to take action in order to reduce the cost of its production, for eg. by increasing the efficiency of utilization machines. To meet this objective it should be proceed with analysis presented in this paper. The analysis concerns to availability of utilization selected mining machinery, conducted using the model of OEE, which is a tool for quantitative estimate strategy TPM. In this article we considered the machines being part of the mechanized longwall complex and the basis of analysis was the data recording by the industrial automation system. Using this data set we evaluated the availability of studied machines and the structure of registered breaks in their work. The results should be an important source of information for maintenance staff and management of mining plants, needed to improve the economic efficiency of underground mining. [ABSTRACT FROM AUTHOR]

The hydraulic support is the key equipment of the residual coal stoping working face, which provides the safe working space and the wind circulation channel for the remining. Scienti?c mining of residual coal is on the basis of the optimization of hydraulic support structure and working resistance. The Hydraulic Support Optimization (HSO) is mainly in?uenced by geological factors, including seam thickness, dip angle, roof rock fracture structure, especially the Roof Caving Zone (RCZ) distribution. The contribution of this paper lies in HSO of 3101 residual coal sublevel caving face at Shenghua Mine, with the combination of physical simulations, theoretical analysis, and ?eldmeasurements. In?uenced by forward RCZ and sudden instability of coal pillars, the main roof across the caving areas fractured and caused rotary instability towards the goaf. The hinged roof structure of "long key blocks across the caving areas" was thus formed, which resulted in the mutagenic increase of support working resistance. Reasonable working resistance and structure of the support under such conditions were obtained, and the conduction of pre-grouting solidi?ed the roof in the caving area and reinforced the coal pillars, thus enhancing the bearing capacity. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Mining Sciences is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For large inclined angle coal face, the increasing coal seam dip angle and height of the hydraulic support, there is a tendency for toppling and downslide towards the work face and conveyor belt. Thus, in these cases it is vital to consider anti-skid measures for the hydraulic support and slip resistance of the conveyor, from the three machine equipment of hydraulic support, coal cutter and belt conveyor. In a fully mechanized coal face, the relationships among this set of equipment are based on a hydraulic support which must stands steadily to prevent conveyor belt slip, as a steady conveyor belt is essential to the coal cutter to form a reliable transportation channel. Considering these relationships, the measures of anti-skid and slip resistance at large inclined angle coal face are taken as factors in the design of the hydraulic support. [ABSTRACT FROM AUTHOR]

Technology UCG is worldwide presented as the technology with the lower adverse effect on the environment in comparison to all until now applied techniques of the underground and surface coal mining. The present paper deals with the pollution from the underground coal gasification in situ taking into the consideration the amounts of the gasified coal based on the samples from the simulated gasification and chemical analysis of tar. Pollution of rock surrounding can be caused by evasive gas, aromatic hydrocarbon, extractable non-polar substances and solid residues. During individual gasification, there are raising polluting gases as hydrocarbon, hydrosulphide, carbon disulfide, oxide nitrogen, mercaptans. Such gas compounds have high toxicity and significant stink. Some of the less qualitative sorts of coal obtain till 6 % of sulphur, that is oxidised during gasification and burning to the sulphur dioxide, and hydrosulfide is also rising. By not perfect coal burning, there are also raising polyaromatic hydrocarbons (PAH), many of them are toxic, or they have mutagenic effects. The question is how these tars will affect the underground and surface water in the area which has been encumbered with the mining and chemical industry for a longer period. [ABSTRACT FROM AUTHOR]

Hard coal mining is characterised by the complexity and specificity of problems related to the use of machines. These problems, which occur at the stage of design, construction and production of machines, build up when the machines are being used. The process of most effective hard coal mining is considerably influenced by reliable mining machines. Every downtime due to a failure translates into the effectiveness of the whole mining process. For this reason the mining industry is searching for new methods and tools which would allow it to improve the production (mining) process in a hard coal mine. The article presents one of the quality management tools used in various industry branches - a Pareto chart, by means of which downtimes in the work of cutter-loaders has been analysed. This tool allowed classifying the causes of particular failures as well as showing which of them are the most significant and which should be removed first. [ABSTRACT FROM AUTHOR]

