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Actuality of master's degree work
Practical utility of degree work
Relevance and the purpose of work
Current and planned results on the subject of researches
Actually an about 30% of Donbas coal is won on outburst-prone and endangered coal veins using measures for coal and gas blast prevention [7]. Gas-dynamic effects (GDE) at seam mining and most difficult of them - gas and coal outbursts, lead to loss of life and highly economical outlays. The workings are whelmed by the extruded coal on considerable distance (to 200 m and more).A mining equipment is deranged. A lining is ridded up and becomes distorted. Roaches are deteriorating. Workings are filled with a gas. It results in the long-term outages and attended with the danger of coal dust and gas explosion in workings. Rectification of the consequences of blast take toll on the technical-and-economic indexes of mines work.
At the moment the following complex of measures is used on the mine named after F.E. Dzerzhinskogo during delf of lift 1146 m:
— current predication of outburst zone on seism-acoustic activity of coal seam;
— concussion blasting or shearer mining with the use of hydro loosening and by control of hydro loosening efficiency on the dynamics of gas emission [1].
Taking into account high probability of the coal and gas blast in the opening, will consider the possibility of application seism-acoustic methods of control which was developed in MAKNII in the last years. The prognosis of outburst hazard on the parameters of acoustic signal consists in registration, processing and evaluation of spectrum signal, excited in a rock mass by the technological affecting him shearer, tunneling or chisel machines and mechanisms. An anticipating is conducted by the seism-acoustic signal transmission equipment (SSTE) and programming and computing suite. SSTE consists of underground block, containing a seismic pick-up and surface block. Programming and computing suite is the personal computer with a printer and is destined for registration, processing and analysis of acoustic signal parameters on the special program and determination about the anticipating results [4].
The proposed package takes into account the last developments in the sphere of the gas-dynamic phenomena anticipating, has more wide functional possibilities and higher anticipating integrity.
Consists in that, the anticipating of outburst hazard is carried out automatically using a computer by comparing of current values of acoustic signals predictor to their critical values. Due to it processing and analysis of acoustic signal parameters will become simpler, more tenable and more exactly
To implement modern ceaseless automatable and more tenable the gas-dynamic phenomena prognosis method and to carry out changeover of obsolescence and physically out-of-date equipment of the similar functionality. Due to it the decrease of accident rate and expenses will be well-to-do on overcoming of gas-dynamic phenomena consequences .
The basic researches contemplation is possibility of usage the degree work results in the Ukrainian coal mining industry.
Result’s of master's degree work will be used for recommendations for introduction and use of SSTE on mine named after F.E. Dzerzhinskogo, that will be able to furnish more easy and exact prediction.
Area of mine named after F.E. Dzerzhinskogo SE «Dzerzhinskugol'»forms part of Dzerzhinsk Donetsk region of Ukraine according to division.
The mine named after F.E. Dzerzhinskogo reposed in 1860. The last underground reconstruction was executed in 1987, which included the Pugachevka mains skip shaft reconstruction with a conjoined implementation of a new 1026 m level. The mine named after F.E. Dzerzhinskogo is removaled by four centrally disposed shafs: «Pugachevka», «¹4», «Central», and «New».
Shaft ¹ 4 passed to the mark 1213 m. A shaft is oriented for the fresh supply in a mine. At the same time a shaft serves for lowering and delivery of people from working levels 916 m and 1026 m, and also from the win level 1146 m.
A mine works off cragged seams with the angle of hade 560 -600 .
The mine named after F.E. Dzerzhinskogo is belonged to dangerous on the gas and coal outbursts. Mine absolute gas content is 22-67 m3/min, relative – 67m3/t. A mine ventilation method is exhaust . Exhaust air from a mine is given out by the main fan VCD-47U [3].
Geological summary of coal seam l3 Mazurka of working area 81-1146 m Coal height:
— geological - 0.67- 0.85
— useful - 0.60 - 0.65
— extracting - 0.77- 1.17
— Seam and waste angle of slope 60-620.
A coal seam along the whole length of the mine section has a complex structure. Lower (basic) patch has a height 0,60 – 0,65m - coal is semibright, stratified structure, with inclusion of sulphuric sulphides lenses, cracky, dip azimuth cavity is 50, angle of slope is 55.Coal is nesh and medium hard. Coal broken condition type is II. Laminal grapholith "sound" for pressure by thickness of 0.02-0.05m deposits above. Laminal flowing tender carbon-bearing shist intermittently transients in coal by thickness of 0.05-0.09m spaces higher . Broken condition type is III. Lenticular structure fitchery carbonaceous-argillaceous shist deposits higher and forms draw slate, by thickness 0.10-0.32m
Coal seam joint with enclosing roof and floor are distinct, overhead - "sound" for pressure, lower - tender.
Ñîal seam hypsometry is smooth, coal is close-burning, coal rank is met bituminous . Natural gas content is 20 – 22 m3/d.a.f.b., devolatilization is 28.2 – 30.0%, coal ash-content is 32.5-37.5%, sulfur content is 3.1-5.8%, moisture is 1.5 -2.2%. Coal hardness on the scale of prof. Protod'yakonova is 1.0 -1.2, unit specific gravity is 1.32t/m 3.
A coal seam is dangerous on the gas and coal outbursts, dangerous on coal fall, dangerous on coal-dust explosibility, prone to spontaneous ignition, on rock bump is not dangerous. Workings walkable thru a coal seam are potential danger on the methane inrush from a footwall[3].
For outburst hazard checking an acoustic signal, nascent during work of combined machine on a long wall, is transmitted on a surface through the SSTE and became computer fodder for post processing. Two seismic pick-ups are placed on the wall opposite the conveying belt of 5-25m and 15-40m from a longwall for registration of acoustic signal. Seismic pick-ups is set in holes long 0,3-0,7 m, it is squeezed up against by a holing block to the overhead wall and wedged against for providing of reliable contact with a mountain group [9].
From the SSTE underground block a signal is transmitted by the loop line in a surface block, from there it passes to computer, where this datamatics is executed on the special program, and tape recorder for a reference recording. During every new setting of seismic pick-up overman or locksmith makes tuning of magnifying, for what during combined machine work on a longwall from the lower limits of magnifying of it on a concordance with an operator increase. An operator fade processing program of outburst hazard prognosis and determines the level of signal during combined machine work on the longwall.
Outburst hazard control on the acoustic signal parameters is carried out during combined machine work on a longwall. Registration and acoustic signal processing is carried out continuously within the limits of one combined machine work cycle s of which for outburst-prone seams to 1,1m. Before the beginning of combined machine work overman or leader must call on seismostation and report about position of longwall and combined machine cut-in on a longwall. An operator fade processing program, write in a passport, identify a noise level and proceeds to the acoustic signal processing. An operator registers position of longwall, size of hindrance and useful signal. After the coulisse of coal and breed on one cycle of longwall pushing combined machine work is stopped, overman or leader inquires operator about the prognosis results. If on results the signal processing a computer estimated a situation in a longwall as not dangerous, an operator settles the coal and breed coulisse on a next cycle, registers the results of prognosis. If a computer gave out a report «near-accident», it is necessary to halt works on a longwall, to report about it to over in a longwall, to the shift man (with a parallel record, on a tape recorder). Report on the computer display a «near-accident» testifies to included of longwall in a dangerous area. A prognosis is «dangerously saved» no less 6m (area of supply) on motion working from the moment of report «near-accident». In a magazine an operator does the proper record, unseals the prognosis results and acquaints with them under signed receipt of service chief [4].