Summary:
The Jagannath Area lies in the Talcher Coalfield of Odisha, consisting of coal-bearing formations of the Lower Gondwana era. The main geological units are the Talchir Formation (basal shales/sandstones with no coal) followed by coal measures of the Karharbari and Barakar Formations.
Coal seams occur primarily in the Barakar and upper Karharbari measures. The Barakar Formation seams in Jagannath and Ananta OCPs are typically thinner but more numerous. Overall seam gradients are mild (on the order of 1 in 10 to 1 in 25) reflecting the broad gently-folded structure of the Talcher basin.
In the Jagannath OCP expansion block (Padma block), six coal seams have been identified. There are five seams are workable (from Talcher II to Talcher V A).
In the Ananta block, there are total 21 seams, out of which 18 seams are workable.
Bhubaneswari mine
Bhubaneswari block is located in the eastern part of the Talcher coalfield in Odisha state. Barakar and Karharbari are the two coal bearing formations in the block with Barakar being the store house of majority of coal seams (II to XV).
The sedimentary strata of this block are recent sediments, Barakar, Karharbari and Talchir Formations lying over Pre-Cambrian metamorphic basements.
Mostly soil, alluvium or weathered mantle cover the area in succession. As such, the geological features of the block are interpreted mainly on sub-surface data. The sub-surface borehole data as well as floor contour and cross-sections across the block reveal that the block is traversed by 25 faults, trending both east-west and northwest-southeast. Some east-west trending faults dip northerly and some southerly. Fault F1-F1 traverses midway through the block dividing the block into two sectors, with throw varying from 8-120m.
Sequence of coal seams and its description
In this block altogether 31 distinct splits/combination of Barakar Formation, including 4 local seams in ascending order viz, Seam-II BOT, II COMB, II TOP, L0, III BOT, III COMB, III TOP, Loc 1, IV+Loc 1, IV, Loc 2, V, Loc 3, VI A TOP, VI A, VI A BOT, VI B TOP, VI B BOT, VII, VIII TOP, VIII BOT, IX, X, XI TOP, XI BOT, XII TOP, XII BOT, XIII TOP, XIII BOT, XIV, and XV. Out of these, 1 local coal seam L0 has been identified as either not so potential or having localized development and hence, is not dealt in detail. The remaining 30 coal seams of Barakar Formation from seams II BOT to XV including three locals Loc 1, Loc 2, Loc 3 are studied.
The geological exploration has established 13 coal seams of Barakar formation for opencast quarrying, including 3 local seams, occurring as 22 distinct splits, viz. Seam II Bot, II Top, II Comb, III Bot, III Top, III Comb, L1, IV, IVL1, L2, V, L3, VIAB, VIAT, VIBB, VIBT, VII, VIII Top, VIII Bot, IX, X, XI Bot and XI Top occurring in ascending order.
Among these, seam II TOP, II COMB, V, III COMB, IV and IV+LOC 1 are the most potential coal horizons in this block.
This integrated block is covered by soil of thickness varying generally from 0.6 metres to 8.6 metres. It consists of sandy soil, clay and lateritic soil.
The general thickness of weathered mantle ranges from around 3.3 metres to 13.6 metres and consists of laterite, sandstone, sandy shale, intercalation of shale and sandstone, carbonaceous shale etc.
The coal seams occurring in this integrated block are interbanded in nature. The coal is generally having high moisture, high ash and high volatile matter contents and belongs to sub-bituminous rank under non-coking coal category. Moisture %, Ash% and VM% on 60% RH & 40oC generally vary between 2.8–10.7 %, 11-65 % and 18-35 % respectively on I100 samples. Generally the grade of the coal seams varies from G9 - G12.