The ecological state of soils as a component of technogenic and industrial systems has been characterized in the impact zone of mine terricones of empty coal-mining rocks. The results of analytical works showed the regional features of lithostrats and soils: the increased total content of hexavalent chromium (700 maximum permissible concentration (MPC) or more) and trivalent iron (18000 mg/kg or more). This is due to the relationship between the geochemical background of the area and natural technogenic factors under the conditions of monsoon climate promoting acidogenesis development. [ABSTRACT FROM AUTHOR]

Opencast coal mining is an anthropogenic activity that changes the antecedent soil profile, including its physical, chemical and biological properties. The compaction resulting from large machinery can have a substantial effect on the reconstructed soil pore structure in opencast coal-mine dumps, thus it was important to reconstruct a suitable soil pore structure for vegetation growth during land reclamation endeavours. To better quantify the characterization of reconstructed soils in opencast coal-mine dumps, high-resolution and lossless computed tomography (CT) images were used to study the effect of dumping and land reclamation on the soil pore structure by scanning soils from the Antaibao Opencast Coal-mine in the Pingshuo mining area. The soils were taken from an undisturbed area and the dump platform using a loess parent material covering with different reclamation time. Photoshop and ArcGIS software were used to process the scanned images and conduct statistical analysis, and multi-fractal theory was used to analyse the distribution characteristics of soil pores. The multi-fractal method can quantify the distribution characterization of the reconstructed soils based on CT images, and multi-fractal parameters, e.g., D (0), D (1), D (0)– D (1), Δα and Δf , can reflect the heterogeneity of different aspects of the soil pore distribution. Mining and dumping activities significantly affected the pore distribution of reconstructed soils; however land reclamation can be used to develop the soil pore distribution of reconstructed soils. [ABSTRACT FROM AUTHOR]

It is imperative to have an in-depth understanding of the change in methyl and methylene groups during low-temperature oxidation of coal not only for detecting and preventing coal spontaneous combustion in coal mining industry and for reducing emissions of hazardous gases. The Fourier transform infrared (FTIR) spectroscopy equipped with in-situ reactor cell was introduced to investigate the change in the methyl and methylene groups of different classes of coals (lignite, sub-bituminous and bituminous) during their low-temperature oxidation at temperatures below 230 °C. The reaction kinetics of the methyl and methylene groups was obtained from the real-time measurements of the change in aliphatic hydrocarbon content in coal matrix. These results clearly show that the low-temperature oxidation of coal can be separated into three stages with respect to the activation energies for the change in methyl or methylene groups, which indicates that the reaction regime for the change in methyl or methylene occurrence switches during the spontaneous combustion of coal. At the first and second stages the reaction activation energies of the methyl or methylene groups showed significant difference for the three types of coal, and at the third stage the activation energies were very close for all of the coals. These results indicate that the spontaneous combustion propensity of coals can be evaluated on the basis of the kinetic parameters at the first and second stages. Furthermore, the relationship between the changes in methyl and methylene groups and the emission of carbon oxides (CO 2 and CO) was also explored on the basis of the experimental findings. [ABSTRACT FROM AUTHOR]

Cutting arms are the main productive units of coal shearer machine that contact directly with coal seam. More importantly, the cutting arms operate under a high-stressed environment. In this paper, in order to suggest an optimum maintenance plan for the subsystem of shearer machine, firstly, we conducted a failure and reliability analysis using the data acquired from the Parvade coal mine, Iran over the two years. The analysis shows that the Power Law Process model provides a good fit to the failure data. Also, we applied estimated distribution functions and calculated cost parameters to identify the cost-based optimum preventive maintenance interval. Furthermore, we conducted a sensitivity analysis of the studied machine and identified that if we consider the variation of the world price of the raw coal then the maintenance plan is sensitive to the price. The analysis showed that, big changes in world price of raw coal are not so effective on maintenance plan but have a considerable effect on maintenance costs of the cutting arms of the shearer machine. However, the effects of this change on reliability improvement are almost zero. [ABSTRACT FROM PUBLISHER]

