Additional results from 1997 Fort a la Corne drilling program
Kensington Resources Ltd KRT
Shares issued 23,966,435 Mar 30 close $0.45
Mon 30 Mar 98 News Release
Mr David Stone reports
The company has received the following results for 1997 diamond exploration
at the Fort a la Corne project, 65km east of Prince Albert, Saskatchewan.
To date, 34 of the 69 kimberlite bodies tested by drilling at the project
contain macrodiamonds.
The 1997 program consisted of two conventional rotary drill holes as well
as three reverse circulation airblast drill holes which were underreamed
totalling 1,153.7m. A small diameter rotary hole was drilled into each of
the previously untested kimberlite targets 605 and 612. The large diameter
RCA/UR drill holes were drilled to further evaluate kimberlite bodies 150,
176 and 220 where encouraging diamond results were obtained from previous
holes. The RCA/UR drill program used procedures and equipment considered to
be optimal for recovery of diamonds from the borehole and was audited by a
tracer recovery program using diamond simulants and synthetic diamonds.
Kimberlite material was processed for microdiamonds at the Saskatchewan
Research Council and Kimberley Acid (KAL) laboratories. The corresponding
mini-bulk samples were processed and evaluated at the DeBeers macrodiamond
recovery facilities in South Africa.
Microdiamond recovery results for the samples composited from holes 150-05,
176-02, 220-02, 605-01 and 612-01 drilled during 1997 were obtained for
analysis by the SRC and subsequently reported in Stockwatch September 5
1997. In addition, results for holes 150-05, 176-02 and 220-02 have been
augmented by further microdiamond analyses determined by KAL. The
microdiamond results from the two laboratories are combined as follows:
Kimberlite Weight of Diamonds Total*
sample treated recovered diamonds
thickness sample per 10kg
(m) (kg) No. Cts sample
No. Cts
----------------------------------------
Hole 150-05
158.5 82.0 16 .00163 2 .00020
Hole 176-02
170.5 77.4 22 .00198 3 .00026
Hole 220-02
78.0 78.4 159 .03957 20 .00505
* Includes microdiamonds and macrodiamonds
Minibulk samples were collected from the five holes drilled during 1997. A
total of 72.9 dry tonnes of the greater than 0.85mm kimberlite fraction,
representing a theoretical mass of 129.9 tonnes excavated from these drill
holes was processed for macrodiamond content at DeBeers' diamond recovery
facilities in South Africa. In total, 31 macrodiamonds (greater than 1.0mm
in one dimension) collectively weighing 2.52 carats were recovered from
kimberlite bodies 150, 176 and 220. No macrodiamonds were recovered from
the minibulk samples obtained from kimberlite bodies 605 and 6512. Twenty
stones were recovered from kimberlite body 220, which accounts for 1.27
carats of the total and includes a single 0.7 carat white macrodiamond with
abundant inclusions. Macrodimonds recovered for each of the three drill
holes are as follows:
Hole 150-05
Kimberlite sample interval - 159.5m
Theoretical mass tested - 59.70 tonnes
No. of stones - 3
Wt of stones - 0.475 carats
Avg No. stones (per 100 tonnes) - 5.1
Avg grade (cpht) - 0.8
Hole 176-02
Kimberlite sample interval - 162.5
Theoretical mass tested - 42.67 tonnes
No. of stones - 8
Wt of stones - 0.775 carats
Avg No. stones (per 100 tonnes) - 32.4
Avg grade (cpht) - 3.1
Hole 220-02
Kimberlite sample interval - 84.0
Theoretical mass tested - 27.53 tonnes
No. of stones - 20
Wt of stones - 1.270 carats
Avg No. stones (per 100 tonnes) - 75.3
Avg grade (cpht) - 4.6
The average macrodiamond grades calculated for the minibulk samples
obtained from these three holes may be minimum estimates, particularly in
view of the extrapolated macrodiamond grades shown below. This potential
understatement of the grade is mainly attributed to insufficient sampling
and possibly some diamond losses in the drilling system as indicated by the
results for the tracer program below:
Summary of grade estimates for commercial-sized diamonds based on
extrapolation of microdiamond size distribution and macrodiamonds recovered
