The Application of European Shaft-Sinking Techniques to the Blairmore Formation

Large production shafts can be successfully sunk through the ubiquitous Blairmore formation of southern Saskatchewan by employing the freezing process and by the installation of a cast iron tubbing lining. Although the freezing technique for shaft sinking and the use of cast iron tubbing to preserve the shaft are new to the North American continent, these procedures have been employed in Europe for the past eighty years. More than 200 shafts, covering a wide variety of ground conditions, have been sunk by the freezing process, and most of these have been lined with cast iron tubbing. The No. 1 shaft of International Minerals and Chemical Corporation, near Esterhazy, Saskatchewan, comprises the first major example in Canada of the employment of European methods to overcome extremely difficult ground conditions. The Blairmore formation was solidified by the deep freezing process, employing a lithium chloride solution as the refrigerant, with input temperatures ranging to -55°F. The shaft was then sunk within the protection of the ice wall, and a cast iron tubbing column of 357 feet was installed simultaneously. This paper outlines the European techniques of sinking a shaft by the freezing process and of designing and installing a cast iron tubbing lining. Reference is made to the application of these techniques for the sinking of new shafts through the Blairmore formation in Saskatchewan, and a brief description is included of the one completed project employing European methods in Canada
Keywords: brine, cast iron, lithium chloride, potash, Southern Saskatchewan, Cast iron, Concrete, formation, Freezing, Ice, Lining, Linings, potash, Process, Shafts
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