Objective: In this simulator-based study, we aimed to quantify performance differences between joystick steering systems using first-order and second-order control, which are used in underground coal mining shuttle cars. In addition, we conducted an exploratory analysis of how users of the more difficult, secondorder system changed their behavior over time. Background: Evidence from the visuomotor control literature suggests that higher-order control devices are not intuitive, which could pose a significant risk to underground mine personnel, equipment, and infrastructure. Method: Thirty-six naive participants were randomly assigned to first- and second-order conditions and completed three experimental trials comprising sequences of 90° turns in a virtual underground mine environment, with velocity held constant at 9 km/h–1. Performance measures were lateral deviation, steering angle variability, high-frequency steering content, joystick activity, and cumulative time in collision with the virtual mine wall. Results: The second-order control group exhibited significantly poorer performance for all outcome measures. In addition, a series of correlation analyses revealed that changes in strategy were evident in the second-order group but not the first-order group. Conclusion: Results were consistent with previous literature indicating poorer performance with higherorder control devices and caution against the adoption of the second-order joystick system for underground shuttle cars. [ABSTRACT FROM AUTHOR]

Considering the specific working conditions of the machines and devices used in coal mining, the selection and exploitation method which takes into account changes of these conditions during the machine's work, is very important. Presented here is the overhaul process of the main fan used for ventilating the mining excavation sites and the innovative solutions applied in the process. The overhaul processes before and after implementing an innovative solution have been compared and the resulting benefits for the company have been pointed out. [ABSTRACT FROM AUTHOR]

The use of link chains became the decisive success factor in the mechanisation of coal mining in longwall face working. The development of chain technology in recent decades has been characterised by the rapid development of larger chains with more and more compactness and complex geometries. This article discusses potential further steps in development and the limitations of conventional chain technology. The objective of development is to increase conveyor capacity while at the same time improving operational safety. The conveyor capacity is limited by the actual loading cross section achievable and the chain's speed; both these parameters cannot be increased at will. Research relating to the fatigue strength of chains and the management of the required pre-tension force/slack of return chain indicates that, from the perspective of chain technology, longer longwall mining faces are possible than are mined today. Der Einsatz von Gliederketten wurde bei der Mechanisierung der Gewinnung von Kohle im Strebbau zum entscheidenden Erfolgsfaktor. Die Entwicklung der Kettentechnik in den letzten Jahrzehnten ist gekennzeichnet durch eine rasante Entwicklung größerer Ketten mit immer kompakteren und komplexeren Geometrien. Der vorliegende Beitrag diskutiert mögliche weitere Entwicklungsschritte und die Grenzen der konventionellen Kettentechnik. Ein Ziel der Entwicklungsbemühungen ist die Erhöhung der Förderkapazitäten bei gleichzeitiger Steigerung der Betriebssicherheit. Die Förderkapazität ist durch den tatsächlich realisierbaren Beladungsquerschnitt und die Kettengeschwindigkeit begrenzt; beide sind nicht beliebig zu erhöhen. Untersuchungen zu der Auslegung über die Zeitfestigkeit von Ketten und über die Beherrschung der erforderlichen Vorspannkräfte bzw. Hängkette zeigen, dass aus der Perspektive der Kettentechnik größere Streblängen als bisher möglich sind. [ABSTRACT FROM AUTHOR]

To realize dynamic positioning of the shearer, a new method based on SINS/WSN is studied in this paper. Firstly, the shearer movement model is built and running regularity of the shearer in coal mining face has been mastered. Secondly, as external calibration of SINS using GPS is infeasible in enclosed underground mine, WSN positioning strategy is proposed to eliminate accumulative error produced by SINS; then the corresponding coupling model is established. Finally, positioning performance is analyzed by simulation and experiment. Results show that attitude angle and position of the shearer can be real-timely tracked by integrated positioning strategy based on SINS/WSN, and positioning precision meet the demand of actual working condition. [ABSTRACT FROM AUTHOR]

