Ground Source Review Chestnut Mews & Aspen Mews ǀ Boreholes

Task: Drilling


We are on site at Chestnut Mews, and have commenced drilling the communal borehole array.

Drill rig 1:

The day began with drilling 3m of casing for the drill rods with the spoil to be funnelled into the pipes and mud puppy; it soon became clear this wasn’t enough casing as we were losing the flushing water in fractured layers of rock. To resolve this the teams removed the rods and cased a further 10m which reduced the amount of lost water.

Drilling proceeded to a depth of 135m.

Spoil samples were taken every 3m to confirm our geological surveys conducted as part of the design, and although we did not hit any potential coal layers at 120m all other geology was as expected. The hole was grouted and the team progressed onto the next hole having the inspection pit already dug.  

Drill rig 2:

Expect to have completed their first borehole by the end of the day to a depth of 150m.


Project in a nutshell


  • Design and install communal ground source heat pump systems into two blocks of three-storey flats
  • Drill 40 boreholes to an average depth of 140m
  • Manifold the boreholes to 12 individual ground arrays
  • Trench back to the 60 flats
  • Remove old inefficient night store heaters and hot water cylinder
  • Replace with a Kensa Shoebox 6kW, a highly efficient hot water cylinder and a wet radiator system
  • Install thermostatic and time controls to allow total control for residents with individual heat requirements

Read more about the background to this project here:

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