Just had my theory of using water pressure to dig fernies validated this morning. The local gas company is installing a new gas main along our street and used an unusual method of locating the gas drop lines to the homes. They had a power washer with an extended nozzle tube to flush away the soil and a large vacuum system to draw the slurry out of the hole. All of this is a commercial truck-mounted system of water and slurry tanks. Digs down about 4 feet and doesn't even scratch the gas lines.
