Projects
Freeze shaft in Canada, PCS shaft Scissors Creek
Design and construction of a freeze shaft through the Blairmore formation down to the salt deposits at a depth of around 1,100 m.
The Scissors Creek shaft is the first of a new generation of potash shafts in Saskatchewan. Design, sinking and lining of the shaft were based on the experience gained whilst developing the deposit in the 1960s and 1970s.
The geology consists of claystones, highly water-bearing quick sands and fissure water bearing limestones. Sinking down to the Blairmore formation was done using ground freezing technology. Below the Blairmore formation, shaft sinking continued after prior pre-drilling and cement grouting.
The freezing process is necessary in order to allow sinking through the water-saturated, quick sands of the Blairmore formation. The final permanent shaft headframe was used for sinking. The concrete shaft lining extends down to 427.5 m depth and the tubbing lining down to 594.2 m.