Maintaining Gas Lines In The Gateway City

July 2014, Vol. 69 No. 7

Ask any underground contractor what is the most crucial element to a successful utility installation operation, and you will almost always be told to follow proper utility locating procedures.

Best practices recommend “potholing” – using a locator augmented with a vacuum excavator to visually identify underground utility lines prior to digging.

Potholing is easily accomplished in dirt. However, when utility lines need to be visually identified underneath a street, it’s necessary to break apart the concrete or asphalt. This adds additional expense and time to a job. An alternative to jackhammers and replacing concrete sections is a technique called keyholing, which has been widely adopted by many utility companies and contractors.

Keyholing (or coring) is a process where a crew utilizes a vacuum excavator in combination with a core drill. The drill has a circular saw – anywhere from 6 to 12 inches in diameter – and is powered by the vacuum excavator’s hydraulic pump. The drill cuts a uniform hole into pavement or asphalt, minimally impacting the surface structure. Once the vacuum excavation process has exposed the existing lines and utility work has been completed, backfill material is used for reinstatement, the fill material is compacted and the core is grouted back in place, leaving the road surface with minimal disruption.

Laclede Gas Company is the largest natural gas utility in Missouri. The company provides natural gas service to more than 645,000 customers throughout eastern Missouri, including Greater St. Louis (combined statistical area), which is the 19th-largest metropolitan region in the U.S. According to its director of operations support, Steven Wahlig, Laclede has 138 crews who work throughout St. Louis and eastern Missouri.

The Laclede Gas construction and maintenance department employs more than 500 utility professionals responsible for maintaining more than 16,000 miles of gas lines. Wahlig says the division handles everything that is required in the natural gas industry.

“We install new mains and new services, cathodic protection, leak work – anything that you would have in the gas industry. I can run off 30 or 40 different scenarios. We do everything that’s out there that requires installing and maintaining our system,” he says.

The 136 individual crews are specialized by type of work. There are 38 main line crews, 50 service and installation crews and 50 leak crews. With that many crews working to maintain the expansive network of gas lines, Laclede needs to stay efficient, yet the crews will expose utilities nonetheless.