Most of the drillers I work with have stoves in their drill rigs, made by their shop. Basically a modification of a wood stove design. Steel tubing approx. 20" dia +/-, a door with a air intake/flue in the front, welded shut at the other end and a stove-pipe at the top-back. A set of legs, a sheet of metal bent into a ] shape welded on top for a cooking surface, and you're in business. A fine-threaded valve drips fuel onto sand/lava rock for combustion. I'd add a thermocouple and 12volt solenoid/valve to shut the flow off if the temp goes way low, to avoid a messy spill! A lot of heat for little money. If anyone builds one, post pics and details!!