Complex sentence: Driefontein is the historical name of a mine, Driefontein Mine in the West Witwatersrand Basin (West Wits) mining field, which was discovered in 1931 and commenced operations as Venterspost Gold Mine in 1939.
Split into simpler sentences: Driefontein is the historical name of a mine, Driefontein Mine in the West Witwatersrand Basin (West Wits) mining field. The West Wits field was discovered in 1931 and commenced operations with Venterspost Gold Mine in 1939.