Provided below is the first part of an in-depth conversation with The Unknown Geologist on the geological model for the one-and-only Goldboro project owned by Anaconda Mining (TSX:ANX).
Peter Bell: Hello. To start, please can you tell me a bit about your relationship with the company?
Unknown Geologist: Sure, Peter. As you know, I have been following the Goldboro story ever since I left the property in the early 1990’s. I approached Anaconda recently and told them that I could help them. We signed a contract whereby I perform some specific knowledge transfer tasks. The first part of the assigned tasks has been completed…the remainder shall be completed this year. I am happy that Anaconda is keen to listen, to me it shows that they are serious about Goldboro. Why not listen to one of the few living people who have ever been underground in Goldboro.
I believe that what I already presented to Anaconda can potentially save a lot of time and money, especially the structural theories on where one can find high-grade ore shoots in Goldboro. The theories may not be right, but if they are, a much more effective and efficient drilling program can be devised.
I'm supposed to go down to the Goldboro site for a couple days to look at the core and, hopefully, the high-grade model they are enhancing. I want to see where they drilled, why they drilled there, and whether it all lines up with what I always thought? We'll see soon enough.
Peter Bell: Great. Going back to that transcript of our first conversations, a few things that you said jumped out at me. I understand if you want to keep some details private, but I wanted to talk about it all again. I looked through the technical report and found lots of weird bits of information about the history of the project and maybe we can get to some of those things. To start with, I wanted to discuss your statement that the high-grade has never really been drilled for continuity.
Unknown Geologist: Sure. If you go to their website, then they have a bunch of good diagrams we can use to discuss things. You see the one with all that green stuff (resource blocks) and all the holes/white spaces between it? That's what I mean by non-contiguous. All the spaces of white in between should be all green at some point. They are not green yet as they probably do not have drill intersections to be able to state such.
Unknown Geologist: Now, the other thing to consider is that it's all showing as “green”, but the there are many units stacked one on top the other and it’s not clear which green units they are actually showing there. Is it just one or two or five of them? It's hard to tell from that image.
If you keep scrolling down, then you can see a good comparison they have between Goldboro and the Bendigo deposit. See the growth potential?
I don't want to talk too much about the geophysics, but I will point out one thing that I flagged to the Anaconda guys a couple months ago. See on the geophysics image where it says, "0.5 kilometers" on the east side of the map? There's a small reddish area there and I think that could be another anticline. It doesn't have the same signature as the main anticline, but it has a little bit of a signature. That's important because of something subtle on the image describing the similarities with the Bendigo Camp image.
The Bendigo Camp is 1.2 kilometers deep. What do you see at the bottom of it? There's another anticline parallel, right next to the main anticline. That could happen at Goldboro and the geophysical signature I was just pointing out could indicate that second one. That would be a great similarity to Bendigo, if that's the case.
Goldboro is on the right of that Bendigo diagram and it runs 350 meters deep and all the little red units are basically argillite units. I call them stacked belts. It was all flat once and then it was just folded. I don't know how many belts are even shown in that diagram – probably 15 or 20? Each one of those belts will have more than likely high-grade zone within it and maybe even two on each limb.
Unknown Geologist: I know the Boston Richardson model very well. I remember reviewing a diagram of the Boston Richardson belt that shows the historic mining, and it highlights the top and bottom of an ore shoot on both limbs. If you use the Boston Richardson as a model for what the other belts should look like, then there's no reason why each one of them shouldn't have a high-grade concentration somewhere, probably due to a secondary flexure on the main anticline. That type of structural control can create dilation zones, which are the areas where the really good stuff gets concentrated. If you flex the rock in a certain way, then you'll get more of a concentration of liquid in certain areas than others.
All this affects how you approach exploration drilling. What Osisko did was a perfect example: they went out there and drilled every 25 meters on the north and south side of the anticline because gold occurs on both limbs. They drilled a hole and they'd get three or four intersections of really nice stuff, which is like 6 grams or better based on what I used to see at Forest Hill. When you have so many belts to drill through, you can hit this stuff in many different places and Osisko was trying to tie it all together into a massive open pit model, but no one has ever said, "There are 6+ grams in that one belt here – let’s see if that continues up and down dip by drilling 25 meters east or west of that 6+ intersection."
Osisko moved the drills parallel to the anticline to just see what's there on a broad, regional scale, as they were looking for the big open pit deposit. It was more of a grid drilling approach as opposed to chasing high-grade ore, which is completely different drilling/exploration approach.
Anaconda now knows about quite a few of these high-grade intersections with hundreds, if not thousands, of grams per tonne. I saw those at Forest Hill, too – not many of them, but a few. And every single time that we had a thousand grams per tonne, we were in the middle of the ore shoot. Even when we were in the hundreds of grams per tonne, we were in an ore shoot.
