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.
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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.