RE:RE:RE:RE:RE:RE:RE:RE:RE:Let's speculateIdle and blue,
You and Blue indicated: " the whole objective of the bulk is to confirm whether or not the resource model is valid". Agreed as well. I would add some comments, ...particularly...
- to confirm the grades obtained from the tiny samples (~2-inch diameter) they had from the cores and the large spacing. The spacing for infill could be 25m which would be acceptable for interpolation purposes with respect to resource estimate for an NI Tech Rept. In some quarters, they would go for 10 m spacing. But, even 10-m is still huge compared to a 2-in cores from which the information is used to build the RE model. Anyhow, 10-m spacing would be acceptable for the mining community (and would satisfy the regulators).
- bulk samples would be used in a pilot or prototype scale to validate the metallurgy obtained from a Lab bench scale.
Relevant to the discussion: de Jong said in the 22 Feb 2017 NR
“As the Company’s exploration ramp at Triangle gradually approaches the proposed bulk sample target, impressive drill results like those reported today continue to demonstrate the future potential of Triangle. Infill drilling within the proposed bulk sample target has exceeded expectations in both grade and thickness, and extensional drilling on deeper structures suggest that Triangle has the potential for further growth,” noted Integra President and CEO Stephen de Jong. (Underlined mine).
Let`s go to the C2 section (dated 20 Feb 2017) where the area for bulk sample (in a gray box) with around a dozen dots and squares showing the grades. Most of the grades are above 10gpt, the min is 2.5gpt and the max is 71.61gpt, rather than 459.07gpt (hole 261). Note that hole 259 with 21.95gpt (max is 111.69gpt in the Table) is just about 15m outside the sampling boundary, and hole 260 is shown at 10.83gpt (rather than 71.61gpt, see Table in NR). The apparent inconsistencies may be due to the conservatism taken in some kind of capping or averaging by management.
The real UG scenario, when they send the machinery (chisels and hammers) down to collect the samples:
The sample area is irregular, but this frontal area in C2 x-section can be approximated by an area of 150m x 70m = approx 10,000 m2. Assuming a sampling spacing of 10m, say poking, with an air hammer in front of a bulldozer, about 50 holes in that rock face. Each hole would be a site for collecting about 100 tonnes of samples (two 50-tonne truck loads for each big hole).
Next question is how would management decide to locate the holes, randomly, or specifically targetting the jewellery boxes.
Personally (no mining engineer here) I would target the jewellery boxes separately, including the those outside the boundary (e.g. 259) and put their samples in separate piles, for processing separately (to get the cash, since 2 truck loads of high grades, say "61gpt, or 2 oz per tonne, is worth something like $300,000. Three of those boxes would fetch the company $1M.
To be on the conservative side, management could calculate the average grade of the bulf samples excluding the jewellery boxes, but the results of the jewel boxes should be mentioned, or included in the average, as facts (validation, de-risking, etc) for people to consider, since this is what ICG gets after the analysis using tiny core samples...and of course the metallurgy for a much larger scale prior to production.
Just my musings for the day.
GH