Click here to recieve updates directly to you e-mail

Wednesday, June 1, 2016

Pretivm - Bulla Crustulum or Raptus regaliter?

Pretivm released a new set of drill results from the Valley of the Kings yesterday. It had the typical mix of spectacular grades and so on...
"R" one of IKN's readers pointed made this comment:
"To your point -- the most telling excerpt from the PR: "True thickness to be determined."
Good to know you don't know true width of the infill drilling on the years 1-3 planned stope areas?"
and if you go back to Pretium's and go to the Brucejack project page (link), they state the objectives of 2015/16 infill drill program, which is:

"The planned drill program has been expanded to include extensions of Domain 20 which are adjacent to areas being mined in the early years of the 2014 Feasibility Mine Plan. Definition drilling from five underground drill stations is in progress and is expected to be completed in the second quarter of 2016. When completed, roughly 200 vertical meters over a strike length of 250 meters will have been drilled at 7.5 to 10-meter centers.

This means they have drilled >200 holes into an area that measures 200m x 250m, with a drill-holes every 2-3 car lengths, and with all that data they do not have enough confidence in their own data to estimate the true widths of the veins/gold bearing structures.  Just a couple of questions:
  • Just how complicated is this deposit? 
  • If they can't calculate the true widths of the veins, how will they mine them?

Grade control is going to be a bitch!

They allude to this in the various maps that accompany the May 31 PR.

Plan Map
each of those grey lines is a drill hole.
When you look at the sections (I've included a couple below, but please download the pdf''s that accompany the PR's for higher quality images). You can see the issues facing Pretium. There is an extreme nugget effect, the structures are not to to follow in adjacent (i.e. 5-10m apart) drill-holes. I haven't visited the project and looked at the drill-core so it may be easy with very clear veins, or it could be more complicated.

Note: the spacing between the horizontal lines (50m apart) are much (40%) larger than the spacing of the vertical lines (also 50m apart). I assume this is to make the section easier to read,
And we see the same on every section. A few narrow super grade intervals with a wide zone of up to 1g/t Au. Try and join up the narrow high grade zones (in red). Here are a couple of my attempts.
Obviously veins dipping steeply to the north
Definitely vertical veins

Let's have some fun and mess around with the assays:
VU-696 - 17m @ 50.31 g/t Au
  • 1st vein: 0.5m @ 183 g/t Au
  • 2nd vein: 0.5m @ 1510 g/t Au
  • The rest: 16m @ 0.5g/t
VU-708 - 16.5m @ 15.2 g/t Au
  • 1st vein: 0.5m @ 42 g/t Au
  • 2nd vein: 0.5m @ 412 g/t Au
  • The rest: 15.5m @ 1.5 g/t Au
VU-723 - 14.04m @ 14.84 g/t Au

  • 1st vein: 0.5m @ 125 g/t Au
  • 2nd vein: 0.5m @ 271 g/t Au
  • The rest: 15.5m @ 0.8 g/t Au
This is repeated time and time again. Hopefully the narrow high grade structures are close enough together and contain sufficient grade that when they are mined at 2-3m width (taking 0.5m of vein and 1.5-2.5m of barren country rock) there is enough gold to cover costs.

I get the feeling that this could be a project with issues.