Blominmäki sewer excavations

​Blommäki sewer excavations about to begin

The Blominmäki wastewater treatment plant excavations will begin in early May with excavations of sewer tunnels in Mikkelä in Espoo. The excavation and mining contractor for the project is Lemminkäinen Infra Oy. Lemminkäinen has been excavating the Blominmäki waste water treatment plant from September 2015 onwards. Lemminkäinen's excavation work on the sewer tunnels will last an estimated six to nine months. The excavations progress about 20 metres per week. A maximum of approx. 1200 metres of tunnels will be excavated, wherein the tunnelling ends are nearing the Espoo Kauklahti railway track region. The tunnel size will be about 4.5 m (width) x about 5.5 m (height).

Look map at zoomable version (pdf, 15Mb)

The sewer tunnel excavations work periods are: 

  • Explosions on weekdays from 7.00 to 22.00, possibly on Saturdays from 9.00-18.00 
  • Drillings on weekdays from 7.00 to 18.00 and from 18.00 to 22.00, if the noise level up to less than 40 dB indoors
  • The blasted rock is removed on weekdays and weekends if necessary
  • Quiet (noise level up to 30 dB in bedrooms) work is done, if necessary, around the clock.

Kalliotekniikka Consulting Engineers Oy has done building inspections and vibration insulation for sensitive devices in the buildings in the nearby area. The same company will perform a post-inspection on the buildings at the end of the excavations. In addition, during the whole blasting work the Rock Technology Consulting Engineers will carry out vibration monitoring measurements with continuously operating vibration gauges in the nearest buildings. Permissible vibration limits are based on the the blasting industry standards drawn up by the Ministry of Labor and are defined by an outside expert. The progress of the excavation and the the amount of charges to be detonated are adjusted based on the measurement results obtained, in such a way that damage to property cannot occur.

Lemminkäinen strives to ensure that disturbances caused by the excavation work to residents in the nearby area are minimal and short-lived.  Lemminkäinen does the excavation work professionally and in accordance with all applicable safety and regulatory guidelines. Lemminkäinen regrets any disturbances caused by the construction work. If, despite all precautions, unforeseen problems arise in the area surrounding the construction site, you can contact Lemminkäinen's contact person, project engineer Jarkko Meriläinen (GSM 0400 753 317), jarkko.merilainen(at)