Where are the Geos ?

In the interests of considering all the aspects of this story , are there any geotechs or mining engineers out there that can throw NEGATIVES or HURDLES or ROADBLOCKS at why flyash proppants may NOT be the holy grail for the fracking industry as everyone here seems to think ?
All we are hearing atm is layman research about the size of the industry and the incredible advantage LPT's tech has and the amazeball savings it will bring to the frackers.

I am just interested to hear from anyone with any hands on experience or background that equip them to give an overview on the CHALLENGES that may exist.

Sorry to start a new thread but at least it is not a TOOT TOOT BUY YOUR TICKETS thread and I would appreciate it if it did not turn into one.