POSSIBILITIES OF LIMITING METHANE EMISSION INTO ATMOSPHERE ON THE EXAMPLE OF MINES IN THE JASTRZEBIE COAL COMPANY

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1 In collaboration with The South African Institute of Mining and Metallurgy Founded in 1894 POSSIBILITIES OF LIMITING METHANE EMISSION INTO ATMOSPHERE ON THE EXAMPLE OF MINES IN THE JASTRZEBIE OAL OMPANY Nikodem Szlazak*, Andrzej Tor**, Marek Borowski*, Dariusz Obracaj* * AGH University of Science and Technology in racow, Poland **Jastrzebie oal ompany, Poland Abstract This article presents possibilities of reducing methane emission to the atmosphere in working mines in Jastrzebie oal ompany by means of proecological solution. They form a new approach towards the problem of rational and effective use of natural resources both in economical and environmental respect. Power and thermal energy for underground air conditioning in mining excavations are produced from the methane, which is drained out of the mine for safety reasons. Introduction Methane and an explosion hazard resulting from its occurrence are still the most dangerous phenomena accompanying extraction of hard coal. Simultaneously they are the most frequent hazards present in coal deposits. Methane present in coal seams, when emitted into mining galleries, is the source of a serious hazard for the miners working underground and for the continuous works of a coal mine. Methane emission from mined coal and goaf is a serious hazard as far as work safety conditions are concerned, both in the form of methane explosion or ignition and in the form of atmosphere without oxygen, which can result in suffocation. Many disasters, which took place in mines, are the result of the hazards just mentioned. Mining coal seams in methane mines requires using special technical solutions in order not to allow exceeding the safe level of methane concentration in mining air. The basic method is the usage of suitable ventilation systems with an intensive stream of air. However, ventilation methods are frequently not very effective. Therefore methane drainage from coal seams and enclosing rocks is necessary. Methane obtained by means of methane drainage is not utilised in the same way during the whole year; therefore it is emitted into atmosphere. From an economical point of view, such a solution does not seem rational or economically justified. Methane drainage of mines is a significant and effective means of methane hazard prevention and at present is carried out in 18 Polish mines. In million m 3 of methane was obtained by means of methane drainage, out of which approximately million m 3, that is 59.9%, was utilised. Although a general fall in the quantity of methane coming out of mines (from 763 million m 3 in 1998 to million m 3 in 2000 and million m 3 in 2001), there was an increase in the quantity of methane obtained by means of a methane drainage system (from million m 3 in 1998 to million m 3 in 2001). Unfortunately methane utilisation fell down from million m 3 in 1998 year to million m 3 in 2001, that is approximately by 10%, which means an increase in the quantity of methane emitted into atmosphere. The conclusion to be drawn is that further steps should be taken in order to utilise more methane drained. Utilisation of methane in mines using methane drainage systems ranged from 0% (oal Mines: hwalowice, Slask, Sosnica, Szczyglowice, Budryk ) to 100% in Brzeszcze oal Mine. There was 18.5 million m 3 of not utilised methane in Pniowek oal Mine, but due to the introduction

2 of a combined heating cooling power system (HP) the utilisation of drained methane has increased from 64% to 71% and the quantity of not utilised methane fell down to 12.3 million m 3. The mines belonging to Jastrzebie oal ompany are the ones with the greatest methane hazards and Pniowek oal Mine has both the highest methane emission and the greatest level of methane drainage. Methane hazard in Jastrzebie mines is the most important natural hazard. Therefore the selection of adequate methods for combating methane hazards must be taken up already at the stage of planning mining works by determining forecasted methane - bearing capacity of a particular excavation. Limiting methane hazard by means of methane drainage of mines helps to improve work safety of miners and continuous work of machinery reducing the number of machinery shutdowns caused by switching off electricity after exceeding critical levels of methane concentration. An effective system of methane drainage is not only