More of a gradual unearthing than one big one.
It was surprised to see a large bulk vessel, the Alppila unloading coal next to my office and over the wall from the little marina with the sailing boats.
Turns out that we’re at one end of this system of underground coal silos, serving the power station 500m away. The little pointy up bit at the top right is what the coal is unloaded into.
If you’re in a cold snowy place, keeping your coal out in the open causes a few problems, so sticking it underground seems like a a good idea, but expensive, right? Not necessarily:
Coal Storage Silos in bedrock were built with the price that the City of Helsinki got by selling the former Coal heap area for building ground to private companies. Average price of underground space is only 100 €/m3, including excavation, rock reinforcement, grouting and underdrainage.
more (will download a 2.2MB pdf) http://www.energiaklubi.fi/energiaklubi_site/mediafiles/pdf-documents/Energy_days/Salmisaari_Power_Plants.pdf
That got me onto more about underground stuff in Helsinki, including this: which I need to visit while I’m here:
And what they’re doing with the excavated rock. Compare this with google maps of the city today:
https://upload.wikimedia.org/wikipedia/commons/c/c5/Helsinki_map_1837_by_Claes_Wilhelm_Gyld%C3%A9n.jpg
The boat, the Alppila, came here from the Vysotsk terminal situated on Vysotsk island in the Gulf of Finland, which handles steam coal exported from the Kuzbass (Kuznetsk) region of SW Siberia. So I’m going to be heated by coal from here: Novokuznetsky District, Kemerovo Oblast, Russia 53.644888, 87.923694 (co-ordinates are “ish”)
http://global.britannica.com/place/Kuznetsk-Coal-Basin