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Cyanamide silo

Building no. 113, built in 1907

Capacity 7000 tons cyanamide.

44m long, 14m wide, 22m high

Function: Storage of cyanamide 

The silo was built by the Norwegian engineering firm Alfred Bonde in Kristiania (as Oslo was then called).



Cyansilo 1917 The cyan silo in 1907. Photo: Kraftmuseet archives


The silo proper is in reinforced concrete while the upper part of the building has load-bearing skeleton in reinforced concrete and non-structural brick panels. The building was one of the very first structures in reinforced concrete built in Norway.


The relief decoration was originally emphasized by a darker colour than the rest of the wall. The building still features original details as stairwells, elevator belt, screw conveyor on the top floor for filling the silo, and spouts for removing product below.


The silo interior is a large room whose walls taper downwards to the spouts below.

Inside the silo. Photo: Kraftmuseet archives



The cyanamide was transported to the attic of the silo through a hammer mill where it was ground finely after having been crushed. The two feeding screws which covered the whole length of the attic distributed the masses across the area before it fell into the different parts of the silo through openings in the attic floor. The cyanamide was removed from the silo in the basement, and packed in sacks. Most went directly to the “dicy” where it was transformed into dicyandiamide. Some was exported as industrial cyanamide. The rest was treated with water to reduce the carbide content, and diluted with finely ground limestone. This was sold as a weed- and moss killer called “Troll powder”. It was also used as a calcium-nitrogen fertilizer for slow-growing plants.

The silo will be preserved as it stands today, but it will be put into a new use, namely as an ice climbing wall.



Troll powder is the trade name used for calcium cyanamide mixed with lime, CaO. It could be used as weed killer or nitrogen fertilizer (about 20 % nitrogen). It was mixed into the soil a few days before planting. 


”I can safely say that I’ve been to the dustiest place in the world. That’s when I carried sacks inside the cyanamide silo. The dust wasn’t poisonous, but if you went off and had a beer then you exploded”.            Smelting plant worker Hermann Skjerveggen from the book Smeltedigelen.




”This building (the silos) is the most prominent amongst those forming the combined carbide and cyanamide factories, and is constructed of reinforced concrete.  It is notable, not alone for its size, but for the neat combination of pilasters  and panels forming the sides. The other buildings in the cyanamide works are,  for most part of brick, corresponding to those in the carbide factory. The steel-work is used for the framing and the brickwork forms simple light panelling, so that in the event of any of the buildings requiring to be extended – and the idea is to increase them fourfold – the  uniformity of design will not be affected.”
Descriptions by Geoffrey Martin and William Babours from 1915 about the world’s Cyanamide production

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Norwegian Museum of Hydropower and Industry

Naustbakken 7, 5770 Tyssedal
Phone: +47 53 65 00 50