the one that creates the possibility of obtaining methane as a natural source of energy but also the one that reduces the negative influence on natural environment, resulting from methane drainage into atmosphere. Methane occurrence and emission in the mines of Jastrzebie oal ompany In general, coking coal deposits are mined in the mines of Jastrzebie oal ompany; therefore the basic output of mines is coal of type 35.1, 35.2 and 34.1 and small quantities of coal ranging from coking to steam coal are mined in Borynia, Pniowek and Krupinski oal Mines. oal seams with methane are included in IVth category of mine rating of methane hazard, with the exception of Borynia oal Mine, whose seams are included in IIIrd category. Methane resources in the mines of Jastrzębie oal ompany are presented in table 1. Mine METHANE RESOURES IN JASTRZEBIE OAL OMPANY Data for 31st December 2001 Area of mine field [km 2 ] Output of coal [Mg] in 2001 Table 1 Methane resources to the depth of 1000 m [mln m 3 H 4 ] Balance resources Total commercial resources Borynia , 504, Jas-Mos , 693, Krupinski , 138,700 1, Pniowek , 687, 100 1, Zofiowka , 291, 800 1, JSW S.A , 315, 800 5, arbon deposits covered with overlayers of hard permeability with variable thickness of Quaternary and Tertiary sediments can be found in the geological structure of the southern part of the Rybnik oal District. The lithological quaternaries were developed from sand and gravel with interbeddings and insertions of mud, clay and silty clay. Sea sediments of Miocene clays with insertions of sand and dust, having the character of sandwater at the bottom of those layers, represent the tertiary. Methane content of the seams in the Upper Silesian oal Basin is very irregular. In the northern and middle part of the Basin there is no or very little methane. However, in the southern part of the Basin there is very high methane content. Both in the southern-eastern part the deposits of Brzeszcze and Silesia oal Mines and in the southern-western part the deposits of the mines belonging to Jastrzebie and Rybnik oal ompany have high methane content. As slightly permeable clayey cap rode from Miocene is present in overburdens in the mines of Jastrzebie oal ompany, directly in the roof of arbon there is a zone m wide with high methane content of seams, frequently exceeding 10 m 3 H 4/ Mg csw. There are also seams with an increased methane content and high saturation with methane close to zones of faulting, which were the paths of methane migration out of the deeper parts of the deposit and they finish where they come into contact with an impermeable overburden. In Jastrzebie and Moszczenica oal Mines (at present functioning as one mine Jas-Mos ), which were the first to be built, while the first mine openings were being drilled in the upper overburden there was an intensive spontaneous methane emission, reaching dozens of m 3 /min. When mining was started, methane emission even increased. There was different

3 , , , , , , , ,8 dynamics of methane emission in deeper mines, which were built subsequently. Inflows of methane during opening operations were relatively small and it was only when mining operations were started that there was an increase in methane emission (Berger, Nowak, 1999). On the basis of the research conducted so far it can be concluded that methane present in coal deposits takes two main forms: - of sorbed methane physical-chemically bounded with coal and less frequently with clay rocks, - of free methane present in pores and open pores of barren rocks and coal seams (can also be diluted in formation water present in pores of sandstones). Sorbed gas is present mainly in coal seams. In Rybnik oal District one tonne of coal, depending on the depth of its bedding, can contain up to 18 m 3 of methane in the physical-chemically bounded form (seam No. 502/1 in Moszczenica oal Mine) [Kozlowski, Grebski, 1982]. The presence of free methane is closely related to favourable geological textures enabling methane accumulation. Both forms of methane occurrence are closely related to each other. It is assumed that as a result of coal spalling during mining sorbed methane is emitted and transformed into free methane, starting from the zone of cracks [Roszkowski, Szlazak, 1999]. In 2001 absolute methane bearing capacity in the mines of Jastrzebie oal ompany was equal to m 3 H 4 /min, out of which m 3 H 4 /min was drained through a drainage system, which was conducted by the Institute of Methane Drainage of Mines. In this period of