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Friday, February 1, 2019

Sun Metals - Stardust in Central BC

There are very few 'new' discoveries being made, and most junior explorers are flogging dead dogs that have been around for such a long time that most you can ignore.

This was my initial opinion of Sun Metal's Stardust project, it had a tiny resource but has had a lot of work done on it, ~398 RC and diamond holes, or ~70Km of drilling.

Not much here

What a POS - a small, low-grade, well explored project in the middle of nowhere. The didn't seem to be much potential in the existing resources. They appeared to consist of a series of narrow, variable grade zones that have had the crap drilled out of them. 

lots of narrow zones

So where were Sun Metal's going to find more mineralization? Projects like Stardust are quite common for it to go any further, you want to see some potential that it could host resources around >10Mt @ >3% CuEq to get a mid-tier miner (e.g. Crapstone) involved.

I'm just focusing on the skarn mineralization. I know that the project has several other mineralization styles, but they aren't the focus on the technical report, which suggests that they aren't important economically. You can get the 3D model from here (link), there was only a small proportion of the historic data that I could get in.

For those getting massive erections from the Porphyry zone, it has been drilled and no results are mentioned in the technical report, so I assume that it is unmineralized, but the lack of mineralization in it could be:

  • Negative (the majority of intrusive rocks) the magma that formed the stock was relatively metal poor, and therefore any mineralization associated with it will be small and uneconomic.
  • Positive (e.g. Santa Eulalia, Mexico; Taylor, Arizona, Las Bambas, Peru to name a few) – the stock was emplaced into a reactive rock (the limestones) that 'sucked' out all of the metals to form large skarn/CRD bodies leaving the behind an unmineralized porphyry.
However, the recent drilling (link and link) did look interesting. I wanted to check that they were doing more than confirmation drilling, i.e. twinning good old holes to con people into believing that they had found something new.

Simply put, they did a bit of both. Tested the known zones (probably because the historic core is missing), and they tested a few geophysical targets.

The good news that came out in October was from a confirmation hole (i.e. one that was drilled into an area that had been drilled before), and we got this section.

We can clearly see that the majority of the skarns are hosted in narrow limestone units within the phyllite package, which explains the narrow, irregular nature of the resources, which is not a good situation if you want to find a big deposit!

However, drill-hole 18SD-421 was good, it drilled through the phyllites and passed into the underlying limestones where it intersected 2 previously unknown, thick, high-grade skarn/massive sulfide zones.

This is great news as it shows that Sun Metals has found something new, rather than rehashing old news, and it appears that this phyllite-limestone contact is virtually undrilled! This zone appears to be open in most directions, especially up-dip.

The down-dip potential could be limited by hole LD2010-02 that may have drilled the down-dip continuation of this zone but hit nothing, but the hole may have been terminated before hitting the mineralized horizon.

I don't know the ground conditions at Stardust, but maybe there is an opportunity to reenter and extend holes 013 and 016 to drill through the phyllite-limestone contact as this would allow them to quickly determine (in 2D) the orientation and up-dip extent of this new skarn zone.

In summary, Sun Metals have a well explored project, but the discovery by hole 421 has identified a new target that has returned the highest-grade and thickest skarn intercepts on the project. However, with just a single hole intersecting this zone it is very hard to determine its size potential. 

In addition, they may want to look at conducting a down-hole geophysical survey, for example Mise-à-la-masse that has been used successfully in many other polymetallic sulphide deposits to determine its lateral extents.


  1. Is this an HDI project? Lustdust to Stardust smells like Fish Lake to Prosperity.

  2. "A Preliminary Site Investigation and Detailed Site Investigation have both been completed and report elevated levels of antimony, arsenic, cadmium, chromium, and mercury in the soil at the mine site."

    The above is from the tech report. The site includes a former mercury mine. One wonders...even if there is a decent sized mineral resource...where would one send the concentrate? And what environmental liabilities would result?

    Sun has optioned the property and will only ever hold 70% of any outcome, with NSR royalties to Lorraine on any production.

    1. There is no mention of the deleterious metal grades in the skarn mineralization. The Hg should be from the distal epithermal veins.

      We'll see what additional drilling will find, but they've found something new at a well explored project, so it will be interesting to see if it was a one-hit wonder or builds into something.

    2. There I go....think like an operator again!

    3. You ask where is the limestone/phyllite contact at surface. You don't need it, you need the limestone in contact with the intrusive at depth so it's good to see that slice of marble between the two zones. Quite a few indications this skarn is prospective and that includes the porphyry proper being sub-economic. In any case you don't need to extend very far in any direction at hole 421 widths and grades.

    4. You're correct, I was referring that the permeability difference between the limestone and phyllites could act as a conduct for vapors/fluids from the porphyry.

      You are also correct that often porphyries adjacent to skarns are poorly mineralized, some examples were given, but you do want evidence that the porphyry could have contained volatiles and incompatible elements (metals). The fact that different styles of mineralization (a zonation from skarn to distal epithermal and Hg mineralization) suggests this.

    5. I see your point on the fluid conduit. My thinking is no on the channeling because while Stardust has all the classic CRD zonation features, the zones themselves don't extent over substantial distances as they might on something pervasive like that. So I think the magic's more in the complex faulting and fractures and you have to trace those back to the intrusive especially if you suspect limestone. In one video discussing the project Peter Megaw is seen sheepishly stating the importance of tracing the system on structural control. Historic operators never bothered to investigate this adequately as the system always gave them targets near surface but never with the tonnage for a payoff because carbonate was too low. I suspect they even found some thicker limestone but un-mineralized so they ignored it. Lots of exploration effort and dollars were wasted if only they were more demanding of their objectives (so what else is new)?

  3. I took a look at the technical report from 2010 with holes LD2010-01 and LD2010-02. The hole shown in the cross section above is actually most likely LD2010-01. Both holes were drilled from the same pad but -02 was a NNW azimuth angle hole whereas -01 was vertical so would be the one shown as a straight line up-down. Paper plotting shows hole 421 intercept approx. 100-150 meters from closest trace of -01 and -02. It does seem -01 hit 125 meters of skarn to the end of hole. No limestone or marble accompanying the skarn below a fault but like hole 421 there are two skarn zones with a carbonate slice between them. So could be part of the same alteration package, just above the fault with lack of structures and consequently not a good path for late stage ore-bearing fluids. Importantly though, the barren skarn in -01 doesn't have too much pyrite or magnetite so downhole geophysics could perhaps be useful in tracing potential mineralized trends within it.

    1. we'll have to wait until a few more holes are poked into that area