Hi folks! Couple thoughts --- (btw, Frank, I think you meant 'value' /tonne (not "cost") when you said, "to run a production mine, a cost between $30-$45/tonne will be profitable for Ashton and others in Alberta.").... [Frank, has a minibulk dr.program been initiated for K91?]
Grade vs. Value
Now speaking of value and cost, John Fairchild, your comparisons with NWT are misleading, imo. I realize you're just trying to get a handle on this, but remember, as we recently discussed, Ashton's AB pipes' grades (ct/tonne) can't yet be accurately assessed, but if doing so, the true value/tonne lies in the value of the stones themselves, not just their incidence. We need to learn their value/tonne, not just carat/t (partly why Ashton is using the bi-directional cut-off of 0.8mm). What I mean by this is that the larger, gem stones are what will make these pipes economical.
-And if a greater occurrence of stones is found deeper, then....
Uneroded Pipes
WRT the depths to which Ashton has been drilling-- most of their reporting is from depths less than 100m, with a few holes deeper (191m for one K14-1, K4B-1 141m, K6-1 160m, others). K14 is reported as drilled to 200m, terminating in Kimberlite (a hit).
My point is that, as Fagan has explained, uneroded pipes have a depth of about 300m of crater facies, before diatreme facies begins. It is in the upper 300m of a K-pipe that diamonds occur most sporadically, due to the explosive nature of the beast as it emerges into lower pressures (erupts). Below this first 300 meters, into the diatreme zone (to depths of 1-2km), there is a homogeneity in diamond incidence, as well as a greater number of stones (this is the bulk of the intrusion).
Given this, it seems completely logical that the various K14 holes have been inconsistent, if the uneroded pipe theory turns out to be accurate. ~~The prevalent multi-phase emplacement theory sounds completely plausible, but the variances at these depths seem logical for a pipe that is basically still in tact (if true). I am sure Ashton has considered this. I think the bulk samples could reveal big things.
_____ ______ ______
Intact pipes, obviously, mean way bigger tonnage, and shallow tops... Cost per tonne to mine should be around $15/tonne in AB vs. around $40/tonne for the NWT (plus many other positive variables for AB discussed previous, including an affable government). AB pipes /anomalies found thus far are quite large.
My ignorant musings--- comments anyone?
-j
:>
"The Birth of a Diamond Mine":
mountainprovince.com |
