The material between 100 & 200 meters. The "hot spots" make this project economical. There simply aren't enough diamonds between 100 & 200 meters to make a viable project. ONLY when they approach 200+ meters does the project become profitable/economic.
Another way of saying this is: Much of the kimberlite between 100 & 200 meters can be considered "waste kimberlite" and those ranges on their own would not be economical.
It's too bad the hot spots weren't encountered first. They could be mined and when the grade/diamond counts began dropping off the Mining co. could elect to stop and re-focus elsewhere. As it is, the mining co. has to go through all of this material.
As a simple illustration of the term "waste kimberlite", consider this statement from the Diavik website...."The less dense waste kimberlite fraction is directed to the processed kimberlite containment (PKC) area for permanent storage. The heavy mineral concentrate (containing diamonds, garnet, diopside, olivine, and spinel) is conveyed to the recovery circuit."
So yes, I admit my choice of words was not 100% correct. But my point was/is: the material between 100 & 200 meters contains more waste kimberlite than some understand OR consider.
In the next 2 posts I'll attempt to post (hope the links work!) two separate Bar Charts (taken from Shore Gold information). The 1st chart shows "Grade" @ various depths in the Star kimberlite. The 2nd chart shows "Diamond count" @ various depths in the Star kimberlite.
GLTA
Pickinbottles