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英文原文Mine gas drainage and outburst control in Australianunderground coal minesNaj Aziza, Dennis Blackb and Ting Renaa School of Civil, Mining & Environmental Engineering, University of Wollongong,NSW 2522, Australiab PacificMGM, Mining and Gas Management Consultants, Wollongong,Australia (www.pacificmgm.com.au)Abstract:Australia produces both black and brown coal and is the worlds fourth largest producer of black coal, after China, USA and India. Australian underground coal mines operate under controlled safety codes. The establishment of the mine safety management system, including the 1994 outburst management plan, contributed to a significant improvement in mine safety leading to non-fatality in outburst related incidences since 1994. The management of outburst risk, as a part of the overall safety and health management system is described. Also discussed are the introduction of outburst threshold limit values and the desorption rate index which forms the basis for determining safe mining conditions along with the “Authority to Mine” process The measures taken and lessons learned from safe mining of Australias outburst prone mines represent an opportunity for improved mining safety in other countries, such as China. The role of the Australian Coal Association Research Program, which supports research in critical are as such as outburst risk control and management, is also discussed.Keywords: Mine, Gas, Outburst, Mine safety management, Threshold limit values, Risk management1.IntroductionAustralia produces both black and brown coal and is the worlds fourth largest producer of black coal, after China, USA and India, and the fifth largest producer of brown coal, after Germany, Russia, Turkey and USA. In 2009, Australia produced approximately 346 Mt of saleable black coal from 451 Mt of total raw coal production, and approximately 68 Mt of brown coal 12. Almost 98% of Australian black coal production is sourced from the two eastern states of New South Wales (NSW) and Queensland (QLD) while brown coal is produced mainly in Victoria, with 98% coming from the Latrobe Valley. All of the brown coal production is utilised within Victoria for power generation. In 2009, Australia supplied 29% of global black coal export market, and has been the leading exporter of black coal since 1984. Black coal is Australias principal export commodity, generating A$55 billion in revenue for the nation last year. Australia produces and exports both metallurgical and thermal coal in approximately equal proportions. The majority of Australias metallurgical (coking) coal is produced in Queensland, while New South Wales produces predominantly thermal (steaming) coal. The Australian coal mining industry directly employs approximately 30 000 people and indirectly supports the employment of a further 100 000 people who provide services to the coal industry. Coal seam gas represents a potentially significant risk to the safety and productivity of underground mines. Ineffective control and management of coal seam gas increases the risk of creating conditions that may result in either a coal and gas outburst or a methane and coal dust explosion. Poor