Client: Viridor Waste Management Location: Shelford Landfill, Canterbury Provian Earthworks is an approved Gas Infrastructure Installer for Viridor Waste Management and now has a team of trained operatives, proficient in butt fusion and electrofusion welding and fully compliant with Viridor's Quality Assurance procedures. Our Earthworks team have completed a variety of works at Shelford Landill in Canterbury and Beddington Landfill near Croydon. These works include the installation of a new ring main at Shelford landfill site. The project involved the fusion welding and laying of over 5,000m of pipework, ranging from 63mm to 355mm diameter, together with approximately 2km of gas collection pipework and installation of 25 new gas wells. The pipeline followed the waste boundary around the perimeter of the site and required the team to work under and alongside high voltage overhead cables. The excavators working under the overhead electric cables were fitted with height restricting limiters to prevent any possible contact between the cables and the excavator bucket. The pipes were placed in a trench to provide a minimum of 750mm cover to the crown of the pipe, to allow sufficient depth for working of the land when returned to agriculture. To ensure safe location at a later date, the pipes are covered with a metallic marker tape. The welding of the long strings of pipes were carried out using a Trackmaster self-contained welding machine. The machine is a butt fusion welding machine which can track along the path of the pipe. This is an efficient alternative to a standard butt fusion machine, which is stationery and requires the pipe to be ‘pulled through it’ to continue the welding operation. This method can be problematic as, due to long lengths of pipe strings, handling of the pipes can be cumbersome. Following the welding of the pipes, the lines are pressure tested. This is carried out by Provian’s trained operatives using a combination of air or water testing to seven bar pressure. The pipes are required to maintain the test pressure for one hour and are witnessed by the client’s representative. The pipeline remains exposed during the testing, allowing easy access to find any faulty or leaking joints. In the event of a fault or leak, repairs are immediately undertaken and the pipe re-tested. The 25 gas wells were installed through the landfill waste to depths ranging from 10m to 38m by a specialist drilling contractor. Provian’s operative then fitted the well head to the pipework, laid in trenches across the site, which is connected to collection manifolds. The manifolds featured control valves and sampling points so the gas can be controlled according to methane strength and pressure.