King Eider kimberlite proves complex

Eager to get a better handle on the diamond distribution of the known King Eider kimberlite on Victoria Island, partners Diamonds North Resources (DDN-V) and Canabrava Diamond (CNB-V) have drilled two angle holes across the pipe.

Drilled at minus 50, the first hole intersected kimberlite under 5.5 metres of overburden. It passed through several minor blocks of limestone before exiting the kimberlite body at 125-130 metres down-hole. The hole was shut down in country rock at a final depth of 140 metres. Samples from the first hole were divided into five sub-groups based on an interpretation of different phases of kimberlite.

The geophysical signature of King Eider, which is on the Hadley Bay property, is incredibly complex, says Diamonds North Vice-President Bernard Kahlert. The magnetic anomaly measures 300 by 200 metres in total. The eastern half of the anomaly consists of a magnetic low measuring 150 by 200 metres, whereas the western half is a mag high of about the same size.

An upper, 67.3-kg sample taken from 5.5-26 metres down-hole returned four microdiamonds plus one macro measuring 1.17 by 1.17 by 1.13 mm. (A macro is here defined as exceeding 0.5 mm in one dimension.). The upper sample represents a positively polarized or normal kimberlite. The second sample, weighing 58.2 kg, represents a magnetic low section of kimberlite between 31 and 50 metres down-hole. The first two sub-groups of kimberlite look the same, but there is a reversal in polarity, Kahlert tells The Northern Miner. “Geophysically, we have two very different kimberlites,” he says.

The 58.2-kg sample yielded seven micros and one macro.

Microdiamond results remain pending for the next sample interval of 50-79 metres of depth.

The fourth interpreted phase of kimberlite, at 79-101 metres of depth, returned 18 micros and seven macros from 68 kg of tested material, including four stones greater than 0.5 mm in two dimensions, the largest being 1.45 by 1.2 by 0.66 mm.

Results are also pending for a fifth kimberlite unit representing the remainder of the hole, and for one sample weighing 40.3 kg taken from the second hole, which was drilled in the opposite direction as a “scissor” to the first. “It gives us a complete east-west section with continuous kimberlite of 96.5 metres or so [across], if you project it vertically upwards,” says Kahlert.

Based on an interpretation of the geophysics, Kahlert says there may be other kimberlites at depth to account for the big magnetic halos. “We only exited the kimberlite at ten to fifteen metres on each end. It is a huge signature and we don’t think we have answered it yet.”

In addition to re-testing King Eider, the Hadley Bay joint venture discovered a cluster of four new kimberlites and a separate new kimberlite dyke, for which microdiamond results remain pending.

Canabrava can earn a half-interest in the Hadley Bay project by spending $5 million on exploration over four years and issuing 250,000 shares to Diamonds North.