The study of coal mine equipment’s comprehensive evaluation index system and evaluation method

1 Limitations of current evaluation index system of coal mine equipment While the operating mechanism of coal enter-prise changes, the equipment management’s state isimproved constantly. But the enterprises’ equipmentmanagement developed unevenly, presenting a trendof polarization. Some listing coal enterprises that havegood mechanism and bent on making progress reformand innovate constantly. They have formed the man-agement mode of equipment with their own charac-teristics. But the effect …     

The study of coal mine equipment＇s comprehensive evaluation index system and evaluation method

Equipment management is one of the important parts of business administration of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index system. Based on the analysis of the equipment evaluation measures of reform and the applications, the paper built up a comprehensive and effective evaluation index system of coal mine equipment, and improved the evaluation method with the use of fuzzy theory, analytic hierarchy process and entropy method.     

The research of the evaluation system for the sealability of hydraulic supports and jacks’ seals

In order to enhance the sealing quality and assemble efficiency of hydraulic supports, the evaluation system for the sealability of the hydraulic support and jack’s seals was established through the testing and experimenting technology in respects, such as seals’ dimensions, reasonable amounts of compression, sealability, life, resistance to pressure, etc. Through life detecting test of the seal, found the longest life seal ring under the same conditions, and through the reciprocating test of the hydraulic support, found the most appropriate amount of interference between the groove and the seal ring, thus, to decrease the leakage and extend the life span of the hydraulic support.     

Major Tasks of the Ministry’s Department of Planning and Development for 1996

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Quality evaluation and control of impregnated dia-mond bit

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A heuristic approach for in-pit crusher and conveyor system’s time and location problem in large open-pit mining

Cost efficiency and high reliability of In-Pit Crushing and Conveying (IPCC) system make it more appealing to be used in deeper open-pit mining activities. Determination of the optimum time and location (OT–OL) for applying the IPCC system were always a challenge. Application of mathematical programming approaches suffers from reduced computational efficiency due to a lot of decision variables. The situation will be worse; by adding the IPCC’s time and location variables to these models. Also, the problem involves a lot of variables that each one of them is a function of others. To tackle these, this paper provides a new heuristic approach to find a good quality solution hierarchically (here in two levels). The problem was broken into two parts (i.e. OT and OL). The model works in a discrete time horizon. It has been verified by the data gathered from Sungun copper mine of Iran. Our computational results show that the system is efficient for developed countries with a stable and low interest rate.     

The research analysis and application of stability of ventilation system

The stability of ventilation system includes stabilities of branch, network and main fan. The ventilation system is a dynamic process. The parameters in the ventilation system vary with time. In the paper, a group of mathematical models of quantitative analysis are set up, and the mathematical models are suitable to any ventilation system.     

Formation of tension and delamination areas in a long excavation’s roof

The article discusses assessment of geomechanical state and behavior of roof rocks in a long excavation as the production heading is advanced. Initial conditions and propagation of growth conditions of delamination fractures have been found, including dynamic regime.     

Analysis on evaluation ability of nonlinear safety assessment model of coal mines based on artificial neural network

Based on the integration analysis of goods and shortcomings of various methods used in safety assessment of coal mines, combining nonlinear feature of mine safety sub-system, this paper establishes the neural network assessment model of mine safety, analyzes the ability of artificial neural network to evaluate mine safety state, and lays the theoretical foundation of artificial neural network using in the systematic optimization of mine safety assessment and getting reasonable accurate safety assessment result.     

Comprehensive evaluation and study on material consumption of coal machinery

Based on fuzzy mathematics, comprehensive comparisons among four kinds of materials for manufacturing shearer bits were made in six aspects which are respectively hardness, tensile strength, impact toughness, relative wearability, relative lifespan and relative cost. Material 4 is preferred to be the targeted choice for manufacturing bits with superior comprehensive and economic performances.     

Causes of Decreased Discharge and Damage to a Dewatering Well’s Gravel Coat

Drainage wells used in lignite mining have to be operated at high efficiency in order to achieve a targeted drawdown in the shortest time period possible. However, oversizing of pump units and excessive pumping can cause accelerated aging of wells and over time, decrease a well’s drainage efficiency. This article analyzes the case of a well that was operated for 10 years and then abandoned at a lignite mine. A common practice in installing dewatering wells in Poland is to protect the well screen with a pre-fabricated granular layer (called a “gravel coat”) that is attached to the screen when it is lowered into the hole. The combination of the gravel coat and well screen is surrounded by a protective gravel pack. Samples of the gravel coat were obtained from the abandoned well. The percentage by weight of precipitates in, and the porosity of the gravel coat from the abandoned well were determined and compared with the properties of new gravel coat material. Tests were conducted in the laboratory to compare hydraulic losses, apparent seepage velocity, effective velocity, and the hydraulic efficiency of the well’s gravel coat. The results of the tests explain the low hydraulic efficiency of the abandoned well and the origin of the damage to the gravel coat. The actual yield was also compared with the calculated theoretical safe yield, which was estimated based on the results of geological records from the construction of the well.     

