Complex sentence: Duntilland Collierie began production in 1896 with a work force of just under 200, their main production was specializing in coal types of/in manufacturing, anthracite and steam.
Split into simpler sentences: Duntilland Collierie began production in 1896 with a work force of just under 200. Their main production was specializing in coal types of/in manufacturing, anthracite and steam.