time relative methane bearing capacity was equal to 13.0 m 3 /Mg of output. The characteristics of absolute and relative methane bearing capacity in different mines of Jastrzebie oal ompany are presented in table 2. In 2001 total methane drainage in the mines of Jastrzebie oal ompany was equal to 92.3 million m 3, out of which 70.7 million m 3 H 4 was utilised, which is 77% million m 3 H 4 was drained out to the surface together with return air. If losses of methane drained through a methane drainage system equal to 21.6 million m 3 H 4 are added to the previous value, the total of methane drained into atmosphere in 2001 was equal to million m 3 H 4 - fig. 1 (a fall by 2.2 million m 3 H 4 compared to 2000). MINE METHANE BEARING APAITY IN J in 2001 Relative methane bearing capacity [m 3 H 4/Mg] Table 2. Methane bearing capacity [m 3 H 4/min] Effectiveness of methane ventilation drainage total drainage [%] Borynia Jas-Mos Krupinski Pniowek Zofiowka J Methane drainage and utilisation in J Drainage Utilisation , ,6 [thousand m 3 H 4] , , , , , , Fig. 1 Methane drainage and utilisation in the mines of J from 1993 to 2001

4 Methane release when the structure of rock mass is not disturbed during mining operations is small due to geological conditions of methane occurrence in a coal deposit and small desorption of Polish coal. Therefore, the quantity of methane released is strictly connected with the range of mining operations, both opening and proper mining of coal seams [Kozlowski, Grebski, 1982]. Negative experiences of foreign companies as far as methane drainage through bore-holes from the surface in the unstressed parts of rock mass is concerned confirm the thesis that there is little methane release from such a rock mass. Mining, at present conducted in 100% with caving, additionally releases methane present in rock mass between coal seams. In the mines of Rybnik oal Basin, characterised by high methane content, methods for combating methane hazards have not been sufficient since their construction was started. Therefore, they were forced to use different methods of combating methane hazards, that is methane drainage of opening, development and mining workings. As more mines were being built, it became evident that their coal deposits differed not only in methane occurrence conditions but also its emission into mining atmosphere, which required using different methods for methane drainage, proper equipment for underground drilling and construction of methane drainage stations with a greater and greater performance. An increase in the concentration of coal mining required using more and more effective methane drainage methods. Among the methods of methane drainage used so far, the following distinction can be made: - methane drainage of development headings - pre-drainage conducted before mining in an unstressed rock mass with an original state of stresses is started, - methane drainage during mining conducted at the same time as coal seams are mined in a rock mass, where the original equilibrium of the deposit was disturbed by mining and the process of methane drainage is conducted in rocks with variable stresses, - methane drainage from behind stoppings Methane drainage of rock mass is the most effective way of controlling methane hazard ensuring the fall in methane outflows into workings and preventing or limiting phenomena such as: blow-outs, abrupt break-outs of methane and coal etc. This method helps to keep ventilation parameters at the required level, but at the same time it poses some requirements as far as the methods of entry drivage in gassy seams is concerned. In 2001 in the mines of Jastrzebie oal ompany about 59% of drained methane was obtained from methane drainage of rock mass by means of bore-holes; the remaining quantity, that is 41%, was drained from sealed cavity. 8.5 m 3 H 4 /min, that is approximately 5%, was obtained from methane drainage of development headings and development workings and 95.5 m 3 H 4 /min, that is 54%, was obtained from methane drainage of longwalls. Methane drainage of rock mass by means of bore-holes consists in making bundles of holes from an excavation or stables drilled earlier and connecting them with a drainage pipe in order to reduce pressure below the pressure present in an excavation. As rock mass close to an excavation is cracked a bore-hole in this zone is sealed by means of a cemented pipe-holder in order to limit airflow into this hole. However the sealing is not perfect and some air gets into a