gas management may also lead to general body gas concentrations exceeding statutory limits necessitating the cessation of production activities within the affected area. Over 730 outbursts have occurred in Australian mines since 1895. Table 1 lists both fatal and other incidents related to coal seam gas explosions and gas outbursts. Such incidents have shaped coal mine legislation and operating practices and provide the motivation to develop and maintain safe working conditions and operating practices. Many of the leading Australiancoal mining companies now strive for “Zero Harm” and significant resources are dedicated to achieving this goal. Australian mining now relies on the use of Safety and Health Management Systems (SHMS) that identify hazards and other potential risks present at individual mines and requires the development of management plans and operating procedures that detail the process to identify and assess hazards and implement appropriate controls to reduce risks to as low as reasonably achievable. The management of the Mine/Colliery is required to reduce and minimise the risks associated with outbursts in development panels and on longwall faces. This aim is achieved by the drainage of inseam gas to reduce in situ content to below defined Threshold Limit Values (TLV) and implementing a system of measurement and assessment of outburst risk prior to authorising mining activities to take place in any part of the mine. Table 1: Gas explosions and outburst incidents in Australia2.Outburst Risk Management The Outburst Management Plan (OMP) 6 is an integral part of a mines SHMS and is developed and maintained to effectively control the risks associated with the outburst hazard. An example of a typical relationship between the OMP and other components of the mine SHMS is illustrated in Fig. 1.The prime objective of the Mine/Colliery OMP is to facilitate exploratory inseam drilling and gas drainage with the aim of reducing in situ coal seam gas contents, in all areas of the mine where development and longwall operations (and subsequent longwall extraction) are to be carried out.Reducing the pressure and content of gas within the coal seam through focussed gas drainage has beenproven in Australia to be the most effective control to ensure that the risk of an outburst (or other release of dangerous quantities of noxious or flammable gas) is minimised and allows normal mining operationsto be carried out. In exceptional circumstances, where conditions within the coal seam prevent effective gas drainage, the OMP makes allowance for alternate mining procedures to be used, under strictly controlled and considered circumstances. In all circumstances the intent of the OMP is to maintain the protection provided to employees and the operation. The OMP applies to all employees of the Colliery who are engaged in development mining, longwall mining, gas drainage or associated tasks and any other parties associated with the application of the OMP. It covers the strategies associated with prediction and prevention techniques as well as methodologies associated with the protection of personnel and the operation from the effects of an outburst.If a coal seam is identified to be outburst