Maciej (Westschacht) shaft – a unique underground water intake in Zabrze

Maciej Shaft is a historic mining plant, a legacy of Zabrze and Silesian coal mining. It used to be part of the Concordia Mine, and has been since the 1990s. In the 1970s. is undergoing a transformation, turning into a socio-cultural space that is attractive to visitors who want to take advantage of its food and entertainment offerings.

Origins

Today, the Maciej shaft is located in Zabrze, on Srebrna Street in the Maciejów district, in the industrial complex left over from the Pstrowski coal mine. When its exploration began in 1922, it was named Westschacht because it was to provide access to the western part of the mining field of the Concordia Grube mine, which had been in operation since 1841. This area fell to the Germans after World War I, uprisings and a plebiscite in 1922.

At the time, Zabrze was called Hindenburg, the current Maciejowice was called Mathesdorf, and the street was called Silber Strasse. Most of the dozens of mines fell to Poland after the plebiscite, only 14 of them remained on German territory, and therefore, in order to increase coal production, all of them had to be modernized and new mining sites had to be sought. This is how the story of a rather unusual facility for which water is of primary importance begins.

Drilling work

Excavation of the shaft began with a circular shaft disk with a diameter of 4350 mm. At the same time, on the surface, work began on providing the basic infrastructure of the mine: the hoisting tower, the buildings of the engine room, the shaft top, the sorting plant, the switchgear, the converter, the fan room, as well as the administrative and residential buildings for the employees were being constructed. While investments on the surface were going smoothly, from the very beginning below the surface, work was moving very slowly, which was related to the difficult hydrogeological conditions.

Initially, they drilled into Quaternary formations, which consisted of alternating layers of clay and highly failing sands, often fine-grained. Before drilling through 30 meters of the youngest geological formations, they repeatedly encountered cupping, which is a mixture of fine sands, clays and water trapped between them under considerable pressure. When cut, they behave like a homogeneous liquid mass, often posing a danger to mining. Below the Quaternary formations, shales and Triassic sandstones were encountered, lying to a depth of about 82 meters, the latter also heavily waterlogged.

The aquifer extended in the foot part of the Triassic formations in a series known as the Spruce Tree strata. The sandstones and sands that occur here in the form of several levels do not maintain continuity – they are interspersed with clay layers. Directly beneath them lay Carboniferous sediments, including coal seams. Due to intensive groundwater inflows, the drilling was eventually terminated at a depth of 198 meters, and this occurred only after ten years. At this depth, it was connected to a trench from the mining level in the main Concordia mine field.

The Westschacht shaft was secured with a cement mortar masonry casing with a total thickness of 50 cm, which made it watertight. From then on, it began to fulfill the roles of ventilation, mining, material, downhill and dewatering. As it turned out, coal mining was not at all its most important function. Only three low-flesh coal seams were encountered here, which were additionally severely tectonically disturbed, but they provided the basis for the mine’s output for the next few years.

Water production

In addition to coal, water turned out to be the mine’s real wealth. It was decided to make use of its surplus, and in 1928 a Water Supply Plant was established to produce drinking and industrial water based on mine water from the Westschacht shaft and the Jan shaft of the Mikulczyce mine. One of the two pump stations was installed in the Westschacht shaft. On site, the water was filtered, chlorinated and subjected to a de-gelatinization process. Quite quickly, the Water Works expanded. New buildings were constructed in the vicinity of the shaft, and as drilling progressed, groundwater was exploited from the two aquifers of the Westschacht shaft and from several levels of the Jan shaft.

In addition, groundwater was also exploited from four deep wells (50-100 m deep) located about 1.5 km north of the Westschacht shaft. The total length of the water supply network soon reached 30 km. The main water supply system was located along the railroad line connecting Gliwice and Bytom and supplied water to the surrounding towns, mines and steel mills. Water pipes made of cast iron or steel ranged in diameter from 150 to as much as 500 mm.

The Water Supply Plant’s annual production reached 8 million^m3. Underground water from behind the Westschacht casing seeped into a reservoir at the 110-meter level and from there was directed to the bottom of the shaft, where it mixed with water flowing in from other areas of the mine. From there, they were pumped by pipeline to the surface, to a de-gelatinizer, and from 1938 they were also subjected to a chlorination process.

Maciej shaft

In 1945, Zabrze found itself within the borders of Poland. The Westschacht shaft was renamed Maciej, the Water Supply Plant was nationalized and in 1949 was handed over to the Zabrze Coal Industry Plants for management. For more than 30 consecutive years, the Maciej shaft was an extremely important point on the map of the city’s water supply. The Concordia Mine, then as Ludwik-Concordia, and in the final phase of its operation as Pstrowski, was obliged to maintain a continuous supply of groundwater, but due to specific geological conditions, the intake was quite often contaminated with sand and clay, which forced stoppages in supply.

In the 1950s, a new water treatment plant was built, equipping it with new gravel filters, treated water tanks and a new pump station. At the end of the 1980s, the coal deposits were depleted, and thus the Pstrowski mine began decommissioning some of the workings along with the surface infrastructure. It ceased operations in 1997, and its heir was the Siltech Mining Company, which – as the first private coal mine in post-war Poland – took over the exploitation of the rest of the deposit.

As part of the ownership transformation, the Maciej Shaft area was leased to the Demex Mining Company, which proposed converting it into a water intake and buying out the remains of the above-ground part, thereby saving the entire complex from liquidation. The project envisaged decommissioning the lower part of the shaft (in Carboniferous formations) by backfilling it with rock material and cutting off the remaining workings with clay plugs. The upper part of the shaft was adapted in 1993 into a water intake according to the scheme shown below. This is the only technical solution of its kind in Poland (and probably in the world). The groundwater inflow to the shaft currently takes place from the Triassic Swierklaniecki strata at the level of 64-79 meters. The waters are pumped to the surface by submersible pumps, after which they go to the Water Station, from where, after filtration, they were transferred to recipients.

Demex also carried out repair and conservation work on the surface infrastructure, which culminated in the entry of the buildings into the register of monuments and the revitalization of the entire complex for tourist purposes, taking into account the protection and use of the water intake. In 2005, Maciej Shaft was included in the Route of Monuments of Technology, and in 2011 Demex was awarded the Laureate Diploma for its exemplary concept of adapting the engine room of Maciej Shaft for tourist purposes.

Since 1997, Zabrze’s waterworks have given up receiving water from the Maciej Shaft, but the intake itself has been working due to the need to dewater some of the mine workings of the Pstrowski mine in liquidation. These waters are used, among others, by the Zabrze Combined Heat and Power Plant. A water dispenser – a vending machine for purchasing drinking water – has also been installed in the vicinity of the Maciej shaft. The approved resources of the intake amount to 120^m3/h and it currently has the status of an alternative source of water supply for the city of Zabrze.

Photo. main: Maciej Shaft

In the article, I used, among other things. z:

1. Barecki Z., 2012, Decommissioning of the “Maciej” shaft with conversion to a deep well. P.G. Demex sp. z o.o.
2. Razowska-Jaworek L., Chmura A., Wantuch A., 2016, Groundwater of the cities of Poland – Zabrze. PIG-PIB Warsaw
3. Żabicka-Barecka D., Barecki Z., 2015, Revitalization of the historic “Maciej” shaft. – transformation of a mining shaft into a water intake, in: Wiadomości konserwatorskie województwa śląskiego. Water. Silesian Provincial Conservator of Monuments in Katowice, Silesian Cultural Heritage Center in Katowice, Katowice.
4. szybmaciej.pl.