Tawnyport, you seem to have some understanding of hot rocks and...

Tawnyport, you seem to have some understanding of hot rocks and may be able to answer my questions. I don't understand how this fracture stimulation works, from what I can gather, they force fluid under high pressure into to bore holes and this forces crack through the granite at the target depth, is this the case?
Additionally, once they do fracture the rocks (and assuming they are just cracks), how do they get any sort of flow rate through them, wouldn’t the two fractured surfaces be pushed together by weight of the 5Km of rock above them?
Been on GRK and a few of the other geothermal’s web sites, but they don’t really explain how it all works. Except of course for GRK’s alternative of tapping into hot aquifers, that seems pretty straightforward.
If anyone else can shed any light on this process it would be appreciated, Thanks.