prone, it is a requirement for the Mine/Colliery operating in such coal seam to develop and operate in accordance with an outburst management plan (OMP). This plan has been developed to address the risk of a gas induced outburst. The OMPs prime operational objective is to carry out effective in-seam drilling and gas drainage, sufficiently in advance of development mining, in order to reduce in situ seam gas contents to below the normal mining thresholdsand allow mining to be carried out under normal conditions. The main elements of the plan include Prediction, Prevention and Protection (Control).2.1 Prediction There are several factors that are accepted as the key parameters associated with outburst prediction.The geological structures of coal, excessive gas content and ground tectonic stresses are the key factors.In general, geological structures are likely to be the location of any outbursts. Geological structures are considered to present an increased risk of outburst as such structures may create stress concentrations and create a barrier that results in a high gas pressure differential. The detection of geological structural anomalies ahead of mining is achieved by in-seam drilling and the nature of the anomalies are subsequently elaborated through the use of various geophysical logging methods such as 2D and 3D seismic surveys, and the use of other technologies such as radio imaging and radar.Other methods of gas outburst prediction tools include the prediction indices 7 and using tube bundle and/or real time gas monitoring systems to detect the gas concentrations throughout the mine. In each mine the mine geologist will be responsible for the collection, analysis (with regard to outburst potential) and maintenance of the data; the mine surveyor 8 will be responsible for a drill log summary sheet for each in-seam borehole drilled within the Colliery for the purpose of exploration,structure prediction core sampling or gas drainage and plot any anomalies recorded by drillers onto the Surveyors plan, independent of the geological interpretation of that data. The gas drainage engineer willestablish documented standards and assessments for drilling of in-seam boreholes, connecting the drainage holes to the gas drainage system in the mine, and the monitoring of gas flows from boreholes, and maintenance of the gas drainage system to maximise effectiveness and the safe means of clearing a borehole suspected of being blocked. Other responsibilities of the mine geologist, the surveyor and the gas drainage engineer are described in the New South Wales Department of Mineral Resources OMP 6.2.2 PreventionThis is related to the effectiveness of gas drainage coupled with gas flow monitoring, and regular core sampling, so that the mine manager is always aware of the seam gas and structural environment into which the mine is about to develop or extract. Prevention of outburst during mining of development roadways is achieved by the deployment of gas drainage in reducing seam gas contents to below the appropriate threshold value for the composition of the prevailing seam gas.Both prediction and prevention form the input into the Authority to Mine (ATM) process which, upon completion, will