Complex sentence: He worked with the NCB for 23 years, as a mining engineer from 1964, the year he joined the National Union of Mineworkers (NUM) until 1987, he started his career with the NCB in the Lanarkshire Coalfield, at Auchlochan Colliery.
Split into simpler sentences: He worked with the NCB for 23 years, as a mining engineer from 1964, the year he joined the National Union of Mineworkers (NUM) until 1987. He started his career with the NCB in the Lanarkshire Coalfield, at Auchlochan Colliery.