GEOPHYSICAL STUDY TO DEMARCATE PROMISING SITES OF IRON ORE IN KIRANA HILLS SARGODHA

Abstract

This project is concerned with the delineation of iron mineralization in the subsurface Kirana hills which are about 24 kms south of Sargodha. The total area is about 3 sq . kms . Since the area is almost flat, a grid pattern ( 25x25m) was designed to make gravity and magnetic measure ments . Totally 5000 g ravity and magnetic stations were estab lished in the project area. Gravity observations were made with Worden gravimeter (with scale constant 0 .09 02) and magne tic measurements were made "with Proton Precession magnetometers. Station No . YY-O has been taken as a base station both for gra vity and magnetic surveys. Gravity and magnetic field data were reduced to the base station by applying necessary correc tions, and thus Bouguer anomaly and total magnetic intensity maps were prepared. These maps were analysed qualitatively and quantitatively. Both gravity and magnetic map s indicate high gravity and low magnetic values between profile No .4 7 to profile No .60. It gives a good correlation between low magnetic and high gra - vity values indicating the presence of probably heamatite iron ore beneath the surface . A gravity section running accross the project area has been modeled, taking a ferrogeneous zone in the basement rocks. The thickness of ferrogeneous zone at the base station is approximately 72 meters and lies at the depth of 62 meters . This zone continues its thickness in a range of 72 meters to 100 meters up to 100th profile after which it sharply decreases and thins out to be 17 meters at the 120th I I profile. A test hole around station No.d- 57 down to 140 me ters is recommended at this site to ascertain the presence of iron ore .