1、 467Journal of Mining Science,Vol.47,No.4,2011 MINERAL MINING TECHNOLOGY CHARACTERISTICS OF METHANE RELEASE IN HIGHLY PRODUCTIVE COAL MINES K.N.Trubetskoy,A.D.Ruban,and V.S.Zaburdyaev UDC 622.817 The article discusses the research of methane release intensity versus average daily output in coal mine
2、s featuring different geological and mining conditions in Vorkuta and Kuznetsk Coal Basins.The authors describe degassing of producing and superimposed methane-bearing coal beds in highly productive longwalls,at the stages of coal face output of 26 thousand tonnes per day and in the first months of
3、operation.Coal bed,mine,working site,longwall,methane content of coal bed,coal production,methane release The volume of methane release,given the present-day depth reached in underground coal mines,is de facto 1820 m3/t or 4 13-14 kg/t 1,which appreciably affects production rates and profitability o
4、f underground extraction of high methane coal.It is extremely important to promptly prepare coal beds for extraction,ensure sufficient airing of headings and entries,plot efficient degassing measures to reduce methane flow in headings and entries as well as to recover standard quality methane from u
5、tilizable gas-air mixtures.Without implementation of the above listed measures in,it would be impossible to efficiently take advantage of high-production coal-winning machines in fully mechanized headings during high methane coal extraction,while the share of the fully mechanized mine workings is 89
6、%in Russia.Apart from standard ventilation,gas-saturated fully mechanized headings must involve a package of special methods and schemes for degassing of producing and superimposed coal beds,at maximum possible efficiency in the specific mine conditions:not less than 30%degassing efficiency in produ
7、cing coal beds,7080%degassing efficiency in superimposed coal beds and mined-out spaces.The coal mine ventilation analysis shows often negative stability of airing in working areas,and instances when working areas become gassy in Russian mines total 840980 per year on average 2.Effective degassing m
8、easures reduce over-gaseousness in mines and enhance safety of high methane coal extraction.Effective degassing must be in the limelight when planning abatement of methane emanation from producing and superimposed coal beds into face areas,according to recommendations RD-15-09-2006 3.Actual gas test
9、ing data on core materials extracted in mines of the Kuznetsk Coal Basin(Kuzbass)show that coals of different ranks,occurring within depth range 100750 m have considerable discrepancy in methane content limits(see Table 1).Average relationship between coal methane content Research Institute of Compr
10、ehensive Exploitation of Mineral Resources,Russian Academy of Sciences,E-mail:ruban_admail.ru,Moscow,Russia.Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh,No.4,pp.76-85,July-August,2011.Original paper submitted January 10,2011.1062-7391/11/4704-0467 2011 Pleiades Publ
11、ishing,Ltd.468(m3/t,dry ash-free basis)and coal occurrence depth (m)may be presented empirically as follows:5.205.0=HX,(1)which implies that methane content in coal beds expands by 5 m3/t,dry ash-free basis,per every 100 m of depth and upper methane limit is averagely at a depth 0H of 50 m from dayl
12、ight surface.The present research authors have calculated)(HfX=for the largest mines in Kuzbass,based on the actual data obtained in methane content tests of core material 4.Methane content of a coal series influences the intensity of methane release into headings 4,which is also governed by the coa
13、l production rate in a mine as is illustrated by the curves of the actual average daily coal output versus methane emanation in a number of the Kuzbass mines in Fig.1.Let us take,for example,coal bed Boldyrevskii(coal bed 24):its methane content =15.2 m3/t,dry ash-free basis(this indication is omitt
14、ed henceforth while is implied without saying),average preliminary degassing factor is 0.2 in the depth range 350400 m from the ground surface.After borehole degassing,the same coal bed had methane content 2.12=X m3/t.Natural degassing factor in this bed was estimated as 0.69 5.Methane content in th
15、e coal cutting area was 2.4=cX m3/t.Volatile content at the face was%40=dafV.At the coal cutter output 4.7=j t/min,the methane emanation intensity in the cutting area was 9.8=I m3/min.The data on coal outputs in mines and breakage headings,as well as methane release intensity and proportionality fac
16、tors 4 show that their numerical values decrease as the daily coal output grows,both in mines and at headings.To reveal the physical meaning of this phenomenon observed in enhanced coal extraction,we need to justify it theoretically.Preliminary degassing of producing coal beds via boreholes and natural degassing of the face-adjacent coal owing to ground pressure relief substantially decrease gas content in the coal cutting area.Table 1.Gas content limits in coal beds in Kuzbass by methane conten
