Binnian Tunnel


The Binnian Tunnel was constructed between 1947 and 1950/51 and is located under the Mourne Mountains in County Down, Northern Ireland. The main purpose of the tunnel is to divert water from the Annalong Valley to the Silent Valley Reservoir underneath a number of mountains including Slieve Binnian, after which the tunnel was named.
A high degree of engineering skills were employed in the building of the tunnel. A workforce of 150 was involved in two tunnelling teams which started from opposite ends and met in the middle nearly 800m under the roof of the mountain. The tunnel was created using drilling and blasting techniques. The shelters for the workers can be found on Slievenaglogh.
The tunnel was designed to carry of water per day, be long, high and wide. When the two teams met in the middle on 6 December 1950, they were only two inches out. The tunnel was officially opened in August 1952.