The borehole was required in order to serve as the pumping well in the enabling works for other site operations.
Drilling started off with 1400mm diameter to ensure that the borehole could be advanced through the overburden and peet layer expected at approximately 4m bgl. It was vital that the peet was not allowed to dewater, as there was a possibility that this could cause issues with ground movement nearby.
The artesian flow started almost immediately, at approximately 0.5m bgl. The diameter of the borehole reduced as the borehole advanced in depth as more temporary lining tubes were added as the depth progressed. The borehole was temporary lined the full depth of the borehole, and the artesian flow contained.
The decision was made to terminate the borehole at a depth of 45m bgl, and a 15″ diameter screen and gravel pack were installed in the bottom section of the borehole. The screen was supplied by Boode of Hinkley, Leics, who shipped the screen from Holland in super quick time.
The gravel pack was sourced from our supplier, and introduced very slowly and carefully.
Test pumping was carried out at a rate of 80m3/hour and for a period of 4days.
The site had its own constraints, it was accessed via a very nice residential area, and the drilling site had to be kept to an absolute minimum as it was on the car park for the local sports club. There were existing United Utility abstractions also in the vicinity of the new borehole, which was the only supply in the area, so was vital that no interference with the existing sources. The borehole was also drilled adjacent to a water course which fed to a stream and then into the Manchester Ship Canal. The Rushton Bucyrus cable tool drilling rig was chosen due to the sensitivity of drilling a new source in the vicinity of a vitally important existing source, environmental impact with the peet section, the noise issues of disturbance to local residents, and the site size constraints ensuring no disruption to users of the car park, all of these issues were satisfied exactly using this type of rig.
The works were completed in 6 weeks, borehole head works fenced off and painted, and all parties were very happy with the works 😉