Monday, March 31, 2014

Hamilton Syphon

You could be forgiven for thinking that Brisbane's current inclination to tunnel under the city to solve infrastructure problems is a new thing. The Clem Jones tunnel under the river has been completed; the Legacy Way tunnel that is to connect Toowong to Kelvin Grove is well under way; and there is now a proposed under-river bus and train tunnel (BaT tunnel for short, apparently - If only Heath Ledger were still around to open it!!) that will connect Dutton Park to Bowen Hills.

The Clem Jones tunnel was dug out with this rock-eating marvel, Matilda, from Germany, and the other projects will be similarly kitted out.
 (Photo: Erikt9 via wikipedia.com)

But the Brisbane City Council has tunnelled under the river before. Many decades earlier, in fact - and the reason was to help solve a sewerage problem.

As mentioned in the recent post about Clem Jones, Brisbane lagged far behind other cities in providing sewerage to outer suburbs. The following headline from the Courier-Mail on 13 January 1949 indicates that the problem was well-recognised then, and was likely to require many years of rehabilitation.
(www.trove.nla.gov.au)

One of the efforts to improve services was to transfer sewage from the south side of the Brisbane River to the treatment plant on the northern side. The proposed way to do this was to construct a tunnel to pipe the waste under the river from Cowper St Bulimba to Kingsford Smith Drive Hamilton.

Known as the Hamilton Syphon (or Siphon, if you prefer), the project was put to tender by the Council and won by local firm MR Hornibrook Pty Ltd for an amount of £154,515. The work involved sinking two vertical shafts - one each side of the river - 140ft (43 metres) into the ground, and connecting them with a 2000ft (610 metres) tunnel under the river.

And you can forget about tunnel-boring machines from Europe, as have been used in the Clem7 and Legacy Way underground tunnels. This tunnel was constructed the old-fashioned way by men using cumbersome rock-drilling machinery. Progress was slow - the tunnel was lengthened by about 30ft (9 metres) each week. Here is a description of the working conditions on the job:
The four experienced miners at the tunnel face work in a roaring, wet, grey fog. They guide two long rock-drills fixed to a wheeled hydraulic mounting, the 'Jumbo.' River water seeps down the brightly-lit walls enclosing the 10ft. diameter tunnel. The men leave the tunnel when gelignite plugged into the drill-holes is exploded electrically from above.
 (CM 19/01/1951 via trove.nla.gov.au)

Below is a photograph of the four men at work in the tunnel. Look closely to find the two men at the front of the drill.
(BCC-B54-1555)

Once the tunnel was finished it had to be lined with a special concrete sealer to prevent leaks into the tunnel from the river.
 (BCC-B54-3942)

And below is a section of completed tunnel with sewerage pipes in place.
(BCC-B54-4423)   

Work commenced on the tunnel in 1948 and it was completed in 1955. The tunnel is still used today, and has just undergone a major renovation to repair cracks and upgrade access areas.

Once again the work was difficult. Here is  a summary of the challenges that were faced by the firm that completed that project, Meyjor Industries Pty Ltd:
Tough engineering challenges were inherent in this project from the start, including the requirements of confined space entry, the likelihood of sulphuric gas being present in the horizontal tunnel and requiring ventilation, workers requiring breathing apparatus in case of emergency and the difficulties with being able to get a man box down the shaft to ensure workers could safely remove and install platforms. Intensive planning was undertaken by the project crew before works commenced to ensure safety of workers was paramount, and to ensure project completion would be on schedule. 
(http://www.meyjorindustries.com.au)

As somewhat of a claustrophobe, I dips me lid to the tunnel workers, past and present!

tff

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