from minibulk samples for kimberlite bodies drilled during 1997:
Hole No. 150 (112 ha), has an estimated mass of 336,000,000 tonnes
Hole No. 176 (26 ha), has an estimated mass of 45,000,000 tonnes
Hole No. 220 (24 ha), has an estimated mass of 87,000,000 tonnes
Microdiamond Samples Macrodiamonds
Extrapolated Recovered from
Macrodiamond Grade Minibulk Samples
(cpht)2
-----------------------------------------
Total Higher No. of Grade
Body Grade Zones Stones (cpht)
Hole No. 150
11 15 36 4.9
Hole No. 176
36 50 17 3.4
Hole No. 220
25 n/a 24 6.6
A comprehensive tracer program designed to simulate the recovery of
diamonds at the drill site was implemented to assist with the evaluation of
the three RCA/UR holes drilled during 1997. Diamond simulants and synthetic
diamonds were introduced into the drilling system and subsequently
recovered along with the kimberlite cuttings. Although qualitative in
nature, the results indicate inconsistent and lower than expected recovery
of the various tracers, divergent behaviour between the various tracers and
natural diamonds, along with areas where the recovery of natural diamonds
may be at some risk. It should be noted, however, that the tracers have not
behaved in a manner entirely analogous to natural diamonds. This is due to
the nature of the tracers as well as their means of introduction into and
recovery from the drilling system.
In view of these results, future sampling programs will include more
indepth tracer studies. Moreover, the RCA sample recovery procedures will
continue to be reviewed on a continuing basis with the prime objective of
maximizing the diamond recovery. The impact on the value of diamonds
associated with fragmentation of stones during the drilling and sample
collection process will also be assessed.
Dr Luc Rombouts valued 31 macrodiamonds recovered from the minibulk samples
collected in 1997 and incorporated these values into the historical dataset
for all the macrodiamonds recovered at Fort a la Corne which was also
updated to the end of 1997. Values for the 1997 stones range up to US$150
per carat with the best gem recovered from kimberlite body 150. Global
average value for all macrodiamonds recovered is US$32 per carat based on
720 stones weighing a total of 37.3 carats and using the end of 1997
prices. Gem stones comprise 95.3% of the total stone value to date.
Fourteen kimberlite bodies have yielded more than 15 stones each. Average
carat prices for the individual kimberlite bodies vary from US$3 to US$89
per carat assuming end of 1997 prices. The highest average carat price of
US$89 was from kimberlite body 150 and it is based on 36 stones. In Dr
Rombouts' opinion, it is reasonable to expect that the average carat price
for many of the Fort a la Corne kimberlites could be in the US$50 to US$100
range, particularly since his statistical studies of the microdiamond
analytical data indicate that several kimberlite bodies could have the
potential to contain larger and better quality stones than those generally
recovered from the minibulk samples to date. The entire inventory of
macrodiamonds recovered at Fort a la Corne, including the 1997 stones is
68.8% gems, 20.5% near gems, and 10.7% industrial grade stones.
The company is encouraged by these results and plans to participate in a
follow up drilling program during 1998. Discussions on the 1998 program are
in progress. In general, this significant program comprised of several
large diameter RCA drill holes will be designed to further evaluate a
selected number of diamondiferous kimberlite bodies which are considered to
often contain more than 100 million tonnes of kimberlite each and have the
greatest economic potential on the basis of the current data.
The Fort a la Corne diamond project is a joint venture with Kensington
Resources, Uranerz Exploration, Cameco Corporation and Monopros Limited. As
at December 31 1997, each of Cameco, Monopros and Kensington have a 30%
interest and Uranerz has a 10% carried interest.
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