Greef Report - February 1997, Page 1/3

	Download the entire report in Word 97 format Page 1 - 2 - 3 Page 1/3 REPORT ON GEOPHYSICAL SURVEYS CARRIED OUT ON THE FARM MUIRTON, NORTH WEST PROVINCE, ON 29 AND 30 JANUARY 1997. by G J Greeff (Ph.D.) Introduction In response to a request from the shareholders of the Global Mining Company, the writer travelled to the North West Province and conducted geomagnetic surveys over the surface of their farm Muirton which lies on the West bank of the Vaal River between Schmidtsdrift and Delportshoop. The farm Caerwinning lies adjacent to the north, and the farm Mosesberg lies adjacent to the south. Gravel beds which occur along the riverbank on Muirton have been washed by diamond diggers since the last century, and more recently, gravels which occur at greater depths near the eastern boundary of the farm have been deeply excavated and treated for the recovery of diamonds. A drilling program to determine the position and thickness of the subsurface gravel beds and to provide material which could be tested for diamond indicator minerals had already been carried out (Geologic Report - 19.9.96 and an Addendum - 14.10.96 by C.H.E.Visser, and also the Drilling Program - 8.11.96 by G.Fisher.) Geomagnetic Survey Using the Western boundary of the farm as a base line, a 100 metre grid was set out at right angles to this in order to take readings towards the east, commencing ten metres away from the wire fence. Geomagnetic field values in Nanoteslas were recorded at ten metre intervals along these east-west grid lines, progessing up to thornscrub along the riverbank on the eastern side of the farm. Readings were also taken along two lines 100 metres apart parallel to the western boundary fence. A datum value of 27900 Nanoteslas was chosen as a base of reference in order to reduce the measured field values to more manageable readings which were then entered onto the magnetic traverse positions along the grid lines on the diagram of the farm (MAP 1). The positions of the boreholes that had been drilled on a separate grid prior to the geomagnetic survey were also on MAP 1. As can be seen, the survey grid and the drilling grid are not coincident, as the latter was set out at right angles to the northern boundary fence of the farm which makes an angle of 80 degrees with the western boundary fence which was used as the base line for the geomagnetic survey grid. Page 1 - 2 - 3