HISTORY

 

Glaerum limestone mine lies on the north side of the Surnadalsfjord in Nordmore. This fjord lies almost due east – west and is a continuation of the Halsafjord. Geologically, most of the Surnadal area belongs to the strata of the Trondheim field with heavily folded1.jpg (29055 byte) Cambro-Silurian slate. The Surnadal area is an outcrop from the Trondheim- field, and Surnadalsynklinalen (the Surnadal syncline) is a well-known geological term
In the green slate in Surnadal there are several parallel limestone veins, and of particular importance is that which runs from Aarnes at the western end of the Surnadalsfjord, and up into the valley of Rindalen. The thickness varies from 0 up to 20 meters and more. Limestone has been found at level – 100z by diamond drilling. It is this part of the limestone vain which runs along the Surnadalsfjord which today is of mining interest. The vein slopes towards the south at an angle varying from 40 to 70 degrees.
2.jpg (87867 byte)It seems clear that the limestone in Surnadal has been known and used in the valley, at all events locally, for many years. Old place names indicate this and further remains have been found of small limekilns of early date. Around the turn of the century (19th to 20th) industrialists started securing for themselves limestone deposits in Surnadal. Some exploration was carried out towards the end of First World War, but operations did not start until 1927.
Practically all the limestone is extracted by underground mining, which adds to the cost. Three mines have been in operation in this limestone seam. Further to the west lays Aarnes Limestone mine, which did belong to the Electric Furnace Products Co. Ltd., Sauda. The mine has been closed in many decades.
Further east lays Sjoflot Limestone mine, last owned by Aardal og Sunndal Verk, the mine was shut down in 1960.
East of this there is Glaerum Limestone mine, Until 2002 the mine was owned by the employees. The mine was taken over by the employees in 1991, from Hydro Aluminium Ltd. In 2002 the Belgium company Lhoist purchased the mine. Finally in December 2009, the Norwegian company Norock & Co purchased the mine from Lhoist, and is now running the production.

 
The limestone in Surnadal is among the best we have in this country. The following is an average analysis:

Undissolved ........................................................... 0,50 %
Fe2O3          .........................................................  0,06 %
Al2O3           ......................................................... 0,25 %
MgCO3        ..........................................................1,10 %
CaCO3         ........................................................98,09 %

Total                                                                     100,00 %

3.jpg (182607 byte)When the Germans during the occupation (1940/41) were preparing to embark on the expansion of their aluminium production in Norway, they needed large quantities of limestone for the planned production of 4.jpg (107310 byte) alumna. The mines and quarries which were being worked at that time were too small to provide the necessary quantity, and it was decided that Nordag themselves should start their own quarrying or mining operations. The choice fell on Glaerum in Surnadal. The first plans aimed at an annual production of limestone of 1,2 mill tons, but this was later reduced to 500,000 tons per year of metallurgical limestone. The plant cost 16 mill. NOK and was almost ready when the war finished. It has since been partly rebuilt and expanded in 1957, 1970 and 1972.
Sales have been, and are, to carbide factories, cellulose factories, smelters and the building industry as granular additive and as filler. In recent years there has been a large increase in sales for agricultural purposes.
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The deposit is extracted in two main adits at levels 86z and 10z (meters above sea level). The first years, some of the deposits were quarried, but this system has been abandoned, to avoid harm to the scenery, and also to avoid flooding.
Until 1987 shrinkage stoping has proved to be the most suitable method. A 1-metre thick layer of limestone was left on hanging walls and a half metre thick layer on footwalls, to avoid contamination to the limestone with slate. Bolting was carried out on both hanging walls and footwalls.
7.jpg (207861 byte)Loading was from mechanized chutes into 6 and 8 tons Granby cars, which automatically tip their loads into a mine silo on level 86, where most of the operations take place today. An accumulator-driven locomotive provided the traction.
The stopes are about 75 meters long and about 80 meters high. A regular pattern of pillars is left.  The chutes were built with a centre-to-centre distance of 15 meters, and were operated by compressed air.
The entire crushing plant and production silos for the old facility are underground, and use the full height from 10z to 86z.
In 1987, the production in the stopes was stopped. Instead it was started conventional
6.jpg (172967 byte) tunnelling with modern tunnel-rigs. The transportation is now based on dumpers, and wheel-loaders take care of loading.
In 1972 a new fine fraction plant was built on the surface to supply limestone to the industry and for agricultural purposes. Here there are five silos, each with a capacity of 500 tons for the following fractions: 0-1 mm, 1-4 mm, 3-8 mm and 8-16 mm.
8.jpg (209156 byte)Most of the finished product is shipped from our own 60 meters long quay with a draught of 8 m. Agricultural limestone is transported by truck to the nearest district. Around 1950 there were a good 100 men employed by the three mines. Today only Glaerum Limestone mine is operating, with 3 employees.