March 11, 2003
Ground Magnetic And Gravity Survey Results
TORONTO, CANADA - Tsodilo Resources Limited (TSX Venture Exchange: TSD) is pleased to present the initial results from ground magnetic and gravity surveys that are currently in progress over magnetic targets at Nxau Nxau, in the west of the Corporation's Ngamiland property in northwest Botswana. All grids were surveyed along North - South lines, with a 200 metre line spacing and 50 metre station spacing along the lines.
Results have thus far been received for the targets designated A37, A38 and A12. The accompanying Figure 1 (Magnetic Intensity, 1st Order Residual) and Figure 2 (1st Order Gravity Residual) illustrates the results for the grid that covered both of the targets A37 and A38.
The anomaly designated A37 resolved into two discrete magnetic bulls-eye highs (Figure 1). One magnetic bulls-eye high, designated A37a, is located at the south-centre of the grid, while the second, designated A37b, is at the west-centre of the grid. A37a is associated with a gravity "low" (Figure 2), displaced to the southwest of the magnetic bulls-eye, which indicates a source body approximately 350 metres by 250 metres. A37b is associated with a deep gravity low with a north-south dimension of 600 to 700 metres, which probably coalesces with A37a. Although the survey did not cover the western portion of this gravity feature, the information available indicates that A37 is a large composite body, comprised of two separate intrusive centres with a large combined surface area of 30 to 40 hectares. The grid will be extended by two further lines to the west to provide a more reliable estimate of the dimensions of this target.
A38 is a prominent magnetic bulls-eye target in the northeast of the grid (Figure 1). The ground geophysical survey identified two subtle magnetic "highs" immediately to the northwest, and at least one further subtle high to the southeast of the main A38 bulls-eye feature. The A38 magnetic bulls-eye, and the more subtle magnetic highs to the northwest and southeast are associated with a linear gravity low, located parallel to, and immediately to the south of the line of magnetic "highs" (Figure 2). This linear gravity low varies from roughly 150 metres, to over 600 metres in width and is over 1.6 kilometres in length; and probably continues to the southeast of the grid. In order to cover this extension, the grid will be extended by two additional lines to the east.
The ground geophysical grid over A12 has shown that this target is also associated with a gravity low located immediately to the south of the magnetic bulls-eye. The gravity results indicate that the source body has dimensions of roughly 350 to 400 metres by 300 metres, and a surface area of 10 hectares.
These initial results from the Nxau Nxau area are regarded as extremely encouraging. Tsodilo Resources recovered kimberlitic ilmenites over both targets A37 and A38, which is consistent with previous sampling carried out by Reunion over these targets. Sampling has also shown that A12 is associated with a major, isolated heavy mineral anomaly. In the Kalahari environment, coincident or near coincident magnetic bulls-eye targets together with gravity lows, associated with isolated concentrations of kimberlitic ilmenites (which are dense, and not readily dispersed from source) provide very compelling evidence for the existence of sub-Kalahari kimberlites. These results therefore provide strong evidence that anomalies A37, A38 and A12 have kimberlite sources. Follow-up soil sampling and drilling are planned to confirm the interpretation of the geophysical results.
Many of the world's largest economic kimberlites are composite bodies, composed of two or more separate intrusive centres. Examples in Botswana include Orapa (110 hectares), which consists of at least two intrusive centres, and Jwaneng (44 hectares), which comprises three coalescing pipes. The preliminary data indicates that A37 comprises two separate intrusive centres, with a large combined surface area of 30 to 40 hectares, while A38 is probably composed of a number of intrusive centres, controlled by a line of structural weakness. A38 is comparable in dimensions and shape to the exceptionally rich Argyle pipe in Australia. The latter is also a linear body, composed of a number of separate intrusive centres, 2 kilometres in total length, and varying in width from 150 to 500 metres, with a surface area of 50 hectares.
The results further indicate that A12 is comparable in size to the largest kimberlites previously found in the Nxau Nxau area, while A37 and A38 are both very significantly larger bodies. This is regarded as highly significant, because in southern Africa, the richest pipes in a cluster of kimberlites are typically the largest. These targets are therefore potential sources for unexplained kimberlitic heavy mineral anomalies to the west, in Namibia. These unexplained kimberlitic heavy mineral anomalies both contain G10 garnets, while diamonds have been reported from one of them, in quantities sufficient to indicate their ultimate derivation from a rich primary source, or sources.
Tsodilo Resources is an international diamond exploration company engaged in the search for economic kimberlites at its Ngami project in northwest Botswana. The design and conduct of the Company's exploration program is the responsibility of Dr. Andrew Moore, a professional geologist registered with the South African Council for Natural Scientific Professions.
The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release.
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