determine the mining methodology to be used to develop each roadway or sequence of roadways and extract longwall panels.2.3 Protection or Control This is offered to development operators by way of routine training in outburst awareness, the identification of outburst warning signs and use of first response rescue and escape equipment, the provision of that equipment in the development panel at all times and the ability to suspend mining and initiate an inspection at any time should outburst warning signs be observed. Various systems and measures, which contribute to control/or protection from outbursts to include: l Ground destressing, which includes stress relief drilling, stress relief mining, inducer shot firing and gas drainage, l The use of OMPs6,l Hydraulic fracturing; a method that has increasing application both for UIS and SIS operations, l Pulse infusion shot firing, l Water infusion. Pulsed infusion shot firing and water infuse are not generally used in Australia. Fig. 1 Mine safety management system 3.Authority to Mine (ATM) The prediction and prevention provisions are designed to develop a clear picture of the conditions prevailing ahead of development panels and to reduce the seam gas content to below the threshold value corresponding to the seam gas composition prevailing in that area. The data generated as a result of the prediction and prevention provisions provide the input into the Authority to Mine process. The method of working will be decided for each set of circumstances by using the available and recognized outburst decision making flowchart” 6. The Outburst Risk Review Team (ORRT) will be responsible for and manage the ATM process.The ATM will be co-authorised by the mine manager, undermanager-in-charge and the gas drainage engineer. ORRT is a group responsible under the OMP to review data relevant to outburst risk at the mine and to manage mining activities through the ATM process. The group normallyconsists of mine manager, gas drainage engineer or ventilation coordinator, undermanager-in-charge, gas drainage engineer, mine geologist, workforce representative and development coordinator. The mine manager, undermanager-in-charge and gas drainage engineer are responsible for approving an ATM. 4.Threshold Limit Values (TLV) Following the last outburst related fatality in Australia, which occurred at West Cliff Colliery, Illawarra Coalfield, Sydney Basin, on 25th January 1994, the NSW Department of Mineral Resources (DMR) issued a directive to all mines operating in the Bulli seam detailing actions to be implemented to prevent further outburst related fatalities. Arguably the most significant of these actions was the stipulation of limits on seam gas content prior to mining, known as outburst Threshold Limit Values (TLV). Fig shows the Bulli seam TLV prescribed by the DMR 9. The TLV varied linearly based on gas composition, decreasing from a maximum in CH4 rich conditions to a minimum in CO2 rich conditions. The Level 1 TLV indicates the maximum gas content limit for normal mining above which outburst mining procedures must be followed. The Level 2 TLV indicates the maximum gas content limit for outburst mining above which mining must only be