Ananda Wunschel presents a case study showing how a mine is lifting productivity with hydraulic drives
Eti Bakır is Turkey’s most comprehensive mining and metallurgical operation. The company’s underground copper mine in Küre is also Turkey’s most productive, combining superior yield with low production costs. Hägglunds hydraulic direct drive systems, which power the site’s critical belt conveyors, make a key contribution to that success.
Driven by electrification and the green economy, the global demand for copper has increased dramatically in recent years. Eti Bakır’s mine in Küre is an important source of supply, boasting almost 60km of tunnels that reach a depth of 960m. Each day, the mine produces 4,000-6,000 metric tons of copper ore, amounting to a yearly capacity of 1,600,000 tons.
To protect those high volumes, Eti Bakır’s operations are both modern and forward thinking. “Just doing the regular maintenance isn’t sufficient to guarantee an efficient flow of copper ore,” says Kazım Küçükateş, production and planning coordination manager at Eti Bakır. “It’s correct equipment with high quality that safeguards continuity in production.”
That philosophy is exactly what led Eti Bakır to Hägglunds hydraulic drive solutions in 2014.
No Time For Costly Production Stops
The Küre mine has a main shaft that is 600m deep, through which all of its ore exits. The ore is brought to the surface by means of a bucket system, which is able to lift 12 metric tons at a time. A belt conveyor, measuring 160cm wide and 52m long, delivers the ore to the shaft and loads it into the bucket. If either conveyor or bucket should fail, no material would be able to leave the mine.
Unlike most belt conveyors in Turkey, this one is equipped with a gearless hydraulic drive system, rather than an electromechanical drive. Eti Bakır made the choice carefully, based on the conveyor’s importance and a firsthand look at a Hägglunds drive solution.
“Any unwanted production stop will result in expensive losses for the company,” says Küçükateş. “Küre has a project lifetime of at least 20-25 years, so we made a longterm investment in a drive that rarely needs maintenance. After seeing a similar Hägglunds system working problem-free at a Finnish mine, we realised that this was exactly what we wanted. The initial investment may have been higher, but we can be sure this drive system will always work.”
High Precision, Low Drive Maintenance
Naturally, the drive solution has had immediate benefits as well. The fully variable speed, combined with automation, allows Eti Bakır to use Küre’s bucket lifting system to the fullest.
“The drive system interfaces with our upper-level automation, and the variable speed lets us stop the conveyor exactly where we want it to stop,” says Küçükateş. “We can run the conveyor at 0.35m/s up to a first weighing point, for example, then continue moving it at 1m/s to stop at a second weighing point. Then, if our control system gives the approval for the load, the speed can be increased to 3m/s for loading into the bucket. Afterwards, the cycle begins again.”
Küçükateş notes that this would be difficult to achieve with an electromechanical drive system. Not only would it be complex, the solution would also require far more maintenance.
“Hägglunds systems need less maintenance than a system with an electric motor, gearbox and frequency converter,” he says. “Our conveyor drive needs very little maintenance at all, and it’s easily planned hydraulic maintenance that can be done without any problem.”
Always Moving – Even When Over-Loaded
What Eti Bakır is most keen to avoid is an expensive production stop, caused by an unpredicted failure. Although the company keeps an additional Hägglunds motor and hydraulic pump in stock at the Küre mine, no unplanned stops have occurred since the drive system was commissioned in 2015. This is a notable contrast to previous conveyor drive solutions.
“We used to drive long belt conveyors with gearboxes and hydraulic couplings,” says Küçükateş. “Those systems had problems once a week, which negatively impacted our transportation of ore. Sometimes a conveyor would become overloaded, and the old systems didn’t have enough torque to get started at low speed. We would have to empty the conveyor with shovels before it could move, which led to big production losses.”
With the Hägglunds drive solution, things could not be more different. Because of the drive’s high starting torque, which can be maintained for an unlimited time, moving a belt conveyor is no issue – regardless of the speed and load.
“If the conveyor is overloaded, we can switch the drive into manual mode to solve the problem,” says Küçükateş.
“Using the infinitely variable speed, we can move ore into the bucket at any speed we need to. We can load the bucket without failure, and the bucket itself is neither overloaded nor underloaded.”
A Drive Solution Worth Repeating
Based on the high reliability, Eti Bakır has continued to invest in Hägglunds conveyor drives. With the Küre mine growing deeper, a new belt conveyor was added at 475m depth in 2021. Like the conveyor in the main shaft at 200m depth, this one is powered by a Hägglunds hydraulic solution. Moreover, Eti Bakır has taken the drive concept beyond Küre.
“Eti Bakır has invested in a new underground mining site in Siirt, where the ore is also being lifted from a shaft,” Küçükateş explains. “We’ve chosen a Hägglunds drive system again, because we know the solution works without issue and meets our requirements when it comes to automation. I know, for sure, that we can always reach our daily goals regarding the tonnage to be transported.”
“I’m convinced that long belt conveyors require an alternative solution to traditional drives,” Küçükateş concludes. “Whenever we invest in a new underground mine with a shaft, we’ll be using Hägglunds again.”
Ananda Wunschel is with Hägglunds