Salmisaari Coal Storage

The four underground coal silos built in connection with the Salmisaari Power Plant in the early 2000s are located at a depth of 120 meters below sea level. When completed, the Salmisaari underground coal storage facility was the first of its kind in the world. The silos are 65 meters high, 40 meters wide and can accommodate 250,000 tons of coal.

The shape of the storage silos was a result of a shift to full automation. The cylindrical coal silo allowed for the use of gravity in the handling of the coal and it was also optimal for rock mechanical reasons. As a result of situating Salmisaari’s coal stores underground in the rock, the former surface coal field was released for commercial and office use.

Helen Oy is committed to phasing out the use of coal. Coal from the Salmisaari Power Plant is planned to be replaced by 2029. We look forward to seeing how Salmisaari’s underground facilities will be used in the future!

Helsingin Energia (now Helen Oy)

Principal design, architectural, rock mechanics and tunneling and structural design

Related References

West Metro

Länsimetro Oy

With the West Metro extension, the Helsinki metro network will reach Espoo, increase in length by 21 kilometers and see 13 new stations constructed along its run.

Vuosaari Transportation Tunnels

Tiehallinto/ Vuoli-projekti

Rockplan designed Vuosaari Harbor’s Porvarinlahti road tunnels and Labbacka railway tunnel in cooperation with Finnmap Infra Oy. The 1,600-meter-long submarine road tunnel in Vuosaari is approximately 25 meters below sea level at its deepest point.

Viikinmäki Wastewater Treatment Plant

Helsingin vesi (now Helsinki Region Environmental Services Authority HSY)

The Viikinmäki rock treatment plant, which was built mainly inside the rock, was put into operation in 1994. The treatment plant’s process is based on the activated sludge method.


For more information please contact Miika Kalliokari
+358 40 557 5113