FUGRO ENGINEERING Services recently finished a survey of a pipeline route along the southern bank of the River Ribble from Preston city centre, across Penwortham Golf Club and west to Hutton March.
Work was carried out for United Utilities as part of its Preston bathing water scheme. It was supervised by Montgomery Watson Programme Management.
FES put down 12 boreholes, starting with cable percussion drilling to 32m depth. Eight were extended down to a maximum 50m by rotary coring with a truck-mounted Puntel drill rig using the Geobore S drilling system.
A 10m window sample was taken and a dynamic probe hole carried out to assess ground conditions within a flood protection bund.
Piezometers were installed in the boreholes and geophysical borehole logging, including calliper, density neutron, sonic and acoustic borehole imaging were carried out in five of the rotary holes. Particular focus was on any evidence of water inflow to help establish groundwater levels.
FES's Consett laboratories carried out physical classification over 300 rock tests - mainly point load index tests, as well as contamination testing.
The work follows an earlier over-water investigation by FES for Montgomery Watson to study three possible pipeline routes across the River Ribble. This work was carried out from a jack-up equipped for both rotary and percussion drilling.