CO129-509-15 Water supply- development scheme 30-1-1928 - 17-1-1929 — Page 36

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The line of the pipes may have to be varied

East or West, as the rock shown on the sections on the

Kowloon side is much deeper below the surface than the

rock on the Victoria side, and this might cause the

connections on the Kowloon side to be more expensive.

Assuming that exploration and survey showed that it would be possible that a subway 8 feet by 8 feet

could be driven across the Harbour, basing calculations

on granite or other hard rock tunnelling in this country, the probable cost would be about 10 (Ten Pounds) per

foot run in round figures. This assumes that the rock

would be of such density as would enable the work to be constructed without lining.

In the present case, it does not seem possible

to carry on work from more then two faces, i.e. one on

each side of the Harbour, and all the material excavated

will require to be delivered and taken away through the

subway from either one side or the other. The facilities

and organisation to do this will largely influence the

time to be taken to construct the work.

Assuming that the nature of the material is

suitable and that at least 5ft. or 6ft. drills can be

used on two faces, it is probable about two yards or 6

lineal feet for each face can be driven per day of 24

hours.

The length of the heading is 2000 yards or 6000 feet, divided by 4 yards equals 500 working days or

approximately 18 months. The laying of the pipes need

not delay the matter, as they could proceed as the tunnelling proceeds..

Taking 6000 feet at £10 per foot, the cost

would be 60,000, but this would be substituted for work

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