The document summarizes the stratigraphy, exploration methods, and drilling techniques used in the Kothagudem Coal Belt in Andhra Pradesh, India. The stratigraphy includes the Talcher, Barakar, and Kamathi formations from the Permian period. Exploration has involved surface mapping, borehole drilling, and geophysical surveys. Drilling methods used include rotary, wireline, and diamond drilling to obtain core samples. Geophysical logging of boreholes provided data on coal seam depths, thickness, and faults through measurements of spontaneous polarization, resistivity, and natural gamma radiation.

1. Stratigraphy, Exploration and drilling methods of Kothagudem Coal Belt,
Khammam District, Andhra Pradesh.
Vadde.Ramesh1, Dr.V.Swarup Kumar1, K.Sagar2
1Department of Geology, Andhra University, Visakhapatnam-530003
2L&T InfoTech Limited Chennai
Vadde.ramesh@gmail.com
ABSTRACT
The Kothagudem coal belt is about 15km length, form an integral part of Godavari
Valley field in its Southern Part and the Northern western Margin. Generalized stratigraphy of coal
measures of this area based on the geological mapping and interpretation subsurface borehole data.
Staratigraphic succession in Kothagudem coal belt, Permian age, lower gondwana group, formations
Talcher –green grey sandstone and clays , Barakar-Dominatly sand stone with three regionally prominent
coal seams and subordinate shale/clays, Kamathi-Coarse to pebbly feldspathaic sand stone with shale and
clays. The depositional trend appears as a crescent shape and shallow towards the out crop side while its
gradually deepens in the dip side i.e. away from the basin margin which was also studied by isopach map
in this coal belts shows Folds and faults structural features.
Exploration methodological prospects in kothagudem area, the exploration work carried out
by both SCCL and GSI Including regional and detailed surface and surface exploration investigations.
Drilling id the process of mining holes in the ground or rock. It has been employed in
geological work for Prospecting, Exploration, Blasting, during exploration for development drills may be
manually operated or mechanically operated either by compressed air, water under pressure, petrol or
diesel engine, electricity, high temperature flames and rarely steam. Kothagudem coal belt to drill
borehole of the study of sub-surface data, the rotary, Wire- line and Diamond drill types are used,
methods of drilling indicates that the entire area first divided into grids according to grid plan with an
interval between bore holes in of 400m. These are two types of drilling operations carried out at
kothagudem coal belt-1.core drilling, 2.none- core drilling. During core drilling to note roof rock, coal
seams, inter seam parting etc. Details drilling operation carried out with diamond or Tungsten Carbide
bits.
The Geophysical methods of exploration carried out in kothagudem coal fields include Geophysical
Survey and geo physical logging methods. Geophysical survey electrical resistivity surveys of exploration
horizontal resistivity profiling Vertical Electrical Soundings (VES) were conducted to delineate the in
crop horizon of coal seam and various faults located. Geophysical logging has been conducted at borehole
drilled by Singareni Calaries Company Limited (SCCL) and Geological Survey of India (GSI) at
kothagudem by exploration wing, using EG&G Mount SO Pris Instrument Ltd. USA Series-III-
Geophysical logging system. The borehole logged for spontaneous Polarization (SP), Resistivity natural
Gamma of the strata. Entire borehole converted by geophysical logging to the interpretated depths and
thickness of coal seams and dirt bands along with some log exposure.
The highlighted in the studies Geological importance of kothagudem coal belts, exploration and drilling
methods and geophysical methods of kothagudem coal fields.