Tunnelling began on April 27, 2016 with a 21.5ft- (6.5m-) diameter TBM, and mining completed for the first tunnel in the fall. Excavation of the second tunnel began on November 29, 2016.
Each tunnel is about one mile long (1.6km) — from the future Expo/Crenshaw Station at Exposition and Crenshaw boulevards to the Leimert Park Station at Crenshaw and 43rd. There is also a station in between at Crenshaw and Martin Luther King, Jr. Boulevard.
Walsh-Shea Corridor Constructors is the contractor and comprised of Walsh, Shea, HNTB, Comstock and Arup.
Metro said mining progress was about 60ft (18m) per day and for the second tunnel. A crew of 75 workers manned the TBM over three shifts, five days per week.
The USD 2.058bn project is projected to open in the fall of 2019.