Mammoth MTS is the UK’s main HammerHead Trenchless dealership supplying impact hammers for installation, ramming and piling operations as well as HammerHead pipeline replacement systems for pipe bursting.
Mammoth MTS recently supplied a HammerHead 130 mm diameter impact hammer (mole) to Mark Taylor Groundwork which was contracted to install some 300 m of new pipework as part of a project for a company based in the Midlands, which supplies timber products to one of the UK’s major DIY chains.
The project was to replace part of an 800 m long water ring main that was exhibiting severe leakage to the tune of some 18 m3 per day which was costing the company around £880 per day.
Investigations as to possible solutions for the ring main installation showed that open cut works for the whole project would impact significantly on the daily operations of the client site, so an alternative was sought.
Horizontal Directional Drilling (HDD) was investigated but estimates put the cost of the works at around £46,000 to complete the 300 m long section. After enquiries with Mammoth MTS, it was believed the project could be completed for around £10,000 by using the impact hammer installation technique. This much reduced cost not only covered the cost of the mole and the crew but also the ancillaries that are required to operate the mole effectively and safely.
After further consultation with Mammoth MTS to ensure that the correct mole was selected, Mark Taylor, owner of the contracting company, opted for a new HammerHead 130 mm diameter mole for the job. On delivering the mole to site the Mammoth engineer also undertook full training on the safe operation and capabilities of the mole with the Mark Taylor crew.
A standard excavator was used to establish start and receive pits across the 300 m run of the installation with the mole working from one pit whilst others were being excavated.
The size of the mole led Mark Taylor to look at how site efficiency could be improved, thereby limiting crew numbers and time on site. To this end Mark designed his own launch cradle for the mole which enabled the crew to set up and launch the mole without the need for personnel entry into the start pit, a major safety aspect of the project for Mark, as well as ensuring good alignment of the mole on the desired line and level prior to starting the moling run.
The technique used for the moling runs is known as ‘stitching’ with each small mole run feeding into the next ‘start pit’. The launch cradle is then simply moved from one pit to the next, the mole is resettled on to the cradle aligned, the pipe connected as required and launched.
The project took a total of four (4) weeks to complete given the pit excavations and the other works necessary to establish the ring main. However, over this time scale the mole was only in operation for a total of 5 working days. In practice some 21 pits were excavated, each spaced about 14 m apart. The mole was then used to install the ring main pipe which comprised 90 mm diameter butt-fused PE pipe.
By the time the work was completed and the new ring main was operational the leakage from the client’s site had fallen from the peak of 18 m3 per day to around 0.8 m3 per day, measured as a loss of just 8 m3 over a ten day period.
Commenting on the project Alexander Holt, Sales Manager – Trenchless Technology for Mammoth MTS said: “This was first time Mark had used this technique for such a job as this, but he took to it with great enthusiasm and designed his own launch cradle to make the site more efficient for him and his crew. It was great to see such a keenness for the technology.”
Mark Taylor further commented: “This technique was really useful and both our client and I have been well impressed by the speed and accuracy achievable with the moling system. Further to this the cost saving it offered was huge compared with other possible trenchless options. It became a no brainer to use the stitching technique for this project with the impact mole.”
For the client, the site manager said of the works: “Mark’s team caused no distribution for the site what so ever and we were very pleased that he kept the site tidy. No efficiency was lost throughout the installation of the water ring main. These points were very important to the smooth operation of a national distribution centre business.”
On completion of the project, Mark Taylor was approached by a local farmer to find out what had taken place. He said he was asking because since the works has been completed his fields, which lay adjacent to the works site, had dried up, something which had not happened for some 25 years, the wet soil making his fields unusable at times. The farmer was very pleased with the outcome and this shows some of the positive impact of the works for the local community.