bore-hole. During the existence of a borehole some extra cracks are formed as a result of mining stresses that cause an increase in airflow into a borehole, which in turn causes the fall in methane concentration in the mixture drained. Methane and air mixture with concentration of 50-60% H 4 is drained. This method of methane drainage results in steady stream of mixture and the concentration of H 4 varies depending on: - barometric pressure oscillations, - methane inflow from bore-holes and from behind stoppings, - leak tightness of underground drainage pipe-lines. Methane drainage through bore-holes is conducted from development headings, entries and operating faces. At deeper levels of the mines methane drainage by means of drilling takes place only in working faces. Pre-drainage is hardly or not used at all in the mines of Jastrzebie oal ompany as coal permeability is too low; therefore a methane drainage method is not effective enough. Moreover an increase in concentration, intensification of mining and shortening the time of drilling development workings enables obtaining positive results of pre-drainage of seams without putting into use processes simulating liberation and flow of methane (hydraulic fracturing of coal seams in bore-holes) [Berger, Nowak 1999]. The following aspects should be taken into consideration when considering arguments for methane drainage of coal deposits: - safety as methane is drained into pipelines at the same time reducing the quantity of methane emitted into streams of airflow and limiting burst hazard,

5 ecological aspect as natural environment is protected due to the fall in methane emission into atmosphere, - economic aspect resulting from the fall in the quantity of air necessary to ventilate excavations and profit from the sale of two carriers of energy coal and methane. The process of restructuring Polish coal mining, which is taking place at the moment, requires taking specific actions so as to reduce the costs of coal mining. In the mines using methane drainage systems the costs of coal mining also include the costs of methane drainage. The characteristics of methane bearing capacity in the mines of Jastrzebie oal ompany from the beginning till the end of 2001 are presented below. Methane bearing capacity in the mines of J [m 3 /min] 360 Borynia Jas-Mos Morcinek Moszczenica Krupinski Pniowek Zofiowka Fig.2. Absolute methane bearing capacity in J When analysing absolute methane bearing capacity of the mines belonging to J in the period presented above, it can be concluded that the mines with the greatest hazards were: Pniowek and Moszczenica oal Mines, where the highest absolute methane bearing capacity reached, respectively m 3 /min H 4 and m 3 /min H 4 and in the remaining mines, except Borynia oal Mine (below 50 m 3 /min H 4 ), the highest methane bearing capacity reached 200 m 3 /min H 4 ( Zofiowka oal Mine m 3 /min H 4 ). Average absolute methane bearing capacity in the period given above had the following values: Pniowek m 3 /min H 4, Moszczenica m 3 /min H 4, Zofiowka m 3 /min H 4, Jastrzebie + Jas-Mos 89.3 m 3 /min H 4, Krupinski 88.0 m 3 /min H 4 and Borynia 24.9 m 3 /min H 4. After analysing the dynamics of methane bearing capacity, it can be concluded that there was an intensive increase in methane emission from the time a mine started operating for the next 10 to 15 years; afterwards there was a gradual decrease in absolute methane bearing capacity. In all the mines analysed, methane drainage of rock mass is conducted while the intensity of drainage operations depends on methane content of coal seams and absolute methane bearing capacity of particular galleries. Most of the time methane drainage effectiveness in the mines analysed (except Borynia oal Mine) ranged from 30% - 70%, on average 36.6%; but in Borynia oal Mine it was equal to 8.4%. The mixture of air and methane drained in greater and greater quantities also turned out a valuable power material of great economical importance. The level of methane utilisation is variable. In the analysed period of time the greatest utilisation of methane obtained by means of methane drainage was achieved by: Zofiowka oal Mine 93.5%, Jastrzebie + Jas-Mos 87.0%, Pniowek 79.5%, Moszczenica 78.3%, Morcinek 68.1%, Krupinski 45.4% and Borynia 6.8%. Utilisation of methane from methane drainage Methane drained during the process of methane drainage of seams and surrounding rocks in mines is not uniformly utilised in time and its unutilised part is emitted into atmospheric air.

