DaveM,
At the King property the kimberlite is still dipping. My question to Teevee or other geology/mining experts is what are the possibilities that the dyke starts to go back up to the surface to complete the cone from some central point? Maybe the source is under King property since the source could be at the deep end, in my limited understanding of geology.
A point source (or feeder pipe) no longer seems likely. The fracture(s) occupied by the dyke is itself the "plumbing system". As the dyke continues to dip, at some depth the confining pressure of the overlying rock will meet and exceed the pressure exerted by the dyke immediately post emplacement and prior to cooling/solidifying. At that depth, the fracture through which the kimberlite intruded will have closed up again. In other words, at some depth, the dyke will narrow and eventually pinch out. Also, given the depth of origin, it also seems reasonable that at some point, the dip will dramatically steepen until near verticle. In short, there are geological risks, and expensive ones, chasing the dyke at ever greater depths. Alternately, should the dip continue to flatten and remain sub horizontal, it could conceivably extend for at least a few more kilometers. Only expensive deep drilling will resolve these questions, unless the dyke can be recognized with some sort of seismic imaging system. If there is a geophysicist on this thread, perhaps he could comment as to whether the dyke is thick enough and if the velocity contrast between kimberlite and granite is sufficient to image the dyke with a seismic survey. If it could be done, it would be a cheap way to chase the dyke and evaluate potential additional deep resource tonnage before committing to an expensive and deep drilling program.
regards,
teevee |
