What started as a simple post has turned into a thesis that may...

What started as a simple post has turned into a thesis that may not be for the faint hearted.  For me it is in part a trip down memory lane, long and meandering (some apologies) as well as a comment about exploration past and present in the Fraser Range and Thompson Nickel Belt (TNB).
These issues fascinate me and hopefully will be an interesting weekend  read for some.

The grades of Ni Cu in this announcement are what triggered my interest.  IMO these may simply be background values in a more enriched ultramafic and not necessarily associated in any way with an economic deposit.  LEG obviously considers them to be significant and I hope this proves to be the case.



Below I will present some information from my past experience in the TNB and WA that show how I come to have such a viewpoint.

The background level of nickel in certain ultramafic rocks is 3-4000 ppm and as such not treated as economic.
In the north of the Golden Grove stratigraphic package (Scuddles/Gossan Hill Zn/Cu VMS) some of the RAB holes encountered such grades and they were totally discounted!  Perhaps wrong environment and we were looking for base metals.  The Fraser Range is very different.

One thing that has puzzled me from my early geological days working for Inco in the 1970,s is how assays in the sub 0.5% level can be seen as potentially economically significant.

Another thing that surprised me was when I saw Mt Kieth being developed at a grade of around 0.6% Ni in the 1980s and 90's. From my short stint in the Thompson Nickel Belt, Manitoba I was aware that Inco had several similar size and grade deposits that even now sit under lakes and swamps undeveloped.

The Location map and Table below lists many of the deposits known in the TNB (not all).


Deposits 2, 3(all) and 7 are all potentially of a similar size and grade as Mt Kieth, Yakabindie or Honeymoon Well.  I don't know why they haven't been developed (I suspect a combination of being under lakes/rivers, geotechnical, metallurgical and other issues that are more easily overcome by the WA examples.)  A company called Royal Nickel is trying to get the Dumont deposit off the ground in Canada at the moment (~1Bt at 0.2% Ni and other credits).
Maybe there are some deposits like this in the Fraser Range?

The table above gives some idea of what a Nickel belt is.  Multiple deposits whereas at the Fraser Range, to date, there is only Nova and rumours of a new discovery by a Mark Creasy backed entity.
[Voisey's Bay also seems to be an isolated occurrence (but wow!).]

A simplified version of the TNB exploration Vs Fraser Range.

The TNB began as a prospector's discovery outcrop on a lake shore (with anomalous nickel) that attracted INCO and other companies in the late 1940's?  Using airborne electromagnetic techniques INCO surveyed the area and came up with a large number of anomalies which they prioritised and began to systematically drill.

The Moak and Mystery deposits were discovered quite early.  Before the Thompson discovery Moak was, I believe, going to be the first mine in the area.   

A few anecdotes about discoveries in the TNB.
One I heard about the Thompson discovery was that a drill rig couldn't be moved across the unfrozen Burntwood River during freeze up (Oct/Nov) so they decided to stick a hole into an AEM anomaly that was low priority while waiting to cross!  The rest is history.  Serendipity can trump the best science sometimes.

Another about Birchtree (#6)  where INCO drilled a single hole into an AEM anomaly and realised they had a potential discovery.  However, another company (Conwest?) had the claims on northern extensions of the anomaly.  INCO moved the drill away and waited until the northern claims expired and began to peg them at a minute past Midnight when they were available and the other company hadn't renewed (physical pegging was the rule of the day).  The folks in the Conwest camp awoke the next morning to find orange paint from INCO canoes that were dragged through their camp in the wee hours of the morning.  Birchtree had a checkered mine life but produced maybe 30 M tons of ore in its long life.

The final one has to do with Manasan Quarry (#8) which I think may be a deposit drilled by the team that finally began to work out the stratigraphy of the TNB as it is shown in this report (Thompson Nickel Belt model). They approached management with a geologically based target in Ospwagan lake.  Asked what they expected to find - they replied "40 Mt at around 2% Ni".  After considerable thought the decision as parphrased by the person who told me was "OK guys you can go and play with it!". The mentality of executives who cut their teeth on massive 100+Mt >3% deposits in Sudbury?  I heard the exploration target was realised but it still sits under the large lake/river system 30+ years later.

Anecdotes - True?  basically, I think, as some of the folks I knew were involved.

The big picture:


Voisey's Bay is probably in a different tectonic environment.

WA major tectonic boundaries on with magnetics.


For the Fraser Range it is still early days compared to the 70 years work done on the TNB where the stratigraphy and possible genetic models have been sussed out. As per Lightfoot et al's summary/work.


As more information becomes available a more coherent picture may come for the overall Fraser Range.

Individual deposits and overall tectonic patterns could also emerge.



A lot of food for thought.  By no means complete but already (as I expected way over the top for HC).
GLTAH to folks who choose to invest/risk their hard earned money in companies that have a statistically low chance of finding mineral deposits.