Risks of excavation near St John's Co-Cathedral

Alex Torpiano (February 27) presented his one-sided support for the proposed rock excavation adjacent to St John's Co-Cathedral.

My circumspect contribution on this matter was to identify for non-technical persons, the geological risks of deep excavation in Valletta.

Geological problems affecting foundations and excavations are widespread and part of Maltese recent collective memory. Hindsight shows that engineering skills for mitigating damage to adjacent buildings during excavation have not proved to be effective in Malta.

A recent example is the damage to the historical chapel opposite Stella Maris church in Sliema. There are many more cases of damage to private homes that go unreported on the media.

However, Mr Torpiano seems confident that "engineering skills" and his "right experts" can mitigate these risks in the case of the St John's project, although project proponents have not expounded on these, not even succinctly.

Mr Torpiano did publicise his engineering skills during a public presentation he delivered few years ago on the Tigné construction project, where he is chief architect.

Despite using particular geophysical methods, he showed a picture slide of an unanticipated cavern above sea-level with the integrity of its roof precariously breached by a pile (a deep foundation for weight bearing structures). A detailed geological survey (not just coring) of the entire site before construction would have revealed more unstable features and caverns on what is Malta's largest building site and also a decommissioned military site.

Nevertheless, Mr Torpiano adds that he did gain "experience" from "tunnelling" under a heritage structure at Tigné. Such experience is not relevant to surface excavation proposed for St John's museum project. Ultimately, rock excavation in Valletta must not be considered as just another new learning "experience" with an uncertain outcome, mainly due to the possible irreparable damage to our unique cultural heritage.

Malta's dismal track record in excavation and foundations is rooted in the philosophy that Mr Torpiano, Dean at the Faculty of the Built Environment, expressed by the contentious phrase "things can be done, irrespective of the geology".

Would this philosophy be the "standard practice" taught to local civil engineering graduates, who will become Malta's future architects, building restorers, planners and road designers?

Are civil engineers adequately educated on the complexity of local geology and aware of geological risks? The public will expect the University of Malta to do something about this serious matter. The Prime Minister and the Archbishop already jointly did so a few weeks ago.