Roberts Victor- McCandless Teaching Collection Macrodiamonds develop a distinct set of shapes and surface features that relate to their growth in the mantle, and to their resorption in the transporting kimberlite. This collection is designed to let the observer become familiar with these characteristics. Vial # Shape Description 1 single octahedra sharp-edged octahedral crystals. Very easily distinguished under the microscope (N=9). 2 resorbed octahedra note rounding of crystal edges. The assemblage of diamonds in this vial exhibit resorption at different stages of advancement (N=9). 3 tetrahexahedroida ‘thh’ octahedral faces replaced by thh sufaces. This form is incorrectly referred to as ‘rounded dodecahedron’ in older literature (N=10) 4 octahedral twins octahedral crystals grown together in symmetrical fashion (N=7) 5 resorbed twins crystals like those shown above but now resorbed to have thh surfaces present (N=5) 6 aggregates octahedral crystals grown together in random fashion (N=7) 7 resorbed aggregates resorbed equivalent of the aggregates (N=9) 8 distorted octahedra diamonds with one or more of their crystal axes and tetrahexahedroida longer than the others (N=12) 9 broken crystals single broken stones, including resorbed forms. Most of the crystal is still present (N=9) 10 fragments broken stones that have less than half the original crystal present (N=15) 11 uneven resorption stones that exhibit resorption of varied intensity over their surfaces – xenolith diamonds (N=6) The collection should be examined in order, from 1 to 11. The goal of the exercise is to become familiar with the shapes and in particular the surface features that distinguish diamonds from most other minerals. Note that the groupings are not perfect, and diamonds in one group may exhibit features that are also present on diamonds in another group.
10000.0 Kimberlite A- MDT 0.1517 t Kimberlite A- DMS ~0.1cpt; 11 t Kimberlite E-MDT, 0.195t, ~1cpt 1000.0 Diamonds per tonne 100.0 10.0 1.0 0.1 0.0 +0.100-0.150 +0.150-0.212 +0.212-0.300 +0.300-0.425 +0.425-0.600 +0.600-0.850 +0.850-1.180 +1.180-1.700 +1.700-2.360 +2.360-3.350 +3.350-4.750 +4.750-6.700 Sieve Class, mm
Toronto Stock Exchange April 2, 2012 Trading Symbol: PGD For Immediate Release PEREGRINE REPORTS TONNAGE ESTIMATE AND NEW MICRODIAMOND RESULTS FOR CH-6 KIMBERLITE AT CHIDLIAK Peregrine Diamonds Ltd. ("Peregrine” or “the Company”) (TSX:PGD) is pleased to report an independently verified tonnage estimate for the CH-6 kimberlite of up to 5.7 million tonnes of kimberlite to a depth of 375 metres below surface. The kimberlite pipe remains open at depth. A detailed technical report, prepared in accordance with National Instrument (“NI”) 43-101, will incorporate this new tonnage estimate. CH-6 is located within the Southern Focus Area on the 100 percent-owned, 8,580 square kilometre Chidliak project (“Chidliak” or “the Project”), Baffin Island, Nunavut, Canada. New microdiamond results from the CH-6 kimberlite continue to confirm a coarse diamond size distribution. A cumulative 1,512.3 kilogram sample of drill core collected from CH-6 in 2011 yielded 4,867 diamonds larger than the 0.106 mm sieve size, including 166 commercial-size diamonds larger than the 0.850 mm sieve size which weigh a total of 6.77 carats. The Saskatchewan Research Council Geoanalytical Laboratories (“the SRC”) classified the colours of the 166 commercial-size diamonds as follows: 42 percent white/colourless, 40 percent off-white, 14 percent yellow, 3 percent grey and 1 percent brown. The largest four diamonds were described by the SRC as a 0.60 carat off-white aggregate, a 0.43 carat yellow octahedron, a 0.34 carat off- white octahedron and a 0.32 carat white/colourless octahedron. Mr. Brooke Clements, Peregrine’s President, said “Completion of an independently verified tonnage estimate for CH-6 of 5.7 million tonnes of kimberlite is an important step in advancing the Chidliak project. We are especially encouraged by the microdiamond results from CH-6 which continue to be some of the best ever seen in Canadian diamond exploration. The diamonds recovered to date from CH-6 show a predominance of white/colourless, off-white and yellow colours and a coarse diamond size distribution. Continued evaluation of CH-6, beginning with more core drilling in 2012 and the collection of a bulk sample by reverse circulation drilling in 2013, will confirm the grade of the pipe and is designed to recover a minimum 200 carat parcel of diamonds in order to begin formal diamond valuations.” CH-6 Tonnage Estimate Geostrat Consulting Services Inc., a consulting firm specializing in kimberlite geological modeling and resource evaluation, verified the CH-6 tonnage estimate. Based on the current geological model, it is estimated that CH-6 hosts 5.7 million tonnes of kimberlite to a depth of 375 metres below surface. Of the 5.7 million tonnes, 3.6 million tonnes is considered reasonably defined with good drilling support. The remaining 2.1 million tonnes has been identified with limited drilling support and the confidence level of this tonnage will be increased with more drilling. Real potential exists to add significant tonnage at depths below 375 meters. This tonnage estimate does not constitute a mineral resource and there is no assurance that a resource will be identified through further exploration work of CH-6. The current geological model of CH-6 was defined from core drilling completed between 2009 and 2011. To date, 12 vertical and 12 inclined drill holes have been completed for a total of 4,701 metres. The geological model was prepared to the base of current drilling at a depth of 325 metres, with an additional projection to 50 metres below the base of drilling, at 375 metres depth. The tonnage estimate was determined using kimberlite volumes from the geologic model and specific gravity data for each geologic unit. The average specific gravity for 323 separate measurements was 2.58 g/cm 3 . A detailed technical report prepared in accordance with NI 43-101 incorporating this new tonnage estimate will be filed on SEDAR within 45 days.
