Oilfield exploration----more Seismic Survey trucks on Biglorryblog. Thanks to Bill Taylor we now know what they do and how they do it!

                                                           SEISMIC SURVEY

                                                                   Bill Taylor

In the March 2003 issue of Classic Plant and Machinery, Nick Baldwin included a picture of a seismic survey vehicle.  Unfortunately, the vehicle shown in the picture was sheeted down and the image on its own did not give a true indication of how the machine operated or the way it was used.  On seeing the picture it rang a bell with me and after quite a lot of digging in the archives I eventually found the series of photos I was looking for.

In March 1985 in my home village of Friskney, on the Lincolnshire coast between Boston and Skegness, all households received a leaflet explaining that over the next few days a company called Rees Geophysical was to undertake a seismic survey in the local area, pointing out that householders should not be concerned at the arrival of a number of large off-road vehicles and their activities.  Soon, a series of markings were painted on a number of roads around the village and we began to wonder what was in store for us.  A few days after the publicity campaign and after the markings had been painted, a team of workmen arrived to set up a number of control cabins at various places.  On the grass verge at the side of the roads metal probes were pushed into the ground adjacent to each of the paint marks.  The probes were then connected to long lengths of cable which were run to the control cabin.  With the preparation complete, a convoy of strange vehicles quickly arrived.

The convoy comprised a formation of four similar vehicles, all operating in a synchronised manner.  A fifth vehicle seemed to be roaming around on its own, seemingly on stand-by in the event of a breakdown on one of the other four.  In operation, the convoy would come to a halt with the vehicles closely spaced and each adjacent to one of the sensor boxes on the grass verge.  On coming to a halt, the driver lowered the large central pad mounted on large hydraulic jacks to the ground until it lifted the wheels just off the ground and the whole weight of the vehicle was supported on the pad.  Additional pneumatic jacks connected to each load pad were then pulsed with air to send vibrations from each vehicle into the ground.  After a period of about 30 seconds the pulsations ceased, the main jacks were retracted and the moved on to the next test point where the cycle was repeated.

Because the convoy was hard at work I did not have an opportunity to quiz the drivers about their strange machines.  However, from the manufacturer's markings on the vibration equipment it seems that the vehicles were made by a company called Mertz, based at Ponca City, Oklahoma.  Power came from a Detroit Diesel V8 engine which was running at a constant (and high) rpm to drive the hydraulic pumps and air compressors.  I had thought that a hydrostatic transmission was fitted to the vehicles but scrutiny of the photographs shows conventional axles and differentials.  The driver sat in the centre of the heavily protected cabin and a front-mounted winch was carried by each vehicle.  From the tyres it was clear that these vehicles had a phenomenal off-road capability and although at some stage I did see them working along a few farm tracks, they looked quite out of place working along a stretch of the A52 coast road.  Almost as quickly as they arrived, the survey teams departed.

The picture in the March 2003 edition seems to show a machine very similar to those which visited Lincolnshire in 1985, although its registration number (AOT 174V - with AOT 173V also visible) is not in the same sequence as those of the Rees Geophysical group.  For the record, the five Lincolnshire vehicles carried the registration numbers: GWC 193Y; GWC 195Y; GWC 196Y; B355 JFU; and *****.

We never did hear what the outcome of the survey was.  However, almost eighteen years later our village thankfully still has no oil wells and seems unlikely to become the new Klondike.