Projects

Lapointe Discovery

Introduction

The Lapointe discovery is located in the Temagami North area of Ontario and was the location of a micro- and macro-diamond find. They were recovered from caustic fusion analyses of the Lapointe Kimberlite discovery. The largest diamond, a 1.7 mm, is described as clear and white, and weighs 0.0665 carats. Other diamonds from Thunder Bay include fragments greater than 0.5 mm in one dimension, which suggests that the Lapointe Kimberlite has an encouraging coarse diamond size distribution (refer to Table 1). SGS-Lakefield reported a single micro-diamond which remained on the +212 micron screen from 198.5 kg. The Lapointe Kimberlite was discovered on May 18, 2005 within the first hole drilled by Tres-Or. Please see CASE STUDY: LAPOINTE KIMBERLITE DISCOVERY (PDF)

Regional Geology

The geology of northeastern Ontario and Quebec is considered favorable for primary diamond deposits due to the underlying Archean Superior craton that has been stable for at least 2.5 billion years and major, deep structures favorable for the ascending kimberlite magmas such as the Lake Timiskaming Structural Zone. This is supported by research and exploration results that demonstrate the upper mantle in eastern Canada is significantly diamond-bearing.

The Lapointe Kimberlite is a large, multiphase pipe in excess of 21 hectares in surface extents, based on airborne magnetics and the first 4 drill holes which intersected the body. A 3,500 metre drill program is underway to delineate the recently discovered Lapointe Kimberlite in Ontario. This delineation program is designed to test all parts of the body, which has already been shown to be comprised of at least 3 intrusive events, each of which has returned diamonds. The encouraging diamond recovery, backed up by favourable indicator mineral chemistry (including sub-calcic [G10] pyropes and eclogite garnets with compositions similar to inclusions in diamonds) has led to the decision to undertake this delineation program. Three drill holes have been completed and were collared and exited in kimberlite. Drill core is being logged, split and shipped to the lab for caustic fusion analysis.

Airborne Magnetics-Horizontal gradient shows the Lapointe 1 target referred to in our May 12, 2005 news release. The background is the horizontal gradient of the total magnetic field data. The Lapointe 1 priority target in the in the centre top of image is a large coincident magnetic, electromagnetic, and indicator mineral target that appears to be comprised of two coalescing lobes. The horizontal gradient is used on the magnetic data as it highlights the edges of the rock creating the magnetic anomaly. Kimberlites which have a vertical pipe like shape show up as donut shaped anomalies. The diabase dykes in the area (not of economic interest) show up like railway tracks. The red outlines show the land position. The multi-coloured pies depict the kimberlite indicator mineral results taken down ice of the Lapointe 1 target. The size of the pie is related to the number of indicator minerals in the sample. The colours represent the different types of indicator minerals. Red for pyrope garnets, Blue for ilmenite, Green for chrome diopside, Orange for eclogitic garnet and Brown for chromite. (refer to Airborne Magnetics-Horizontal gradient) and (Till Chemestry)

Exploration

The drilling to date is entirely consistent with the Lapointe kimberlite covering approximately 20 hectares at the surface, as originally interpreted from its magnetic signature. The indicated size of the Lapointe kimberlite makes it possibly the largest kimberlite yet found in Ontario, although significantly more drill holes will be required to confirm the size.

The 3rd hole was drilled south at a 65 degree inclination from the center of the eastern lobe of the magnetic anomaly (300 m east of the discovery hole) and intersected kimberlite from 73 m to 309 m. At 309 m, the drill hole entered granite consistent with the contact of the kimberlite pipe based on the magnetic signature, and was terminated due to squeezing of the rods up the hole. Kimberlite intersected by this 3rd hole differs markedly from the kimberlite in the 1st hole, supporting the interpretation of different intrusive events forming the two lobes, and thus each lobe has the opportunity of carrying a different mantle sample and diamond grade.

The 4th hole tested a slightly more magnetic portion of the western lobe 130 m east of the discovery hole and terminated today (July 7, 2005) at 260 m in kimberlite. The hole was inclined at 60 degrees drilling to the south towards the centre of the magnetic anomaly. The 4th test hole entered kimberlite directly beneath overburden and supports continuity of kimberlite between the eastern and western lobes.

Complete suites of kimberlite indicator minerals (Cr-pyropes, eclogite garnets, chrome diopside, chromites, Mg-ilmenites, olivine, and enstatite) from the Lapointe drill core have been analyzed by electron microprobe at SGS-Lakefield laboratories in Lakefield Canada, and demonstrate they have the same diamond–favourable chemistry previously reported (see news release dated May 19, 2005) from till samples collected immediately down-ice of Lapointe 1 target. Included among the favourable indicator minerals in the Lapointe kimberlite core are numerous sub-calcic (G10) Cr-pyrope garnets (10% of analyzed Cr-pyropes are moderately Cr-rich G10s), orange garnets with elevated Na2O similar to most eclogite garnets found as inclusions in diamond, and Cr-rich chromites (maximum Cr2O3 65.61%). This indicator mineral chemistry is sharply distinct from, and more diamond-favourable than chemistry from other reported kimberlites within the New Liskeard field (to the south) and the Kirkland Lake field (to the north), with the single exception of Contact Diamond’s 95-2 pipe, which is also reported to carry 5 to 10% moderately Cr-rich sub-calcic (G10) pyropes.

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