Wawa, Ont. — The Wawa area on the north shore of Lake Superior has been the site of diamond exploration for over 20 years, with millions of dollars spent.
Late last year, a new player,
Leadbetter had been panning gravels from Lena Creek about 12 km north of Wawa in 2003 when he recovered three diamonds, including one that was 1.39 carats and gem quality.
Looking for the source of the diamonds, the following spring he panned and sampled upstream from his original find, and sampled overburden and bedrock from the Lena Creek drainage basin.
Outcrop was abundant in the area, with vegetation having been burned off by the emissions from an iron ore scintering plant, closed in 1999.
He even thought that he had found kimberlite outcrop, which he sampled. The rock contained diamonds.
The diamonds were real but the kimberlite was not. What he had found is now called the “Diamond Bearing Rock” (DBR) unit, which is actually a heterolithic conglomerate, and the source of the diamonds.
Leadbetter sampled the DBR unit, and tested its continuity with three diamond drill holes. He recovered 332 diamonds of varying size up to 0.11 carat from this bedrock sampling.
Dianor President John Ryder visited the property in September 2004 and was impressed with the results of Leadbetter’s work, and the extent of the diamond-bearing rock. Dianor began due-diligence sampling and a deal was signed last December.
Dianor’s due diligence consisted of sampling 5.5 tonnes of bedrock from 12 pits about 35 metres apart, covering about 400 metres of strike length. An independent third party (the late Winfried Brack) took the samples in the vicinity of Leadbetter’s.
About 3.3 tonnes of the sample material were sent to the Saskatchewan Research Council (SRC) for caustic-fusion diamond analysis and 2.2 tonnes were sent to SGS Lakefield for processing by dense media separation (DMS).
Several hundred kilograms of rock samples were also sent to Charles Fipke’s C.F. Mineral Research in Kelowna, B.C., for attrition milling in order to find indicator minerals and extract diamonds.
Processing of the samples sent to the SRC plus some samples collected by Dianor itself yielded a total of 19,827 diamonds (micro and macro).
Based on the SRC results for all diamonds recovered, an estimated diamond grade of 1.22 carats per tonne was projected for the Leadbetter property DBR.
In the final batch of samples processed, the two largest diamonds measured 2.1 mm and 2.00 mm in their longest dimensions, and together weighed 0.059 carat. The larger diamond was colourless while the other was white and cloudy. The remaining diamonds varied from colourless to yellow, amber, grey, white, pink, black and green; colourless diamonds made up the largest portion.
Results from SGS Lakefield using DMS indicated that diamonds having commercial characteristics (greater than 0.85 mm and gem quality) could be recovered using conventional technologies.
Attrition milling at C.F. Mineral Research of 395 kg of rock produced 822 diamonds, of which 78 were greater than 850 microns in size. Kimberlite indicator minerals (KIM) including olivine, clinopyroxene, chromite and picroilmenite were also recovered.
The original Leadbetter property consists of 19 claim units totalling 944 hectares in Chabanel Twp. and is easily accessible by road. Dianor issued Joe Leadbetter 1.5 million shares of the company upon signing the agreement. Within six months of the signing, Leadbetter received $415,000. Over the four years following the signing, Dianor will pay $3 million in cash and stock and will spend $5 million on the property, paying an additional $5 million within eight years of signing.
An option to acquire a 70% interest in the Leadbetter Extension property (49 patent claims covering 646 hectares) to the east and south of the original option was announced in March 2005.
In August, Dianor signed a deal with Charles Fipke-led
Dianor’s property interests in the area now cover 40 sq. km.
Systematic exploration and sampling of the property began this year. By June, one rig was drilling NQ core every 200 metres along an east-west line to define the thickness and extent of the DBR unit, while a second rig drilling BQ core was delineating the northern, southern and eastern limits of the DBR.
The rocks on the property can be divided into three main lithologies: an upper volcanic rock consisting of pyroclastic debris and pillow lavas overlying the DBR unit; a conglomerate; and an underlying basal unit of fine clastics consisting of a sequence of thin-bedded alternating siltstone/sandstone layers.
The DBR is interpreted by Dianor’s consulting geologist Allan Miller to be a series of diamond-bearing debris flows of poorly sorted heterolithic, cobble-to-boulder-clast-sized conglomerate units. It is Archean in age, around 2.7 billion years old.
The diamond mineralization model for the DBR is that of a sedimentary diamond deposit in a submarine basin with possible local inputs from mantle-sourced igneous events that may have been erupting in the basin.
Analogies may be found in the Archean-age Witwatersrand basin in South Africa, and in the present-day alluvial diamond deposits off the coast of Namibia.
Drilling has extended the DBR for at least 1,300 metres in an east-west direction and it is still open downdip to the north. The unit dips about 35 to the northeast.
Due to the extent of the DBR, the unit has been divided into three sections for systematic evaluation. On the northern section, exploration and delineation drilling (NQ core) is ongoing as is a mini-bulk sampling program. In the central sector, mini-bulk sampling and geological drilling is in progress, while in the Southern section geological drilling is proceeding.
The mini-bulk sampling is a two-part program. Part one consists of collecting about 120 bedrock samples of 5-6 tonnes, each on the northern and central sectors of the DBR. The second part consists of sampling the alluvial deposits of sand and gravel flanking the DBR’s southern exposures. Approximately 800 tonnes of sand and gravel will be processed to test the diamond-hosting potential of the surficial deposits.
According to Ryder, a preliminary resource with a three-dimensional model for the northern section should be ready in about 18 months.
The rocks on the Leadbetter property are unexceptional in appearance. Geologists looking at them could conclude that they are no different than other conglomerates throughout the Canadian Shield. But the tiny secrets that these rocks hold set them apart, and may encourage a closer look at other conglomerates for their diamond potential.
— The author is a freelance writer based in Toronto.
I met this man at a doctor’s office in Sault Ste Marie. He is down to earth and very kind. This couldn’t have happened to a better person! It was refreshing to talk to a man with old fashioned morals like my grampa!!
I wonder what ever happened to the 5216 diamond that were recovered from a wawa drill site between metalex mori diamonds and dianor.Anyone knows anything I would really Like to know
My impression is the Dianor diamonds turned out to be too small, though of nice quality. Too bad! John Cumming