Former hard coal colliery at Mariadorf, closed in 1962, with surface structures demolished and only the spoil heap surviving as a visible remnant.
Grube Maria was a hard coal colliery founded in 1848 on the territory of Hoengen, now the Alsdorf district of Mariadorf, in the Aachen coalfield. It was established by Eduard Honigmann, Friedrich Bölling, and Leopold Schoeller, and named after the wife of its first director. The mine achieved first coal production in 1848, six years before its neighbour Grube Anna.
Through a series of ownership changes it passed to the Aachen-Höngener Bergwerk-Aktiengesellschaft in 1863, was leased and then purchased by the Vereinigungsgesellschaft für Steinkohlenbau im Wurmrevier in 1887–1890, and became part of the Eschweiler Bergwerks-Verein (EBV) through merger in 1907. Over its operational life the mine operated through three successive shaft complexes — Maria I (Reserve), Maria II, and Maria-Hauptschacht (centred on the Maasschacht) — and reached an annual output of 608,000 tonnes with a workforce of around 2,200 in its mid-century years. Wartime damage in 1944–1945 caused severe flooding of the lower levels.
Production resumed in 1947 and continued until 30 September 1962, when the mine was closed as a rationalisation measure, the extracted Magerkohle being difficult to sell and geological conditions having become particularly demanding. Surface structures were demolished after closure; the former mine II site hosted the EBV's Maschinenhauptwerkstatt until 1992. The surviving Bergehalde (spoil heap) at Maria-Hauptschacht is noted as the only remaining visible remnant of the surface workings.
Grube Maria was founded in 1848 by Eduard Honigmann, Friedrich Bölling, and Leopold Schoeller, with the concession for the 1.74-square-kilometre Maria field granted on 14 May 1848. The field name was chosen by Honigmann after his wife Maria. Exploratory drilling had begun in 1846 in a wooded area near Hoengen, where a borehole at approximately 43 metres depth struck coal — an easier encounter than at the neighbouring Anna field. The first shaft, designated Förderschacht I (later Maria I or Maria Reserve), reached a depth of about 134 metres and first coal was raised in 1848, making Maria the earlier of the two great Alsdorf mines.
A coking plant was added in 1851. By 1853 the workforce numbered 265, and a settlement for miners' families was built adjacent to the mine, initially called Mariagrube and later renamed Mariadorf. The mine was refirmiert as the Aachen-Höngener Bergwerk-Aktiengesellschaft in 1863. In 1872 a new spoil heap was laid out and named Maria-Hauptschacht. The mine gained a rail connection in 1870 when the Rheinische Eisenbahn opened the Stolberg–Alsdorf line; a 750-metre branch to the mine was inaugurated the same day. In 1875 the Aachener Industriebahn established a connection to Aachen-Nord, and the nearby railway junction took the name Bahnhof Mariagrube after the colliery.
A second shaft complex, Maria II, was developed but found to be unproductive, and its winding was ended in 1886. In 1882, work began on a new, third shaft — sunk initially from underground levels and from the surface from 10 July 1882 — which received the name Maasschacht (after Justizrat Johannes B. Maas, a supervisory board member of the Vereinigungsgesellschaft). The Maasschacht had a diameter of 6.25 metres, was designed for double winding, and reached 650 metres depth. It entered production in 1890. A further shaft, the Suermontschacht, was sunk in 1899 and served primarily for personnel transport. By 1887 the financially strained Aachen-Höngener Bergwerk-Aktiengesellschaft had leased the mine to the Vereinigungsgesellschaft für Steinkohlenbau im Wurmrevier, which purchased it outright in 1890. The Vereinigungsgesellschaft established a briquet factory on the former Maria II site in 1894.
In 1907 the Vereinigungsgesellschaft merged with the EBV, bringing Grube Maria under EBV ownership along with its coking plant and briquet works. After 1907 the EBV rationalised the site: the coking plant at Maria-Hauptschacht, which by 1911 operated 75 Koppers ovens producing 129,000 tonnes of coke annually, was itself closed in 1932. The older Maria I (Reserve) shaft had already been shut in 1925. In 1930 a new Neuschacht was sunk on the Maria-Hauptschacht site to replace Maria I, entering service in 1932. By this period the mine operated two main production shafts (the Maasschacht and Neuschacht), three air shafts, and a coking plant, with an annual output of 608,000 tonnes.
During the Second World War, Grube Maria sustained severe damage from six weeks of artillery bombardment in 1944–1945. When power was cut, the electric pumps failed and the 820-metre level of the Neuschacht flooded. The 1,050-metre level was permanently lost. Post-war reconstruction was slow; production did not resume until 1947. In the 1950s, the old Maasschacht was dismantled and the mine by the early 1960s employed approximately 2,200 workers raising 2,800 tonnes of coal daily. An underground connection was made between the 580-metre level of Maria and the 710-metre level of Grube Emil Mayrisch at Siersdorf.
The closure decision was taken in 1961 with a view to rationalising output through Emil Mayrisch. The entire workforce transferred to Emil Mayrisch. All production at Grube Maria ended on 30 September 1962. The primary reasons given in sources are the weak market for Magerkohle and the particularly difficult geological conditions. After closure, the Neuschacht was filled to the 580-metre level and thereafter served as a ventilation shaft for Emil Mayrisch. Demolition of the surface structures continued from 1963 and was completed by 1966, when the Suermontschacht was also filled. A Westkauf supermarket briefly occupied the former pithead baths building for approximately fifteen years. The former Maria II site hosted the EBV's Maschinenhauptwerkstatt until 1992. The only remaining surface remnant noted in sources is the Bergehalde (spoil heap) at the Maria-Hauptschacht site.