Two hi-tech machines are working their way into the history books deep beneath Sydney as they drill their way through 88,000 holes in the delivery of Sydney Metro, Australia’s biggest public transport project.
The drilling rigs – nicknamed Emily and Edith – have so far drilled 56,000 holes so important railway infrastructure can be installed in Australia’s longest railway tunnels.
“Sydney Metro is a world-scale project and a mammoth undertaking – we’ve pulled out all the stops, including these custom-made drill rigs that allow us to get the job done as quickly as possible,” Baulkham Hills State Liberal MP David Elliott said.
“This isn’t a case of popping down to the local hardware and picking up a few drill bits, these technical marvels are drilling around 30 holes a minute with millimetre precision so metro services can start as quickly as possible.”
Edith and Emily drill about 500 holes a day.
The holes are the first step in installing overhead wiring inside the twin 15km tunnels between Bella Vista and Epping as well as a walkway in each tunnel and the trays that carry cables and other essential services.
Each rig has six drills on it that can run simultaneously, operated by a crew of up to five workers and progressing 200m a day – about four times faster than doing the work without the custom-made rigs.
The rigs drill their holes to a maximum depth of 110mm and use 12mm and 16mm drill bits.
The rigs have worked their way through about 19km of tunnels and have another 11km to go before April, with 32,000 holes left to drill.
The rigs were made in Brisbane and took two days to transport to Sydney fully-assembled as over-sized loads.
They were named after Emily Warren Roebling, a self-taught engineer known for her contribution to the completion of New York’s Brooklyn Bridge, and Australian women’s rights campaigner Edith Cowan.
On major tunnelling projects around the world, underground workers look to Saint Barbara for protection and, because of that, machines that work underground are traditionally given female names.