Preserved headframe and winding engine at the Ármin-akna site, now home to Hungary's first open-air industrial museum in the Csingervölgy valley near Ajka.
The Ármin-akna colliery in the Csingervölgy valley near Ajka was developed from 1903 as part of a coalfield first systematically explored in 1865 by the local landowner Gyula Puzdor and subsequently sold through a series of owners before passing to the Bécsi Szénipari Egyesülés, who constructed a branch railway to the site. The shaft operated for brown coal extraction until 1960, powered by a twin-piston steam winding engine manufactured by the Schlick works in 1903. On the centenary of coal mining at Ajka in 1965, the surviving pithead buildings and machinery were formally opened as the Ajkai Bányászati Múzeum — Hungary's first open-air industrial skanzen.
The Schlick winding engine and the principal buildings were designated as protected monuments by the Országos Műemléki Felügyelőség in 1983. A 54-metre demonstration adit was added in 1977, and a fossil and mineral gallery opened in 1978. The mine's final skip of coal was brought to surface in 2004, and the museum continues to operate under municipal management.
Coal-bearing outcrops in the Csingervölgy area near Ajka had long been known locally, but systematic prospection only began in 1865 when the landowner Gyula Puzdor commissioned the mining engineer Hout to survey the estate. This was prompted in part by the recommendation of the Hungarian geologist Miksa Hantken. Coal was confirmed in the Felső-Csinger area on the Puzdor family property, and a mining concession was opened. The Puzdor family sold the extraction rights to the Kohen brothers of Pest in 1869. Barely three years later, in 1872, a further ownership change brought the operation under the Bécsi Union Bank Verein, which passed it the same year to the Bécsi Szénipari Egyesülés. This company took the enterprise seriously, constructing the branch railway line connecting the then-independent settlement of Csingervölgy with Ajka railway station. By the 1870s the coalfield had grown into four principal mines: Kossuth Akna, Ármin Bánya, Jókai Bánya, and Padragi Bánya, graduating from shallower workings in the north-east to the deepest mines in the south-west. Production served both the local market and the growing demands of the Graz–Budapest railway and its construction works.
The Ármin-akna — named after the mine inspector and director Riethmüller Ármin — was established in 1903, when construction of the shaft and its surface buildings began. The shaft was equipped with a twin-piston steam winding engine manufactured that year by the Budapest firm Schlick, a machine considered a masterpiece of Hungarian engineering. An additional single-cylinder Schlick steam engine, installed in 1904, drove the surface ropeway from Alsócsinger and served as the winding engine's brake pump until 1926. The Ármin-akna operated continuously through the first half of the twentieth century, producing brown coal from the Cretaceous-age Ajka coal seam, a formation also notable for containing ajkait — a fossilised sulphurous pine resin unique to the locality. A serious mine disaster at the Ármin-akna in 1909 claimed the lives of 55 miners. Production continued through both world wars and the early decades of the socialist state, with the shaft finally ceasing operation in 1960 when the winding engine stopped for the last time.
From the 1930s onwards the wider Ajka district developed significant bauxite resources in addition to coal, and in 1943 an aluminium plant and smelter were opened. Coal and aluminium production together defined the industrial character of Ajka through the mid-twentieth century. After the regime change of 1989–1990, both the coal mines and the bauxite–aluminium complex were progressively closed.
The idea of preserving the Ármin-akna site as a museum had already been discussed by 1960, when clearance and restoration works began. On the centenary of coal mining at Ajka, in 1965, the museum was formally opened by Dr Faller Jenő, director of the Központi Bányászati Múzeum. The institution was the first open-air industrial skanzen in Hungary. In the following decades the site expanded considerably: a 3,000 square-metre outdoor machinery park was established around the surviving buildings, displaying over 200 items of mining and tunnelling equipment including heading machines, compressors, underground locomotives, and coal cutters. A 54-metre demonstration adit was inaugurated in 1977, illustrating the full range of underground support and tunnelling methods used in Hungarian coal mines. A fossil and mineral gallery opened in 1978 in the former mine rescue station building, eventually housing over 1,000 specimens. The main buildings and the 1903 Schlick winding engine were designated as protected monuments (műemlék) by the Országos Műemléki Felügyelőség in 1983. A rare Skoda-manufactured single-cylinder rope-haulage engine of 1926 was subsequently relocated to the museum from a demolished building at Alsócsinger. The museum's final connection to active mining came in 2004, when the last skip of coal was brought to surface and placed on permanent display. Museum management passed to Csingervölgy Nonprofit Kft. in September 2022.