Mining in the Upper Harz

Mining in the Upper Harz region of central Germany was a major industry for several centuries, especially for the production of silver, lead, copper, and, latterly, zinc as well.

[2] The taxes raised from this contributed significantly to the revenue of the royal houses in Hanover and Brunswick-Wolfenbüttel and helped to secure their positions of power and influence within the empire.

[1] The first water wheels to supply energy to the mines were constructed in the 13th century in the Pandelbach valley southeast of Seesen.

Plague epidemics during the Middle Ages depopulated the Harz to a great extent and almost brought mining operations to a standstill.

Another factor was probably that mining had reached its technical limits at the time with depths of up to about 60 m. A clear recovery followed from about 1520 onwards, initially at the instigation of the Duke of Brunswick-Wolfenbüttel, Henry the Younger.

In order to entice the necessary labourers, tradesmen and even mining companies to the Harz, the dukes granted 'mining freedoms' (Bergfreiheiten) based on Bohemian and Saxon practice.

It collected water from the mines in Bockswiese, Lautenthal, Zellerfeld, Clausthal and Wildemann and transported it to Gittelde on the edge of the Harz.

Overexploitation during the First World War and plummeting metal prices resulted in major closures at the height of the Great Depression in 1930, when the big mines around Clausthal-Zellerfeld, Bockswiese and Lautenthal had to close.

The ore deposits that lay immediately on the surface were quickly exhausted and, as early as the 12th and 13th century miners were forced to switch entirely over to underground mining.

There were two reasons for this approach: firstly, it had to be possible to extract ore from the beginning (as soon as the shaft was sunk) in order to make the pit economic as early as possible.

From these gangways, miners began to extract the ore, heading downwards into the floor, by 'brushing down' (Nachreißen) in stepped fashion, a technique known as underhand stoping.

The packing (gangue material used for filling) from the upper main gangways was placed in the exhausted cavities (the so-called 'old man' or Alter Mann).

If the expected supply of ore or its quality did not justify sinking the main shaft deeper, or if the workings were a long way from it, draw-shafts were sunk.

Next one or two transverse boreholes with a 6–7 cm diameter were drilled by hand Usually two-man boring was employed: one turned the borer whilst a second hit it with his sledge.

Unlike blasting with modern explosive, the stemming had to be wedged in using an iron rod centred on the borehole and a thick wooden prop in a slot (Bühnloch) on the opposite side.

After clearing the blast debris, the material to be screened was loaded into wagons (Hunde or Hunte) using rakes (Kratze) and tubs (Trog).

That meant the miners worked on top of the packing and could transport the ore under gravity using so-called chute holes (Rollöcher or Rollen) rather than shafts.

Trials with sublevel stoping (Teilsohlenbruchbau) and square set timbering (Blockbau mit Rahmenzimmerung) did not get past the experimental stage.

When using the latter method the wheel's rotation was converted into reciprocating motion using a crank mechanism ( Krummen Zapfen) and transmitted over twin flat rods, several hundred metres long, to the shaft.

Chief Mining Engineer (Oberbergrat) Wilhelm Albert (1787–1846) made a cable out of steel wire which was first successfully tested on 23 July 1834 at the Carolina Shaft.

As the distance between shaft and workings lengthened and increasing quantities of material had to be moved, wheelbarrows or small wagons (the Hunte or Hunde) were used underground as horizontal methods of transportation.

One feature mining in the Upper Harz was the underground transportation of material in boats on the Tiefe Wasserstrecke about 300 metres deep, in Clausthal and Zellerfeld from 1835 to 1898.

In 1833, master miner (Oberbergmeister) Georg Ludwig Wilhelm Dörell (1793–1854) came up with a simple, but ingenious mechanical method of getting in and out of the mine, the man engine.

Due to the water wheel drive and frequent bends in the inclined shafts only a few miners could be transported simultaneously to begin with and they had to periodically switch over to ladders.

On the one hand water was used as an energy source; on the other it was used to wash out the unwanted clay and to separate ore from gangue by making use of the different density of the minerals.

Until the beginning of the industrial era, mechanical processing was carried out as follows: The resulting concentrates (Schlieg or Schliech) were sold to the smelters.

Only by adapting and developing the smelting processes over the course of the centuries could mining in the region be maintained, because the lodes changed their primary metal content sharply with increasing depth.

Since the 1980s the mining archaeology team of Lothar Klappauf and Friedrich-Albert Linke have carried out excavations and undertaken a considerable amount of archeological and archaeometallurgical research.

The transportation of logs as rafts and the use of water power led to the selection of advantageous sites on the rivers in the Harz - such as the Innerste, Grane and Oker.

The steadily rising demand for wood from the pits and smelting works led to overexploitation of the forests by the Early Middle Ages.