CONSTRUCTION OF HUME DAM 1919-1936
In today's photo, the dissipator trough and wall are completed and holding water. The Victorian wing wall and earth embankment are well advanced.
In the foreground, the granite "plums" wait to be unchained before being lifted and placed into the wet concrete by the flying fox.
All plums were pressure cleaned before use.
Across the centre of the photo, a loco shunts crushed granite for the mixers.
Toward the background, is a stack of concrete blocks. Overruns of concrete on the conveyer belt were not wasted. Called crest blocks, they had a similar use as the granite plums.
What can't be seen is the inspection gallery. It has a domed roof and is comfortably large enough to walk through. Well over 1km long, this tunnel traverses the valve and spillway sections before linking up with the drainage and inspection tunnel at the base of the Victorian core wall.
The entire gallery extends as far as the bend shown at the extreme top right corner of the photograph. It contains monitoring equipment for movement, seepage and uplift pressures. It is also the anchorage point for a large number of tensioning cables installed in the 1960s when the dam's capacity was increased. Inspections are carried out almost daily.
Higher up is a much shorter tunnel. Known as the Winch Gallery, it houses equipment for the emergency operation of the spillway gates as well as the main electrical switchboard.
The process of inserting large rocks into wet concrete is termed cyclopean concrete. Seventeen per cent of the spillway comprises these granite displacers of between two and eight tons each.
Locals used the term "plums" for the rocks. Many were left half exposed, allowing the next pour of concrete to be keyed into the one before. Both levee banks and coffer dams were used during construction, the largest area enclosed by a coffer dam was 12 and a half acres around the Victorian end of the spillway.
Many carts and drays were used while constructing the Weir. Dray spelt backwards is yard, which is the load of soil they could carry.
In all, Victoria had 10 steam locos working on the earthen embankment using a 1.05m gauge. NSW had four running on their 900mm gauge.
Stone from the quarry was gravity fed to the mixers using the 900mm line - locos returned the empty wagons to the quarry.
Albury and District Historical Society meets the second Wednesday of each month at the Commercial Club Albury at 7.30pm, all welcome.