Why Saskatchewan Freezes the Ground to Reach Its Potash

Why Saskatchewan freezes the ground to reach its potash. At the Jansen project, BHP reports freezing the ground to a depth of 800 metres to build its potash shafts: refrigerated brine in a ring of pipes, and frozen ground holding back water and sand while crews excavated roughly a kilometre down. The freezing is temporary. A lining of concrete and steel, built from the surface to below the lowest water-bearing formation, takes over the job for decades. This is the documented story of a route protected twice: the Unity shaft that flooded in 1961, the Blairmore Formation, the freeze plant finished in 2011, the last cut at 1,005 metres in 2018, a design life of 70 to 80 years, Esterhazy's shafts closed nine months early, and the mine that now recovers potash by dissolving it. In this video: BHP's 2012 annual report: a closed refrigeration system circulating brine; the coolant stays in the pipes and the groundwater freezes around them Unity, in the Canadian Institute of Mining's archive: sinking from 1952 by conventional methods and grouting; in 1961 the shaft flooded with water and sand from the base of the Blairmore at 550 metres; sealed in 1968 Keller's published shaft work: freeze pipes surveyed for direction and spacing; a thermal analysis of their number and the time to a sound wall; flowing groundwater that can slow or prevent freezing The closure check in a monitoring well near the centre, and a fall in groundwater levels during excavation as a possible inflow warning TESC's freeze plant, with its freeze ring, completed in October 2011 DMC's shaft boring roadheaders developed with Herrenknecht: a cutting drum on a telescopic boom, cuttings removed by suction Sinking from 2012, paused in 2014 for adverse ground conditions; the service shaft's final depth of 1,005 metres on 18 August 2018 Machines of about 350 tonnes raised back out; final liners of concrete and steel built in modules in Estevan; an internal diameter of 7.3 metres The Canadian Mining Journal, 2021: brine to be warmed slowly over months or even years, with ground and water conditions monitored Jansen's technical report: a welded outer liner, water seals at the base, a design life of 70 to 80 years, maintenance and monitoring, corrosion protection Both shafts excavated and lined by October 2022; a production headframe of more than 50 metres and about 2,000 tonnes in 2025 Esterhazy, 4 June 2021: Mosaic closed its K1 and K2 shafts nine months early as brine inflows accelerated; inflows managed since 1985 Patience Lake: solution mining from 1989 after a conventional start; Saskatchewan's pioneering use of freezing during shaft sinking, in Nutrien's record Key figures: 800 metres of freezing, as BHP reports; roughly a kilometre of shaft; 1,005 metres at the last cut; 550 metres at Unity; 7.3 metres of internal diameter; 70 to 80 years of design life; nine months. Timeline: 1952, 1961, 1968, 1985, 1989, 2011, 2012, 2014, 2018, 2021, 2022, 2025. Watch next:    • The Road to a British Columbia Gold Mine R...   The Road to a British Columbia Gold Mine Runs Over a Glacier: the ice under the vehicles, and the road moved as the glacier retreats    • Why Quebec’s Route 138 Becomes a Ferry   Why Quebec's Route 138 Becomes a Ferry: the highway that boards a ship, and the bridge still at the study stage Chapters: 0:00 Frozen to 800 metres 0:25 A ring of pipes 1:09 The Blairmore Formation 1:36 Unity, 1961 2:11 A kilometre down 2:52 The short answer 4:24 Checking the drilling 5:35 The freeze plant 6:24 The closure check 7:26 October 2011 7:50 Shaft boring roadheaders 9:07 1,005 metres 10:10 Liners from Estevan 10:58 The plan for thawing 11:36 Lining to the bottom 12:41 Both shafts lined, 2022 13:01 70 to 80 years 14:00 The new headframe 15:23 Esterhazy, 2021 16:26 Solution mining 17:34 The ledger Every claim in this video is drawn from the documented record: BHP's annual report for 2012, its announcements of 24 August 2018 and 31 October 2022, its 2021 project briefing, its September 2025 headframe report and Jansen's technical report summary; the Canadian Institute of Mining's archive on Unity; DMC Mining; Herrenknecht; TESC; Keller's published guidance; the Canadian Mining Journal, November 2021; Mosaic's announcement of 4 June 2021; Nutrien's 2025 filing and site history. Figures carry the qualifiers their sources attach to them: the 800 metres is BHP's reported freezing depth; the design life is a design basis, not a guarantee; Mosaic's announcement gives no basis for calling Esterhazy a failure of construction freezing. Living persons are described by their published work and the official record only. Subscribe and turn on notifications. Tell us in the comments: which part surprised you most, freezing the ground, building the permanent lining, or deliberately using water in a solution mine? #Saskatchewan #Potash #Jansen #BHP #GroundFreezing #Shaft #Esterhazy #Mining #Canada #Geography