Kops II pumped storage works: construction contract 3 – machine caverns / Pumpspeicherwerk Kops II: Baulos 3 – Maschinenkaverne

125,000 mm³ of excavation were completed in only 14 months, between October 2004 and December 2005, for the powerhouse and transformer caverns. The excavation of the shafts and tunnels - altogether 1,782 m - was undertaken parallel to the excavation of the caverns with a total volume of 78,000 mm³. The internal construction works were also remarkable. From December 2005 to May 2007, which is a period of only 1.5 years, 48,000 mm³ of concrete were placed in the caverns. The multitude of linings and backfill concreting in the tunnels, shafts and other subsidiary works were constructed at the same time as the concrete work in the caverns. This extraordinary performance was only possible through intensive preparation work, continuing during the construction phase, and the involvement of specialists. At peak times, 130 skilled construction workers were employed on the site. All works were carried out in continuous operation with day and night shifts. The only interruption was for the traditional Christmas and Easter holidays.