By: Paul Neufeld, P.Eng., Project Manager, Gensource Potash Corporation
Dear Editor,
In response to the article titled “A Tale of Tailings” in the March/April 2017 issue of The Professional Edge (Issue 167), one strategy of proactive tailings management was absent from your discussion, particularly under the section “Potash Searches for Solutions.” What if potash tailings were not created in the first place? The concept of no tailings is truly an “outside the box” approach to tailings management, and that is exactly what Gensource Potash Corporation is intending to achieve through the application of the selective solution mining technique.
Gensource’s Vanguard One project, which is currently nearing completion of the feasibility study stage, will employ a selective solution mining technique referred to as “selective dissolution.” Selective dissolution mining of potash consists of using an almost NaCl (salt) saturated solution to selectively dissolve KCl (potash) from a potash bed (sylvinite ore) within a solution mining cavern. There are no salt tailings or brine ponds required for selective dissolution mining, as NaCl is not produced. Without a salt tailings pile, there is no need for brine retention ponds, and therefore no brine containment structures whatsoever. Also, since the mining solution is almost saturated in NaCl, process and mining water can be obtained from brackish groundwater sources. While these mining methods are new to the province, they are by no means untested as they have been in continuous use for over a decade in the United States. In fact, the “secondary mining” component of the conventional two-well solution mining method patented by Edmonds et. al. (US Patent No. 3,096,969) as currently employed in Saskatchewan, is a batch mode implementation of selective dissolution.
In my opinion, this is an innovation that is worthy of more attention because of how it revolutionizes environmental liabilities and long-term challenges currently faced when dealing with potash tailings. As such, I believe the application of selective solution mining to be THE most promising approach when it comes to potash tailings management.
Paul Neufeld, P.Eng.
Project Manager, Gensource Potash Corporation