Indonesian mine brings DCS into current era

Oct. 23, 2019

“The crater is so wide it’s not feasible to mine from the surface any more.” PTFI’s Bendang Sameto explained how things are changing at the Indonesian mine during a presentation at Innovation Days in Austin, Texas.

It’s the end of more than one era for PT Freeport Indonesia (PTFI).The mining company, which produces concentrates containing copper, silver and gold, is transitioning from surface operations to move underground, even as it wraps up a methodical, 17-year modernization program for its automation and control systems.

“Our primary mine is the Grasberg surface mine in Papua, Indonesia,” explained Bendang Sameto, APC engineer at PTFI, in a presentation about the mine’s various upgrades at this week’s Schneider Electric Innovation Days in Austin, Texas. “It will be closed, and we will move our mines underground. The crater is so wide it’s not feasible to mine from the surface any more.”

This transition to a completely underground operation comes on the tail end of a control-system modernization that has already spanned nearly two decades. The operation includes crushers and equipment to transport the crushed ore to stockpiles. After crushing and grinding and converting to slurry, it’s then transported to a pipeline, which carries it to a dewatering plant portside, where it’s readied to be sent by ship. Throughput topped out in 2001 and again in 2009 at 238,000 tons per day on average.

During that span, the company embarked on a modernization program to bring legacy Foxboro DCS system components up to the current EcoStruxure Foxboro DCS standard. DCS workstations and software were modernized, and new enclosures added. The 12-node local area network (LAN) was upgraded to fiberoptic. Controls were upgraded from CP40A controllers to Field Control Processors 270 (FCP270) with Field Device Systems Integrator (FDSI) modules.

“We now have 800 Fieldbus Modules (FBMs) installed,” said Ade Jaya, control systems leader at PTFI. The Grasberg mine also includes 8,000 field wiring terminations, 950 control loops, about 6,000 calculation blocks and 730 operator graphic displays.

DCS modernization needed

The DCS upgrade objectives were to improve workstation reliability and maintainability, reduce or eliminate network-related problems and upgrade infrastructure to support new projects.

The first task was to evaluate and upgrade workstations in six different styles running various software versions. “Many workstations dated from the early 1990s,” said Jaya. “Spare workstations and components were no longer available for older workstations, which are not capable of running the current-system software, which fixes many bugs in the version we were running.”

Refurbished workstations were purchased and older ones were upgraded to a common standard with a system software upgrade, as well. Network issues such as missing terminators, improper grounding, dirty cabinets and damage from welding sparks were identified and corrected.

“We migrated from LAN to a mesh network, which can route around multiple faults,” said Jaya. Additional nodes were brought onto the mesh network, and the fiberoptic infrastructure was improved.

The older controllers and gateways were upgraded because of end-of-life issues and limited capabilities. “As I/O points increased and control loops became more complicated, some of these controllers had become overloaded,” said Jaya.

Schneider Electric’s current offering of controllers and workstations all require a mesh network, he added. “Establishing a good network design ensures total flexibility into the future,” said Jaya. For example, it has allowed PTFI to upgrade its FCP270 controllers to FCP280s—current state-of-the-art for the Schneider Electric EcoStruxure Foxboro DCS.