We got partial assays from hole 19 at Alpala, let us see what that it shows and does to the official bad (tm) resource calculations.
- My predictions were very average
- My officially bad resources have gone up
- Copper 15% to 320Mt @ 0.54% Cu or 6.4Blbs contained copper
- Gold 10% to 299Mt @ 0.56 g/t Au or 5.3Moz Au
In an earlier post I made some predictions about future drill results, for hole 19 they were:
- 0.5% Cu and 0.6 g/t Au from 325.6 to 1161.5m
- including ~0.6-0.8% Cu and ~1 g/t Au from 850 to 1161.5m
- 325.6 to 850 will run around 0.4% Cu and 0.35 g/t Au
And this is what it looks like in technicolor
|Zoomed in - Cu (right) - green zone starts at 572m depth|
However, you can clearly see the very high grade zones (>1% Cu and >1g/t Au) hit in adjacent holes doesn't seem to occur in hole 19. We have 2 options here:
- The zone does exist in hole 19, but is much narrower and hasn't been separated in the summary assay table
- The very high grade mineralization is small, and restricted to specific zones.
So my prediction was wrong, which sucks, and mineralization appears to be ~200m deeper than originally thought, but i did do a better job at
I'm going to give myself a 4/10. Must try harder....
So what does it do to the resources? Here are the updated numbers.
Another 10-15% increase in contained copper and gold, and it seems that we have squeezed over the magical 5 Moz contained gold, which is very nice.
For this I've used the following parameters:
- Specific Gravity = 2.7
- A NW-SE trend on mineralization - this appears to be similar to that being used by SolGold in their presentation.
- 200m search (i.e. Leapfrog connects intervals that are within 200m from one another)
- this is comfortable for an 'inferred' resource.
I've decided to have a closer look at the data to see what upside there is at Alpala.
|red dashed line = my estimate to the limits of mineralization - think of it as a >0.5% CuEq grade shell|
We can see that hole 13-003 was drilled over the main mineralized zone, and hole 19 is extending this zone (albeit in small systematic steps) to the SE. We can also see that the grade drops off to depth. This is suggesting the holes are entering the high temperature core of the system, where it is too hot to precipitate copper minerals.
Here is an annotated version of figure 4 that accompanied the latest PR (link).
|cyan - where I think the holes being drilled will go; green - holes I would like to see SolGold drill|
- Hole 20 - will probably hit the high grade zones intercepted by holes 08, 14, and 18 - it will give good numbers but not significantly change the size of the deposit
- Hole 21 - that will intersect the same zone hit by hole 19, just 30-50m south of it.
I've drawn a number of green lines on the figure above, these are hypothetical holes that I would like to see drilled (but then again, drawing lines on a map in an air-conditioned office is easy), but it would test some areas where the mineralization is open (especially the zones hit by hole 07 and 17), and change Alpala from a large into a very large deposit.