Jun 03, 2005. /Lesprom Network/. Ainsworth Lumber Co Ltd. said it will start a $200 million expansion of its oriented-strand-board (OSB) mill near Grande Prairie in Alberta, Canada. The Vancouver British Columbia-based company said the expansion will increase annual production capacity by about 600 million square feet and will include the construction of a hardwood sawmill in Valleyview, Alberta, east of Grande Prairie. The OSB mill expansion and the sawmill are expected to be completed by early 2007. Ainsworth's expansion will include the addition of a second production line at the existing Grande Prairie site that will produce both OSB and other engineered wood products. Once completed, the expanded Grande Prairie mill will have an annual capacity of nearly 1.3 billion square feet.