Tuesday, June 16, 2020

Havieron, Greatland Gold

I apologize for the delay, basically I've been lazy and catching up with some personal projects during the 'ronavirus crisis.

Sticking with the Patterson Range, I've manage to compile the drilling data for Greatland's Haverion project, currently being drilled by Newcrest with 9 rigs.

An updated Leapfrog viewer file can be got from here (link)*, so you can have a look at the data in 3D.

At first pass, the data suggests that Greatland/Newcrest have found a good deposit, but we want to dig a little deeper to see:

  1. Size and grade potential
  2. Possible issues and questions
  3. Regional upside


Feel free to ignore this section, it is dull.

Here is a long section of the deposit, showing the Au and Cu distribution

We can see that the mineralization is a long-way down. We have ~400m of post-mineral Permian cover rocks (young rocks for WA).

We can see that the highest copper grades are found at the contact with the Permian rocks (maybe some localized supergene enrichment?) whereas with gold you do get some high-grade (>2.5 g/t Au) throughout the deposit.

We can also see that the Au-Cu mineralization is restricted to a breccia with some high grade narrow intercepts related to sulphide veins, this appears to be similar to what is seen at Telfer, just with a big difference.

Figure from GSDRPT 97 by Govt of WA

At Telfer they had stratabound quartz-sulphide reefs, it would be interesting to see if the high-grade crescent sulphide zone is actually one of these stratabound zones or formed through the deformation of the breccia into the crescent shape shown on the plan map below?

It is a very busy map

From the plan map and mineral distribution we can see the core area, where we have thick intervals of high-grade mineralization and 2 narrow limbs of high-grade intercepts continuing to the NW. Core area, probably at the nose of fold/deformation zone, with 2 narrow, but high-grade (>1% Cu) limbs striking to the NW.


We've had lots of holes drilled into Havieron, at least 60 holes so far, so I'm expecting that we should see an initial resource estimate some time this year, so taking the available data, this is what I've come up with:

You can see that at Haverion there is a bit of copper, but essentially it is a gold project, depending on the cut-off grades used, I think 100Mt @ 1 g/t Au and 0.5% Cu is a good start. Is it a bit small to develop on its own, maybe, but it is only ~50km from Telfer that the ore could be transported to the Telfer mill for processing which would minimize CAPEX.

Potential Problems

Looking through the data, one thing that I saw was a lot of grade smearing, especially in the drill-holes that intersected mineralization peripheral to the Crescent zone.

The right-hand section is going through the core of the Crescent zone and left hand section is from the NW continuation of the breccia zone, with hole HAD066 reporting the PR banner intercept of 82.1m @ 2.4 g/t Au.

In the core of the Crescent zone, I'm less concerned and the UHG veins/zones are generally wide and often surrounded by breccias grading > 1g/t Au, but the biog issue I see, and one that to me, limits the size potential at Haverion is the continuation of wide zones of economic mineralization outside of the core Crescent zone, and drill-hole HAD-066 summarizes it quite well:

  • HAD066 - 82.1m @ 2.4 g/t Au inc.
    • 0.2 @ 59 g/t Au
    • 1.5m @ 86 g/t Au
If we remove those narrow high-grade zones the grade of the surrounding breccias decrease from 2.4 g/t Au down to just 0.7 g/t Au, a 70% decrease. This suddenly changes HAD066 from intersecting a wide-zone of economic mineralization to just a couple of narrow high-grade hits in a sea of low-grade waste.

It appears to indicate that the breccias do continue to the NW, but they don't appear to be economic, and to me, limits the size potential of Haverion. It still appears to be a decent size, the mineralization appears to be open to depth (but will require very deep drilling).

Regional Exploration

Virtually all of the exploration to date has focused on Haverion but there do appear to be other interesting targets in the area that look interesting

The Haverion body is a nice magnetic high, and we can see several other similar features on the regional magnetic data shown in Greatland's presentation.

For me, Kraken looks very interesting. It has a similar magnetic anomaly to Havieron, , whereas London and Blackbeard appear, to me, to be picking out a folded magnetic unit with the metaseds of the Paterson Range rock package.


It is great discovery by Greatland Gold, there are potentially excellent synergies with Telfer, that, in my opinion, make this deposit an excellent take-over target for Newcrest. I'll be following the drill results closely and I would like to see a few holes stated to be drilled in the other targets to see if there are other breccia bodes in the area.

*thank you to Tumshie, I had accidentally made the 1-2.5 g/t Au grade shell invisible.