I see that in today's press release, Falcon is conveniently using an older resource estimate for the Karoo Basin. There's actually a newer (and MUCH LOWER) estimate that came out in 2014 by, of all people, South Africa's own Petroleum Agency:
"SA petroleum agency’s Karoo shale-gas estimate ‘far lower’"
"THE Petroleum Agency South Africa (Pasa) estimates that recoverable reserves of shale gas in the Karoo are about 40-trillion cubic feet — much less than the US Energy Information Administration’s (EIA) estimate of 480-trillion cubic feet."
http://www.bdlive.co.za/business/energy/2014/02/21/sa-petroleum-agencys-karoo-shale-gas-estimate-far-lower
jmo