It follows that doing work with smaller street openings requires more precision in determining just where the excavation needs to be done. The latest electromagnetic pipe locators can find substructures with pinpoint accuracy. But in situations in which electrical interference or a lack of a working locating wire on plastic pipes is a problem, ground-penetrating radar, a technology that owes many of its recent refinements to the military and the space program, can be an excellent alternative. Once the small hole is drilled, a practical way to remove the dirt is through vacuum excavation, which works very much as you'd expect. The dirt is sucked into a kind of vacuum cleaner bag and can be re-deposited in the hole when the repair or other operation is completed.
Workers use special long-handled extension tools to repair the substructure from ground level.
After the hole is filled, a soil-compaction monitor is used to help ensure the excavated area has been properly restored. The final step is to repair the pavement opening. The aim is a virtually seamless replacement of the pavement-almost as if the job was done by a top plastic surgeon. In Their Own Hands It appears unlikely that any U.S. gas utility is currently using every one of these still-evolving keyhole technologies. In fact, the adoption and spread of these procedures has been something of a grassroots phenomenon, with individual companies devising their own methods and even making their own tools.