6 Although methane drained during the process of methane drainage of mines is the fuel of full value, containing even 30% H 4, its utilisation runs into many problems, which is caused by contradictory requirements of a gas producer, which is a mine and its recipients. Mines generate gas in the process of methane drainage as a by-product of coal mining. As mining conditions of methane drainage change all the time, the composition of gas and its quantity change as well. However for a recipient the condition of the proper process of gas utilisation is its calorific value, constant chemical constitution and keeping deliveries of methane on a fixed level [Roszkowski & Szlazak, 1999]. Methane and air mixture cannot be delivered to a pipe network without expensive purification and enrichment to achieve the parameters of network natural gas. Therefore at present the only possibility of its utilisation is its use in industrial installations of Jastrzebie oal ompany and Power Stock orporation Jastrzebie. It is utilised in: boiler houses and driers belonging to the mine, processing plants, heat and power generating plants, gas engines installed in Krupinski and Pniowek oal Mines. Jas-Mos, Pniowek and Zofiowka oal Mines are the only ones that have opportunities of gas transmission to recipients outside and there are no pipe networks in other mines, so drained methane can be utilised only on the spot. Gas is transmitted through a network of hired pipelines approximately 30 km long and with diameters of 250 and mm. Methane utilisation varies in winter and summer due to its seasonal character and great differences between demand and supply as the recipients of drained methane and air mixtures are mainly heat and power plants. The level of utilisation ranges from 90% in winter to 50% in summer, which refers mainly to methane from Pniowek oal mine, which is the main manufacturer of methane in J 46% of the total drainage in the company. Table 3 presents parameters of installations for methane utilisation and table 4 presents methane drainage and utilisation in PARAMETERS OF METHANE UTILISING INSTALLATIONS Mine Installation Specific methaneair mixture consumption [m 3 /min] Monthly consumption [x 10 3 m 3 ] Borynia Boilers HVTO 100/ x 1.2 MW t Jas-Mos R. Drier ROW Moszczenica Krupinski Drier ROW Pniowek Aggregate TBG 632 V ,280 Zofiowka SEJ SA E Moszczenica SEJ SA E Zofiówka SEJ SA ieplownia Pniowek EEG Suszec Sp. z o.o. Boilers OG-64 Boiler PWPg-5 Gcal/h Boilers OP-140 Boiler PWPg 6 Gcal/h Boiler WR-25 Boiler PWPg-5 Gcal/h Boiler PWPg-6 Gcal/h Aggregate TBG 632 V (max. 140) (max. 70) ,300 3,300 1,500 2, ,120 Table 3 Mine Total quantity of methane drained [x10 3 m 3 per year] METHANE DRAINAGE AND UTILISATION IN 2001 Utilisation of methane drained (100 % H 4 ) Total quantity and participation % of Specification methane drained Quantity of Way of utilisation [x10 3 m 3 per methane [%] year] [x10 3 m 3 per year] Table 4 Borynia Gas boilers 2 x 1.2 MW t Jas-Mos 8, , ,388.6 E Moszczenica Krupinski 20, , , , ,376.1 Aggregate TBG 632 V16 Boiler WR Floto-concentrate drier Pniowek 42, , ,616.3 E Zofiowka

7 J 92, , , , ,511.5 E Moszczenica Boilers of HP Plant Pniowek Aggregate TBG 632 V 16 Zofiowka 21, , ,821.2 E Zofiowka 2, , , , , , , ,734.4 Possibilities of increasing methane utilisation Plants of J including: Gas Boilers. Borynia Mine Floto-concentrate drier Krupinski Mine SEJ SA including: E Moszczenica E Zofiowka Aggregate TBG 632 V 16 Boilers WR Total In order to increase methane utilisation and at the same time to reduce its emission into atmosphere (in million m 3 H 4 and in 2001 already million m 3 H 4 ) in J the programme, which assumes taking some steps aiming at total utilisation of drained methane, was started. The enterprises focused on reconstruction, modernisation and development of engineering systems and realisation of new investments so as to fully utilise drained methane and eventually to enable intensification of underground drainage, at the same time reducing the quantity of methane drained from a mine by means of a ventilation system. The programmes take the following directions: - reduction in the emission of extra methane, dust and gas pollution by means of modernisation of boilers and building new production units, - expansion of power systems by production units based on gas engines for combined generation