ARCHWAY ENGINEERING has launched a new Competitor sampling rig, the Competitor 150. The rig is ideal for environmental investigations and has already proved itself on a number of contracts, including a recent project in Oldham.
The new rig is a upgraded version of the Competitor 130, launched in 1997. The new machine, developed with the help of a DTI Smart grant, is mounted on a mini crawler base and is just 650mm wide and 2.3m high, making it suitable for limited access work. It uses a percussive system to drive sample tubes into the ground and is designed to allow simultaneous sampling and casing to depths of around 10m to 12m. It can be used to carry out U100 and U38 sampling, dynamic probing and SPT testing.
For environmental work, cross-contamination is reduced as with sample tubes incorporating a clear rigid plastic liner.
The mast has a carriage mounted on it that holds up to 5m long drill strings. It can be raised or lowered using an integral hydraulic jack with 8t pullback capacity and is designed to swing clear of the mast. This allows the string to be pulled clear of the borehole and the sample tube to be removed and a fresh tube attached without having to uncouple the rods.
The machine also has rotary coring capability to core through hard standing or to obtain rock cores at the base of a borehole.
In Oldham, Arch- way's sister company Global Probing & Sampling used the rig to drill a single bore- hole and install a gas and groundwater monitoring well on a site next to a gassing landfill and sewage treatment plant. The company was working for geotechnical and environ- mental consultant Geotechnical Developments (UK), working for Kingspark Developments.
The Competitor was chosen because it could obtain a continuous soil profile and case the 10m deep hole to allow installation of the monitoring well. The hole was drilled in under six hours and sample quality was 'excellent' says Global Probing & Sampling director John Allsop. 'Soil fabric was fully preserved.' Sampling confirmed that only shallow depth of fill was beneath the site and that landfill gases were migrating together with leachate through glacial material at depth.