The Singareni Collieries Company Ltd.
CONCEPTUAL REPORT OF LAKSHMIDEVIPET LONGWALL
1.0
LOCATION
The Lakshmidevipet Longwall Project is carved out of two
geological blocks viz., Lakshmidevipet – Palampet Block and
Peddapur Block in the north-western part of Mulugu Coal Belt.
These blocks fall in the Venkatapur Mandal of Warangal District of
Andhra Pradesh in Godavari Valley Coalfield. The Lakshmidevipet
Longwall includes Sector B of Peddapur Block and Lakshmidevipet
Sector of Lakshmidevipet – Palampet Block.
The Mine Block is bounded by North Latitude 180 17’ 55’’ to 180 20’ 35’’ East
Longitude 790 55’ 19’’ to 790 59’ 28’’. It is covered in Survey of India Topo
sheet No.56N/15.
2.0
COMMUNICATION
Mallayapalli -Laxmidevpet PWD road which connects the Pasra-Ghanpur
PWD road at Palampeta is passing through the central part of the
Laxmidevpet Sector. Nearest railway station is Jammikunta, 50 Km away
from Laxmidevpet Village as crow flies. Pasra-Ghanpur PWD road is
passing at 6 Km away towards south of the block. The district head quarters
Warangal, is located about 70 Km South east of Bhopalpalli.
3.0
PHYSIOGRAPHY
The ground level varies from 188.83m above Mean Sea Level (MSL) to
237.33m above Mean sea Level (MSL). In general the area is of gentle
undulatory.
4.0.
LAND USE PATTERN
Out of the total Mine block area of 9.258 Sq. Km (3.018 Sq Km Sector B of
Peddapur Block and 6.24 Sq Km Laxmidevipalli Sector) about 1.35 Sq Km is
covered by the Lakshmidevipet reserved forest. The remaining area of 7.908
Sq km is Non forest land. Out of which 0.227 sq Km is under habitation i.e.
three villages Porkapalli, Anandapur and Patwaripalli.
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4.1.
SURFACE FEATURES
Most of the area is covered with paddy fields and forest area. The surface
features are three villages (Porkapalli, Anandapur & Patwaripalli), seasonal
small nallahs, three small tanks, power line and the PWD road connecting
Mallayapalli to Palampeta.
5.0
MINE BOUNDARIES
The Mine block boundaries are
a. NNW-ESE
Boundary fault
b. South West Incrop of IVA seam
c. South East
Fault F3-F3
d. North west
split line of III seam in Peddapur Block
6.0
GEOLOGY AND STRUTURE
Barakar and Barrren measure formations are exposed in the mine block.
Total about 128 boreholes have been considered for the assessment, out of
which 39 are in the sector B of Peddapur block & 89 are in Lakshmidevipet
sector. The borehole density is 13.8 BH/ Sq km.
The general attitude of the coal measures is WNW to ESE with
corresponding north easterly dips. The gradient of the seams varies from 1
in 2.8 to 3.3. The entire block is virgin.
6.1 GEO-ENGINEERING PROPERTIES
Studies on geo-engineering data indicated that the roof rocks of all seams of
Peddapur Block are poor to excellent and roof rocks of all seams of
Lakshmidevipet are Fair to Good.
PEDDAPUR BLOCK
Compressive
strength of roof
Seam
rock in Kg /sq cm
IA
79 - 312
I
95 - 340
II
112 - 676
Roof
Fine to Medium grained
Grey white sandstone
Medium to coarse grained
Grey white sandstone
Fine to Medium grained
Grey white sandstone
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Floor
Medium to coarse grained
Grey white sandstone
Fine to Medium grained Grey
white sandstone
Fine to Medium grained
Grey white sandstone
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LAKHSMIDEVIPET SECTOR
Compressive
strength of roof
Seam
rock in Kg /sq
cm
IA
I
259 - 405
170 - 583
II
172 - 543
IV
223 - 666
7.0
Roof
Floor
Medium to Course grained
Grey white sandstone
Medium to Course grained
Grey white sandstone
Sandstone/ shale /carb.
shale
Medium to Course grained
Greywhite sandstone
Sandstone/ shale /carb.
shale
Sandstone/ shale /carb.
shale
Medium grained Grey
sandstone
Sandstone/ shale /carb.
shale
DESCRIPTION OF COAL SEAMS
7.1
SEAMS PRESENT
Total 10 seams are present in Peddapur Block namely, IB, IA, I, II, IIIB, IIIA,
III (split into two sections), IVA & IV and Index below IV. 13 coal seams are
present in Lakshmidevipet sector viz. IB, IA, I, Index, II, Index, IIIB, IIIA, III,
IVA, Index, IV and Index band.
