| | | |
Rock |Center heading | 93+58 | 92+42 |Nov. 14, '07|Dec. 27, '07|
| | | | | |
Rock |Bottom heading | 92+42 | 91+05 |Dec. 27, '07|Feb. 24, '08|
| | | | | |
Mixed |Rock cut | 91+05 | 90+57 |Feb. 24, '08|Mar. 20, '08|
--------------+-----------------+---------+---------+------------+------------+

--------------+------+--------+--------+--------------------------------------+
| | |Rate of | |
|Number| |progress| |
| of | Linear |in feet | |
Material. | days.| feet. |per day.| Remarks |
--------------+------+--------+--------+--------------------------------------+
{| 14} | | {|Excavation in normal air, and before |
Rock {| 15}57| 69 | 1.21 {|advance of shield. |
{| 28} | | {| |
{| | | {| |
| | | | |
Rock {| 26}55| 53 | 0.96 {|Bottom heading timbered to avoid the |
{| 29} | | {|possibility of a break. |
| | | | |
Mixed | 25 | 22 | 0.88 |Bottom heading timbered. |
| | | | |
Mixed | 54 | 65 | 1.20 | |
| | | | |
Earth | 94 | 723 | 7.69 | |
| | | | |
| | | | |
Mixed |190 | 515 | 2.71 | |
| | | | |
Rock | 21 | 38 | 1.81 | |
| |