Initially, the team was commissioned to complete the ground investigation works at the site, and then subsequently won a tender to complete the stabilisation works, by drilling and grouting, working alongside AmcoGiffen. Central Alliance and AmcoGiffen have a long history of collaboration to deliver complex investigation and remedial work on railway infrastructure. This project has proved no exception – the request for the additional services came after the client was impressed by the results of the original bill of work, which were completed ahead of budget and programme.
“The stabilisation works were required to stabilise the ancient mine workings that were identified during the investigations and posed a risk to the railway,” commented Central Alliance joint managing director Richard Pidcock. “The programme of works had to be completed on weekend nights, with only limited mid-week night-time working, every six weeks. It had to be well-planned and organised to maximise the very limited working window for the two Fraste PLG rigs employed on the project.”
Given site access constraints, road-rail vehicles were used to transport the drilling equipment to the site each shift. The rigs and relevant drilling equipment and plant were lifted on to RRV trailers and mobilised to the site, before being lifted on to a temporary drilling platform. Temporary drilling platforms were constructed with rail sleepers to avoid any disturbance of the railheads (tracks) and to position the drilling rigs in the correct orientation for drilling operations.
Despite the restricted working time and access, the works were completed on programme and within budget, safely and without incident.