Kärrgruvan mining area
Norberg mining museum
Norbergs turistbyrå 0223-291 30.
Norberg turism >
Slag stone shaft tower, 114 m deep shaft, Wooden pumps, Mineral exhibition.Large water wheel, Wheelhouse, Remaining parts of wooden rods for power transmission, Walking-path, Nature, Pits, Ore.
Norberg mining museum and park Mossgruvan
One of the richest iron ore deposits at Norberg is Mossgruvan, where the mining museum is situated today. The visitor is given an idea of how it was to work and live by a mine more than a hundred years ago. The correct name is Risbergs konstschakt and the building was raised in 1876 over a 114 metre deep mine shaft. The shaft was originally sunk in the 18th century.
A very important function of the shaft was to drain the mine. From the shaft it was possible to keep several adjoining pits free from water. The pump equipment was operated using power transmitted from a water wheel by means of a ”stånggång”, a long wooden construction.
The old pumping station has been restored. Visitors are today shown how water is pumped up from the mine. They can also look down the mine shaft.
Apart from the pumping station, a cable operated lift car to carry the miners as well as a canteen, a small foreman’s office and a forge are shown in the pit head building. Visitors can see the tools used by the smith and the old machine used to plane wood, still in working order. A visit to the mining museum may be combined with a tour of Mossgruveparken, a museum park with a signposted walk leading between the old water filled mine holes.
The Mossgruve park is a deserted mining field with deep and water filled open cast mines. Iron ore was mined here from the Middle Ages until the beginning of the 1900s. A sign-posted walking-path runs through the park.
In the Norberg district, the iron ore deposits used to be easily accessible. The plentiful resource of good quality ore meant that there was never any need to make the mines very deep. Until the 17th century the average depth was not more than six metres. When the mines became flooded by water or it was too difficult to get the ore up out of the mine, the mine was abandoned and a new pit was sunk alongside the old one.
Svinryggen is a narrow shelf of rock, left between two rows of old mine holes. Altogether there are no less than eighteen mine holes on each side of the path. Not until the late 18th century were technical aids introduced such as horse drawn winches and water pumps. Polhem’s wheel, which is situated only a few hundred metres from Svinryggen, is what remains of an extensive system of water wheels and a power transmission construction made from wood – ”stånggång”. It used to operate pumping stations at the Mossgruvefält mines, of which Svinryggen is a part.
In the very old days, ore was extracted during the winter. During the four to six weeks following Christmas, the mine was drained. The water was ladled by hand into wooden tubs which were then carried up out of the mine. Then the ore was extracted using the fire-setting method. The ore was then brought to the surface in special barrows. If the mine holes were long, horse and sled could be used for transportation as long as the track was suitable and the ground was frozen.
The Polhem wheel, serving the Mossgruvefält mines (of which Svinryggen is part) has been named after the technical inventor and constructor Cristopher Polhem (1661-1751). The idea of connecting wooden rods used for transmission of power already existed in Germany, but Polhem improved the capacity and solved various technical problems like how to convert the reciprocating motion into rotary motion of mine-hoist drums.
The wheel was supplied with water via the water conduit entering the north side of the wheel house. The conduit was connected to a three kilometre long canal from lake Bålsjön. An example of a turning point has been preserved and stands on the original place on the other side of the road Polhemsvägen.
The system was fitted with a bell that rang night and day as long as the system was in motion. If the bell stopped ringing, it meant that the pumps had stopped and something had to be done about it before the mine slowly filled with water.
The Polhem wheel was in operation from 1877-1920. It is remarkable that this 18th century technique was used for new installations as late as 1877, when steam power was already was available at Norberg. Also considering the fact that electricity was introduced at an early date by international comparison.
To make sure that there always was a sufficient supply of water to keep the Polhem wheel running at all times, a three kilometre long canal was built running from the nearest lake. Up to the top of the wheel there is a water conduit, which also is a big attraction to foolhardy youngsters who use it for climbing, running and cycling. In the canal and in the conduit there were always lots of cray-fish.
The canal has been preserved and makes a nice walk.
The key to the Polhem wheel can be borrowed in the kiosk close by.