Jones Bros overcomes geotechnical challenges as Pen Bryn Oer nears completion11th Jan 2018

The final turbine has been erected at Pen Bryn Oer Wind Farm in South Wales.

Contractor Jones Bros Civil Engineering UK is now carrying out reinstatement work on the site ahead of the three-turbine wind farm being handed over to client REG Power Management.

The project presented Jones Bros with significant geotechnical challenges because the wind farm was built on an old coal opencast site. The civil engineering company constructed piled foundations to help create a stable foundation following substantial mining treatment works.

This work involved drilling 17 900mm diameter holes, each approximately 20m in length, beneath each turbine and then filling them in with steel reinforcement and concrete to create the piled foundations

Site agent Rhys Roberts said: “It’s been a very challenging project and the team have done a fantastic job to keep the schedule for hand over on track.

“Due to the nature of the works involved with the mine treatment, it was a complete unknown as to how much grouting, which is carried out to fill the historic coal workings below the turbines, was required.

“Each turbine had varying degrees of mine treatment carried out over the course of six months which involved drilling exploratory boreholes and filling them up with a grout mixture of pulverised fuel ash and cement.

“Our work on site also included cement stabilising 1,000m of tracks. This ensured the amount of imported stone aggregates was minimised resulting in approximately 500 lorry movements to site being prevented.

“We had to overcome many different challenges on this project over a 12-month period and I am very grateful to all of the team here at Pen Bryn Oer for completing the works safely and efficiently.

“To date we have worked more than 55,000 hours safely on this project and this is something I am very proud of.”

With an installed capacity of 6MW, the wind farm is expected to generate around 18 GWh per year, enough to power approximately 4,400 homes per year.

Founded in the 1950s and employing almost 350 people, Jones Bros has grown rapidly in the last decade.  It is currently working on contracts in various sectors including the construction of waste management facilities, highways, flood and marine defence and renewable energy projects around the UK.