In the years since the last super cycle ended, many mining companies have turned their focus to optimization.

It is the logical approach: Maximize recoveries from existing mines now, and resume new site explorations once commodity prices rebound. But the push for optimization also comes at an especially opportune time. Advances in control technologies combined with the move toward “smart” or connected mines are helping mining companies see into their operations and refine overall process control like never before.

Perhaps the most essential element in any mine-optimization effort is a modern distributed control system (DCS).

A modern DCS connects all aspects of a mining operation – from the extraction site, to material transportation, and finally down to processing and refining. This mine-wide control approach does away with many of the hassles associated with using multiple, unconnected systems for disparate or distant areas. When operations are not controlled by a single, unified control system, data sources become siloed, materials can be hard to track across vast locations, and processes can become difficult to synchronize.

A modern DCS helps ease all this. It enables centralized control and breaks down data silos – thus creating one version of the truth – across an entire mining operation.

Standardized control & information

A modern DCS unifies in a single platform specific capabilities in separate, independent systems. These capabilities include integrated process, discrete and motor control – benefits mining companies have been using for decades. It can scale to the requirements of any mine while also providing a highly reliable architecture, the performance and reliability that mining operations demand. It provides a deep set of standardized process-control programming functions that creates access to comprehensive plant and operations information from anywhere within the operations.

A modern DCS uses common control hardware, workstations and servers and has a standardized application layer. This creates a common data platform to avoid sorting through and synchronizing disparate data sources – instead, operators can access a single source of the truth that runs across the entire mining enterprise.

Upon implementation, a modern DCS can bring a mining operation to a high-performing steady state, dramatically increasing the productivity of the mine. From there, advanced control technologies, such as model predictive control (MPC), can be applied to get additional yield and productivity.

Platinum producer improves visibility with DCS

For a sense of what a DCS can do, the world’s largest platinum-mining company provides an example.

South Africa’s Anglo Platinum annually processes nearly 40 percent of all newly mined platinum. The company was recently experiencing challenges with the aging process control system at its precious metal refinery. The system was unable to meet needs of complex processes, was difficult to update due to multiple vendors, and required a specific skill set.

As a result, the company wanted to upgrade the control system to satisfy its complex refining process for the next 10 to 15 years.

After implementing the PlantPAx* modern DCS from Rockwell Automation and scaling it to the refinery’s specific requirements, Anglo Platinum gained access to real-time process data. Operators are now able to use this data to track recipes in real time, including comparing batches and key performance indicators, and identifying if and when a batch is deviating. They can then make adjustments as needed.

“Our operators have gained valuable information to help them understand why a certain batch took 20 hours to produce when it was supposed to take 16 hours,” said Hermanus du Preez, control technology specialist for Anglo Platinum. “This improved visibility enables us to identify constraints in the refinery’s processes that we weren’t always aware of before.”

The new system also has reduced batch variability with insight into processes. Because it was a single-vendor system, it has also eased implementation and customization to meet the company’s unique process requirements.

*PlantPAx® is a trademark of Rockwell Automation® Inc.

Optimizing the mine

Compared to a more traditional control approach, a modern DCS can make mining operations more efficient, improve productivity and drive down risk.

A good example is the use of disparate control systems for separate areas of a mine, which can prevent those areas from talking to each other. Consider the damage that can occur when events at a processing site are largely unseen by operators at an excavation site. If that processing site goes down, it can result in costly, unexpected backlogs on a material conveyor and grind excavation operations to a halt.

With a modern DCS, however, information from any point in a mine can be instantly shared with stakeholders elsewhere. Site managers and operators can see what is happening in real time, and make any necessary adjustments should a process disruption occur.

A modern DCS also can provide better visibility into equipment performance to help reduce downtime. For example:

  • Smart flowmeters can detect failures and errors. They can also spot questionable process issues like partial flow resulting from a blocked or leaking pipe.
  • Visibility into an intelligent motor control center can reveal abnormalities, like high current on a pump, and indicate equipment or process problems before severe damage occurs.

Issues like these can easily go undetected or generate false readings in conventional systems, leading to failures that are time-consuming and difficult to troubleshoot.

Quality management is another area where better visibility can make a big difference. In most mines, excavation sites want to feed processing plants a stable ore grade. But tracking multiple stockpiles that all have different yields can be difficult. A modern DCS can help manage this complexity by tracking large volumes of material and their different yields through the entire production process. This makes a consistent quality much easier to achieve.

Beyond these operational benefits, a modern DCS also can help reduce total cost of ownership. By standardizing technology across a mine, a modern DCS can reduce the life cycle costs associated with engineering, inventory, training, maintenance and future system expansions. The system also can collect energy-usage data to help mining companies build an energy-management strategy.

After the rebound

As commodities begin to recover, mining companies will shift their focus from existing mines to new mines.

Typically, part of the planning process for a new mine includes scheduling a control system overhaul every decade or so. These overhauls can require a full shutdown of the mine, and a complete rip-and-replace of the control technology.

A modern DCS, however, can operate in a constant state of renewal. Individual systems can be replaced as they each reach their end of life – and predictive diagnostics can be used to provide advance notice as they near that endpoint. They can also be upgraded as performance requirements change.

This can help minimize downtime in a mining operation, as well as eliminate costly and time-consuming infrastructure overhauls. It further drives home the point that a control system, while only accounting for about 1 percent of total capital expenditures in mining operations, can have long and lasting impacts on a multibillion-dollar mining operation.

Hein Hiestermann is director of Global Industry Metals, Mining and Cement, Rockwell Automation. In his role, Hein is responsible for delivering consistent and leading-edge technology to mining customers globally. Hein began his career in 1988 at Gencor in South Africa, where he worked in gold, platinum and coal mines as an E&I engineer, control engineer and later as a consulting engineer. In 1997, he became the principle at HIPROM, a systems integrator. Hein joined Rockwell Automation when HIPROM was acquired by the company in 2011. Hein has a degree in electrical engineering.