2 New Microdiamond Results The following table summarizes caustic fusion diamond results from the CH-6 kimberlite. The analyses were performed at the SRC. SUMMARY OF CAUSTIC FUSION DIAMOND RESULTS FOR 2011 SAMPLES FROM THE CH-6 KIMBERLITE Numbers of Diamonds According to Sieve Size Fraction (mm) Carats Sample (+0.850 Weight +0.106 +0.150 +0.212 +0.300 +0.425 +0.600 +0.850 +1.180 +1.700 +2.360 +3.350 Total mm Unit (kg) -0.150 -0.212 -0.300 -0.425 -0.600 -0.850 -1.180 -1.700 -2.360 -3.350 -4.750 Diamonds size) KIM-A 298.4 420 262 159 96 55 45 18 12 2 1 0 1,070 1.17 KIM-B 929.5 924 640 362 224 131 94 44 21 9 3 1 2,453 3.40 KIM-D 179.3 194 127 100 62 40 26 10 8 2 1 1 571 1.22 OTHER* 105.1 312 175 111 73 41 28 18 10 5 0 0 773 0.98 TOTAL 1,512.3 1,850 1,204 732 455 267 193 90 51 18 5 2 4,867 6.77 * Additional work is required to classify this kimberlite material. KIM-C was not sampled during the 2011 drilling. The CH-6 kimberlite is a steep-sided, near-vertical, southwest plunging kimberlite pipe with a kidney-shaped surface expression of approximately one hectare. The current geological interpretation of CH-6, based on detailed core logging and three dimensional modeling, suggests that there are four main kimberlite units. Differences between the units are subtle with few clear geologic contacts and all units contain a variety of mantle xenoliths. The four main units are as follows: • KIM-A: a dominantly pyroclastic textured kimberlite found in the upper 120 metres of the pipe. It has carbonate xenoliths with fewer gneissic xenoliths. • KIM-B: a dominantly coherent textured kimberlite that is the most volumetrically significant unit at CH-6. It has gneissic xenoliths with fewer carbonate xenoliths. • KIM-C: a coherent kimberlite that is found in the lower two-thirds of the pipe, marginal to KIM-B. This unit lacks carbonate xenoliths. • KIM-D: a complex textured kimberlite that is found in the lower two-thirds of the pipe, marginal to KIM-C with many features similar to KIM-A, including the presence of carbonate xenoliths. In addition to these four main units, the upper 40 metres of the pipe is capped by a weathered kimberlite horizon. There are volumetrically insignificant, minor kimberlite units that need further analysis in order to be grouped with the four main units. Diamond results reported today are from three of four main units, KIM-A (holes 15 and 16), KIM-B (holes 16, 17, 21, and 23) and KIM-D (hole 23) as well as some minor units (holes 15 and 16). The KIM-C unit was not sampled during the 2011 drilling. As announced on December 6, 2010, a 14.11 tonne mini-bulk sample from CH-6 returned 40.04 carats of commercial-sized diamonds larger than the 0.85 mm sieve size for an average grade of 2.84 carats per tonne (“cpt”). The sub-samples, which were processed separately and ranged in size from 1.03 to 7.56 tonnes, returned diamond grades of 6.81, 3.49, 2.82 and 2.03 cpt. The sub-sample with the highest grade was collected from the upper portion of the southern half of the pipe, an area not tested in the 2011 drilling. Details of the 2011 core drilling were reported on September 12, 2011. Suite 201 -1250 Homer Street, Vancouver, British Columbia V6B 1C6 Tel: 604 408-8880 Fax: 604 408-8881 www.pdiam.com
Recommend
More recommend
