| 1 | Foreman | @ | $3.75 | per | shift |
| 1 | Laborer running grout machine | " | 2.00 | " | " |
| 2 | Laborers handling cement and sand. | " | 1.75 | " | " |
| 1 | Laborer tending valve and grout pipes | " | 1.75 | " | " |
After the grouting was finished, the arches were rubbed over with wire brushes to take off discoloration, and rough places at the junctions of adjoining lengths or left by the block laggings were bush-hammered.
Face of Bench Concrete.—The form used for this portion of the work is shown on [Plate XLV]. It consisted of a central framework traveling on wheels, and, from the framework, two vertical forms were suspended, one on each side, and equal in height to the whole height of the bench. Adjusting screws were fitted at intervals both at top and bottom, and thus the position of the face forms could be adjusted accurately. The face forms were built very carefully of 3-in. tongued and grooved yellow pine, and one 50-ft. form was used for 3,000 ft. of tunnel without having the face renewed. Great care was taken to set these forms true to line and grade, as the appearance of the tunnel would have been ruined by any irregularity. Joints between successive lengths were finished with a V-groove.
The concrete was received at the form in dumping buckets; these were hoisted to the top of the form by a Lidgerwood hoister fixed to a trailer. The concrete was placed in the form by shoveling it from the traveling stage down chutes fitted to its side. The quantity of water to be used in the mixture needed careful regulation. The first few batches in the bottom had to be very wet, and were made with less stone than the upper portion, in order that the concrete would pack solidly around the niche box forms and other awkward corners.
The forms for the ladders and refuge niches were fastened to the face of the bench forms by bolts which could be loosened before the main form was moved ahead, and in this way the ladder and niche forms were left in position for some time after the main form was removed.
At first the forms were kept in place for 36 hours after finishing a length, but, after a little experience, 24 hours was found to be enough. In the summer, when the rise of temperature quickened the set, the time was brought down to 18 hours. The average time taken for a 50-ft. length was:
| Laying concrete | 4½ | hours. |
| Interval for setting | 18 | " |
| Moving forms ahead and resetting | 5 | " |
| ——— | ||
| Total | 27½ | hours. |
The typical working gang was:
Laying Concrete.
| 1 | Foreman | @ | $3.25 | per | shift. |
| 2 | Spaders | " | 2.00 | " | " |
| 8 | Laborers | " | 1.75 | " | " |