Wednesday, April 1, 2020

Pretium - Brucejack production

So why should bad news be spread over a single post, we looked at the 'improved' resources, so now let us look at the mine production figures

Pretium have done an excellent job with the mill upgrade
 

It has been consistently producing 5-10% above nameplate capacity, and they ramped up throughput to 3800 tpd on schedule.

Recovery is still excellent:

However, we see that mined grade is still way off the original Feasibility Study, approximately half that calculated by Tetratech.

 Understandably, this has had a massive knock-on effect to the Au production.

We can see that it is way off, but why don't we plot on the latest reserve grades.


You can see now that the new reserve grades is very close to the actual mine grades. It will be interesting to see of they can keep at this level.

It will be interesting to see if Tetra Tech or Snowdon have any comments on why their 2013 and 2019 resource calculations were so different to mine production and latest resource estimates.

4 comments:

  1. Yes they have done a good job on executing their plan. The big question has always been grade. The high CoV in the original estimate suggests significant unreliability in the grade estimate. Not having looked at the new estimate I wonder if the stats have changed or if not then what? And your questions on the original estimator are good ones.

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  2. Interesting that the grade and contained ounces were both reduced in the latest resource/reserves estimate. On Feb. 12th the company announced that their Vice President Geology, who was also Chief Geologist, was leaving to pursue other opportunities. Wonder if the two events are related.

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  3. If Wayne's final concept was accepted, Brucejack would have lived up to expectations. He wanted to extract large volumes, knowing that the grade would be variable. Quarterly or yearly production grades would fluctuate but, in the long run, the grade would be 10-15 gpt. Of course, this approach wasn't accepted because engineers, analysts and management had to have short term predictability. near term Guidance and reconciliation carried the day. After a short while, grades didn't jive with block estimates. What to do, what to do. Open up more stopes and do very close spaced drilling. All in the name of blending to give predictable results. Production costs shoot way up and the profit margin plummets. What can you do????

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