Expensive trenching likely for broadband roll out

In other words it will have to go underground for many thousands of kilometres and in many places new trenching/ploughing will have to be done.
CCF member Alex Wolfe of Wolfe Civil in Perth, who has trenched through hard rock for about 300km on new RJ Vincent subdivisions in the city, says the advantage of laying fibre optic cable is that it can be closer to the surface than water pipes, sewer lines and electricity cables.
He said cable ducts he laid for Telstra were commonly just below 700mm and the last of as many as five laid in a common trench. A common charge to Telstra was $8 a m for the duct and $8 a metre to lay it. 
Telstra involvement
Meanwhile Telstra has indicated it might engage with the governments National Broadband network. Observers say that if Telstra does cooperate, the cost could be far lower than $43bn.
Also, the word is that Optus is in discussion with the government about selling its assets to the NBN while Nextgen, owner of the third biggest fibre-optic network has hinted that it would prefer to rent its assets to the NBN company.
But where new trenches have to be excavated to accommodate new fibre optic cable, it could well cost as much as $400/m, Alex Wolfe said. Then there would have to be access pits at every house costing between $300 and $500 each plus $200 for installation.
He said directional drilling would offer substantial cost advantages, at about $250 a m plus traffic control, for a 50mm diameter tunnel. But that would only work where the soil was suitable and there was not a mess of other pipes and cables to be negotiated. In same places there was already so much underground piping, cabling and ducting, that directional drillers would not contemplate new work.
Hard rock
Alex said many people thought Western Australia was all easy-going sand. But the areas where his company was trenching and installing services in subdivisions, meant engaging with often extremely hard rock even a D10 and ripper wouldnt adequately impact. And hammers were too slow.
He has found the best trenching equipment to be Erkat box cutters on Caterpillar 330D excavators. They work down to 8m and are 20 times faster than breakers in bluestone, limestone and blue capstone commonly found around Perth.
Alex said he had recently had expressions of interest from the Cloudbreak iron ore mine, to use his equipment to keep open cut mines in the north of the state, free of water.
He believes a herringbone pattern of about 400mm deep Erkat cut trenches, draining into sumps, would keep the iron ore dry for the Wirtgen surface miners to operate satisfactorily.  
At an international fibre optic conference and exhibition in Melbourne in mid May, the focus was very definitely on the NBN and new technologies various companies would like to emply to have a share of the fibre optic cable roll out.
Groovy installer
One company called TeraSpan, was promoting the use of a rotating groover, mainly excavating a 72mm deep by 30mm wide groove in the asphalt, beside concrete guttering It was then installing a 50 by 25mm Canadian made plastic duct into which it blew up to 1km of fibre optic cable at a time.
It had already laid a pilot in Mildura, Victoria with the councils blessing.
Another new company in Australia for the NBN roll out is Marais-Lucas Technologies p/l, Macquarie Park, NSW. Marais is a French company and has been planning to enter the Australian market for two years. It has teamed up with publicly listed AJ Lucas p/l to market its truck mounted Cleanfast wheel excavator capable of excavating a narrow trench to 500mm while vacuuming the earth it removes into the truck body.
MD Gal Courcoux said the fully imported $1m machine demonstrated in Melbourne, was likely to start work on the NBN when the project got underway in Tasmania.