Risks of proposed excavation at St John's

In his contribution titled Political Intervention In The Planning Process (February 21), Alex Torpiano refers to the geotechnical and geological advice I had given to an NGO on the geological risks of excavating next to St John's Co-Cathedral. However, he also added that the "possible use of geotechnics to assess such risks scientifically" may "anticipate whether engineering solutions are necessary to solve the risks identified".

Prof. Torpiano has some experience in geotechnics as the chief architect for the massive Tigné construction project in Sliema. During a public presentation delivered a few years ago about the project, he had described the geotechnics he used to assess ground conditions at Tigné, when he was unable to anticipate the several large underground caverns during the construction of building foundations at Tigné. During his presentation, he described how piles penetrated the ground until they breached the roof of these caverns, which are unstable.

If with his methods Prof. Torpiano failed to anticipate underground caverns several metres wide, what type of "possible use of geotechnics to assess risks scientifically" is he proposing to identify just centimetre-wide joints in the proposed excavation adjacent to St John's cathedral? Who will take responsibility for such a risk?

Prof. Torpiano also somehow compares the proposed excavation to the modern pyramid structure adjacent to the Louvre in Paris. Was this an irrelevant comparison or is he implying that the geology in Valletta is the same as that under the pyramid in Paris?