Atomic Minerals Directorate for Exploration and Research (AMD) is adopting latest technologies for the exploration of concealed uranium deposits occurring in increasingly complex and deeper mining environments. The state-of-art ground geophysical surveys are being increasingly employed in delineation of target areas for uranium exploration. Geophysical techniques are mainly utilized in delineating locales of uranium mineralization based on its association with metallic mineralization, sulphides, graphite and carbonaceous phyllites. The techniques are also effectively utilized in understanding the subsurface structural controls of uranium mineralization and aid in identification of faults/fractures, shear zones and alteration features.
During the last five decades, the Exploration Geophysics group of AMD was actively involved in applying latest and advanced geophysical techniques in different parts of the country as an aid in uranium exploration. Regional and detailed ground geophysical surveys are conducted over an area of 9,700 sq km in various geological domains. Geophysical techniques are effectively employed in various geological domains viz., of North Delhi Fold Belt - Rajasthan and Haryana; Aravalli Fold Belt – Rajasthan; Singhbhum shear zone – Jharkhand, Cuddapah basin – Andhra Pradesh and Telangana, Bhima Basin – Karnataka; Kaladgi Basin – Karnataka, Kotri-Dongagarh Belt – Chattisgarh. Geophysical techniques are also utilized in the exploration of RMRE minerals and heavy mineral beach sand deposits.
Exploration Geophysics Group is equipped with the state-of-art geophysical equipment which includes,
i) Gravity meters (Sodin and Scintrex CG-5)
ii) Advanced Proton precession magnetometer with GPS facility (GEM Systems)
iii) Cesium magnetometer (Scintrex)
iv) Resistivity/Induced Polarization (IP) equipment (Scintrex, IRIS & IPV-8 Phoenix make)
v) Multi-function (Electrical & Electromagnetic) Transmitter-Receiver CSAMT system (Phoenix make).
vi) Transient Electromagnetic (TEM) equipment (EM-37, Geonics & terraTEM systems)
vii) Very Low Frequency (VLF) system (Scintrex make)
viii) Slingram-horizontal loop EM system (Scintrex make)
ix) Turam frequency domain EM system (Scintrex make)
x) Seismic Equipment (DMT, Germany)
xi) Multi-para-logging system (Geovista, UK)
The other ancillary Instruments available with the group for surveying are
i) Hand held Global Positioning System (GARMIN)
ii) Differential Global Positioning System (SOKKIA, Spectra Precession 80, Trimble, Epoch 50)
iii) Theodolite(Nikon and Wild make)
iv) Total Station (Pentax)
v) Transreceivers (Motorola & ICOM make)
EGPG group is also equipped with the following laboratory instruments to measure the physical properties of rock samples collected during field investigations.
i) Magnetic Susceptibility meter (Terraplus KT-10)
ii) Conductivity meter (Terraplus KT-20)
iii) Density meter (Walker & Steel balance, Indian make) and precision electronic balance (Precica)
iv) Sample core IP tester (GDD instrumentation)
Software for Processing and Integrated Interpretation of Geophysical data
Exploration Geophysics Group utilizes state of art software capabilities for processing and integrated interpretation involving 2D and 3D modelling and inversion of geophysical data and successfully translates the output of geophysical inversion process into geological models relevant to the exploration. The software indigenously developed by the group was well received by the earth scientists throughout the world. The software developed by the group are MAGPROS, MAPPROS and GMINV for processing and interpretation of profile and gridded gravity and magnetic data. A software program EXPFIT was also developed for interpretation of secondary IP effects.
To optimise the drilling program and accelerate the decision making, industry-standard geophysical software from various international software developers are utilized. The software include
i) GEOSOFT-Oasis Montaj: This software package was purchased from Geosoft, Canada for gravity and magnetic data mapping and processing of gridded data and modelling of the profile data with GMSYS.
ii) RES2DINV: This software package, purchased from Interprex Pvt. Ltd., USA, is available for processing of 2D resistivity and IP data.
iii) EM VISION: This software package, purchased from ENCOM Technology, Australia, is available for analysis and interpretation of TEM data for obtaining layered earth information.
iv) IX1D v3, USA: This software performs forward and inverse modelling in terms of layered earth with resistivity for TEM sounding method.
v) Maxwell-EMIT, Australia: This software performs forward and inverse modelling, presentation and visualisation of TEM data.
vi) VISTA: Seismic data processing software.