Summary:
All mines of the Pench Area are located within the Pench-Kanhan-Tawa Valley Coalfield, which is occupied southern limb of Satpura Gondwana basin.
Dhankasa UG mine is located in the Geological blocks of Dhankasa Block (5.20 km2) and a small part of Naheriya Block - Sector-4 (0.30 km2), is in structural continuity with Sector-3 of Dhankasa block. Sector-4 of Naheriya geological block was not included in Naheriya UG mine due to 20-30m down throw fault F8(N)-F8(N) and Gunor River flowing over this sector. These Geological Blocks are located in the north-eastern part of Pench-Kanhan Valley Coalfield.
Strike And Dip
The strike of the coal seam is in general NE-SW swerving to NNE-SSW. However, local undulations and drag effects can be seen near the faults. The dip of the coal seam, in general, is towards north-west and varies from 3° to 6°. The gradient is varying from 1 in 10 to 1 in 20.
The Geological Block of Dhankasa is divided into 17 sectors and having 12 nos of faults with throw varying up to 40m.
Description Of Coal Seams
Exploration in Dhankasa Block has confirmed the presence of all the five major coal seams (and their sections) of Pench-Kanhan Valley Coalfield, namely: I, II, III, IV and V in descending order. The youngest Seam-I is represented by three sections namely, IA, IB and IC. Seam-III and IV occur as coalesced as well as split sections designated as Top and Bottom. Seam-II and V occur as independent seams.
Two seams (Seam II & IV) with thickness ranging from 3.50 m - 4.75 m are workable (excluding intervening parting). Grade of coal is G-7. Degree of gaseousness is Degree-I while gradient is 1 in 14.
The Naheriya Geological Block forms eastern to north – eastern contiguous part of Urdhan Block and Thesgora Block “B” of Pench – Kanhan Valley Coalfield, DistrictChhindwara, Madhya Pradesh. Naheriya UG Mine falls under Naheriya Geological Block.
Seam-I occurs in 3 sections: IA, IB, IC designated form top bottom. The Section – IA is very thin, impersistent and very poorly developed within the block. It has not attained workable thickness of more than 0.90 m anywhere in the block. Seam – I cannot be considered from exploitation point of view.
The Seam – II ranges in thickness from 0.31 m to 3.13 m (Average thickness 2.20 m) whreas Seam –III ranges in thickness from 0.18 m to 2.34 m (Average of 1.70 m) Both the seams have a parting of 3 m in whole mine field except at the boundary of the dip side property, as such, both the seams namely Seams – II & III are to be mined out contiguously in the rest of the area. Beyond fault F6(N) upto Fault F8 (N), only Seam – II has developed whereas the thickness of Seam – II is less than 1.2 m and the parting between Seam – II and Seam – III in this sector [F6(N) & F8 (N)] is by and large less than 3 m. As such, in this area, only Seam-II will be worked, by driving drifts across Fault F6 (N).
Seam – IV ranges in thickness from 0.65m to 5.04 m (average 3.25 m) whereas Seam – V ranges in thickness from 1.19 m to 3.48 m (average 2.45 m). An iso-parting line of 3 m has been drawn on seam folio plans of Seam IV & V. it can be seen that Seam-IV might be worked in larges area, because of its adequate thickness compared to Seam–V. Panes 1, 2, 3, 5, 6, 8, 8A & 8B might not be worked in Seam –V, as it maintains a parting of less than 3 m with Seam-IV in these panels. Panel-9 might not be worked in Seam-IV, as its thickness is less as compared to Seam-V and parting between Seams-IV & V is less than 3 m in most of the area of this panel but it will be worked in Seam-V.
The gradient of seams varies from 1 in 11 to 1 in 18.
The Mahadeopuri underground mine is located in the northern part of the Sial Ghoghri Block within the Pench-Kanhan coalfield.
In Vishnupuri, occurrence of five seams has been observed that have mostly been splitted into different sections separated by partings. The uppermost workable seam is seam-IA and lowermost workable seam is seam-VB/VB2. The seams include I/IA, IB/IB+IC/IC, II/IIA, IIB, III, IV/IVA, IVB, VA /VA1, VB/VB2, VC & VD.
Four seams namely Seam-VB2, Seam–IVA, Seam –III & Seam-IC with thickness ranging from 0.1 m - 5.38 m are workable.
Urdhan-Jamunia Block (Dip Side Area) contains five regionally co-relatable consistent coal seams within Barakar Formation with even its splits occurring as individual coal seams. Depending upon their thickness, stratigraphic positions, quality and consistency in occurrence over considerable part of the block under report, a total number of 11 corelatable coal seams, viz., Seam I, Seam II Top, Seam II Middle, Seam II Bottom, Seam Local, Seam III, Seam IV Top, Seam IV Middle, Seam IV Bottom, Seam V top & Seam V Bottom in descending order are identified. Among these, Seam II Middle, Seam III and Seam IV Middle are found to be major coal seams.