Intersection between C2 and Electrical-Bay cross cutWhat I found most interesting and relevant to the underground mining using the ramp is this iten in 1 Feb 2017 NR. Excerpt below:
"C2 Structure Intersected Underground 75 m West of the Known Limit of C2
The C2 structure was intersected underground in a southerly driven electrical-bay crosscut off the Triangle exploration ramp at an elevation of 260 m above sea level or approximately 65 m below surface. This crosscut in the C2 is located approximately 75 m west of the previously known limit of the C2 resource, suggesting additional resource upside may exist within the western extension of C2. Two continuous chip channel samples covering the entire exposed structure were taken on the east and west faces, with the faces located approximately 15 m apart."
A few facts and comments:
- It was a surprise to discover this area, it would seem. I tried to put together a 3-D diamgram. but still struggling. It would be nice if the company put out a nice diagram for everyone to "ooh and aah".
- This hit is quite shallow (65m below surface), so it must be where the ramp is not too far in. Presumably they did some condemnation drilling before doing the cross cutting (from the ramp) to build the electrical-bay. From the description above it looks like they have a wide enough "room" for the electrical-bay, 15m apart from wall to wall (the East and the West wall, and on both sides they saw the C-structures (as shown in the pictures). They took samples of the entire exposed veins on both side, but it was not certain about the length ( 6m ?) and the width of the structures/veins (~4x the width of the pads, where they drove in the bolds, that hold the mesh up?). Assuming the pad is about 10 cm (any experts out there?), the C-veins should be around 40-50 cm wide (did de Jong say some C-veins are over 10m wide?).
- Presumably, ICG would try re-locate the electrical-bay in order to chase these C veins a bit further. Now, they can drill from underground which is faster and cheaper.
- ICG should have located this zone (75m west of the known limit of C2) on the C2 cross section, link below.
https://www.integragold.com/i/pdf/-LS_C2-DDH_20170201_with%20class.pdf
My guess, based on the available information, would place this new discovery area in the 100 x 100m block just NW of the marked area from bulk sampling. It's just a guess, hence please check it out to confirm or correct.
A back of an envelope calculation for a 100 x 100 x 100m block, s.g. =2.8, @ say 6gpt would yield an extra 0.5MozAu. Take away 50%, for conservatism, would still give a significant amount of 0.25Moz.
High grades in a shallow area is good for initial UG (via ramp) operation...noting the NR also says, "individual samples grade up to 18 gpt", so picking 6gpt for the above guess should be conservative?
GH