Preserved ventilation shaft headframe of a Czech-designated heritage colliery complex in Ostrava-Kunčičky.
Důl Alexander (jáma 2), the ventilation shaft of the Alexander colliery, was sunk from 1896 alongside jáma 1 by Severní dráha Ferdinandova in Ostrava-Kunčičky. The two shafts were positioned one hundred metres apart and formed the twin core of a colliery complex celebrated for its Baroque-inspired architectural ensemble. Jáma 2 served initially as the ventilation shaft, housing steam ventilation equipment and later electrical winding machinery.
Its engine house was completed in 1901 and equipped with a steam double-cylinder winding engine of 600 HP supplied by Bromovský, Schulz a syn; the headframe, built for a depth of 600 metres by Vítkovické železárny, measured 30.15 metres from collar to winding-wheel centre. In the 1950s the shaft received a replacement electric winding engine of 400 kW from Závody V. I. Lenina in Plzeň. Following the 1976 conversion of both shafts to ventilation duties, jáma 2 was deepened to a final depth of 775.28 metres.
It was backfilled in 1994. The headframe building of jáma 2 was among the structures designated a Czech cultural monument in 1993, and was restored to its 1901 appearance between 2015 and 2016.
Jáma 2 of the Alexander colliery served as the ventilation shaft of the complex. Its sinking began in 1896, contemporaneous with jáma 1. By the end of 1897 the shaft had reached a depth of 153.3 metres. The engine house and headframe building of jáma 2 were completed in 1901. The strojovna was equipped with a steam double-cylinder winding engine with Radovanovic valve gear, manufactured by Bromovský, Schulz a syn, with an output of 600 HP. The winding drums had a diameter of 4,000 mm and a width of 1,350 mm, with rope wound in two layers. The two-deck cage carried one tram per deck, or eleven persons per cage, at a personnel speed of 6 m/s and a winding speed of 12 m/s. The headframe, constructed to serve a depth of 600 metres, was supplied by Vítkovické železárny and stood 30.15 metres from the shaft collar to the centre of the winding wheels, which had a diameter of 4,000 mm.
Initially equipped with a steam fan of the Guibal type, jáma 2 later received a Halsbach-type fan with electric drive by Siemens-Schuckert Vienna, manufactured at Vítkovické železárny in 1899. Ventilation was one of its principal functions throughout the mine's early decades.
From 1 August 1926, following the merger of the Alexander colliery with Důl Zárubek, both shafts took on modified roles within the enlarged combined operation. In 1926 the original engine house composition at the surface was altered as part of the wider jáma 1 reconstruction works.
The last significant modification of jáma 2 recorded in the sources occurred in the 1950s, when the ventilation shaft received a new electric winding engine of 400 kW output, delivered in 1952 from Závody V. I. Lenina in Plzeň (Škoda Plzeň). In 1976, when the lower Alexander workings were reassigned to Důl Jeremenko, both shafts were formally converted to ventilation duties and equipped with new axial fans. Jáma 2 was deepened to its final recorded depth of 775.28 metres at this stage.
Coal extraction across the combined Alexander-Zárubek operation ceased on 31 December 1992. Jáma 2, with a depth of 775.3 metres, was backfilled in 1994, one year after jáma 1. The headframe building of jáma 2 was included in the group of six structures designated Czech cultural monuments on 30 June 1993 under register number 10423/8-3329. It was also covered by the Ministry of Culture designation of 24 September 2001.
During the 2015–2016 restoration programme carried out by DIAMO's ODRA branch, the jáma 2 headframe building was restored to its 1901 appearance, in contrast to the jáma 1 building which was returned to its 1992 state. The headframe of jáma 2 stands 30 metres in height and was repainted during the restoration period. Visitors attending the public open day held after the restoration's completion were able to ascend the metal structure of the jáma 2 headframe to its full height.