Limestone industry on Öland
The limestone industry on Öland consisted of mining and sales, but also of lime kilns and surface treatment of the stone. The red and gray stones on the Swedish island were polished and shipped. The activities were a profitable part-time occupation of the Öland farmers.
Especially in the north, the island had rich limestone deposits that were easy to exploit. Limestone was used in prehistoric times. The first stone transports for the construction of Lund Cathedral (1103) have already been recorded . In the 19th century, the stones went to Stockholm and Copenhagen , where they were used as building material for floors, stairs and sidewalks.
Chafing in the hike
Working with limestone included grinding the surface, known as "scrubbing". The method called scrubbing was first mentioned in scriptures around 1640, but was certainly practiced earlier.
The scrubbing was initially carried out with the help of the so-called migration. The raw stone block was cut into slabs and then divided into pieces of different sizes depending on the purpose. Before the panels were laid out for scrubbing, the roughest bumps were cut off. About 60 plates were placed in a ring on the floor. An oak post was driven into the center with a beam or two extending from it. The running stones, which rubbed against the stones laid out in the ring, were attached to the beams, which were drawn in a circle by a horse or ox . Water and sand were constantly added as abrasives. The scouring clay, which was used for building walls or mending paths, formed around the scrub area.
When there was scrubbing during the hike, the quarry, as well as transport and sales, fell to the men. The women mostly took care of the cutting and splitting of the panels and the scrubbing. The one week grinding result was at best two sets of polished stones. The last migration happened around 1930.
Scrubbing mills (Skurwerk)
When the wind-powered scrubbing mills came up, a major event for Öland, both methods were used in parallel. Wind-powered scrubbing mills were introduced between 1850 and 1860. The skipper and boat builder Olof Peter Nilsson from Högenäs near Källa is said to be the inventor of this type of mill. Most of the wind power plants had small farmers built. Its effectiveness was far higher than that of migration. In good winds you could scrub a "ring" in one day.
At Jordhamn , three kilometers north of Sandvik , is the Jordhamn scrubbing mill , the only remaining scrubbing mill and the last remaining scrubbing walk. At the turn of the 19th and 20th centuries there were around 30 scrubbing mills on Öland.
The mills and walks were taken out of service in the 1930s when grinding machines took over.
Lime kiln
Lime burning began in large quantities in the 14th century, when brick fireplaces and chimneys became commonplace. The processing of limestone into lime is one of the oldest technical processes in the Neolithic . The oldest screed-like floors come from the mountain temple Göbekli Tepe in Anatolia and are 11,000 years old. Lime was needed to make lime mortar. Mortar is a mixture of sand, water and slaked lime as a binding agent. Lime kilns use a lot of fuel. Since wood was scarce on the island, it was heated with shale or hard coal, which was brought to the island by ship.
In Källa there were two coal-fired lime kilns in the second half of the 19th century, of which the one southwest of Nyby next to the large disused quarry Vibrotten has been preserved to our day. To the north of Bruddesta, a former fishing village on Kalmar Strait, there are the last two lime kilns that were in operation on Northern Öland. The last firing was carried out there around 1918. In Bruddesta there is another lime kiln maintained by the local history association between the fishermen's huts.
Nyby's stove
Nyby's furnace was built in 1868 and operated until 1874. It measures 4.5 × 5.5 m and has been preserved up to a height of two meters. Limestone fragments and field stones were used as building material. The outer walls are partially grouted with lime mortar. The stones inside the stove are porous and weathered by the fire.
The process
To burn lime, the kiln had to be “charged” alternately with a layer of fuel and a layer of limestone. The material was brought up in wheelbarrows. After the entrances were walled up, the stove was lit. The fire lasted two weeks. After the furnace had cooled down, it was opened and the burnt limestone was "extinguished" with water in the nearby shed. A sieve was used to separate the unquenched from the quenched stones. The slaked lime was loaded onto barges from the port in Källa and shipped.
literature
- Markus Forslund (Red.): Nature and culture on Öland. Länsstyrelsen Kalmar län, Kalmar 2001 ISBN 91-973802-4-5 .