[en] In this paper the results of airborne gamma ray spectrometric surveys over 1100 sq. km of area (Survey of India toposheet nos. 64 D/10 and 14) in Rajnandgaon District of Madhya Pradesh, India are presented. The area surveyed forms part of Dongargarh Super Group. Bodal and Bhandaritola uranium prospects are located within this area. Uranium mineralisation in these prospects occurs in metabasics, metarhyolites and/or quartz porphyry and is practically free from thorium. As per the analysis of some rock samples from Bodal area thorium values are elevated compared to uranium values in all rock types with the exception of mineralised amphibolites. The airborne spectrometric data is presented in the form of total radioactivity anomalies plotted on the flight path indicating for each anomaly the respective half-width, intensity in counts/sec. of total channel and contribution from uranium, thorium and potassium qualitatively estimated from the flight data. Narrow belt of about 20 km x 2.5 km having predominantly uranium anomalies has been delineated from the airborne data in contrast to the thoriferous anomalies in the rest of the area as recorded in these surveys. This well defined belt comprising of granite, metarhyolite and pegmatites is considered to be a good target for uranium exploration, which is trending NW-SE and is located about 5∼7 km southwest and south of Bhandaritola-Bodal axis. (author). 1 table, 11 refs

[en] Regional emanometric survey using the closed circuit technique was carried our for measurement of radon and thoron concentration in the soil covered areas of Mogarra and Bijepar, Bhandara district, Maharashtra. The aim of the survey was to delineate potential areas for subsurface uranium bearing horizons to be taken up for detailed investigations. The radon and thoron values obtained from the survey were correlated with the soil samples analysis data by the method of class intervals and cumulative frequency analysis. Anomalous zones holding promise for subsurface uranium occurrences have been identified, substantiated by statistical treatment and recommended for detailed investigations (author). 11 refs., 5 figs

[en] The aeromagnetic and aerial spectrometric data of the two areas in Bilaspur block and Raipur block are studied. The F-W magnetic lineaments stand out well and have been deduced from their magnetic signature that is due either to the lateral displacement of magnetic horizon or its discontinuity. From spectrometric data it is seen that most uranium anomalies are located near the NW-SE faults and contact zones. (N.B.)

[en] An integrated geophysical approach was attempted for uranium exploration in Jamiri area, Arunachal Pradesh, using the techniques of magnetic, self-potential (SP) and resistivity profiling, coupled with solid state nuclear track detection (SSNTD), to delineate favourable structures controlling uranium mineralisation in phyllitic quartzites and quartzites of the Precambrian Daling formation. Three promising zones of uranium mineralisation were recognised based on integrated results from these surveys. Magnetic survey identified lithologic contacts and faults in the area. A high-order SP anomaly of -900 millivolts was observed near the contact of phyllites in the east and phyllitic quartzites in the west. A very low resistivity of 1.0 ohm.m and high SSNTD values of 120 tracks/mm² over a background of 20 to 30 tracks/mm² were also recorded near this contact. These anomalies are characteristic of a fault that channelises radon and gives low resistivities. The SP anomaly may indicate sulphide mineralisation, and hence, uranium mineralisation in this contact zone may be associated with sulphides. The phyllitic quartzites west of this contact are characterised by magnetic highs ranging from 540 to 900 gammas. Here, SP anomalies are also small closures of -80 to -100 mV. The SSNTD values range between 100 and 120 tracks/mm². This rock unit (phyllitic quartzite) appears to host uranium mineralisation along with sulphides at some places where radon anomalies are high. A fault in the western portion of the area interpreted from the magnetic map separates phyllitic quartzites in the east and quartzites to its west. The faulted contact is characterised by a high SP gradient and SSNTD anomalies of 100 to 140 tracks/mm². This contact may also be promising for uranium mineralisation at depth. (author). 10 refs., 8 figs