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.

Many soundings were conducted in the Pas-de-Calais from 1847, showing that the Valenciennes coal basin extended westward. The Société des mines de Béthune was constituted on 1 October 1850 to explore for coal in the Pas-de-Calais department. Founders were the Boitelle brothers, Constant Quentin, Petit-Courtin, André Courtrai and Courtray-Copin. The company explored the area west of Béthune, which had not yet been surveyed by other companies, making the first drilling at Annezin, where coal was found on 26 April 1851. Further test drills at Fouquières, Haillicourt and Bruay found coal at depths between 130 and 182 metres (427 and 597 ft). Based on the favorable results, the exploratory company was changed to an exploitation company on 25 September 1851.

Another exploration company, the Société des mines de Bruay, was formed in 1851 to explore for coal in the region by Leconte, Lalou and others. The owners of the Mines de Béthune acquired shares in this company, and on 13 April 1852 the six partners of Bruay sold to Constant Quentin, Petit-Courtin, Joseph Tellier, Alexis Boitelle and Lobez, in their capacity of president and members of the society of Bethune, all the results of their soundings and their rights.

M. Dusouich, an engineer from the Arras mines, advised the administrators of the Mines de Béthune to abandon work they had started in the Bruay and Béthune region and to establish themselves in the area between Lens and Nœux. The first site was near the village of Bully (today Bully-les-Mines), with 400 inhabitants. The land was poorly wooded, so the company had to bring timber and workers from Cambrai. On 17 February 1852 the drill hole reached coal at 146 metres (479 ft). Sinking of Mine 1 at Bully began on 26 March 1852, and the mine came into operation in 1853..

An imperial decree of 15 January 1853 granted the Compagnie de Béthune, created by act of 25 September 1851 and represented by Constant Quentin, Petit Courtin and Joseph Lobez, the concession for coal mines in the communes of Haisnes, Auchy, Violaines, Cuinchy, Beuvry, Sailly, Labourse, Sains, Bouvigny, Aix, Liévin, Loos, Hulluch, Cambrin, Annequin, Noyelles, Vermelles, Mazingarbe, Grenay and Bully in the arrondissement of Béthune, Pas-de-Calais. The concession was named the Grenay concession. The 5,176 hectares (12,790 acres) Grenay concession lay between the Noeux and Lens concessions. At first the company had great difficulty disposing of the products, which had to be transport by horse-drawn carts to Arras, where it could be transferred to barges or railway cars. An attempt to form a company to make coke near the canal at Violaines in 1856 failed.

The company decided to connect their mines by rail to the waterways and to the projected new railways. In December 1859 a decree allowed the company to build a railway from Bully to Violaines. Decrees of 29 August 1863 and 8 March 1865 authorized the Mines de Béthune to extend their railway network to Béthune and Lille. A limited company named the Compagnie du Chemin de fer de Lille à Béthune et à Bully-Grenay was formed on 11 May 1865 to operate the railway. Additional mines were sunk between 1859 and 1909 in Vermelles, Loos-en-Gohelle, Mazingarbe, Auchy-les-Mines, Annequin, Sains-en-Gohelle and Grenay. Coal was typically reached at a depth of 135 to 150 metres (443 to 492 ft). The coal had increasingly volatile content ranging from 9.5% in the north to 34–38% in the south.

Charles Ignace Plichon (1814–1888) was Deputy of Nord and Minister of Public Works in 1870. He was the son-in-law of Alexis Boitelle, an administrator of the Company, and became an administrator himself. He was president of the administrative council from 1873 to 1883, when he resigned, apparently due to a conflict with Bouitelle. The company faced many difficulties during his term of office, and had only moderate growth, since neither Plichon nor Boitelle had technical training.

Louis Mercier (1856–1927) was made director-general of the Mines de Béthune in 1877 and became a member of the Comité des forges in 1878. With the appointment of Mercier, helped by an improvement in the economic situation, the mines became more prosperous. After a survey of the Aix-Noulette region, the original concession was increased to an area of 6,352 hectares (15,700 acres) by an act of 1877. An 1881 encyclopedia entry described the concession as covering 5,761 hectares in the Pas-de-Calais, with 6 or 7 mines. It produced 231,711 tons in 1870, 220,519 tons in 1871, 200,817 tons in 1872, 253,124 tons in 1873 and 279,526 tons in 1874. Coal production steadily increased, interrupted only by World War I (1914-18) and the 1932 economic crisis.