Copyright of Mining Report is the property of GVSt,GesamtverbandSteinkohlee.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In China, coal seams are divided in accordance with the degree of their inclination and called the almost fiat seam, the gently inclined seam, the inclined seam and the steeply inclined seam with inclination angles smaller than 8°, ranging from 8° to 25°, ranging from 25° to 45° and greater than 45° respectively. According to their thickness, coal seams can also be divided into thin, thin-to-thick and thick ones with the thicknesses of being less than 1.3 m, 1.3-3.5 m and 3.5m respectively. In recent years, with coal working increasingly mechanized, especially with the successful development of the apparatus for working in steeply inclined seams, the development of mechanized working technology is prompted for the comprehensively mechanized working in steeply inclined seams. In this aspect, the Hongling Coal Mine in Shenyang, and the Lvshuidong Coal Mine in Huayingshan are pioneers in opening comprehensively mechanized working face in steeply inclined coal seams. The Tangshan Coal Mine in Kailuan and the Zhangshuanglou Coal Mine in Xuzhou have made great achievements in opening comprehensively mechanized working faces in steeply inclined coal seams. All this points to the fact that it is mature to apply the long wall mechanized working technology in coal seams with the inclination angle smaller than 35 degrees. In addition, experiments have been successfully conducted trying to apply comprehensively mechanized working technology in coal seams with inclination angles ranging from 35 to 45 degrees. However, the key technology fails the application of the comprehensively mechanized working technology in the seams with an inclination angle greater than 45 degrees. Against the above-mentioned background, the present paper aims at introducing our recent researches on the possible application of comprehensively mechanized technology and techniques in coal seams with an inclination angle greater than 45 degrees in Huainan mining area. Rich in coal reserves, Huainan and Huaibei mining areas are the largest and the last remaining mining area in East China, with the identified coal reserves amounting to 22.69 billion tonnes, of which the reserves with an inclination angle greater than 45 degrees amount to 0.913 billion tonnes. The reserves are mainly distributed under the ground in areas where Xizhuangzi, Pansan, Lizuizi, Panbei, Xijier and Xijisan mines are located. Our project consists of researches on the application of the hydraulic support, the shearer and conveyor in coal seams with an inclination angles ranging from 35 to 72 degrees with the maximum being 72 degrees, an inclination angle for the remaining coal seams locally found in the 3232(3) working face in Lizuizi mine after the preliminary working. The comprehensively mechanized long-wall working technology under study can appropriately applied in coal seams of 2.2- 3.5 m in height, with the average working height of 2.8-3.0 m. Aiming at finding a solution to the working problems encountered in the steeply inclined coal seams in Huainan mining area, our research is characterized by the innovative application of comprehensively mechanized working technology in steeply inclined coal seams, with safe production and efficient working ensured. After a short period of trial application, the integrated apparatus and technology are now applied in 6 working faces located in 4 coal mines in Huainan and Huaibei mining areas, and what we have done can be regarded as a technological invention for coal working which will ensure the safe and efficient working in East China with an annual production capacity amounting to 100 million tonnes. [ABSTRACT FROM AUTHOR]

This paper aims at studying the maintenance of machine type T2052 used for taking the coal in Turceni power station's coalyard. After a brief presentation of the machine construction is analysed its functionality, by highlighting the frequency of continuously failures, the sub-assemblies which go to accidental down-time through failure. Analysis shows that the superstructure's rotating system is most commonly exposed to damage. The maintenance study of this system shows that it is necessary to adopt preventivemaintenance strategy planned in order to avoid the occurrence of defects [ABSTRACT FROM AUTHOR]

This article discusses the changes in the coal industry in the U.S. as of 2005. There is a prominent number of people who showed up when coal companies had their first job fairs in 2004. Furthermore, community colleges in the Virginia area that five years ago could not find enough students who wanted to take mining certification or safety classes are increasing their programs. However, hiring qualified employees who understand how to work the equipment's modern technology has proved more difficult than finding applicants to fill the openings for entry-level positions.