Stuart Wells assisted in the recovery of a 6” Borehole Pump, with a weight of 120kg, which had been lost inside a well.
The “fishing trip” was to catch the 4” Wellmaster Boreline that the pump was installed upon. Due to the restricted access of the pit, it was not possible to utilise a roller system which meant that the failed pump had to be removed by using two clamps on the flexible riser pipe. One clamp was fixed to the riser and then lifted. The second clamp was then clamped lower down on the riser, allowing for the top clamp to be removed and the procedure was then repeated.
To keep the pit tidy, each section removed was cut off as it was lifted out from the well. However, the grip of the retaining lower clamp was not tight enough to keep hold of the flexible riser main, and frustratingly, it slipped through due to the weight of the pump still in the well. Using CCTV inside the borehole, the hose was seen to be standing proud at 26 m bgl. A self-closing, spring-operated, clamping tool was then developed and installed inside the well. This clamping tool, controlled with a metal riser pipe, guided the fishing tool over the previously cut riser pipe and clamped itself to the main pipe.
Due to the clever design of the fishing tool, as it engages the riser pipe and takes on the weight of the pump, it closes even tighter causing the teeth of the fishing tool to bite into the Wellmaster Boreline even more. Thanks to the fishing tool, the pump was successfully removed allowing for the installation of a replacement pump. Furthermore, the operation saved the costs and inconvenience of re-drilling a replacement borehole down to 120 metres below ground.
