When it comes to extracting potash from the ground, companies have two options available: conventional underground mining and solution mining.
But deciding which mining method to use isn’t as simple as flipping a coin, it all comes down to the geology of the deposit.
Below we will have a brief look at why companies choose solution mining and the process.
Why solution mining?
While conventional mining seems like the way to go, when it comes to potash, this mining style has its limitations because if potash reserves are found deeper than 1,000 meters.
Potash found at depth in sedimentary rocks is a prime candidate for solution mining as sedimentary rocks tend to collapse when they are dug too deep, and deep mine shafts are also prone to flooding due to the porosity of these rocks. That said, solution mining provides potash companies with a cost effective, and efficient way to process their resource with the added benefits of lower up-front capital cost and a shorter ramp-up time.
The solution mining process
Unlike conventional mining which involves moving tons of dirt to access a mineral resource, solution mining requires boring injection and recovery wells into the ground. From there, a heated brine solution is injected into the deposit, which dissolves the potash salts. The dissolved salts are then pumped out of the cavern to the surface where the water is evaporated, either artificially or in solar evaporation ponds leaving behind salt and potash.
After a company has successfully brought their potash minerals to the surface, and separated out the water, the process to the final product is the same for either conventional or solution mining.
Which companies use solution mining?
While many potash projects are able to be mined through conventional mining, there are quite a few projects that are mine via solution mining.
As the world’s largest potash producer, Potash Corp has both conventional and solution mining projects. The company’s Patience Lake Mine was originally an underground operation, however, it was converted to a solution mine in 1998 after flooding hampered conventional mining operations.
In 2015, Mosaic operated three potash mines in Canada, including two shaft mines with three production shafts and one solution mine. The company also operated one potash shaft mine in the US. Construction of Mosaic’s new Saskatchewan Potash operation, Esterhazy K3, remains on budget and on track to start producing in 2017.
Intrepid Potash supplies approximately 9 percent of the US’s annual consumption of potash. In May, the company released its first quarter 2016 results, reporting a net loss in the first quarter of $18.5 million, compared to a net income of $6.5 million in 2015. They also announced a plan to idle mining at its West facility, located in Carlsbad, New Mexico. The facility generated 42 percent of Intrepid’s potash production in 2015, and is expected to transition to care and maintenance in July.
Western Potash is currently focusing on building a solution mine on the Milestone Property in southern Saskatchewan. The company announced in April that its wholly owned subsidiary, Milestone Potash, awarded the engineering services agreement to Amec Foster Wheeler for the next stage engineering of the Milestone Pilot plant project.
Karnalyte Resources is engaged in the business of exploration and development of agricultural and industrial potash and magnesium products. The company owns a 100 percent interest in the Subsurface Permit KP 360A and Subsurface Mineral Lease KLSA 010. The Wynyard Carnallite Project is an exploration and early stage pre-development property with potassium-containing minerals.
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