Vancouver, Canada (ots/PRNewswire)
- The Company is pleased to
report that laboratory analysis has confirmed the presence of a range
of kimberlite indicator minerals in drill hole samples from its
Nyamigunga prospecting license (PL) in Tanzania.
The suite of indicator minerals identified by a scanning electron
microscope (SEM) includes G10 garnets and chromites, all of which
point to a diamondiferous kimberlite source.
"From an exploration perspective, knowledge of the composition and
relative abundance of garnets and chromites in kimberlite - the
primary source rock for diamonds throughout the world - allows
assumptions to be made about the proximity and economic diamond
potential of a kimberlite," noted the Company's president, John
The Nyamigunga PL is known to host five kimberlite bodies within
an area of approximately two square kilometres. These carrot-shaped
bodies are believed to have been intruded along a dominant
north-south fault zone that provided a pathway to surface for
diamonds and their genetically-related kimberlite indicator minerals.
Visual results from Mineral Services in South Africa were received
in March 2006 and subsequently reported in a news release on April
3rd. SEM analysis was initiated immediately thereafter to confirm the
Mantle-derived garnets and chromites are considered the most
important kimberlite and diamond indicators. The pioneering work of
Dawson and Stephens (1975), Gurney (1984) and Fipke (1989) formed the
basis for using garnets as well as chromites as tools to focus
exploration on areas that are prospective for diamonds.
The origin of diamond is more closely related to fragments of
peridotite (a coarse grained plutonic rock) and eclogite (a granular
rock composed primarily of garnet) which are derived from the Upper
Mantle, the thick shell surrounding the earth's outer core. In order
for diamonds to form, they require extremely high pressures and
temperatures which are only found deep in the earth. It is here that
eclogite forms consisting of red pyrope garnet and green
clinopyroxene. Diamond crystals develop alongside the garnet and
Because diamonds have a close affinity to specific fragments
(eclogite, peridotite) and their respective source areas, they can be
subdivided into ones that have a peridotitic origin (P-type) and
others that have an eclogitic origin (E-type). Even though a diamond
may be found as a single crystal within a kimberlite rock mass,
inclusions or flaws within the diamond crystal can identify its
The flaws or "inclusions" within diamonds often include associated
minerals such as garnet, pyroxene, olivine, chromite, and sulphides
such as pyrrhotite. The chemistry of the mineral inclusions can be
compared with those present in the eclogite and peridotite fragments
in order to determine their source. These inclusions also provide
valuable information regarding the pressure and temperature under
which the diamonds formed as well as their age.
The overall assessment of geochemical information relies on the
recognition of those minerals that are co-genetic with diamonds and
comparing their mineral geochemistry with those of diamond
Two important garnet types are associated with diamondiferous
- G10 garnets: Ca-poor, Cr-diopside free, with elevated Cr2O3.
- Group 1 eclogitic garnets: characterised with elevated Na and
Potential chromites indicating a diamondiferous content for
kimberlite have a chrome content between 60 and 70 wt % Cr2O3, with
an average MgO concentration of between 8 and 16 wt% and a TiO2
content of less than 0.7 wt%. Discrimination plots are therefore used
to define these geochemical boundaries and these plots are available
on our website at: www.TanzanianRoyaltyExploration.com
Poor ground conditions, including heavy water inflows, produced
surface contamination in the drill holes which could explain some of
the low indicator mineral grain counts in the K3, K4, K5 and K6
pipes. (Please refer to the Company's April 03, 2006 press release
Nevertheless, kimberlite bodies within Tanzania often have
variable indicator mineral chemistry without diminishing their
"While much more work remains to be done, the progress we have
made on the diamond exploration front in the past two years has been
nothing short of phenomenal," said Jim Sinclair, the Company's
Chairman and CEO.
"In the past year alone, we have drilled 11 kimberlites, six of
which were brand new discoveries. I take great pride in saying that
we are leading the charge that could one day see Tanzania reinstated
as a major diamond producer," he added.
Analytical results from the K1 and K2 pipes, which provided
statistically sound indicator mineral populations for analysis, are
A total of 106 visually identified garnet grains were micro-probed
and SEM results indicated that 12 are G10 garnets (approx 11%). A
total of 45 visually identified chromite grains were micro-probed and
SEM results indicate that all are kimberlitic chromites. A total of
four grains (8.9%) have Cr2O3 above 60 wt% and hence plot within the
diamond inclusion and intergrowth field.
The presence of G10 garnets and chromites that plot in the diamond
inclusion and intergrowth field, supports the conclusion that this
kimberlite sampled a potentially diamond bearing depleted harzburgite
in the mantle on the way to the surface. Hence this kimberlite is
highly ranked and warrants further follow up.
A total of 171 visually identified garnet grains were micro-probed
with SEM results indicating that 22 are G10 garnets (approx 13%). A
total of 52 visually identified chromite grains were micro-probed and
SEM results indicated that all are kimberlitic chromites. A total of
five grains have Cr2O3 wt% above 60 wt% and thus plot within the
diamond inclusion and intergrowth field. Two of them have TiO2 less
than 0.7wt% and plot within the diamond inclusion field.
The presence of G10 and DI chromites support the conclusion that
this kimberlite sampled a potentially diamond bearing depleted
harzburgite and eclogite in the mantle on the way to surface. As a
result, this kimberlite is highly ranked and warrants further follow
Follow up work associated with these positive results is presently
under way. The Company is currently extending the ground magnetic
survey to the immediate south of these pipes to search for further
kimberlites along the north-south fault zone.
A bulk sample of the kimberlites and gravels lying above the pipes
is planned this year to confirm diamond concentration, quality and
grade. "This will determine the future of this exciting prospect,"
"Alluvial diamonds are the best indicator mineral for
diamondiferous kimberlites," he added. "In fact, alluvial stones in
gravels of the Orange and Vaal river systems led to the initial
discovery of diamondiferous pipes in South Africa."
The Company's Qualified Person is Mr. John Deane, the President of
Tanzanian Royalty Exploration Corporation Limited. He has a M.Sc.
from the University of Cape Town (1993) and is a registered scientist
with SACNASP (Reg. No.400005/05).
The Toronto Stock Exchange and American Stock Exchange have not
reviewed and do not accept responsibility for the adequacy or
accuracy of this release.
Cautionary Note to US Investors - The United States Securities and
Exchange commission permits US mining companies, in their filings
with the SEC, to disclose only those mineral deposits that a company
can economically and legally extract or produce. We use certain terms
on this news release, such as "measured", "indicated", and "inferred"
"resources" that the SEC guidelines strictly prohibit US registered
companies from including in their filings with the SEC. US Investors
are urged to consider closely the disclosure in our Form 20-F, File
No. 0- 50634, which may be secured from us, or from the SEC's website
ots Originaltext: Tanzanian Royalty Exploration Corporation
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