Documents from Perth Public Transport Authority (PTA) director Ross Hamilton suggest that contaminated land issues could add up to AU$320M (£174M) to the cost of the Forrestfield Airport Link tunnel project.
Spoil excavated for the new metro line, which will link the city with the airport by 2020, is said to be contaminated with per- and poly-fluoroalkyl substances (PFAS) that are linked to the use old fire-fighting foams at the airport.
Emails from Hamilton to the authority’s managing director Mark Burgess and Transport Minister Rita Saffioti’s chief-of-staff Richard Farrell were obtained by Perth’s Sunday Times under Freedom of Information Laws. According to the newspaper, the emails say that temporary stockpiling of the contaminated spoil is estimated to cost AU$50M (£27M), while permanent disposal of the 360,000m3 will cost up to AU$270M (£147M).
Saffioti has said that the figures in the email are a worst case estimate and work is underway to ensure the bill doesn’t reach this amount. Saffioti said the PTA was “working positively with Perth Airport with a view to them taking the bulk of the soil for use under the proposed third runway and the North Link project is also using some of the soil as fill material for two interchanges.”
The project has been dogged with tunnelling issues with the tunnel boring machines first stopped in spring following subsidence issues and tunnelling is currently halted following groundwater flooding in September during construction of a cross passage.