Pathakhera Area is operated by Western Coalfields Limited (WCL), a Mini Ratna (Category-1) company and a wholly owned subsidiary of Coal India Limited (CIL), which is a Government of India undertaking.
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Summary:
Chhatarpur-I UG and Chhatarpur-II UG mines
The existing Chhatarpur-I UG and Chhatarpur-II UG mines are situated adjacent to each other in Pathakhera Coalfields, which is the western-most extension of Pench-Kanhan-Tawa Valley Coalfield and is situated in Betul district of Madhya Pradesh. The Coalfield is located in the Southern limb of Satpura Gondwana basin.
Pench-Kanhan-Tawa & Satpura Valley Coalfield covering an area of about 8457.74 sq. km. lies in the Chhindwara and Betul district of Madhya Pradesh. This coalfield has been divided into four parts: Pench, Kanhan , Tawa and Satpura. It is bounded by Latitude 21°45' to 22°45'and Longitudes 77°45' to 79°15' and located in the central part of India.
Structure
The Pathakhera Coalfield is situated in the southern limb of the East-West trending Satpura Gondwana basin, which is also the western continuation of Pench-Kanhan Valley Coalfield. Major part of the coalfield is soil covered except for the eastern and north eastern part. The structural interpretation of the coalfield has, therefore, been established almost entirely on subsurface data accruing from boreholes and underground workings. The lay and disposition of the coal bearing barakars has been arrived at the floor of the most consistent and workable coal horizon namely lower workable seam in this coalfield.
The following major structural features have already been established in Pathakhera Coalfield:
i) The monoclinally northerly dipping Barakar formation in Pathakhera Coalfield trend E-W with significant local variations in their dip and strike including reversal of dip direction associated with anti and synforms.
ii) Board antiforms have been deciphered in the undeground workings of Satpura-II mine.
iii) Coal bearing barakars are trending NNE-SSW towards the east in the vicinity of Tawa Extension/Tawa bloks dipping WNW with angles varying between 1.5° to 15° with general dip of 5°. The strike of bed curves to attain almost E-W trend in the central part of the coalfield i.e. in Pathakhera mine I and II, Satpura Mine-I, eastern part of Satpura Mine-II etc. The westward continuation of the strike around the vicinity of Satpura-II mine shows the development of a broad dome-like antiform which merges westwards into an E-W trending northwardly dipping monoclinical surface. Further towards west two roughly ENE-WSW elongated synforms with a corresponding antiform west of their axis of elongation have been interpreted within the Umri block. Hinge faults upto throw of 150 m are present.
Strike and Dip
The general strike of coal seam as revealed by floor contour is E-W dipping to the north at a gradient of 1 in 7 to 1 in 8. The strike of coal seam in the eastern part of the proposed area is NE-SW dipping towards NW. The gradient in this area is 1 in 6 towards north.
In the southern part of the middle of combined Chhatarpur-I & Extension block including Umri block, the strike of the coal seam varies from ENE-WSW to NE-SW to NNE-SSW dipping towards north-west. The gradient in the rise side is steeper and it flattens out in the dip side.
In the north-central and central part of the combined block, complete reversal of the dip towards south has been found. The strike of the formation in this area swings from NE-SW in the eastern part to NW-SE in the western part.
In the extreme western part, the strike is almost N-S in the northern side with easterly/south easterly dip and in southern side, strike swings to NW-SE to E-W with southerly dipping.
Description of Coal Seams
In Pathakhera Coalfield, four main persistent coal seams in addition to thin carbonaceous horizons have been deciphered. The four main seams are IA Seam, Bagdona Seam, Lower Workable Seam and upper Workable Seam in ascending order. The younger two seams i.e. Lower Workable Seam and upper Workable Seam are by far the most consistent Bagdona Seam is generally workable in the central and eastern parts of the coalfield and is generally unworkable in the Southern and Western parts of the coalfield. The lower most seam i.e. IA Seam is mostly unworkable in the coalfield but has attained workable thickness in the western and eastern part of the coalfield.
Seam thickness range: 0.9 m to 5.6 m.
Tawa-III mine project
Tawa Extension Geological Block is located in the North Eastern part of Pathakhera Coalfield and lies to N.E. of the existing mines and the Tawa Block across the Tawa River.
Two underground mines namely Tawa-II and Tawa-III have been projected in Tawa Extension Geological Block. The existing Tawa-II UG mine is located in a part of Tawa Extension geological block on the southern side of Fault F3 - F3 and dyke. The proposed Tawa-III mine has been envisaged on the northern part of Tawa Extension geological block beyond the northern mine boundary of Tawa-II UG mine.
Tawa–III U/G mining area is characterized by rugged topography dissected by numerous nalla cuttings. Generally the sandstones are massive and it is not possible to determine the strike and dip. However, at places the strata is found to exhibit a NE – SW trend dipping towards NW at an angle varying from 5° – 15°.
Dip and Strike
The structural interpretation of the Tawa–III U/G mining area has been mainly deciphered on the basis of sub-surface data generated through drilling and is presented in the form of Seam Folio plans of Upper Workable Seam, Lower Workable Seam, Bagdona Seam and IA Seam. The general trend of the formation in the area is N – S dipping towards W at a gradient of 1 in 7.5 to 1 in 10.0 i.e., 5.5° to 7.5° dip.
Description of Coal Seams
Presence of all the four correlatable coal seams of Pathakhera Coalfield i.e. Upper Workable Seam, Lower Workable Seam, Bagdona Seam and IA Seam has been established by drilling in Tawa-III U/G mining area. However a general reduction in thickness of the different seams as compared to the central part of the Coalfield has been observed.
The Upper Workable Seam, the topmost seam of the Coalfield has generally reduced in thickness in Tawa-III U/G mining area. Apart from reduction in thickness, several carb shale and shale bands have developed in the seam rendering it practically unworkable in the mining area.
The thickness of the Lower Workable Seam is workable but it has also reduced as compared to the central part of the Coalfield. Bagdona Seam, however, has maintained its thickness, whereas Seam IA has attained workable thickness in Tawa-III UG mine area. In the central part of the block, Seam IA has developed a splinter seam designated as Seam IB. This splinter seam has limited extent and erratic behaviour and is unworkable.