Developing coal burst propensity index method for Australian coal mines

Coal burst is the violent failure of overstressed coal, and it is often accompanied by sound, coal ejection and seismic events. It is subsequently recognized as a serious safety risk of Australia after double fatalities coal burst happened at Austar Coal Mine. Considering the increasing trend of coal burst severity and frequency with mining depth, it is an urgent task to develop the coal burst risk assessment methods for Australia underground coal mines. Coal burst propensity index method is a widely used method of burst risk evaluation of coal as it is summed up from the coal burst research and practice of many countries.This paper presents the experimental and theoretical research of coal burst propensity index method for coal burst risk assessment in Australia. The definition of four indexes including elastic strain energy index(W_(ET)), bursting energy index(K_E), dynamic failure time(DT) and uniaxial compression strength(RC)is introduced in the first part. Then, the standard laboratory test process and test parameter of coal burst propensity index is presented. DT test is conducted with 0.3 mm/min displacement control loading rate while other test is with 0.5 mm/min. Besides, modified data processing and risk classification method of test are proposed. Differentiate analysis of stress-strain curve is adopted in the data processing of DT and KEindex. A four level risk classification form of burst risk is recommended for Australian underground coal mines. Finally, two likely improvement methods of W_(ET) test, including volumetric strain indicator method and theoretical calculation method, are discussed.     

基于计量经济模型的国内外能源价格关系研究

中国经济现面临着很多的制约因素,能源问题是关系中国经济可持续发展的重中之重。目前中国的能源行业存在许多问题,但最终都可以归结为能源价格问题。在经济全球化的背景下,为确定合理的能源价格体系与机制,需要对国内外能源价格的关系进行深入研究。采用Granger因果模型、协整检验、误差修正模型、脉冲响应等计量经济学方法,研究国内外典型市场的石油、煤炭、电力、天然气四种主要能源价格关系。通过分析得出国内原油与成品油价格由国际原油与成品油价格决定;典型能源市场成熟的国家原油价格与天然气交易中心价格共同影响成品油与煤炭价格,进而间接影响终端用户电价与终端用户气价;国际煤炭价格是成品油价格的单向格兰杰原因,澳大利亚煤炭价格是全球煤炭市场的核心。     

AHP在选择项目承包商中的应用

层次分析法(AHP)已经被发现广泛应用于多层系统中涉及多准则的决策制订问题,采用AHP方法来选择项目承包商,为评估准则和希望投标的承包商构建了一个层次结构,提出了分析模型和计算方法,并给出了一个具体实例．通过应用AHP,能够优先考虑判断准则,由此得到承包商逆序排列,从而选择最好的承包商来承包该项目．该方法为减少人为因素的影响、增强决策的客观性和科学性提供了一种有效途径．     

Assessment of energy release mechanisms contributing to coal burst

Coal burst is a dynamic release of energy within the rock(or coal) mass leading to high velocity expulsion of the broken/failed material into mine openings. This phenomenon has been recognised as one of the most catastrophic failures associated with the coal mining industry, which can often lead to injuries and fatalities of miners as well as significant production losses. This paper aims to examine the mechanisms contributing to coal burst occurrence, with an emphasis on the energy release concept. In this study, a numerical modelling study has been conducted to evaluate the roles and contributions of difference energy components. The energy analysis presented in this paper can help to improve the understanding of energy release mechanisms especially under Australian conditions.     

Integration of real options into short-term mine planning and production scheduling

Commodity prices have fallen sharply due to the global financial crisis. This has adversely affected the viability of some mining projects, including leading to the possibility of bankruptcy for some companies. These price falls reflect uncertainties and risks associated with mining projects. In recent years, much work has been published related to the application of real options pric-ing theory to value life-of-mine plans in response to long term financial uncertainty and risk. However, there are uncertainties and risks associated with medium/short-term mining operations. Real options theory can also be applied to tactical decisions involving uncertainties and risks. This paper will investigate the application of real options in the mining industry and present a methodology developed at University of Queensland, Australia, for integrating real options into medium/short-term mine planning and produc-tion scheduling. A case study will demonstrate the validity and usefulness of the methodology and techniques developed.     

