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Gozo tunnel methods under fire

Peter Gatt says geological studies are vital first step. Photo: Matthew Mirabelli

Peter Gatt says geological studies are vital first step. Photo: Matthew Mirabelli

Geological studies should have been carried out before the feasibility study was carried out on the proposed tunnel between Malta and Gozo – for a number of reasons, according to carbon geologist Peter Gatt.

The lack of geological information could have a significant impact on the eventual cost of the tunnel – and if it were not carried out at all, it could prove dangerous, he said, noting that the tunnel between Delimara and Marsa actually cost double the budgeted price because there was rock collapse as a result of inadequate geological information.

Dr Gatt was speaking to this newspaper after news emerged of a feasibility study on a proposed underwater tunnel linking Malta and Gozo, commissioned ahead of a geological study, which he said would take years. “The first thing to do in order to understand whether a project is feasible is to carry out a geological study to get to know the rock that will be drilled into,” he said.

This was the approach that Britain and France adopted for the Channel Tunnel, where the submarine geology has been studied for over 50 years. Despite several geological studies, they still had to change direction in some cases. “The nature of the rock varies every few metres, and you need to be able to predict what type of rock will be drilled into as this could otherwise collapse.”

The seabed between Malta and Gozo is not straightforward, as the channel is full of large and deep faults

The seabed between Malta and Gozo is not straightforward, as the channel is full of large and deep faults. At the same time, at least two of the four options originally presented by Mott MacDonald in a report commissioned by Transport Malta in 2011, pass through an active fault off Gozo.

“Malta does not have detailed information about these faults as it is the only European country without a national geological survey. Instead, we rely on stratigraphical information dating back 40 years. This information was not only outdated, but incomplete, so I do not, for example, understand how the conclusion of drilling 100m below sea level was reached.”

“I’m not against the tunnel project, but drilling without knowing the geological details would definitely push up the project’s price because of emergency action that would need to be taken along the way.”

Asked about the cost of the Gozo tunnel project, he said that when comparing it to tunnels abroad, it would cost more than the proposed €250 million.

The Gozo tunnel will be the main topic of discussion on Times Talk, Times of Malta's programme on TVM on Tuesday at 10.05pm.

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