Camafuca kimberlite project, Angola (51% SouthernEra)
- core drilling program, diamond recovery results
- significant indicated grade increase
- bulk sample processing begins
TORONTO, June 7 /CNW/ - SouthernEra Resources Ltd. (TSE-SUF) is pleased
to report the results of diamond recovery tests performed on the large
diameter drill core (70mm diameter) samples taken during the Phase I core
drilling program completed at Camafuca on the east side of the Chicapa River
late last year. The 160 hectare Camafuca kimberlite pipe, located in Lunda
Norte Province of northeastern Angola, is the largest undeveloped
diamondiferous kimberlite known worldwide. SouthernEra holds a 51% interest in
the project and is operator.
Approximately 8 tonnes of kimberlite drill core, recovered from 23 holes,
was processed in the Company's DMS (dense media separation) exploration plant
installed at the Klipspringer site in South Africa. The core results reported
in this first table below represent material recovered from drill holes
positioned to provide duplicate samples from the locations of earlier core and
large diameter (1.5 metre) bulk sampling holes completed by DIAMANG prior to
1985. The depth of the new holes drilled by SouthernEra varied from about 35
to 130 metres.
Samples from the core holes were combined based on the major rock types
present, and processed. Individual sample sizes varied from 181kg to 750kg.
The plant system was set to recover stones over 1.0mm in size. The
+0.425mm - 1.0mm material is presently being tested separately for fine
diamonds using the caustic dissolution method.
<<
Core Testing Results:
---------------------
SUF Hole Sample Weight Carats Grade
Recovered (carats per 100 tonnes)
303,320 638 kg 0.63 99.5
308 615 kg 0.44 71.5
316* 253 kg 0.08 32.5
323* 240 kg 0.09 36.0
318 282 kg 0.28 101.0
>>
* Note: Duplicate holes drilled at the same location.
All of the above results are from the epiclastic kimberlite grit (EKG)
rock unit which hosts the higher grade material sampled at Camafuca.
The following table provides the overall core testing results for the
three main rock types present in the deposit, EKG, epiclastic kimberlite
sandstone (EKS), and volcaniclastic kimberlite breccia (VKB):
>>
Unit Sample Weights Carats Average Grade
Recovered (carats per 100 tonnes)
EKG 4,789 kg 2.18 45.5
EKS 1,766 kg 0.07 5.2
VKB 1,344 kg 0.10 5.7
>>
The stones recovered from the drill core range from 0.01 to 0.39 carats
in weight, with the average approximately 0.06 carats, and have good colour
and clarity.
The test results reported here show a significant increase in indicated
grade compared to the earlier DIAMANG data, where the average grade for the
EKG unit was indicated to be about 13 carats per hundred tonnes. SouthernEra
regards the apparent grade increase as very encouraging, considering the
relatively small sample size of the drill core material available. (The
DIAMANG large diameter drilling bulk samples averaged about 18 tonnes each).
An independent review of the DIAMANG data by MRDI (Mineral Resources
Development Inc.) has suggested that the DIAMANG results are likely to
represent minimum values for the indicated grades and reserves/resources (13.5
million carats to 80 metres below surface). Caution should be exercised in
interpreting the current results because of the small sample size. As data
becomes available from the large bulk samples currently being tested, the
accuracy of the information will increase.
Bulk Sampling Program:
----------------------
Testing of kimberlite samples taken from several trenches on the east
side of the Chicapa River is now underway. Two additional trenches have been
excavated and a total of nearly 25,000 tonnes is now available for ongoing
processing.
The initial feed to the rotary pan plant during the commissioning phase
has been low grade VKB material from the North Lobe of the pipe. The higher
indicated grade EKG material will be processed later this month now that the
plant operating parameters for optimizing recoveries have been established.
Once a significant diamond parcel has been recovered, the stones will be
submitted for new valuation. Earlier valuation (1997) of stones recovered
previously at Camafuca averaged USD $85-$100 per carat.
Continuing Work:
----------------
Drill core recovered from a 17 hole (1,000 metre) program completed on
the east side of the Chicapa River in April 1999 will be sent to South Africa
for diamond recovery testing. Samples of this material, which were recovered
to do strength testing for the upper decomposed part of the kimberlite have
also been submitted to a major cutting wheel dredge manufacturer in Europe for
a study to determine if this type of equipment can be used to selectively mine
the higher grade, upper, weathered, portions of the pipe. The Company has made
preliminary cost estimates for developing the deposit using a cutting wheel
dredge, and has estimated that total capital costs of approximately US $25
million will be required to achieve a production rate of 3,500 tonnes per day.
Once the trench bulk sample results become available, comparisons will be
made with the information in the DIAMANG database to calculate accurate grade
figures and new reserves/resources. Once valuations have been made on the
stones recovered, an economic study will be undertaken to determine the
feasibility of commercial production. The 1999 program has been budgeted at
approximately US $3.0 million.
SouthernEra is extremely encouraged by the results reported above. The
indicated average grade of 45.5 carats per hundred tonnes for the EKG unit at
Camafuca from the test work reported is similar to that of other producing
kimberlites worldwide, and the potential to exploit higher grade portions of
the kimberlite using cost effective mining technology will continue to be
evaluated. Further results will be reported when available.
Terminology:
The kimberlite rock units referred to above (EKG, EKS, VKB) are
associated with the volcanic craters of kimberlite pipe systems and represent
different types of sediments derived from kimberlitic material erupted from a
kimberlite volcanic vent.
%SEDAR: 00004535E
-30-
For further information: please contact: Christopher M.H. Jennings,
President; A. Lee Barker, Senior Vice President; Frank van de Water, Vice
President, Finance; Kim Freeman, Vice President, Operations; Nicholas Sayce,
Investor Relations; Phone: (416) 359-9282, Fax: (416) 359-9141,
e-mail: inbox@southernera.com; southernera.com |
