Modifies in-situ methods of synfuel production from oil shale consists of (a)conventional mining to develop access and open up expansion slots, (b)brecciation or 'rubbilizing'a chimney of rock to form a retort column. Fragmentation is by blasting with void space controlled by location of the expansion slots. (c) In situ combustion by pumping air into the top of the retort and extracting oil vapor and liquid from the bottom. Combustion is sustained by burning of residual char behind the volatilization front.