Testing old constraints against new conditions
By Tabetha Stirrett, President of RESPEC Canada and Vice-President of Mining & Energy
Recently, someone revisiting a potash project in the United States asked whether RESPEC still had the drill core from work completed more than a decade ago. We did. The drill core had been in storage since about 2014, along with the geological information and project history gathered at the time. The project had been quiet for years, but someone was revisiting the opportunity.
I’m starting to see this pattern in potash. Properties explored during the potash rush of the late 2000s and early 2010s are attracting attention again, sometimes with new investors, different economics, or a new idea for how the resource might be mined.
For anyone bringing one of those projects back into consideration, having history to work from is an advantage. The old drill results, technical reports, and project data show information about the deposit and where earlier plans encountered difficulty.
I tend to come back to one rule: the rocks don’t lie. If a project looks more attractive 15 years later, the geology gives us a starting point. From there, the job is to understand what has changed and whether those changes are enough to produce a different result.
Start with the old constraints
A technical report from 2008 or 2009 may contain economics that no longer apply, but the geological interpretation, drill results, and challenges identified during the original evaluation can still be highly relevant, even when the environment around them has changed.
Potash prices and demand have moved, development costs have shifted, and new production can alter the competitive picture. Infrastructure, processing, and the route from mine to customer may also look different from early assumptions, which makes the old constraints a useful place to start. If access to the market weakened the project before, has that improved? If the mining method carried too much cost or technical risk, does the current plan address it? The point is to connect the renewed opportunity to a real change in the development case.
Investors have asked us to review resurfacing projects and provide a perspective on proposed mining methods and development assumptions. In those situations, years of project data—and occasionally even the original core—allow us to begin with the questions the project has already raised instead of rediscovering them.
When a new method earns its place
Selective horizontal solution mining is one example of how a new approach may change the conversation for certain deposits. The method aims to recover potassium chloride selectively while leaving the salt underground, potentially addressing technical or economic constraints where the geology and operating conditions are suitable.
The question is how much uncertainty the project has to carry to get there. Drilling can be more complex and expensive, and questions remain regarding commercial scale. A method that performs technically still has to support the production levels and costs assumed in the business case.
That may favour a staged approach in some cases. Production could begin with a method with a longer operating history and introduce newer techniques as the operation develops, and their performance becomes better understood. Processing requirements may limit that option, but it allows innovation to be tested against the realities of the project rather than asking the entire development case to depend on it.
And those realities extend beyond the mining method. Potash still has to be processed and moved to a customer. Rail capacity, port access, transportation costs, and a practical route to market can change the development case before the resource ever reaches production.
The same question at mature mines
The need to reassess old assumptions is also showing up at established potash operations. Across mature North American districts, producers are working with deeper deposits, higher costs, and fewer experienced people carrying decades of operating knowledge. Some mines have been productive for 50 or 60 years, and the conditions ahead will ask different things of them.
That need is changing the technical questions producers are asking. Rock mechanics and modeling can help determine how far extraction ratios can reasonably be pushed while maintaining safe operating conditions. Solution-mining operations look for ways to improve recovery, while ideas used elsewhere in industries outside mining may offer another way to approach constraints that have become more difficult with time.
In that sense, mature operations and resurfacing projects deal with a similar challenge. Both have a history to work from, and both have to decide which assumptions still hold. For a project being revisited, we look first at its previous limitations, then ask what has materially changed in the current plan. Changes may be the mining method, the processing approach, infrastructure, market access, or the economics surrounding the resource.
The rocks don’t lie; they give us the baseline. The judgment lies in determining which changes are substantial enough to support a different answer, which is where historical knowledge, current technical evidence, and a clear view of market and infrastructure conditions become most valuable.
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