of heat and power, - usage of methane in the installations of central air-conditioning of a mine (combined heating, cooling and power generation), - enrichment of methane mixtures, - storage of temporary excess of methane. Example of methane utilisation for mining air conditioning Since the beginning of 2001 in Pniowek oal Mine a combined engineering-cooling system, which is a modern engineering trigeneration power plant, has been in use. Trigeneration consists in generating three different forms of energy from one main source. In power engineering, generating heat, cooling and electric energy from methane original energy is called HP (ombined Heating, ooling and Power Plants). At present it is common all over the world to design (tens hundreds KW e ) cogeneration plants HP using natural gas obtained from biomass gasification, biogas from sludge gas or waste-refuse gasification [Szlazak J. et all 2001a]. Such systems BHP (Building ooling Heat and Power) are used to supply buildings, most frequently hotels in the regions where biogas occurs, with electric, heat and cooling power. Small trigeneration installations are most often equipped with gas turbines [Szlazak N. et all 2001a]. A combined engineering cooling system in Pniowek oal Mine with power of 6.4 MW e is the first of its kind in Poland; it uses a gas engine that enables generating the so-called low- and hightemperature heat, which is used to drive absorption chillers. A gas engine drives a generator of electric power, which is partly used in compression chillers. The concept of a fully combined system is based on the priority of cooling water for central air-conditioning in the mine. Therefore this system is strictly connected with the heat distribution and power networks in the mine. When either electric power or waste heat is not generated from gas engines, absorption chillers can be supplied by heat distribution network and compression chillers by power network. However, if this system operates properly, it generates an excess of electric and heat power, which are delivered to transmission networks. The system consists of two identical blocks operating simultaneously. One block includes the following pieces of equipment: - four-stroke gas engine of type TBG 6322 V 16 by DEUTZ ENERGY GmbH company with rotational speed of 1000 m -1, - electric generator by A. Van. Kaick company with rated power of 3993 kva, voltage 6.3 kv and frequency 50HZ,

8 from the second block of chillers - one set of chillers consisting of: - warm-water absorption chiller of type YIA HW 3B3 by YORK company (cooling power 600kW) called AKM1 in block 1 and AKM3 in block 2, - hot-water absorption chiller of type YIA HW 64 by YORK company (cooling power 1730 kw) called AKM2 in block 1 and AKM4 in block 2, - compression chiller of type YL 717 SE-SD 64 WO by YORK company (cooling power 570 kw) called SKM1 in block 1 and SKM2 in block 2. Volumetric intensity of cooled water in a closed system is equal to 150 m 3 /h and the total cooling power of one block is equal to 2.86 MW ch. The second block consisting of identical equipment is characterised by the same parameters. A simplified scheme of an installation of a combined system is presented in figure 3. gas from drainage system 3 25 m H 4 /min electric power 3,2 MW 6,3 kv heating network Flue chimnay high-temperature heat exchanger KOWT 100 o 125 o heating network mechanical cooling tower generating plant A.Van.Kaick G low-temperature heat exchanger MOWT gas engine TBG 6322 V16 85 o 70 o to the second block of chillers warm-water absorption chiller 600 kw 14,5 o o 3 18,5 150 m /h hot-water absorption chiller 1730 kw 4,5 o compression chiller 570 kw 1,5 o instalations with water coolers of air in mining areas o 3 17,5 300 m /h o 3 three-chamber pressure sluice Siemag Fig. 3. Simplified scheme of combined engineering-cooling system in Pniowek oal Mine Three-level cooling was used in order to cool water to adequately low temperature. After going through two absorption chillers, water is additionally cooled to temperature of in the third compression chiller. A combined system also generates 6.4 MW of electric power, which is used only in part to supply the whole power system. The remaining part of electric power is used for mining operations. It must be stressed here that gas engines in both blocks operate independently of a set