Information Memorandum for Thar blocks 2010.pdf - Sindh Board Of ...

Groundwater Source. The past investigation drilling revealed that the coal is in-seams with
extractable thickness of 22 m at a depth of 110 m up to 200 m. The upper seam layer of coal
reserve also reportedly contains in-situ water. A recent, bankable feasibility study in the block 1
area has given the following information:
Groundwater is present in mainly three different horizons.
- The base aquifer with pump tested transmissivities of 7.9x10-3 and 1.8x10-3
m²/s is extending throughout the exploration area at a thickness of about 60
meter. This aquifer has an extension in the Thar Desert of about 15,000 km².
Recharge is possibly from the Northeast beyond the Indian border.
- The middle aquifer is composed of a variety of mainly disconnected sand
lenses and channels with partly high silt content and low permeability within
the lignite bearing Bara Formation and the Subrecent Formation. Recharge to
these aquifers is likely to be poor.
- The Dune Sand Formation acts as a top aquifer with a water column of few
meters only at the formation base on top of the Subrecent. Permeability here
is in the range of 10-5 m/s. Recharge of this aquifer is direct through rainfall
infiltration.
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