Bully-les-Mines is a commune in the Pas-de-Calais département in northern France. It forms part of the Lens-Liévin agglomeration community, which encompasses 36 French communes and 250,000 inhabitants. For many years it was a major coal mining center.

The Compagnie des mines de Béthune, sometimes called the sometimes called the Compagnie de Grenay after the name of the concession, was a French coal mining company in the Pas-de-Calais that was established in 1851 and nationalized in 1946. The company had 11 mines, each with one or more shafts for extraction of coal or ventilation. It had a large facility for screening and washing raw coal, and for producing coke and other secondary products. During World War I (1914–1918) the front line crossed the mining concession, with the northern part occupied by the Germans, but despite constant shelling production of coal continued. Coke production peaked at 565,195 tons in 1928. The company had two thermal electricity plants, and operated 159 kilometres (99 mi) of railway tracks. At its peak the company was one of the largest coal mining operations in the region, with 12,640 employees in 1945.