Deep Navigation Colliery "Account Book 1940"
"Deep Navigation Colliery was situated near Treharris in the Taff Bargoed Valley. In 1878 two shafts were sunk at the site which were, at the time, the deepest pits in the south Wales coalfield. During this period the mine was called Harris' Navigation Colliery after the name of the principal shareholder, F.W. Harris. The same man also gave his name to the neighbouring village of Treharris. In 1893, the Colliery was purchased by the Ocean Coal Co. Ltd. who changed its name to Deep Navigation Colliery. The Colliery produced high quality steam coal which was greatly in demand notably by Cunard Steamlines......................................."
National Union of Mineworkers (South Wales Area): Treharris/Deep Navigation Lodge "Minute Books, 1946-1987.Financial Records, 1943-1983 including account books 1943-1983, income and expenditure analysis book 1958-1975, workmen's local levy account book 1944-1967, summary of accounts 1950-1952, copy of NUM South Wales Area statement of income and expenditure and balance sheets 1955. Administrative Records, 1925-1983 including record of re-assessment of pneumoconiosis cases 1948-1984, compensation administration expenses book 1966-1982, miscellaneous correspondence and reports 1946-1971, desk diary 1983, members transfer ticket counterfoil book 1925-1970, Eisteddfod programmes 1950-1956 and diploma for Nat Edwards in recognition of his services to the Ocean Combine Committee 1946."