Complex sentence: A 46 metre-deep access shaft excavated from the surface took over four years to dig gives access to a bedding plane passage entering the main shaft near the top of Titan and digging continues in an attempt to extend the system in other directions.
Split into simpler sentences: A 46 metre-deep access shaft excavated from the surface took over four years to dig and now gives access to a bedding plane passage entering the main shaft near the top of Titan. Digging continues in an attempt to extend the system in other directions.