undertaken using remote operated equipment, with all personnel remaining clear of the outburst risk zone.Fig. 2 Prescribed Bulli seam Outburst Threshold Limits 9Williams and Weissman 10 introduced the concept of using the rate of gas desorption from crushed coal, during Q3 testing, known as Desorption Rate Index (DRI), to determine TLV applicable to coal mines operating in coal seams other than the Bulli seam. The test involved measuring the volume of gasemitted from a 200 g sub-sample of coal material after crushing for 30 seconds and extrapolating the result to the total gas content (QM) of the full core sample to determine the DRI of the full coal sample (Williams, 1996 11 and Williams, 1997 12). The data presented in Fig, which represents data collected from the 386 panel at West Cliff Colliery 12 demonstrate a strong correlation between QM and DRI for both CO2 rich and CH4 rich coal samples. The relationship was assumed by Williams and Weissman 10 to be representative of all Bulli seam conditions. As shown in Fig.3, the Bulli seam TLV of 9 m3/t (100% CH4) and 6 m3/t (100% CO2) correspond to a common desorbed gas volume of 900 mL. From this assessment, Williams and Weissman concluded that the QM value corresponding to a DRI of 900, based on a unique QM-DRI relationship determined specifically for each mine and coal seam, represent the TLV applicable to that coal mine. Fig. 3 QM relative to DRI for CO2 and CH4 rich coal from 386 panel 125.ConclusionsThe stringent guidelines under which the Australian underground coal mines operate demonstrate that coal mining can be achieved safely. China and other high coal producing countries with abundance of coal reserves may consider the use of SHMSs and OMPs similar to those being used in Australia. In the present era of advanced knowhow and technology there is no reason why underground coal miningcannot operate totally free from injuries and fatalities. This is a great challenge that must not be ignored.中文翻译澳大利亚井工煤矿的瓦斯抽放技术与瓦斯突出控制技术Naj Aziza, Dennis Blackb and Ting Rena卧龙岗大学土木工程学院采矿与环境工程系, NSW 2522 ,澳大利亚 太平洋地区煤炭开采与瓦斯管理战略部，卧龙岗, 澳大利亚摘要:澳大利亚是世界上仅次于中国、美国及印度的第四大烟煤与褐煤的生产基地。澳大利亚煤矿井下工作必须严格遵守安全规则。煤矿安全管理制度的建立，包括1994年颁布的显著提高煤炭瓦斯突出的非致死率的瓦斯突出管理措施。本文描述了做为安全和卫生管理制度的重要的一部分的突出危险管理制度。本文还讨论了突出阀限值的引进利用及煤矿管理系统在确定安全开采条件过程中形成的瓦斯解析率指数。澳大利亚的有突出危险性的煤矿为保证煤矿的安全开采采取的防突措施及治突的经验教训为其他国家的煤炭安全开采提供了一个范本，例如中国。一向支持在关键领域的研究例如突出危险控制和管理的澳大利亚煤炭工业协会研究规划部所起的作用也被提及。关键词：煤矿，瓦斯，突出矿井的安全管理，阈限值，风险管理1.引言澳大利亚是仅次于中国、美国及印度的世界第四大烟煤生产基地及仅次于德国、俄罗斯、土耳其和美国的世界第五大褐煤生产基地。2009年澳大利亚从451万吨原煤中生产约346万吨可供销售的烟煤和约68万吨褐煤。几乎98的澳大利亚烟煤来源于东部两个州新南威尔士（NSW）和昆士兰州（QLD），而褐煤生产主要集中在维多利亚州，全国98的褐煤出自拉特罗布山谷，维多利亚州的电能几乎全部由褐煤生产而来。2009年，澳大利亚出口的烟煤占世界出口市场29，并从1984年开始一直牢牢占据着烟煤出口市场的龙头地位。烟煤是澳大利亚的主要出口能源商品，去年澳大利亚烟煤出口获利55亿美元。澳大利亚生产和出口的冶金和动力煤比例大致相等。大多数澳大利亚的冶金（炼焦）煤产自昆士兰州，而新南威尔士州主要生产动力（汽）煤炭。澳大利亚约30万人直接从事煤炭开采业，煤炭衍生行业间接为100万人澳大利亚人民提供就业机会。煤层瓦斯是影响井工煤矿安全生产的潜在重大隐患。煤层瓦斯管理和控制不利，将会增加煤与瓦斯突出及瓦斯和煤尘爆炸等灾害的发生机率。恶劣的煤层瓦斯管理水平，将可能会使工作区瓦斯超限，导致煤矿不得不停止生产进行整改。自1895年以来，澳大利亚全国发生超过730次瓦斯突出灾害。表1列出了澳大利亚发生过的瓦斯爆炸和煤与瓦斯突出事故。这些事故促使煤炭法规及煤炭作业规范的形成，并为寻找更安全的工作条件和不断完善操作规范提供了源源不断的动力。现在许多技术领先的澳大利亚煤矿公司在实现高产高效的同时争取“零伤害”，并致力于实现这一目标。现在，澳大利亚矿业依靠使用的安全健康管理系统（SHMS）来确定各个煤矿危害等级及其他潜在灾害。详尽的管理计划和作业规程可以用来确定和评估灾害发生状态，并及时采取措施将灾害降到最低。矿山/煤矿的管理要减少或尽量减少在已开拓巷道和回采工作面发生与瓦斯突出有关的灾害。