Channel Tunnel over £3 million. Ten workers, eight of them British, were killed during construction between 1987 and 1993, most in the first few months of boring. A two-inch (50-mm) diameter pilot hole allowed the service tunnel to break through without ceremony on 30 October 1990. On 1 December 1990, Englishman Graham Fagg and Frenchman Phillippe Cozette broke through the service tunnel with the media watching. Eurotunnel completed the tunnel on time, and it was officially opened, one year later than originally planned, by Queen Elizabeth II and the French president, François Mitterrand, in a ceremony held in Calais on 6 May
Channel Tunnel at the English portal, caused concerns. Identified by the 1964–65 geophysical survey, the Fosse Dangaered is an infilled valley system extending below the seabed, south of the tunnel route in mid-channel. A 1986 survey showed that a tributary crossed the path of the tunnel, and so the tunnel route was made as far north and deep as possible. The English terminal had to be located in the Castle Hill landslip, which consists of displaced and tipping blocks of lower chalk, glauconitic marl and gault debris. Thus the area was stabilised by buttressing and inserting drainage adits. The service tunnel acted