7.2
SEAMS ASSESSED
IB, IA, I, II, III (Top section) and III (Composite) are assessed in Peddapur
Block. Where as 6 seams are assessed in Lakshmidevipet sector namely IA,
I, II, III, IVA, and IV seams
7.3
DETAILS OF COAL SEAMS OF LAKSHMIDEVIPET BLOCK
Seam
Depth
Usual Thickness
IV
34.55 - 367.53
1.2
Parting
11.36-25.90
IVA
37.60 - 352.70
Not considered
III
38.85-320.20
Not considered
II
35.90-297.35
2.0
26.03-36.50
61.50-70.54
30.81-41.30
I
43.40-277.00
2.5
IA
39.10-246.20
1.5
23.38-33.10
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7.4
DETAILS OF COAL SEAMS OF PEDDAPUR BLOCK
Seam
III (Top)
Depth
52.33-352.80
Usual Thickness
Not considered
II
37.00-340.00
2.0
I
49.45-332.69
2.5
IA
36.11-296.60
1.5
Parting
52.52-72.50
24.10-38.90
27.85-33.49
16.45-22.60
IB
8.0
44.55-275.84
Not considered
GEOLOGICAL & EXTRACTABLE RESERVES OF WORKABLE
SEAMS
In Sector B of Peddapur Block, IB seam& III seam are thinned down to less
than 1m. No. IB seam has attained workable thickness only in 6 Boreholes
and No. III seam has attained workable thickness only in patches. Hence
these two seams are not considered for extraction.
In Lakshmidevipet sector, most of the area of III & IVA seams is also thinned
down to less than 1m. Hence these two seams are not considered for
extraction.
The details of reserves of workable seams/ sections are presented below.
Geological
Extractable
Reserves(Mt)
reserves (Mt)
IA
9.778
3.91
D
I
18.718
9.46
F
II
19.815
9.31
F
IV
12.444
6.23
C
Total
60.755
28.91
Seam
Grade
The total extractable reserves in Lakshmidevipet mine are around 28.03 Mt.
9.0
METHOD OF WORK
Longwall retreating with caving is chosen as the principal method of mining
in all the seams for the following reasons.
a)
b)
c)
Large extent of property
Potential for Bulk production
To work in steep gradients with better strata control
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d)
e)
10.
Higher percentage of extraction & productivity
Concentrated workings and higher standards of Safety
MODE OF ENTRIES
Four tunnels are proposed from surface, two to No. IV seam & two to No. II
seam for coal transport, conveyance for men, haulage and ventilation.
Further two additional inter seam tunnels would be driven from II seam to IA
seam to work in IA & I seam.
10.1
MINE VENTILATION
Four Inclines will serve as Intake airways and one return air shaft is
proposed up to IV seam by connecting all seams.
10.2
COAL TRANSPORT
From II seam and IV seam trunk belts are planned up to surface. On
surface, a bunkerage of 2000T is provided. Coal from IA & I seam will be
transferred to II seam trunk belt through CCD (central coal drift)
10.2
PUMPING AND DRAINAGE
Two main sumps are proposed in II seam and IV seams. Water from IA
seam and I seam will be conveyed to main sump of II seam through
boreholes.
11.
PRODUCTION CAPACITY AND TECHNOLOGY
The production capacity of the project will be about 1.5 MTPA. To achieve
this, Two Longwall units suitable to 1.2-1.5m & 2.0-2.5m height of extraction
along with 3 Road headers and 3 Nos of SDL are envisaged.
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LIFE OF THE PROJECT
The life of the project will be around 22 years including construction period
at a production rate of 1.5 MTPA.
***
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