Slurry or Diaphragm walls offer minimal movement, maximum water-tightness, and can be built deeper than conventional caisson walls. These walls can also be detailed to form part of the permanent installation. This technique is commonly used in Europe, the United States and many provinces in Canada other than Ontario. One of the first successful installations (1960's) was for Ontario Hydro and stores its spent nuclear cooling rods in a deep tank next to Lake Ontario. Unfortunately an installation performed in the 1970's by a European contractor was of very poor quality and gave this technique a poor reputation in the Southern Ontario market. More recently, this method was specified on a Toronto subway project. Bermingham can utilise its affiliation with Pittsburg's Nicholson Construction, one of North America's largest specialty contractors, to bring this technique to the local market.