Saturday, April 13, 2019

Pretium - Lies, damn lies and Reserves

I've been bashing Brucejack frequently over the 'difference' been mine grade and reserve grade, and with the release of the update resource and resource statement, I decided to look at how the reserves and resources have changed overtime (just for the VoK):

Note: I've added dashed lines to the charts where data is missing (the Dec 2016 resource press release didn't include information for M&I and inferred resources).


We can see that that we had an initial increase in resources from 2011 to 2013 and then a leveling off as drilling focused on improving resource quality and converting resources to reserves. We see that recently drilling has also focused on increasing resources.

Contained Ounces

Ounces have stayed relatively flt over time, we had very large growth in resources from 2011 to mid-2012, then the focus has been on improving the quality of the resources (from Inferred to Measured and indicated) and to reserves in 2016.

Average Grade

I've added a lines for the Life of mine (LOM) mine grades in the 2014 Feasibility Study (FS - orange line) and the new 2019 proposed mine grade (purple line), and one for the 2018 actual mine head grade (grey dashed line).

  • Average grade (all resources) decreased from 22 g/t Au (2012) to 15.8 g/t Au (2019)
  • M&I resources remained constant since 2012 at ~17.1 g/t Au
  • Inferred resources decreased from 35 g/t Au (2012) to 17.7 g/t Au (2019)
  • Reserve grade decreased from 16.1 g/t Au to 13.8 g/t Au
Obviously the reserve and resource grades have dropped because of all the high-grade mineralization mined in 2018......

You will see that in many 43-101 reports the Inferred resources typically higher grade than the other resource categories, they are normally based on the lowest quality data (relatively speaking), the widest spaced drill-holes and can be heavily skewed by a few ultra high-grade holes. However, it is surprising that the grade of the inferred resources have fallen by such a large amount.

This figure was also interesting in the press release:

There was a lot of technical crap in the section accompanying this table, but in I think it means they mined 20% more material than planned, now this will be interesting to see going forward, especially with the mine being expanded to 3800 tonnes per day.

Brucejack produces a lot of gold, but it keeps falling short.

Data for these charts came from:

Feb 2011 resources - link

Nov 2011 resources - link

Apr 2012 resources - link

Sept 2012 resources - link

Nov 2012 resources - link

Dec 2013 resources - link

July 2016 resources - link

Dec 2016 reserves - link

Apr 2019 reserves and resources  - link

Friday, April 12, 2019

Garibaldi - The final cuts!!!!


Nothing special, nothing new, but after 4 months of waiting, Garibaldi have manged to publish the results from the final drill holes at Nickel mountain (link).

We get a smattering of regional exploration holes (all hit nothing), some hole exploring the new (i.e. not found by Silver Standard in the 1960s) and some nice promo-BS holes drilling down the guts of the NE and NW zones, which, I'm guessing weren't as good as expected and would have had no impact on the releasing the results.....

I'm only going to focus on the holes that were drilled in the NW and NE zones. A few holes have been drilled regionally, but they hit nothing, so we can forget about them. However, it would have been nice to have known what the holes were targeting (and maybe which geophysical anomaly), but that isn't the way that GGI operate.

You can find my Leafrog model here and I've also incorporated the surface samples form the Crevasse massive sulfide (link).

Northwest Zone - Explored by holes 36, 37 and 46.

Hole 36 
Drilled to explore for the southern continuation of the NW zone, it intersected a 42 cm zone of massive sulfides just 17m south of the DDH_05 drilled by Silver Standard in the 1960s that intersected 9.5m @ 2% Ni.

Looking small

Hole 37
Vertical hole drilled 22m south of hole EL-17-12 (18m @ 1.15% Ni and 1.09% Cu), that hit a couple of low grade zones.

Thick intercepts of nothing

Hole 46
Unsurprisingly with the poor results from holes 36 and 37, the final hole in the area (and the 2018 program) was a nice BS-hole, designed to drill right through the guts of the mineralization to get as long an intercept as possible.

Should have made the hole a bit steeper

The irony is, the hole did hit a wide zone of <1% Ni disseminated mineralization, but no high-grade and actually returned lower grades compared to adjacent holes (EL-17-05, 17-06,  and DDH_05).

Nice one guys!

NE and Crevasse Zone - explored by 5 holes.

I'm grouping these zones together as they all appear to be part of the same system.

We see that the massive sulfides are found at the contact between the E&L intrusion (purple) and the Hazelton sediments (lime green), and by some amazing fluke (GGI would never have deliberately designed them to be to be BS-promo holes) all 5 holes have been accidentally collared right in top of the of the mapped massive sulfides.

Unsurprisingly, all holes hit mineralization at surface, with each hole hitting a narrow (up to 1.5m core length) massive sulfide zone with minor (up to 18m) disseminated mineralization.

Should have drilled a metric-fuck tonne of 50m holes and got lots of intercepts

With nearly 40 holes drilled into an area that measures 250m by 125m, I am keenly waiting for GGI to commence a resource calculation for Nickel Mountain. I'm sure that they have enough information.

Joking aside, basically we see nothing new, the mineralization is restricted to small zones, there are areas where it can be expanded, but they are limited (and not everywhere as shown on the plan map accompanying the press release), but you need to remember:

Mineralization needs E&L Intrusion + Hazelton Sediments
Missing either = no mineralization

Why is this important - if GGI haven't rocks similar to the E&L Intrusion elsewhere on the property, then potential to discover additional mineralization is essentially zero.

Note - for the pedants