1、翻译部分英文原文Gas content based outburst control technology in AustraliaSheng XueCSIRO Exploration & Mining, PO Box 883, Kenmore, Queensland 4069 AustraliaTel.: +61 7 3327 4443; Fax: +61 7 3327 4666; Email: sheng.xuecsiro.auAbstractThe violent and unexpected nature of the phenomena enhances the mining ris
2、k and danger to mine workers. A number of techniques are used to predict and prevent the occurrence of the outbursts and to protect mine workers from the consequence of outburst incidents. This paper outlines the gas content based outburst control technology, one of the successful outburst control t
3、echnologies, applied in Australian coal mines. Some aspects of the current technology, which are perceived as either inadequate, inappropriate or impractical, are also highlighted in this paper together with the research strategies to address the concerns.Keywords: Coal Mining; Outburst; Outburst pr
4、ediction and control; Gas content1 IntroductionAn outburst of coal and gas is the sudden release of a large quantity of gas in conjunction with the ejection of coal and associated rock, into the working face or mine workings. Outbursts are hazardous through the mechanical effects of particle ejectio
5、n and by asphyxiation and possible explosion from the gas produced. Outbursts occur as a result of mutual interaction of a number of factors such as rock pressure, gas present in coal, and physical and mechanical properties of coal. Gas content is an important factor in outburst proneness. Unless ga
6、s content reaches a critical level, outbursts of gas and coal will not manifest themselves at all. Though gas content, as a basic coal seam parameter, has been used to develop many gas-related indices for outburst prediction in Australia, this has not been used in practice elsewhere. This may be due
7、 to different coal seam conditions outside Australia and the lack of the development of a rapid method to measure gas content.Outbursts were a common occurrence in gassy Australian mines, up until the industry adopted outburst threshold gas content limits following a fatality at West Cliff Colliery
8、in 1994. Since that time, only a handful of outbursts have been occurred with no fatalities. The Australian coal industry has achieved these results mainly through intensive gas pre-drainage practices as well as the use of shot firing or remote mining in coal that is difficult to drain. The current
9、threshold gas contents have been successful in preventing outbursts in Australia. However, there are a number of aspects of the current gas content based control technologies of managing outburst risk that are perceived as either inadequate, inappropriate or impractical/costly in some seam condition
10、s. Technology roadmaps are developed to address the issues.2 Outburst Control Protocols2.1 Development history in AustraliaOutbursts of gas and coal have occurred in both the major coal producing basins of Australia, namely the southern part of the Sydney basin (Illawarra coal field) and the central
11、 and northern part of the Bowen basin. Both pure methane and pure carbon dioxide outbursts have occurred in Australian coal mines. Over 700 outbursts have occurred in Australian mines over the last 100 years. The first outburst occurred in 1895 in Metropolitan Colliery in the Bulli seam. Since then
12、465 outbursts have occurred in the Bulli seam. The latest fatality from an outburst occurred in Australia in 1994. It is, therefore, not surprising that the outburst control technologies in Australia were developed to manage outburst risks in the Bulli seam. The occurrence of outbursts in the Bulli
13、seam was thoroughly studied by a number of researchers in the early 1980s (Hargraves, 1985; Lama, 1982). The studies revealed that the outbursts in the Bulli seam were characterised by the following: Depth of workings is 350 600 m, dip of the seam varies from 20 to 50, gas content varies with seam d
14、epth (from 3-6 m3/t at 350m depth to 15-20 m3/t at 600m depth), seam gas composition varies from pure methane to carbon dioxide, strength of coal ranges from 8 21 MPa, ratio of two horizontal stresses varies from 1.6 to 2.4, intermediate principal stress is 1 1.6 times the vertical stress; Outbursts
15、 often occurred in development headings; As long as minimum distance (about 2.5m) from the structures (faults, dyke, strike slip, sheared zones etc) is maintained, an outburst will not occur; when the barrier width of solid coal and the rib line of a heading was reduced to under 2.5m, an outburst pr
16、ecipitated; No signs of any failure due to induced stress in coal in areas of outbursts; and Majority of outbursts have occurred on structures.Based upon these studies, a mechanism of outbursts in the Bulli seam was postulated. Figure 1 shows the generalised concept. The phenomenon of outburst occurrence in the Bulli seam was placed in the third quadrant (high gas, low stress/strength ratio). As the face approaches the structures and the
