Solution Mining in Canada
With Potash One, K+S has acquired several potash exploration licenses in the Canadian region of Saskatchewan. The Legacy Project currently under development is part of one of these licenses, with production scheduled to begin by summer of 2016. The verified reserves of this deposit are 160 m tons KCl product (KCl = potassium chloride)
Production will be based on solution mining technology, which in comparison to traditional extraction offers greater utilization of the deposit.
Our Graph of the Month illustrates the two-step process of extracting potassium chloride by using extraction mining.
Solution mining necessitates the drilling of two boreholes, down to a depth of approximately 1,600 meters, and to points 80 meters apart. One of these boreholes is used to inject solutions. The liquid dissolves the crude salt from the deposits, and gathers in underground caverns. The liquid introduced into the caverns displaces the generated brine, which is then transported to the surface by another pipeline.
The First Step - Primary Mining
- The graph shows a cross section of the deposit in Saskatchewan, Canada.
- For so-called primary mining, fresh water is pumped into the KCl-rich deposit Esterhazy, via borehole. The connection between the two boreholes via cavern is initially created by solution mining of sodium chloride (NaCl): An underground cavern created is filled with a solution of water and salt. This is represented as a blue area in the chart. Step by step, the three potash deposits are solution mined in horizontal layers, up to a width of 3 meters at a time. Vertically, this process is controlled by an oil barrier (a thin layer of oil on the brine).
The Second Step - Secondary Mining
- Secondary Mining makes use of the NaCl-saturated brine in order to expand the cavern to its maximum size, by using selective KCl-solution processes.
- In addition to its lower energy consumption, Secondary Mining is much more efficient in terms of water use – in comparison to Primary Mining.
For more information on the Legacy Project of K+S in Canada: