Solution Mining Technology

The principle of solution mining involves drilling a large-diameter borehole to the bottom of the targeted carnallite layer, which in this application is at a depth of about 400 to 900 meters.

Heated water is introduced into the well into a thin layer of carnallite below the lowest carnallite layer to be mined for production. The water preferentially dissolves the carnallite, and expands laterally through the layer of the highly soluble carnallite. A second adjacent extraction well is then connected to the first forming a dual well cavern with a diameter of approximately 100 meters. The injection and extraction well pipes are raised from the bottom carnallite layer to start production leaching in the higher layers.

Returning water (brine), enriched in magnesium potassium and sodium chlorides, is recovered and processed at the plant for product crystallization. The rate of mining, cavern shape, and preferential separation of various salts are determined by changing the positions of the inflow pipe at the well, the location of the brine return in the extraction well, as well as adjusting the flow rates and the level of a non-reactive cover blanket.

This high-tech mining technology is accomplished by continuous blanket interface measurement and other techniques to monitor cavern shape and solution concentration.

This brine mining program, which will be conducted by an experienced engineering team will control the shape of each mined cavern, and the wells will be spaced to virtually eliminate any possibility of surface subsidence. When finished, spent caverns are filled with surplus NaCl and MgCl2 brine from the crystallization plant to provide long term stabilisation of the abandoned caverns.

This mining technology has an extremely low impact on the environment. Well-heads and piping systems to the processing plant are the only surface infrastructure. At a similar plant in Germany, these wells are located within cultivated fields and livestock pastures.

The solution mine well field will only utilise approximately 8 square kilometers which is sufficient to supply the Mengo potash plant for 20 to 25 years of production. MagIndustries’ Mengo permit covers approximately 136 square kilometers, which is virtually all underlain by thick continous carnallite horizons.