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  • MMC Rope Access & Confined Space Rescue Teams undertake works in digester for Skanska

    MMC Rope Access & Confined Space Rescue Teams undertake works in digester for Skanska

    Skanska are undertaking a £48 million investment scheme for Welsh Water which will boost the amount of 'green energy' it produces at its Cog Moors waste water treatment works in Sully. Part of these complex works involved removing the pipework from within 2 large concrete digesters.


Client: Welsh Water

Principle Contractor: Skanska

Contractor: MMC Diving Services

Duration: 2 weeks

Date posted: 27-06-2019

MMC Rope Access Rescue Team who are also cross trained as Slinger Signaller with City & Guilds Confined Space High Risk & Rescue; won the contract with Skanska to undertake the operations to remove the pipework within the 2 digesters. The contract lift involved the removal of 2 x 3 tonne central steel columns and associated vent tubes held together with heavy steel brackets. These works were undertaken in a NC 3/4 confined space. MMC Access Teams installed anchor bolts into the soffit of the digester and tested each bolt using our calibrated Hydrojaws 2000, this enabled the Access Engineers to safely traverse along the top of the tank and cut off the stainless steel guard wires holding the vertical pipe in position.

Using a series of 2.0 tonne Tirfers, the controlled cutting and lowering of the breather pipes and associated brackets was undertaken to lower the steel to the base of the digester. This enabled the team to cut the steel sections into sizable chunks to then be removed through the small 600mm access hole with the crane. These works were completed on time and within budget saving time and money for our client.


MMC Diving Services have done a wonderful job at Cog Moors WwTW, the job posed difficult challenges of which the team has met with enthusiasm and professionalism I have rarely seen. The team were knowledgeable and extremely helpful with a can do attitude. Sam and the MMC team have been completely honest and transparent with regards to any and all costs relating to the job. The safety commitment from the team was exceptional, the Risk assessments and Method statements and all paperwork was of a high standard, reports and daily logs etc. were sent out daily on time without exception. An excellent company which I cannot wait to work with again.

On a personal note;

When working on a difficult job which throws surprises at you at regular intervals it can either break or make a team. Your team made it. Sam, thank you again for all your hard work, your professionalism your commitment to doing the best job at a reasonable price. It has been a pleasure working with you both professionally and personally. I'm positive we will be calling regarding further works if not on this project then on another. Please pass on my gratitude and praise to your team who have done a great job.

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