以下两种措施实现了该目的：通过瓦斯预抽排放技术使煤层瓦斯含量降到阈限值（TLV）以下；在进行任何开采活动前需对煤矿各个部位进行突出危险性的测量和评估。表 1澳大利亚历年突出事故汇总表发生煤矿时间(年)深度(m)死亡人数（个）突出气体突出煤量（t）Metropolitan1895425CH4混CO2200Metropolitan18964253矿井瓦斯Metropolitan19264002CO2Metropolitan19544252CH4、CO2140Metropolitan1961425CH490North Bulli1911370CH4、CO2300Coal Cliff1961450CH4、CO21Corrimal1967400CH42Appin1966520CH450Bulli1972380CH460West Cliff1977-1993460CO2100Collinsville1954-1978220300C.C.C.P1978280CH4400Leichardt1975370CO225Tahmoor19851CO2500South Bulli19913CH4West Cliff19941CH4300Central2001400CH4、CO2Brimestone/Oakdale1992-1995CH4、CO260-80Kemira1980CH4、CO210Tower1981-2000CH41-80Appin2010CH42.突出危险管理突出管理计划（OMP）是煤矿安全健康管理系统（SHMS）的组成部分，可以帮助研究开发能够有效控制与突出相关的的灾害的措施，并确保它能顺利实施。图1详细说明了突出管理计划（OMP）与煤矿安全健康管理系统（SHMS）各部分之间的关系。突出管理计划（OMP）最初的目的是研究利用钻孔技术和瓦斯的流动性进行瓦斯抽放进而将煤层瓦斯含量降到安全水平以下。现在OMP已在矿井各个领域广泛应用，无论是开拓还是回采作业。在澳大利亚通过集中瓦斯抽放进而降低煤层瓦斯压力和含量，可以有效的控制瓦斯突出（或其他的有毒或可燃气体的大量释放），并将突出危险性降到最低，进而允许矿井进行正常的采矿作业。在特殊情况下，由于煤层的特殊条件影响，瓦斯抽放很难取得理想效果，在考虑实际情况和采取严格措施后，OMP会采用备用采矿工序。无论在什么情况下OMP的目的是保护工人和设备的安全。OMP与矿山的所有人员有关，无论是从事掘进、回采、瓦斯抽放及其它相关工种的工作人员还是从事OMP服务与应用的相关人员。它涵盖了瓦斯突出的预测与预防技术策略，以及保护工作人员和机器免受突出灾害影响。如果煤层经鉴定后为易突出煤层，则该煤层的开拓和回采应严格按照突出管理计划（OMP）中规定的作业规程执行。这个计划就是为减少突出引发的瓦斯灾害而设计的。OMP首要的目标是实施有效的煤层钻孔瓦斯抽放措施，使煤层在开采前将煤层瓦斯含量降低到瓦斯阈限值以下，以便进行正常安全的回采作业。该计划的主要内容包括预测、预防和保护（控制）。2.1预测以下是几个参数被公认为是预测突出有的关键参数，它们是煤炭的地质结构、气体含量过高和地面构造应力场。一般情况下，地质构造处往往容易发生突出灾害，地质构造往往会增加突出发生的几率，这种构造往往会产生应力集中，阻碍瓦斯流动造成局部地区高瓦斯压力。矿山地质构造异常检测是通过在煤层钻井利用各种地球物理测井方法来确定构造的异常性质，如通过二维和三维地震勘探，或使用如无线电成像和雷达探测等其他技术。其它的瓦斯突出预测方法包括包括预测瓦斯指数和使用管束和/或实时气体监测系统检测到整个矿井的瓦斯浓度。各个煤矿的矿井地质工作者负责收集、分析（有突出危险性的数据）和整理保存数据；矿山测量员负责确定钻孔日志，为取得构造核心有代表性的样本品岩石或为进行瓦斯抽放而在各个煤层中钻孔勘探，并将勘探数据记录汇总，对构造异常现象作出解释。瓦斯抽放技术人员负责建立一套钻孔标准和评价体系，建立完整的矿井的瓦斯抽放体系和钻孔瓦斯流量的动态监测体系，维护好瓦斯抽放体系使其达到最佳经济效益并可安全方式处理堵塞钻孔。在新南威尔士州矿产资源OMP部对煤炭地质工作人员、测量员和瓦斯抽放技术员的其他职责有详细说明。2.2预防有效的瓦斯抽放、气体流量的动态监测和定期核心取样与预防突出有紧密联系，因此矿井管理人员一定了解各煤层煤层气的分布状态及其地质构造情况，事实证明最有效地降低瓦斯突出可能性的措施是，通过钻孔进行瓦斯抽放，使煤层瓦斯含量降低到阈限值以下。将预测结果和预防措施输入到ATM系统中，ATM系统将会确定煤层采煤方法、巷道掘进方法和巷道掘进顺序。2.3保护/控制煤矿工人要经常接受突出演习训练，通过训练，工人须牢记突出危险发生前兆，要确保突出发生时第一反应是使用救命和逃生设备，煤矿要有实时监控回采区段的的设备，并且当发现明显突出前兆发生时，该监测系统要随时立即切断回采区段所有设备的电源，使设备停机，以确保安全。突出灾害发生时有以下几条保护措施和方法：l 减小应力集中，包括钻孔释放应力、开采解放层、诱导应力释放和瓦斯抽放等等；l OMP系统的推广应用；l 水力压裂法；l 脉冲输液开枪射击煤壁；l 注水；脉冲输液开枪射击煤壁和注水这两种方法未在澳大利亚推广应用。3.煤矿管理系统（ATM）预测和预防突出主要是在区段回采前将煤层瓦斯含量降到阈限值（TLV）以下，将预测和预防突出所得的结果输入到煤矿管理系统（ATM）中，ATM系统会通过现有的突出决策流程图为每种独特的开采条件制定一套适合的采煤方法。突出危险性评审小组（ORRT）将负责管理ATM流程。ORRT是OMP下设的通过利用ATM系统专门负责审查与矿井突出危险性相关的数据及控制煤层活动。本小组一般由矿长、瓦斯抽放工程师、通风协调员、井下负责人、煤炭地质工程师和职工代表组成。矿长，井下负责人和瓦斯抽放工程师负责审批ATM所得结论。4.阈限值（TLV）自1994年1月25日，澳大利亚悉尼盆地伊拉瓦拉煤田西崖煤矿发生导致工人死亡的瓦斯突出事故后，新南威尔士州矿产资源部（DMR）发出指令各煤矿加强管理，研究新技术以降低瓦斯突出事故所带来的灾害。并规定了可采煤层的瓦斯含量即阈限值（TLV），图2是DMR绘制的一幅关于煤层阈限值（TLV）示意图。从图中可以看出阈限值（TLV）呈线性,横轴代表气体成分(CO2)，竖轴代表瓦斯含量。随着CH4含量的减少气体成分中CO2含量逐步增加。TLV 1表明正常回采时所允许的瓦斯含量临界值，超过该值，就需要预先采取防突措施。TLV 2表明正常掘进时所允许的瓦斯含量临界值，超过该值时，必需采用远程遥控机械作业，相关人员要撤离到安全区内。在第三季度测试时威廉姆斯和韦斯曼提出利用了煤破碎时瓦斯释放率即解吸率指数（DRI）来确定煤层的TLV。将一块重200g的煤岩样本完全破碎，30秒后测量其释放的瓦斯量，推算出完整岩心样品的瓦斯含量（QM），进而确定瓦斯解吸率指数（DRI）。图3所显示的数据是从西崖煤矿386工作面实测收集而来。从图中可以看出CO2 含量丰富和CH4含量丰富的煤样QM和DRI表现出很强的相关性，威廉姆斯和韦斯曼假设这种关系是布利煤层条件最好的表示。正如图3所示，布利煤层的TLV线9m3/t（100的CH4）和6m3/t（100的CO2）对应一个共同的解吸率指数900毫升。图1瓦斯含量与TLV关系图图2瓦斯含量与解吸率的关系5.结论在严格的指导监督下，澳大利亚的煤矿实现了安全，高效生产目的。中国和其他产煤大国应试着采用参考澳大利亚开发自己的SHMS和OMP系统。在目前先进技术条件下，井工煤矿完全可以实现0伤亡目标，实现这个目标需克服重重挑战。
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