The 1920s and 1930s marked a period of dynamic expansion, including the deepening of shafts I and II, reaching new mining levels at 385 and 550 meters, opening of additional coal seams, and a steady increase in output.

In 1960, the Bojków ventilation and material shaft was commissioned together with the Bojków mining field. Further major development took place in the 1970s and 1980s, when shafts IV and VI were opened, enabling access to deeper mining levels at 750 and 950 meters. These investments led to extensive mechanization of the entire production cycle, from coal cutting and transport to processing and sales.

During the 1990s, the mine underwent technical and technological restructuring aimed primarily at reducing operating costs. Between 1 July 2005 and 29 April 2015, KWK Sośnica was merged with KWK Makoszowy and operated as “Sośnica–Makoszowy” mine within Kompania Węglowa S.A.

Following the split in 2015, Sośnica again became an independent mine and, since 29 April 2016 is operating as part of Polska Grupa Górnicza S.A.