The first ground works for Canberra's light rail line began on Monday with workers digging to find the location and condition of power, gas and telephone utilities.
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Capital Metro Minister Simon Corbell joined crews at the first of about 1000 excavations in Gungahlin, taking part in the digging of small potholes and trenches to help with photographing pipes and wires.
The four-month check of active and disused utilities in the light rail corridor along Northbourne Avenue, Flemington Road and the Federal Highway seeks to reduce risk and keep down the cost of construction of the $614 million line.
Mr Corbell said the cost of finding and moving pipes and wires away from the tram line could be separate to the project's overall budget and could be completed before the start of track construction in 2016.
The investigation work will be carried out by Kambah company Leach Steger and Brown Consulting.
The study will highlight any risk from hazardous materials including asbestos and any other unknown factors before completion of the business case, Mr Corbell said.
"The government is very serious about doing all the work that needs to be done to prepare this project to go to market.
"Obviously a key decision later this year will be the consideration of the final business case and these excavations by the Canberra-based firm will help us to confirm costs and risks as part of that final business case preparation."
Digging will take place between Gungahlin Place and Alinga Street in the city, with some reduced speed limits, traffic controllers and safety signs.
Some work will be scheduled outside peak traffic times.
Mr Corbell said the study could highlight a range of problems and no final decision on remediation works would be taken before the business case was complete.
"We will be looking at all the possible issues associated with the excavations, whether it's old piping, material associated with that piping, whether its utilities that aren’t where they say they are on the map."
Residents in the light rail corridor will receive a posted update from the ACT government in the next few days including construction plans and public consultation on where to position the 13 passenger stops.
Capital Metro agency director Emma Thomas said results of the digging could affect the building cost and time.
"We will continue to do some investigations of soil at the same time, so geotechnical survey works. They are important to understand any other soil condition type analysis, for example of the depot location," she said.
"We will continue to develop our refined definition design which will go towards establishing a business case and our tender materials for the rest of the process that will happen."
After the business case is presented to the government later this year, a decision on construction will be made. With construction due by 2016, the first passenger services are expected on the line in 2019 or 2020.
"Risk from asbestos or any other ground contaminants are always important to understand before a project, so we know exactly what’s in the ground condition and what we need to deal with," Ms Thomas said.
"It is very important that when we put this out to bid we know as many of the risks as possible and know what’s there and where it might be."
Until a design scheme was complete, she said, it would be premature to say which utilities could need to be moved.
"It’s critical at the moment to understand what is there," Ms Thomas said.
As information and consultation efforts continue for the project, weekly updates on the digging work and other activities will be posted on the agency's website.