Origination and development mechanics of the Earth’s morphostructures. Part I: Etiology and evolution of the Patomsky crater

The author suggests a dilatancy-explosion model to explain the nature of the shape- and structure-peculiar crater revealed in the avolcanic Patomsky highlands in the East Siberia. The model rests upon laboratory experiments and estimates of the present author and other researchers, as well as the known facts from volcanology. It is substantiated that origination of the discussed crater is associated with hydrogen degassing and dilatancy-induced channel formation in the Earth’s interior for fluids to elevate up to the ground surface. The mechanisms of the channel formation, fluid flow and fluid mixing with air have been analyzed, which allowed a conclusion that these processes led to explosion of the air and gas mixture, and initiation of a ring structure. The ring structure mechanism is described, the pressure in the channel by the moment of the explosion is estimated, the crater-damaged area healing is described, and the healing aftereffects are discussed. The article ends with generalizations on the topic.     

The white paper Situation and Policies of China’s Rare Earth Industry press conference

This article is translated from the Chinese version sourced from the website of China’s Information Office of the State Council.Should there be any inconsistencies between Chinese and English versions,the Chinese version shall prevail. China’s Information Office of the State Council held a press conference on June 20 to issue a white paper on the country’s rare earth minerals and     

Study on the rights and interests value of mineral resources and its evaluation method

The rights and interests value of mineral resources includes the prospecting rights value and the mining rights value. The mining rights value is made up of the mineral resources value and the compensation value based on the in puts of capitals and labors indifferent exploration stage, the prospecting rights value should be equal to exploration differential rent of resources. According to the stage characteristic of mineral resources exploration and development, the initial evaluating methods and models are used to evaluate the prospecting rights and mining rights value.     

The environment of coal mining areas and the economic evaluation of the land reclamation

The environment impact of the coal resources mining was analyzed. The method of economic evaluation for the coal mining was established to analyze land destruction. The opportunity cost method was used to quantitatively analyze and estimate the economic loss of the land destruction by coal mining. At the same time, the dump land reclamation of the Yuanbaoshan. Open Pit was taken as an example to evaluate environmental and economical benefit with the method of economic evaluation for the coal mining areas land reclamation.     

Analysis for interaction of supports and surrounding rock of gateways in Iongwall minging

Gateway supporting in long-wall mining has been a problem that restricts the mine production and safety, the paper sets up an interaction model between support and surrounding rock ( rock mass structure) and probes the elementary t.heory about ground pressure behaviors of gateway. Based on the analysis of supporting theories, some new viewpoints about gateways supporting and ground pressure controlling are put forward.     

Research of prediction for mine earthquake basing on underground rock’s movement and deformation mechanism

Movement and deformation of underground rock include vertical dislocation and horizontal deformation, and the energy released by mine earthquake can be calculated basing on deformation energy. So put forwards the prediction for degree and spread of mine earthquake according to the underground rock’s movement and deformation. The actual number of times and spread of mine earthquake on site were greatly identical to the prediction. The practice proves the possibility of prediction for mine earthquake basing on the analysis of underground rock’s movement and deformation, and sets up new approach of mine earthquake prediction. Supported by the Education Research Project of Liaoning (20060388); Liaoning Technology University Project (06A07)     

The Effects of Caving of a Coal Mine’s Immediate Roof on Floor Strata Failure and Water Inrush

Large scale roof strata caving that occurs during coal extraction can irreversibly damage floor strata and result in riskier mining operations. Four research models incorporating floor water pressure were assessed for floor strata failure, using eight methods and two classification systems. A connection between floor strata failure and the coefficient of impact risk was developed. The derived equations represent a potentially effective method for providing a preliminary assessment of the risks associated with floor strata failure due to caving. A classification system of floor failure potential can be constructed to minimize risks during mining.     

Hubbert’s theory and the ultimate coal production in temrs of the Kuznetsk Coal Basin

The paper addresses Hubbert’s theory and its applicability to coal production dynamics in terms of the Kuznetsk Coal Basin (Kuzbass). The authors describe and validate the evaluation procedure for ultimate coal production using the lag modeling and the law of ultimate mineral mining efficiency decline, and present preliminary estimates of the ultimate coal production in Kuzbass based on the maximum NPV criterion in the dynamical unconstrained optimization problem.     

Integral evaluation of operating quality and the deciding of management strategy in productive coal mines

According to overall mean square root of weighted deviation, presented an evaluation model of “geology-technique-social conditions“ with a significant index system for the estimation of operating quality in productive coal mines. In the given example, the evaluation result is used to decide management strategy of coal mine, which plays a guiding role in the production.