Discussion on determination of gas content of coal and uncertainties of measurement

Gas content of coal is mostly determined using a direct method, particularly in coal mining where mine safety is of paramount importance. Direct method consists of measuring directly the volume of gas desorbed from coal in several steps, from solid then crushed coal. In mixed gas conditions the composition of the desorbed gas is also measured to account for contribution of various coal seam gas in the mix. The determination of gas content using the direct method is associated with errors of measurement of volume of gas but also the errors associated with measurement of composition of the desorbed gas. These errors lead to uncertainties in reporting the gas content and composition of in-situ seam gas. This paper discusses the current direct method practised in Australia and potential errors and uncertainty associated with this method. Generic methods of estimate of uncertainties are also developed and are to be included in reporting gas content of coal. A method of direct measurement of remaining gas in coal following the completion of standard gas content testing is also presented. The new method would allow the determination of volume of almost all gas in coal and therefore the value of total gas content. This method is being considered to be integrated into a new standard for gas content testing.     

基于业务外包的设备维护承包商评价模型

为了提高设备维护外包收益，降低设备维护外包的风险。从外包战略考虑．企业必须选择一个最优的设备维护承包商．本文建立了设备维护承包商的评价体系，提出了以承包商能提供的设备维护价格、质量、时间、服务和环保5个指标作为设备维护承包商的评价准则，并建立了5个准则层下的相应指标层．同时结合多专家评价差异的考虑，建立了企业设备维护承包商的改进层次分析法（A—AHP：Advanced Analytic Hierarchy Process）决策模型，然后根据该模型进行设备维护承包商的选择．该决策模型为减少人为因素的影响、增强决策的客观性和科学性提供了一种有效途径．     

浅议工程造价

目前流行的计价方法———单价法存在不合理性 ,只有改革旧的造价管理体制 ,建立起以市场竞争形成价格为主的价格机制和与之配套的计价办法 ,才能合理确定工程造价 ,促使投资者和承包方自觉地接受并执行国家政策 ,从而为真正实现建设产品的商品化创造条件。     

基于联合确定基数法的激励合同设计

提出一种基于联合确定基数法的激励合同模型,用以解决业主和承包商在合同谈判时的信息不对称问题.理论推导证明,在此合同框架下,承包商不仅会节约建造成本,且会在合同谈判中提出与实际成本相近的报价.通过实验探索承包商在风险环境下的报价行为,结果表明,在有较大期望获益且存在损失可能时,承包商的风险态度最易偏于冒险,而通过适当报价就能获得正向收益时,承包商的风险态度最为保守.讨论该结论在工程管理实践中的现实意义.     

建设工程代建单位的评价和选择研究

工程代建制在我国发展多年,但一直未建立相对合理的代建单位选择指标体系。文章根据我国目前各省份代建单位选择标准,借鉴FIDIC合同条款中关于承包商选择的经验,构建了建设工程代建单位的选择模型,并对其指标体系的合理性进行验证。实践证明,利用该指标体系可提高业主选择合适的代建单位的效率。     

油田承包商HSE管理存在的问题及对策

要使油田承包商管理收到好的效果,油田机关部门和单位统一要求管理、统一标准考核是基础;深化承包商管理,提升承包商现场管理水平是关键;强化承包商员工HSE意识和技能是途径。只有这样,才能在真正意义上提升承包商HSE管理水平。在具体实践中,要进一步明确工作职责,强化监管责任,加强安全培训教育,加大考核和处罚力度,改进承包商H...     

淮南矿区安全高效绿色开采技术研究与工程实践

分析了淮南矿区煤炭主业开采技术变革历程及安全生产技术现状,研究了安全高效绿色开采技术,开展了管理转型,带动了煤炭相关产业同步发展,建设了新型矿区.     

Characteristics and dominant controlling factors of gas outburst in Huaibei coalfield and its countermeasures

In order to master the main characteristics and controlling factors of gas disasters in Huaibei coalfield, based on data analysis, experimental determination and theoretical research, we analyzed the geological evolution and gas parameters in Huaibei mining area. The results show that Huaibei coalfield is located in Xu-Su arcuate tectonic circle, and the coal seam and gas occurrence took on bipolar-distribution. The dominant controlling factors of gas outburst were tectonic structures, tectonic stress, magma intrusion and mining depth. The geological conditions of Huaibei coalfield were very complicated, and almost all the outburst accidents occurred in tectonic structure zones. The horizontal tectonic stress played a dominant role in outburst accident. The thermal evolution and trap effect of magma intrusion controlled the physical characteristics of coal, gas occurrence and outburst. With the increase of mining depth, the possibility of gas outburst accidents increased significantly. After carrying out several effective regional measurements, the gas control effect was obvious and could ensure safety and high efficiency mining in outburst coal seams.     

