The PI System enables sustainable operations at Goldstrike
- ChallengeA project to change the way gold is extracted at the Goldstrike mine created new complexities in operation, increasing potential environmental harm at the site.
- SolutionImplementing the Asset Framework allowed for real-time reporting of potential environmental incidents or deviations.
- BenefitsThe total number of deviations decreased, as did costs associated with deviations, and the mine’s social license to operate was maintained.
Faced with changes in the composition of gold ore at Barrick Gold’s Goldstrike mine in northern Nevada, the company established a new system for finding additional gold material to extract. But there was a problem: The new method posed environmental challenges. Thanks to the PI System, however, the company is able to operate more efficiently at Goldstrike while complying with strict environmental regulations. Considering that Goldstrike is the most prolific gold-mining district in the Western Hemisphere, that’s good news.
New process challenges operators
As Barrick Gold dug deeper and deeper at Goldstrike over time, the composition of the ore at the site changed. The ore contained increasing levels of total carbonaceous material (TCM), which more easily absorbs gold and gold cyanide complexes, making it difficult to recover gold. Once stockpiles of low-TCM ore ran low, Barrick Gold initiated a $610 million capital project, the TCM Leach Project. This initiative enables the company could leach ore in the presence of thiosulfate and resin, not cyanide, but the process could create more pollution if not monitored properly.
The new process using thiosulfate and resin is very complex compared to the cyanide process, said Ted Olsen-Tank, senior metallurgist with Barrick Gold. “There are numerous recirculating streams, each with their own complex sulfur-based chemistry.” In addition, the expansion doubled the amount of equipment, with minimal to no increase in manpower. Operators, spread out over the additional circuits, learned new maintenance requirements for all the new equipment. They are also responsible for design targets and monitoring temperature, pressure, concentration, and pH throughout the new process. But they found it challenging to ensure environmental compliance while monitoring it.
Making the new system meet environmental standardsTwo groups at Barrick Gold—the environmental and operations units—had to come together in a different way to adapt to the new process.
Goldstrike's environmental group, the official record-keeper, compiles reports for state and federal agencies from a web of interlinked Microsoft Excel files. “They’ve grown and evolved through the ages, and it just keeps building,” Olsen-Tank said. The records are produced days or weeks after the end of each month. The group’s work depends on information from the operations group, which does day-to-day environmental monitoring and reporting.
Before the expansion project, operators who had been running the circuits for many years knew what would cause a permit deviation. On the new system, however, it could take weeks before the environmental group heard about those deviations. “Luckily, I was learning about the new advanced features in the PI System,” Olsen-Tank said, “So, I built something to do something about it.”
Building a real-time reporting system
The main issue was an organizational and workflow disconnect. “The operations group was not able to identify when deviations were occurring in real time,” Olsen-Tank said. “Since they didn’t know a deviation had occurred, they couldn’t report on it. And that’s just not acceptable.”
At first, Goldstrike improved situational awareness by building dashboards that showed how hourly averages and current operational parameters compared to environmental deviation states. While it was accurate, Olsen-Tank said, the dashboard was “just another thing squawking in the busy control room. So we had to come up with something else.”
Benefits and future directionsWhen conditions before and after AF implementation were compared, the total number of deviations decreased by 45%, Olsen-Tanks said. In addition, total fan trips decreased by 61% in similar eight-month periods. In the future, Goldstrike plans to expand the system to other permits at Goldstrike and sister mines. It will also create text message Notifications for operators and revamp environmental record-keeping.
“For business purposes, we ensured our license to operate, which is an ongoing corporate initiative in the mining industry,” Olsen-Tank said. “From a management level, we shifted and streamlined the organizational structure. Operations now knows definitively when they’ve deviated. Once the record-keeping project is completed, engineers’ time will be freed up from performing paperwork, and they can focus on adding real value.”
For more information about Barrick Gold and the PI System, watch the full presentation here.