I think Anaconda should start with all those thousand and hundreds of grams per tonne intersections. Just start looking there and do their infill drilling up and down dip based on those known high-grade intersections. There are so many belts that they could look at and each one will have an ore shoot or two, so you could quickly get overwhelmed by the number of targets out there. What a GREAT problem to have!
If you look at the image of Bendigo again, then you can imagine drilling a vertical hole that slices through a lot of those belts. If you could pinpoint where the ore shoots are located, say 10 or 20 meters north or south of the anticlinal axis, then you could pick off a lot of those ore shoots with few holes.
Peter Bell: I wonder if those shoots are parallel along the different belts at Bendigo?
Unknown Geologist: That’s a good question, Peter. I don’t know the answer to that but we can find out – maybe Bob Moriarty can help us.
I encouraged Anaconda to try a deep, vertical hole at Goldboro. The first hole they drilled went after the Boston-Richardson at 600 meters deep, but it was drilled from way out on the limb rather than vertical. They showed some detail on that hole in one of the diagrams, but it is a bit blurry. Hole 17-06.
Unknown Geologist: They were trying to hit the deep stuff with that hole, 17-06. I thought that if they drilled an angled hole, then they could only go after one target, but when I saw that this image I was surprised. There's gold way out on the limb of the East Goldbrook system, too! That is more typical of things at Goldenville or Forest Hill. When I saw that, I was stunned – there are two or three more targets to choose from than what I had thought previously!
Peter Bell: I will point out that they haven’t yet reported the assays for hole number 6.
Unknown Geologist: No, I don't think they’ve reported anything from that hole yet. Other than what looks like 4 instances of Visible Gold in the diagram here.
Peter Bell: Whereas holes 1 through 5 were reported earlier.
Unknown Geologist: Yes. They hit 480-odd grams over 2.6 meters, right? That one.
Peter Bell: With over 2,500 grams over 0.5 meters.
Unknown Geologist: Right. Ore shoot intersection most likely…nice!
Getting back to your original question about continuity, just look at the title of this image with all the green: "Goldboro Growth Potential". If that green is all one continuously mineralized belt, then you can see where they need to drill holes.
At Forest Hill, there was one ore shoot that was 1.5 kilometers long but only 20 meters high. It's really hard to hit them with drilling, but you know when you hit it because the grade is so high – hundreds or thousands of grams per tonne gold. You could be just outside it and get nothing. It's a small target to hit but very high grade.
The interesting thing about the Boston-Richardson is that they mined the whole belt and documented a high-grade shoot on both limbs. They reported 5+ grams per tonne as the head grade overall, but the most recent estimates I’ve seen put it at 6.25 grams considering the technology they were using at the turn of the century. The tailings have about a gram in them because they didn't have any flotation to get the fines and stuff. They mined the whole belt and got 6 grams, say. Within that, there was probably some 2-3 gram material that they mined and other stuff that was probably a half-ounce or 15 grams per tonne in the high-grade ore shoots.
The ore shoots plunge the same way, but they are hard to identify. You can be on the margins of it and take some other material that is lower grade, but still profitable, and that’s how you can develop your mine!
Peter Bell: Are those shoots those dilation zones you mentioned?
Unknown Geologist: Yes. I talked to Paul McNeil and a couple of senior geologists. I asked if any of them had seen the Boston-Richardson mine plan? There is a detailed diagram of it that is just awesome. It shows the stopes very accurately. On the longitudinal map, they highlighted an ore shoot on one limb and ore shoot on the other limb in the other map. They marked the top and they marked the bottom of the shoot and it goes down from surface all the way down to 700 feet. They mined the whole belt but, like I said, they highlight where the top and the bottom of this ore shoot was.
That was very similar to Forest Hill. There was a high grade zone in there and a couple of veins. The vein was only 20 centimeters wide and it was probably 100 ounces to the ton. We mined it at 1.5 meters and diluted it down, but it was still incredibly rich. The same thing will probably exist in each of these belts at Goldboro.
Just look at all the VG spots indicated now in the diagram from Anaconda. I think they should try to line all of those up in each belt.
When they were here a few months ago, they were in the process of going through all the logs, noting where all the VG sites were located, and getting that information into the geological model. They were doing the same for arsenopyrite concentrations, as well – anything with greater than 5% arsenopyrite and VG is probably in a shoot or very close to one. These shoots should light up like a Christmas tree once you get that data in there.
Peter Bell: Wonderful. I can just imagine the 3D model of that. It’s funny to think of how much other information you’ve had to strip away to really bring that out.
Unknown Geologist: And just imagine if they could compare that with the old Boston-Richardson model showing the ore shoots? That would be a great way to establish infill-drilling targets. Again, it gets a bit tricky to drill them all efficiently because there's so many to drill!
Please note that The Unknown Geologist, Mr. David Hatchette is affiliated with the company but he does not represent the company.
