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ОЦЕНКА СДВИЖЕНИЯ ПОВЕРХНОСТИ НА УГОЛЬНОЙ ШАХТЕ АРГАДА (ИНДИЯ)
В.И. Пронин, ПДСумар
Российский университет дружбы народов ул. Миклухо-Маклая, 6, 117198, г. Москва, Россия
В статье рассматриваются возможные технологические схемы подземной разработки мощного угольного пласта Аргада (Индия). Приведены расчетные значения параметров сдвижения земной поверхности с учетом конкретных горно-геологических условий. Определена система разработки, оказывающая минимальное негативное воздействие на земную поверхность.
Burkunda Colliery, Kharanpur coal basin is located in Bihar state. Mine field incorporates a few coal seams including Argada seam with thickness 24 m and angle of dip 20°. The immediate roof is clay shales of 5-7 m thick. The main roof is sandstone of 12-17 m thick. The average depth of mining is 200 m. The only methods of coal winning with stowing are analyzed in the article. Taking into consideration the necessity to minimize the value of surface subsidence due to mining the methods of mining are considered only from this point of view. With the aim to obtain general representation about subsidence and deformations in case of Argada seam mining the forecast of above mentioned parameters was done. According to calculations the maximum subsidence will reach 4.7 m; tilt along the strike - 17,6 1 O'3, tilt along the dip - 18,3 10‘3. Horizontal deformations will be equal to: along the dip - 111 O'3, along the strike — 6.171 O'3.
Calculation of expected subsidence and deformations was fulfilled with respect to the following technological schemes of Argada seam mining: inclined slices (longwall along the strike and rise), horizontal slices; transverse - inclined slices; room and pillar across the strike. For the first technological scheme the maximum vertical displacement is (for the first slice) rim = 0,25m (0,28m in case of undermining), the tilt along the rise iyl = 1,72 1 O'3, along the dip iy2 = 2,2 1 O'3, along the strike ix = 2,8 1 O'3. Horizontal strains syi = ± 1,3 1 O'3; ey2 = ±1,9 1 O'3; ex= ±1,8103.
These parameters of the surface subsidence were derived for all above mentioned methods of coal winning
Introduction. Burkunda Colliery, Kharanpur coal basin is located in Bihar state. Mine field incorporates a few coal seams including Argada seam with thickness 24 m and angle of dip 20°. The immediate roof is clay shales of 5-7 m thick. The main roof is sandstone of 12-17 m thick. The average depth of mining is 200 m. The only methods of coal winning with stowing are analyzed in the article. Taking into consideration the necessity to minimize the value of surface subsidence due to mining the methods of mining are considered only from this point of view. With the aim to obtain general representation about subsidence and deformations in case of Argada seam mining the forecast of above mentioned parameters was done. According to
calculations the maximum subsidence will reach 4,7 m; tilt along the strike - 17,6 10‘3, tilt along the dip - 18,3 1 O’3. Horizontal deformations will be equal to: along the dip -111 0"3, along the strike -6,171 O'3.
Analysis. With the aim to obtain general conception of surface subsidence, tilt and strain in case of Argada seam mining the prognosis of above mentioned parameters was made. Maximum vertical displacement will make [1]
T]e = 0,9(mi+m2+...+m^ cosa, (1)
where mi, m2,...mn - effective thickness of slices being mined
m, = (hK+h,)fI-Bi)+B, m, (2)
where hK-roof and floor convergence before stowing; hH- incompleteness of stowing; Bi - coefficient of stowing material shrinkage; m - thickness of slice to be extracted.
Tilts of surface: along the strike - in.= 17,61 O'3; across the strike - iB = l 8,3 1 O'3.
Horizontal strains: across the strike - eB= 111 O'3; along the strike - en= - 6,17 1 O'3.
Maximum vertical displacement - 4,7 m.
