Kennecott Canada Exploration has drill-tested five geophysical targets to date on the Legend property in northeastern Alberta, with only one miss — and, weather permitting, a further four targets are scheduled to be drilled prior to year-end.
Kennecott, a division of London-based
The 1.5-million-acre property is 120 km northwest of Fort McMurray and less than 100 km northeast of where
Ashton’s discovery of kimberlites in the Buffalo Hills area of north-central Alberta spawned a province-wide staking blitz in early 1997. By that time, Montello had already spent several years searching for the source of 24 microdiamonds and numerous olivine, chromite and pyrope garnet kimberlite indicator minerals recovered from stream-sediment sampling on the Masumeka property in the west-central part of the province. Masumeka is one of six property blocks in the Hinton area that are held under various participating interests by Montello,
Subsequent drilling by Kennecott in early 1997 was unsuccessful in locating any kimberlites on Masumeka. The testing of eight high-priority magnetic geophysical targets showed only sandstone.
In the meantime, on news that Ashton had entered into a joint venture with
By May 1997, Montello had entered into a joint-venture option agreement with Redwood on the Jazz, Legend, Nina and Swan properties. Redwood earned an initial 30% interest in these properties by making the first option payment of $1.5 million.
The two partners initially concentrated their efforts on the 1-million-acre Jazz property, which is contiguous to Ashton on the southeastern corner of the Loon Lake property. An airborne geophysics survey outlined several clusters of anomalies along a prominent northwest-southeast lineament trend.
A drilling program designed to test 18 highly prospective magnetic anomalies in early 1998 was cut short after the first seven holes proved the anomalies to be non-kimberlitic lithologies at shallow depths. Power said the anomalies appeared to represent ancient drainages, where concentrations of magnetite had collected in the bows.
By July of this year, Montello had completed a $400,000 airborne magnetic survey over the Legend property and, as well, flew an airborne survey over Ashton’s kimberlite pipes to establish a magnetic signature for comparison purposes. Using these data, Montello re-interpreted the geophysical data from the Jazz property and defined 13 new targets.
The airborne survey outlined several obvious magnetic targets on the Legend property. Prior to entering into a joint venture with Montello and Redwood at Legend, Kennecott looked at the geophysical data and chose five targets that looked promising, said Theo Aravanis, a senior geophysicist at Kennecott. Kennecott then conducted ground mag on three of the targets and confirmed their prospective nature.
That work led to the signing of an option agreement between the parties in early September, and, by month’s end, Kennecott had begun core drilling on the Phoenix target. Power described Phoenix as a “whopping anomaly,” with a magnetic signature measuring 400 by 400 metres.
The first hole into the Phoenix target hit kimberlite at a depth of 102.7 metres and remained in the rock unit until the hole was shut down at a depth of 225.8 metres. The kimberlite was described as a green ultramafic rock with a fine-grained serpentine ground mass containing 2-to-4-mm, rounded, olivine crystals and country rock fragments. Aravanis said the kimberlite is typical of crater facies.
A second hole further tested the Phoenix kimberlite, stepping out 50 metres to the east and 90 metres to the south, and, unlike the first hole, encountered both kimberlite and mudstone. “In some places, it looks as if the kimberlite was deposited at the same time as the mudstone,” said Aravanis.
Preliminary palynology (pollen) age-dating of mudstones extracted from the kimberlite discovery indicates Upper Cretaceous ages, which suggests a maximum age for the kimberlite of 82 million years, putting it in the same ball park as Ashton’s kimberlites.
Preliminary heavy mineral analysis of a small, 15-kg sample has shown abundant olivine and ilmenite, along with rare chromite. However, no garnets or clinopyroxenes were found. The lack of certain indicator minerals is a little troubling for Aravanis, but he said there are numerous occurrences of kimberlites containing diamonds without a high-level concentration of indicators.
The first microdiamond results from Phoenix are expected in the coming weeks.
Kennecott intersected its second kimberlite body while drilling the Roc anomaly, which has a geophysical signature measuring about 200 by 200 metres. The kimberlite was encountered at a depth of 120.4 metres. The hole was terminated at a depth of 175.6 metres while still in kimberlite, owing to difficult drilling conditions (there is said to be lots of mudstone in the hole). A second hole into Roc, collared about 100 metres from the first, hit kimberlite at a depth of 135 metres. The third target to be drilled was the Dragon, which, unlike the first two mag highs tested, is a subtle low measuring 300 by 350 metres. Kimberlite material was intersected a depth of 135.9 metres. The hole was shut down in kimberlite at a depth of 193.2 metres. Mudstone is found intercalated in the kimberlite.
The Wyvern anomaly is, to date, the only target on which Kennecott has come up empty. Wyvern is a dyke-like magnetic high measuring 1,000 by 150 metres; however, the two holes that tested the anomaly failed to explain its strong magnetic response.
At the time of our visit, Kennecott was drill-testing the Valkerie target, albeit with some difficulty. After drill crews abandoned the first hole because of problems with the pad, the second hole was drilled, cutting just 2.1 metres of kimberlite at a depth of 128 metres before the drill rods were sheared off. A third hole was in progress.
To date, Kennecott has defined 28 geophysical targets for drilling, and a further four targets are slated to be tested before year-end. These include Pegasus (400 by 300 metres), Griffin (another subtle anomaly measuring 400 by 400 metres), Xena (300 by 300 metres) and Legend (400 by 400 metres).
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