We're performing road surgery

In the past, medical surgery used to always require making a large incision. But thanks to advanced techniques, doctors can now perform many complicated operations though a tiny opening instead. That’s the idea behind a new cost-saving technology that Avista is using to repair and maintain its pipelines.

Dubbed “keyhole technology,” it lets crews access infrastructure under roadways much faster and much easier than digging a huge trench with a backhoe. Noise levels are reduce, and it has the roadway up and running in no time.

Crews use a truck-mounted boring rig to saw a 2-foot circular cut, or “keyhole,” in the pavement. This leaves behind a round chunk of asphalt similar to a manhole cover that can be easily removed to expose the ground surface underneath.

Soil is then extracted from the keyhole using hydro excavation. Crews apply a high-pressure water spray to break up the soil, and a large-diameter hose with powerful vacuum suction lifts and transfers the slurry to a debris tank.

Once the pipeline is exposed, Avista completes its operation, and the hole is refilled with soil and aggregate rock. A bonding layer of is poured, and the original circular piece of asphalt is replaced like a lid and then troweled smooth with the roadway.

Avista is currently using keyhole drilling to replace line connectors between its service lines and main lines. The technology could be used for other natural gas infrastructure projects that can be performed through a small opening.

See a short video of the process.

Watch video


  1. Natural Gas
  2. Project