RE: RL (m) column11 Mar 2021 06:37
Thanks Q55, more awake now (marginally) to understand the reply.
Went back through NC exploration reports and found this 5000m offset was started in the previous set of results. Did anyone spot this at the time? Apologies if it's me that missed it.
They don't do this offset at Red Chris but their datum is already 1500m up a northern Canadian mountain (brr, brr, brrrrrrr) and they don't need to drill so deep to their gold.
HAV is at 265m.
Which got me to thinking why choose an offset of 5000m?
I'm fairly certain if you choose an offset you only want to do so once during the lifetime (ten years plus?) of proving up an asset, starting to mine while drilling around looking for more ore. It would be chaos to try and refer to historic drill datasets with one offset with more recent drills using another.
400m of this offset gets used up to get through the cover material. Let's presume they have roughly double that down the bottom end to make sure deep exploration drill holes don't cross into negative numbers - so a 1000m buffer zone.
This leaves them from 4,600m to 1,000m of depths to play around in finding ore. 3.6km at depth! I'm still getting my head round that....
The deepest Oz mine at the moment at 1800m (thanks to whoever mentioned that last night) which if we matched that on our offset scale would be a HAV mine from 4,600 to 3,200m of useful extraction.
The deepest South African mines go about 3,000m down....so current technology would allow HAV to expand ore extraction from 3,200 to 2,000m on our offset scale.
Which leaves another 1000m of headroom on our offset scale that someone at Newcrest thinks future technologies in the foreseeable will come along to make really realky deep mining possible.
All presuming the ore body keeps going to those kind of depths.....
I'm going to mull over the size of that block cave in 30 years time while munching my morning croissant.