of chillers. When chillers in one block do not work, both gas engines work. Sets of heat exchangers from cooling an engine and cooling exhaust gas can also be connected to a set of chillers in different blocks. Assuming kw of chemical energy in the drained stream of mining gas with the content of 50% vol. H 4, approximately 80% of fuel energy is transformed into electric power and heat in a combined power system. The participation of electric power amounts to approximately 38% and heat to app. 42%. Production of electric power amounts to app kw. As energy consumption of a combined system is equal to 788 kw a mining network can be supplied with app kw of electric power. In fact, power consumption is greater. Nominal electric powers of particular engines in the whole combined system, which affect the total internal consumption of electric power, amount to app kw (drives of heating water pumps in circulations of chillers, fans in a set of fan coolers and airconditioned room of gas engines etc.). A monthly consumption of methane (100% H 4 ) is presented in figure 4. The period of standstill in August and low gas consumption in February are confirmed. In the remaining periods average gas consumption oscillates around 1250 thousand m 3.

9 January February March April May June July August September October November December VH4, [m 3 ] Fig. 4 Value of gas consumption (100% H 4 ) in gas engines in a combined power system in Pniowek oal Mine in 2001 Summary In the mines of J a great quantity of methane is emitted during mining, out of which a substantial part (over 60%) is drained into atmosphere by means of a ventilation system. During the whole year approximately million m 3 is drained by a methane drainage system. The highest methane bearing capacity can be observed in Pniowek oal Mine, where methane emission in 2001 was over 45% of the whole emission in all the mines of the company. In this mine app million m 3 of methane is drained while the effectiveness of methane drainage system amounts to app. 37%. An increase in the effectiveness of methane drainage and full utilisation of gas drained may yield significant economic results. For instance, an increase in effectiveness by 1% results in app. one million m 3 of methane drained worth 150 thousand zloties. An improvement in effectiveness of methane drainage and utilisation of drained methane lead to greenhouse effect and affect ozone concentration in upper layers of atmosphere. These phenomena significantly affect global climatic changes. This paper presents rational and environmentally friendly technological solutions applied by the mines of J, aiming at limiting methane drainage into atmosphere and firstly at economically profitable methods of its proper utilisation in electrical power engineering. Trigenerational power system (HP) in Pniowek oal Mine, designed especially for mining air-conditioning, achieved fully satisfying parameters in A unit co-efficient of fuel power consumption (methane and air mixture) shows that in the second half of the year in block 1 of chillers, 34% to 42% of stream of cooling power was obtained from a stream of original energy supplied. Therefore a combined system of generating electrical and heat power for air-conditioning is characterised by the highest level of power effectiveness in the conditions of Pniowek oal Mine, despite an irregular work of gas engines caused by the quality of fuel obtained form the mine. It significantly reduces the costs of air-conditioning in the mine. The article was written within Statutes Research AGH, No References Berger J., Nowak E. (1999): Methane capture by drilling methods from underground workings and the surface in the mines of Jastrzebie oal ompany. Published by Wiadomosci Gornicze, Publishing o. Ltd, No. 2, Katowice (polish text). Kozlowski B., Grebski Z. (1982): Methane drainage of rockmass in underground mines. Pub. Slask, Katowice (book, polish text). Nawrat St., Gatnar K. (1999): Economic capture and utilisation of coal-bed methane from the mining areas of Jastrzebie oal ompany. Published by Wiadomosci Gornicze, Publishing o. Ltd, No. 1, Katowice (polish text).. Roszkowski J., Szlazak N. (1999): The selected problems of methane drainage in coal mines. Dissertations, Monographies, AGH-UST Publishers, racow (book, polish text)

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