Multiple level methane drainage method

Multiple level methane drainage shaft method

Multiple level preparation of oil shale retort

Multiple zone preparation of oil shale retort

Non-subsidence method for developing an in situ oil shale retort

Oil collection and recovery system for in situ oil shale retort

Oil mining configuration

Oil recovery mining apparatus

Oil recovery mining method and apparatus

Oil shale retort flue gas cooling and cleaning

Open surface flotation method

Operation of an in situ oil shale retort

Placement of explosive for forming in situ oil shale retort

Process for effecting even retort working fluid flow throughout

Process for forming an in situ oil shale retort

Process for in situ conversion of coal or the like into oil and

Process for production of oil and gas through horizontal drainho

Process for recovering shale oil

Process for recovery of carbonaceous materials from subterranean

Process for recovery of carbonaceous materials from subterranean