||2,03,000 sq km
||Telangana and Parts of Andhra Pradesh(North of 15° Lat.)
Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy, South Central Region
AMD Campus, Cherlapally,Survey No.147, Nagaram, Rampally road,
Keesara Mandal, Hyderabad, Telangana Atate-500 083.
||Dr. R.V. Singh
Ph. 040-29708128 ,
Fax : 040-29708129
The Region was carved out from Southern Region in 1988.Prior to it, all the investigations were carried out from Southern Region, Bangalore. The Office of the South Central Region was initially started in a rented building in Hyderabad and since 1993 to 2016, it was functioning within the premises of AMD Headquarters, Begumpet, Hyderabad. in may 2016, the South Central Region was shifted from headquarters to Cherlapally Campus.
Broadly following geological domains occupy major part of the region:
(i) Archaean Basement rocks : These comprise Peninsular Granite Gneiss, Karimnagar Granulite Belt and Eastern Ghat Mobile Belt. Closepet equivalent granites occur as discrete plutons within the basement complex. Besides, number of younger intrusive also occur in the northwestern part of the Cuddapah basin. Number of mafic dyke swarms intrude the basement complex.
(ii) Lower Proterozoic Green Stone Schist Belt: major Schist Belts are : Nellore Schist Belt, Veligallu-Gadwal Schist Belt, Ramagiri-Penakacherala Schist Belt and Peddavoora Schist Belt .
(iii) Middle to Upper Proterozoic rocks :These rocks are exposed in two major geographic domains, viz. (1) Cuddapah Basin comprising sedimentary and igneous rocks of Cuddapah Super group and the Kurnool Super group and (2) Pranahita-Godavari Nasin comprising sediments pf Pakhal Supergroup. Besides in the western part sediments of Bhima basin slao occur.
(iv) Gondwanas (Mesozoic) along Godavari basin : Along the Godavari basin, the Mesozoic Gondwana sediments overlie the Proterozoic rocks of Pakhal Supergroup.
(v) Beach Sand and Inland Placers : These from part of Quaternary group of rocks. Number of rich beach sand mineral deposits are located along the coastal stretch of Andhra Pradesh.
Small exposures of Deccan Trap (Mesozoic age) occur in the northwestern part of the Region.
Srisailam Sub-basin: During 1990’s, with the evolving concept of unconformity type uranium deposits worldwide, radiometric surveys in the environs of Cuddapah Basin, led to the discovery of uranium mineralisation close to the unconformity between Paleo-Proterozoic fertile Mahbubnagar (Closepet equivalent) granite and overlying quartzite of Srisailam Formation. The Srisailam Formation rocks, the youngest sediments of Cuddapah Supergroup, are exposed in the Srisailam sub-basin, having an area of 5,000 sq. km. Detailed exploration in parts of the sub-basin by drilling led to delineation of well-established unconformity related uranium deposits at Lambapur, Peddagattu and Chitrial. In these uranium deposits, the Srisailam Formation is represented by a basal pebbly-gritty sequence followed upward by intercalated grey shale-quartzite with massive quartzite layer at the top.
Important uranium deposits are summarized below:
Lambapur : Unconformity related uranium mineralisation has been established in two ore bodies over an outlier of Srisailam Formation having dimension 1.8km x 0.70km. Mineralisation is largely hosted in the basement granite and partly in the altered basic dyke intrusive into the basement and in gritty quartzite of Srisailam Formation. The ore bodies have a maximum depth of 45m..
Peddagattu : This deposit occurs ~1km south of Lambapur deposit and has similar geological and mineralisation set-up as that of Lambapur. Eight uranium-mineralized blocks occur in an outlier of Srisailam Formation exposed over 10km x 2km. All the ore bodies are confined to a maximum depth of 60m.
Chitrial : The deposit is located about 25km southwest of Peddagattu. The deposit occurs in an outlier of Srisailam Formation. It has similar geological and mineralisation set-up as that of Lambapur-Peddagattu uranium deposits. In Chitrial, the ore bodies have been established having considerable strike length with depth range of 30m-90m in western and eastern sectors.
Four other outliers, with Srisailam quartzite unconformably overlying the basement Mahbubnagar Granite spread over total areal extent of 83 sq. km have been recognised for detailed exploration by drilling to augment additional uranium resources.
