|Location:||Holmestrand harbour, Ferry.|
16-AUG-2014 9:30, 10:15, 11:00, 11:45, 12:30, 13:15, 14:00.
Or contact Roar Hansen.
|Dimension:||Island: L=3,200 m, W=500 m.|
NOAH AS, Postboks 317, 3081 Holmestrand, Tel: +47-3309-9500, Fax: +47-3309-9501. E-mail:
|As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.
|1650s||first limestone quarrying.|
|1737||lime works sold to the Danish crown.|
|1895||first purchase of land by the Christiania Portland Cementfabrik (CPC).|
|1899||begin of cement production and increased quarrying.|
|1899||main part of the island purchased by the Christiania Portland Cementfabrik (CPC).|
|1913||pressure air introduced.|
|1925||crushing of limestone relocated from Slemmestad to Langøya.|
|1937||remaining rest of island purchased from the Navy.|
|1960s||24 families with about 120 people live on the island.|
|1985||end of quarrying.|
|1993||Norcem sells Langøya to NOAH.|
Langøya is an island, located in the Oslofjord, south of the capital, reachable by a short boat ride from Holmestrand. This island is sometimes called Kalkøy (limestone island) as almost the whole island consists of limestone, rather exceptional and rare in the crystalline rocks of Norway. This limestone is important to produce lime and cement, and was thus quarried for some centuries. The result is a huge quarry which covers almost the whole island.
The quarrying of the limestone is first mentioned in the 1650s, at this time the locals were owners of the island and had several lime kilns in operation. The lime works were sold to the Danish crown in 1737. The quarrying got a boost in 1899 when the production of cement started and thus the need for limestone boosted. The Christiania Portland Cementfabrik (CPC) started this by buying a parcel of land in 1895 from squire G. Wankel from Kambo. They purchased the main part of the island in 1899 and started production. Only a small part of the island did not belong to them. It was owned by the Norwegian Navy and they were able to purchase it in 1937.
The cement production required some logistics to transport the limestone. Easiest transportation was at this time on the water. So the limestone was transported in barges to Slemmestad where it was crushed. The quarrying produced enormous amounts of limestone, in 1913 it was 180,000 tonnes per year. First the limestone was drilled by hand, in 1913 pressure air was introduced, 1922 the machinery was electrified. The crushing of the limestone moved from Slemmestad to Langøya in 1925 and from 1931 the stone which was not suitable for cement production was crushed in a separate work and sold as aggregate.
Parallel to the technical development there was a development of the work force. The island had not only working barracks, docks, and railways, but also housing barracks and a canteen. People were living on the island, their children were transported by boat to the school in Holmestrand. During the early 1960s 24 families with about 120 people including 16 school pupils lived on the island. With the decline of the quarrying the people moved away and in 1967 the last two families left.
The mining reached 3 m below sea level in 1951, and at the end of the operation in 1985 the quarry had reached -45 m asl. 47 million tons of limestone were quarried, producing a pit with 10 million cubic meters below sea level.
The island was sold by its owner Norcem to Norwegian Avfallshandtering (NOAH) in 1993. They started to use it as a landfill for hazardous inorganic waste. The limestone and gypsum of the island is used to neutralize many dangerous substances in the waste. They deposit wastes containing magnesium and other alkali and alkaline earth metals, mercury, and cyanide. This is done by processing the waste on the island before it is deposited in the quarry. Up to 400.000 tonnes of inorganic hazardous waste per year are mixed with limestone and gypsum and transformed into a chemically stable matrix. There are two goals met at the same time, to get rid of dangerous waste and at the same time recultivating the island as a valuable recreation area.
The visit to the island is managed by the current owner NOAH. They offer public open days several times during the year. The visitors meet at Holmestrand harbour from where they are shuttled to the island in boats. The explanations on the tour emphasize on the safe waste deposition and the recultivation, not on the limestone quarrying.
We understand why the country is in need for such a dump, but actually we do not understand how it works. At the first sight we see only the danger of the close sea water which could dissolve the waste and pollute the sea around the island. Both limestone and gypsum are soluble, gypsum is dissolved directly and limestone has cracks which allow water to enter and start karstification. Probably this is a reason why NOAH offers open days and visits to the island, to explain their technology and the safety measures to the general public.