Effect of protective coal seam mining and gas extraction on gas transport in a coal seam

A gas–solid coupling model involving coal seam deformation,gas diffusion and seepage,gas adsorption and desorption was built to study the gas transport rule under the effect of protective coal seam mining.The research results indicate:(1) The depressurization effect changes the stress state of an overlying coal seam and causes its permeability to increase,thus gas in the protected coal seam will be desorbed and transported under the effect of a gas pressure gradient,which will cause a decrease in gas pressure.(2) Gas pressure can be further decreased by setting out gas extraction boreholes in the overlying coal seam,which can effectively reduce the coal and gas outburst risk.The research is of important engineering significance for studying the gas transport rule in protected coal seam and providing important reference for controlling coal and gas outbursts in deep mining in China.     

美军战场合同商保障及其战备水平对我军的启示

近年来,无论是平时还是在战时,美军都将大量的后勤保障、武器系统保障以及其他技术服务交由训练有素的合同商等民间企业来完成,并取得了有目共睹的战绩,这与美军合同商保障的高标准战备水平是分不开的。研究美军合同商平战转换期间的战备水平,可为我军在装备保障力量建设中如何在战时利用好军外保障力量提供重要的思路。     

A review of the geomechanics aspects of a double fatality coal burst at Austar Colliery in NSW,Australia in April 2014

A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.     

四川中梁山和南桐矿区晚二叠世龙潭组主要煤层的煤相分析

本文从煤岩学、沉积学、古生物学和地球化学等方面分析了中,梁山北矿 K_2、K_4煤层和南桐砚石台矿四号、六号煤层的煤相;根据从煤中发现的植物残体和含煤岩系中发现的大化石确定了成煤植物的类型;并根据从煤中发现的细菌化石结合地化分析阐述了泥炭沼泽的介质性质。     

EPC总承包新型计价合同——目标合同应用研究

EPC总承包项目规模较大,在投标报价时,工程范围不确定,工程量与最终完成工程量存在很大差异。当采用总价合同作为其计价方式时,承包商则需要承担较大的风险,因而通常报价较高。而且在总价合同条件下业主与承包商双方对工程技术方案优化的积极性不高,业主有扩大工程标准及工程范围的倾向,结果容易导致工程造价增加。目标合同作为一种新型计价方式适用于工程项目范围没有完全界定或预测的风险较大的情况,并给合同双方带来工程技术方案优化的积极性,对降低工程造价有积极的意义。目标合同非常适合作为EPC工程总承包的计价合同。     

Applicability of surface directional wells for upper Silesia Basin coal seams? drainage ahead of mining

Methods of exploitation drainage, which is presently applied in polish hard coal mines in Upper Silesian Coal Basin (Poland), are not effective enough, high risk of methane hazard can be observed, and production capacity of the mining plant is not fully used. Methane hazard, which may occur during planned coal exploitation, is presented in this paper. Following parameters are taken into consideration in the forecasts: coal extraction parameters, geological and mining conditions, deposit’s methane saturation degree and impact of coal exploitation on the degasification coefficient of the seams, which are under the influence of relaxation zone. This paper presents the results of the analysis aiming to verify applicability of drainage ahead of mining of the coal seams by using surface directional wells. Based on the collected data (coal seams’ structural maps, profiles of the exploratory wells, geological cross-sections), the lab tests of drilling cores and direct wells’ tests, static model of the deposit was constructed and suitable grid of directional wells from the surface was designed. Comparison of forecasted methane emission volume between the two methods is investigated. The results indicated the necessity of performing appropriate deposit’s stimulations in order to increase effectiveness of drainage ahead of mining.     

关于工程项目承包商经营特征聚类分析

公正、公平评定承包商是工程项目招、投标中很重要的内容.选择最佳的投标者，需要采用科学的方法建立评标体系.而我国目前采用的评标方法大多采用专家分析评价承包商的财务指标，确定最终的承包商，这种方法不但主观性过强，而且割裂了指标间的相关性.根据系统工程原理，首先构建了评价承包商经营特征的指标体系，采用SAS软件并应用多元统计中的聚类分析方法，对项目投标承包商进行定量的分析与评价，不但克服了上述缺点，而且能客观、公正地反映承包商的综合水平.结果表明它可为公平、公正地评定项目承包商提供重要的参考作用，作为决策者选择承包商的一处重要方法.