Name	Parish	From	To	Comments
Oak Wood	Mirfield, Dewsbury	1882	1884
Oakenshaw	Rhodes, Bradford	1854	1890	Not listed from 1861 to 1877.
Oakroyd	Birkenshaw, Bradford	1877	1887
Oaks	Stairfoot, Barnsley	1854	1896	Oaks, Old from 1897 to 1898.
Oaks Farm	Darton, Barnsley	1919	1937	Abandoned in February 1920. Discontinued May 1936. Abandoned April 1937. Abandoned August 1945
Oaks Farm Opencast	Barugh, Barnsley	1948	1961
Oaks, New	Stairfoot, Barnsley	1897	1898
Oakwell	Adwalton, Leeds	1872	1893	On 1st edition O.S. 1/10560 sheet.
Oakwell (a)	Morley, Leeds	1855	1878
Occupation	Mirfield, Dewsbury	1876	1877	Sinking in 1876.
Ogden Lane Nos.1 & 3	Brighouse	1904	1939	H. Mellors. 43 years. Closed 1939. Working plans suggest mine started 1904. Listing begins 1909, continues to 1946, but working was discontinued in December 1939. Not more than 25 men employed. Plan located only for earliest period.
Old Burtersett	Hawes	1907	1916	Reopened Aug. 1907
Old Flockton	Emroyd, Wakefield	1886	1894
Old Gawber	Barnsley	1856	1863
Old Hall	Roberttown, Liversedge	1874	1896	Sinking from 1874 to 1883.
Old Hall	Liversedge, Dewsbury	1904	1912	Abandoned 1911.
Old Holmfield Pit	Boothtown, Halifax	1947	1948
Old Mill Pit	Barnsley	1855	1883
Old Oaks	Barnsley	1838	1899	Old Oaks - first sunk 1838 - site later occupied by Barnsley Main. Explosion - 12 & 13th December 1866 killed 334 plus 27 rescue workers. A Pumping Station from 1904 to 1918.
Old Oaks	Barnsley	1901	1918
Old Roundwood	Ossett, Wakefield	1853	1966	Called Roundwood Colliery before 1901 and thereafter called Old Roundwood. Sunk in 1853 and closed in April 1966.
Old Silkstone	Dodworth, Barnsley	1855	1899	Also see Dodworth. Sunk to Silkstone prior to 1862 and to Whinmoor in 1927.
Old Silkstone Main	Worsbro’ Park, Barnsley	1855	1884
Old Sovereign	Dodworth, Barnsley	1965	1969
Old Tarn	Saddleworth, Oldham	1873	1873
Old Town	Barnsley	1873	1876
Oldfieldnook	Cleckheaton	1861	1863
Olive Branch	Mexborough, Rotherham	1855	1860
Orchard	Handsworth, Sheffield	1927	1932	Abandoned April 1932
Orchard Lane	Beighton, Sheffield	1988	1988	Pumping Station
Orchard's Head	Pontefract	1901	1941	Includes Eccleshill Sand Mine in 1915 and 1916.
Orgreave	Treeton	1855	1981	Sunk to Barnsley in 1851 and the Silkstone in 1889-90. Closed in October 1981.
Orgreave Opencast	Treeton	1953	1955
Osmondthorpe, Railway Pit	Osmondthorpe, Leeds	1854	1928	Abandoned September 1928.
Osset Common	Wakefield	1855	1860
Ossett	Ossett, Wakefield	1854	1880
Oughtibridge	Oughtibridge, Sheffield	1861	1899
Ouslethwaite	Worsborough, Barnsley	1923	1924
Outcrop	Halifax	1918	1962	Mainly a Fireclay mine. Hard Bed, abandoned 01/07/1962, plan 15206.
Owlet Hall	Drighlington, Leeds	1855	1872	On 1st edition O.S. 1/10560 sheet.
Ox Close	Ossett, Wakefield	1873	1881	Sinking from 1873 to 1878.
Ox-Bow	Leeds	1966		4 miles SE of Leeds - opencast
Oxlee	Hepworth, Holmfirth	1879	1897
Ozzings	Shelley, Huddersfield	1874	1881	Sinking from 1874 to 1878.