- Tsodilo Resources Limited ("Tsodilo") (TSX Venture Exchange: TSD) is pleased to announce the availability of a detailed report on the mineral chemistry of the drill samples from kimberlite A15 drilled in their Newdico (Pty) Limited license block in Botswana.
Background to the discovery of A15
Kimberlite A15 has a coincident magnetic and gravity anomaly with an indicated diameter of approximately 800 - 1,000 meters. The magnetic anomaly is dipolar and roughly circular, indicative of a pipe-like intrusive body. (See, geophysical gravity and magnetic images on the Company's website under Images - Geophysical) The target was tested with a vertical reverse circulation drill hole in October 2004. After drilling through loose sand and a thick section of silcrete (Kalahari formation), numerous coarse kimberlitic ilmenites and pyrope garnets of up to 5 mm in size were visually identified in weathered kimberlite from 34 meters depth.
Due to technical problems of drilling with a high groundwater inflow, the drillhole was stopped at 116m depth still in primary kimberlite. The primary kimberlite appears to be a tuffisitic kimberlite breccia (TKB) but is highly weathered throughout the section drilled. The weathered TKB contains xenoliths of basement shales, quartzite, granite and basalt throughout the section.
Kimberlite A15 is located approximately 25km east of the Namibia / Botswana border in the Company's Newdico license block. The kimberlite lies within the Nxau Nxau kimberlite field where 23 kimberlites have been identified to date. Kimberlite A15 lies approximately 1.5 km from a diamondiferous kimberlite body anomaly 40/97/07, drillhole THC 16) discovered in February of 1998. Previous geochemical loam sampling work over A15 resulted in the collection of numerous picro-ilmenites and a lesser amount of kimberlitic garnet grains.
Drill sample processing
Drill samples were sent to the Scientific Services laboratory for separation of the heavy minerals which were then picked by the Mineral Logic laboratory in order to identify and recover kimberlitic indicator minerals. After splitting of these grains to a representative fraction, 40 garnet grains, 12 chrome diopside grains and 50 ilmenite grains were mounted for electron microprobe analysis:- these are marked as the RC set. A second sample of indicator minerals separated on site by means of panning of drill cuttings was also sent to the Mineral Logic laboratory for further picking and splitting. This set of probe grains are marked as the PC set and consist of 106 garnet and 21 chrome diopside grains.
The probe mounts were dispatched to the Euclid Geometrics laboratory in Kitchener, Ontario, for microprobe analysis. The full set of results and the report of their Consultant Mineralogist are posted on our website at www.tsodiloresources.com/s/MineralChemistry.asp
The following conclusions were reached from consideration of the mineral chemistry:
- The mineral chemistry of the ilmenite suite indicates a reduced environment with a good to excellent potential for diamond preservation, with low resorption.
- The chemistry of the chrome diopside grains indicates that 58% fall into the diamond stability field. The composition of the A15 diopside is virtually identical to that of the Jericho (NWT, Canada) and the Grib (Arkhangelsk, Russia) kimberlite pipes, which are economically viable. In contrast to the typical diopside of kimberlite, these three kimberlites all exhibit a rare jadeite-kosmochlor substitution.
- The composition of the A15 megacryst garnets is similar to the megacrystic suite of the diamond-rich Jericho kimberlite of the Slave craton with both exhibiting a distinct reduced crystal chemistry, which is most promising for the stability and preservation of diamond.
- The A15 mineral compositions are comparable to those of the diamond-rich Jericho kimberlite, a (Na, Ca)-rich rock in which the diopside is jadeite-rich and the G10/G9 line separating peridotitic garnet-with-diamond from garnet-with-graphite is shifted towards Ca-rich compositions. This modified plot places 51% of the A15 peridotitic garnets in the diamond zone.
- Eclogitic garnets were also identified from their chemical composition; 40% of these fall within the diamond inclusion field. As with Orapa and several other producing kimberlites, the potential diamond contribution from eclogites in the A15 kimberlite may be considerable.
These very encouraging results have led to a decision to drill further holes into the A15 kimberlite to obtain both a better distribution and a bigger volume of sample. These samples will be analysed for micro-diamonds as an estimator of the economic potential of this very promising kimberlite. Drilling will begin in mid-May.
President and CEO James Bruchs comments: "A15 clearly indicates that there is a very different type of kimberlite in the Nxau Nxau field. While it is too early to tell whether A15 or similar type kimberlites are the source of the Omatako or Tsumkwe secondary anomalies to the west of our license block, the G10 garnet ratio, as calculated by typical CaO vs Cr2O3 wt.% methods, of our most representative sample (RC) is comparable to those reported for Omatako and Tsumkwe ".
Tsodilo Resources is an international diamond exploration company engaged in the search for economic kimberlites at its Newdico and Gcwihaba projects in northwest Botswana. The Republic of Botswana is the largest producer of diamonds, by value, in the world. Tsodilo has an 81% stake in Newdico while Trans Hex Group, a South African diamond mining and marketing company, holds the remaining 19%. The southern Gcwihaba Project area is 100% held by Tsodilo subsidiary Gcwihaba Resources (Pty) Limited. Tsodilo manages the exploration of both license areas. The design and conduct of the Company's exploration program is the responsibility of Peter Walker, a professional geologist registered with the South African Council for Natural Scientific Professions. Please visit the website, www.TsodiloResources.com, for additional information and background on our projects.
The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this news release. This news release may contain assumptions, estimates, and other forward-looking statements regarding future events. Such forward-looking statements involve inherent risks and uncertainties and are subject to factors, many of which are beyond the Company's control, which may cause actual results or performance to differ materially from those currently anticipated in such statements.
FOR FURTHER INFORMATION PLEASE CONTACT:
James M. Bruchs - President and Chief Executive Officer:
Telephone +1 416 572 2033
Facsimile + 1 416 5724164