Palnad Sub-basin: Palnad sub-basin, which is equivalent of the Kurnool sub-basin with an aerial extent of 3,400 sq. km is exposed in the northern part of Cuddapah Basin. The unconformity contact between Banganapalle quartzite and basement granite is a potential horizon for uranium mineralisation. A small uranium deposit has been located at Koppunuru, Guntur district, Andhra Pradesh near the unconformity. Exploration is underway in similar geological setting in Sarangapalli area in Guntur district, Andhra Pradesh.
Unconformity proximal uranium mineralisation at Koppunuru is largely associated with Banganapalle quartzite. Uranium ore bodies in the form of three sub-horizontal lodes occur in the Banganapalle quartzite, 5-40m above the unconformity and along the unconformity contact transgressing into the Basement granite.
p>Eastern margin of Cuddapah Basin: :
Eastern margin of Cuddapah Basin along Nellore Schist Belt has been explored for vein type / shear controlled uranium mineralisation. Detailed exploration at Kasturigattu (Kasuri Gutta), Gudarukoppu, Kulluru and Chinnagutta area, SPSR Nellore district, Andhra Pradesh has led to better understanding of the mineralisation in Nellore Schist Belt. Seven borehole drilled during F.S. 2018-19 in Kasturigattu area indicated promising uranium mineralisation.
Significant achievements of South Central Region in last three years are enlisted below:
(i)Kappatralla area, Kurnool district, Andhra Pradesh:
Unconformity proximal uranium mineralization has been identified in one outlier at Kappatralla lying 35km west of Kurnool located in the western margin of Cuddapah Basin. The uranium mineralisation occurs along the contact of Paleo-Proterozoic granite basement and overlying quartzites of Gulcheru Formation. The outlier has been explored during the period 2016 to 2018. The uranium ore resource estimation has been made for the northern part of Kappatralla outlier by considering correlatable ore bands intercepted in 16 boreholes within an area of 0.63 sq.km and substantial resource has been identified. Future exploration in the entire outlier having approx. 4.50sq.km area is planned to further augment the resource.
|Geological map of Telangana and Andhra Pradesh showing areas potential for uranium mineralisation
||Geological map of Kappatralla outlier showing uranium occurrences, Kurnool district, Andhra Pradesh.
(ii) Rudravaram line:
The Rudravaram Line marks the contact of undisturbed sediments of Kurnool Group and folded and deformed sediments of Nallamalai Group. The area closure to the eastern margin of the Palnad sub-basin in the vicinity of Rudravaram line, wherein the undeformed Kurnool Group of rocks overlie the folded and deformed sedimentary rocks of Nallamalai Fold Belt, represents a potential zone for hosting unconformity type uranium mineralization. Several hydro-uranium and Rn-in water anomalous zones have been delineated over the Kurnool Group of rocks. Several conducting bodies along structural loci have been identified by ZTEM techniques. Uranium mineralisation is expected to occur at deeper levels in proximity to the unconformity surface.
(iii) Sarangapalli area:
Sarangapalli area, located in the northern part of Palnad sub-basin, exposes Neo-Proterozoic Banganapalle quartzite and Narji limestone of Kurnool Group unconformably overlying Closepet equivalent granite in Guntur district, Andhra Pradesh. Subsurface exploration commenced in the area in 2018 and indicated fairly good uranium potential. Small uranium resource has been inferred in the area based on correlatable ore bands intercepted in 10 boreholes. Primary uranium minerals (coffinite, pitchblende and uraninite) occurring only the microfractures and weak planes have been identified. Drilling is in progress to delineate extension of ore body.
National Core Library:
National Core Library, hosting boreholes core of various uranium deposits of India is developed in 2020 at AMD campus, SCR, Cherlapally. Borehole cores from Lambapur, Peddagattu and Chitrial deposits of SCR, Tummalapalli, Gogi and Kanchankai deposits of SR, Rohil deposit of WR, deposits of SSZ from ER and borehole core from CR have been arranged in core racks. It is a unique national facility that would facilitate examination of core samples with all relevant technical information to AMD as well as outside scientists, and definitely aid in conceptualising mineral deposit occurring in newer areas on earth.