Calculation of expected subsidence and deformations was fulfilled with respect to the following technological schemes of Argada seam mining: inclined slices (long walls along the strike and rise), horizontal slices; transverse - inclined slices; room and pillar across the strike. In case of long wall movement along the strike (along the rise) maximum subsidence according to [1] will make:
77,,, =qi, m, cos a N, N2, (3)
where qo - relative value of maximum surface subsidence; m, - effective thickness of i- slice; N,,N2 - coefficients, depending on relation of D|/Hav, D2/Hav; D, - longwall length, D2 - panel length, Hav - average depth of mining.
To plot the profile of surface subsidence trough the angles of draw were accepted according to [2, 3]:
Thus for the first technological scheme we have (for single slice): t|m= 0,25m (0,28m in case of second slice winning); maximum tilt along the dip tyi=l,72i0'' (1,92 1 O'3); maximum tilt along the rise iy2 = 2,2 10'3 (2,46 1 O'3); maximum tilt along the strike ix =2,8 10"3(3,14 10'3). The same for horizontal strains: syl=±l,3 10'3; ey2=± 1,9 1 O'3; ex = ± 1,83(2,05) 1 O'3
In case of long wall movement along the strike we have: iyi=2,2 10'' (2,46 10" ), iy2 =-3 10'3(-3,36 10'3), sy = +0,95-1.7 10'3 (-1,910'3), ix = 1,75 10'3( 1,96 10'3), ex = 1,5 10'3(1,68 10'3).
When coal winning is done by horizontal slices the length of the face is 75 m. In the direction across the 1 = 2,76 1 O'3, s = -1,83 10 3. The parameters of the trough along the strike will be the same as for inclined slices with coal extraction along the strike.
In case of transverse - inclined slices iy = +3,65 -2,2 10'\ eyi = +0,72 -1,85 1 O'3, ey2=-1,85+1,12 10'3.
Technological scheme of coal winning by room-and-pillar method required calculation of safe dimensions of pillar and chamber. Computer program was used and the width of the room was found equal to 6m, the pillar width - 10 m. Subsequent calculations showed that the width of the pillar can be reduced to 8 m taking into account the thrust of backfill.
Results. The maximum tilt was obtained for transverse-inclined method which is equal to 3,65 per one slice with backfiring. In case of coal winning by horizontal slices subsidence parameters are the same as for longwall along the rise: tx =2,8-10',
ех=1,85-10'3. In case of longwall advance along the strike the tilt is equal to 3 1 O'3 and this is the maximum value for all data obtained. If to take into consideration that the mechanized longwalls are not widely spread in India the application of room and pillar method with backfill may be most attractive from the point of surface protection.
Conclusions. During recent years with an increased concern fore the environment more and more attention is paid to mine subsidence. Thus at present time the assessment of coal winning method should be not only from technical and economical point of view. Surface subsidence parameters have to be taken into account.
REFERENCES
1. Правила охраны сооружений и природных объектов от вредного влияния подземных горных разработок на угольных месторождениях. СП6..ВНИМИ, 1998.
2. Singh, T.N. Underground Winning of Coal. New Delhi. Oxford & IBH Publishing Co.Pvt. Ltd.
3. Mine Subsidence. Edited by B.Singh. SMRS. Dhanbad, India, 1988.
SURFACE SUBSIDENCE ASSESSMENT FOR ARGADA SEAM MINING (BURKUNDA COLLIERY, INDIA)
V. Pronin, P. Kumar
Russian Peoples’ Friendship University Mikluho Maklaya, 6, Moscow>, 117198, Russia
Master of Science, India, Russian Peoples' Friendship University Mikluho Maklaya, 6, Moscow, 117198, Russia
In article possible technological schemes of underground mining of powerful coal layer Argada are considered. Settlement values of parameters сдвижения a terrestrial surface in view of concrete mountain-geological conditions are resulted. The system of development rendering the minimal negative influence on a terrestrial surface is certain.
Пронин Владимир Иванович, канд. техн. наук, профессор кафедры Нефтепромысловой геологии, горного и нефтегазового дела РУДН. Автор более 90 публикаций в области подземной добычи угля и природоохранных технологий разработки месторождений полезных ископаемых.
Кумар П., аспирант кафедры Нефтепромысловой геологии, горного и нефтегазового дела (Индия).
