1873The BKB is founded in Berlin on 26 January, with a nominal capital von 1.6 million talers.

1874Opening of the first open-cast mine “Trendelbusch”

1880 BKB begins mechanising mining.
Opening of the “Treue” open-cast mine

1887 With the commissioning of the briquette factory at Treue, BKB develops from a mining operation into a production operation.

1888 Beginning of electricity generation – for the first time, a generator is used in the “Prinz Wilhelm” colliery.

1900Annual coal output reaches one million tonnes for the first time.

1902The era of small operations comes to an end as a result of concentration processes. Over the next few years, BKB systematically acquires the neighbouring mining companies.

1906-1910The power stations Emma, Treue and Harbke go into operation. On 22 June 1908, the Duke of Braunschweig visits the Treue pit.

1915Merger with Harbker Kohlenwerke AG. BKB becomes the biggest mining operation in the Helmstedt-Staßfurt basin.