For more than 150 years, Engineering & Mining Journal (E&MJ) has kept mining executives and mining engineers informed. Many mining executives are mining engineers that have been promoted through the ranks and they have been familiar with E&MJ, if not avid readers, most of their careers. In the boardrooms of today’s mining companies, mining executives with engineering backgrounds debate investment decisions with financial types as far as the scope of projects in terms of both the scale and cost. When a specialized engineering discipline intertwines with business acumen, the results can be surprising.

Engineers by nature are problem solvers. They are not expected to know everything, but they are expected to know how to find the answers. One of the things that sets mining engineers apart from other disciplines is that they map the face with laser precision and then they extract it with a blast. The rock may or may not be uniform in size and the geology will likely change. So, they need to learn how to deal with variability, be able to accept change, and sometimes learn on the fly.

There is an old expression: there’s never time to do it right, but there’s always time to do it twice. The lesson, of course, is that doing it twice is much more costly (time and money) than doing it right the first time. Oftentimes, engineers do not have the courage to send up a flare and question a process once a project starts, only to realize in hindsight that it would have been the right call. That’s what makes this American Mining story on the POA 11 expansion at Coeur Mining’s Rochester mine so interesting. The project involved building a 1-mile-long crushing corridor to feed the world’s largest leach pad here in the USA, where anything related to mining seems to take forever. It kicked off during COVID-19, which is a story unto itself.

After initial construction was underway, they discovered the orebody properties varied from predictions and the result was more fines, which could be problematic for downstream processes.

Coeur made the decision to take a revenue-generating portion of the project offline and run some tests with secondary and tertiary crushing systems. These tests led to a decision to invest an additional $100 million in an unplanned prescreen facility to manage the additional fines. This decision along with inflationary pressures drove costs higher and extended the project’s timeline. The company had to get creative with financing to bring the project across the finish line, which they did. Rather than forging ahead with the original plan, they likely saved themselves years of headaches by making a difficult and financially costly call early in the project’s timeline, which will now pay dividends in the future.

Steve Fiscor, Publisher & Editor-in-Chief, E&MJ