Grupo Mexico is the world’s fourth largest copper producer and has a strong emphasis on operational efficiency and cost optimization. One of its affiliates, Mexicana de Cobre, operates the La Caridad mine in Sonora, Northern Mexico.

CHAPTER ONE

The most important part of the crushing process

The production process comprises 3 stages of crushing, followed by closed-circuit grinding, flotation, separation, thickening, filtration and tailings management. The mine processes 105,000 tons of ore per day, yielding more than 438,000 tons of copper concentrate per year

According to Alejandro Gámez, Plant Manager at Mexicana de Cobre, the tertiary stage is the most important part of the crushing process. In this final stage of crushing, twelve 84” Hydrocones crush the ore into a -½” feed for the grinding mills.

“By feeding the primary grinding mills with particles smaller than half an inch, we make sure that the grinding media inside the mills can break the ore efficiently, reducing the amount of recirculating feed,” he explains.

The tertiary stage is the most important part of the crushing process. By feeding the primary grinding mills with particles smaller than half an inch, we make sure that the grinding media inside the mills can break the ore efficiently, reducing the amount of recirculating feed.
Alejandro Gámez, Plant Manager at Mexicana de Cobre

CHAPTER TWO

Challenge: re-crushing lowered overall plant performance

However, ensuring a constant supply of the required -½” feed from the Hydrocone crushers proved to be a challenge. In Hydrocone crushers, the closed-side setting (CSS), which controls the size of the crusher’s discharge product, is limited by and adjusted through pressure. This sets special demands on the wear parts. The liners that Mexicana de Cobre was previously using could not fulfill the performance requirements until the end of their wear life. The output was too coarse for the mills and had to be re-crushed, which in turn lowered overall plant performance.

“The liners supplied by the previous manufacturer took a long time to be able to produce the desired -½” product. This had a negative effect on the capacity of the entire crushing plant and resulted in a lot of recirculating material,” Alejandro Gámez says.

CHAPTER THREE

Result: Higher throughput, more fines

To solve the problem, Mexicana de Cobre decided to collaborate with Metso. Ever since 2016, the Hydrocone crushers have been running smoothly and efficiently, yielding the -½” product.

“The optimized Metso liners that we are now using produce the right feed for the mills from the start. With these liners, the crushers can handle a higher throughput throughout the entire liner lifetime, they produce more fines, and the pressure remains more stable,” Gámez notes.

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There is a big difference in the efficiency at which the Metso liners generate the required product. “The previous liners were only able to operate at an efficiency of 35% for fines generation, whereas the Metso liners reach an efficiency of 60%,” the plant manager adds.

All this adds up to better overall performance of the comminution process. So far, the team at Mexicana de Cobre has been pleased with the results of the Hydrocone optimization project.

“The development work with Metso has already yielded very good results, but I think that if we continue the collaboration, we can achieve even better results,” Alejandro Gámez concludes.

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Solution

Chamber Optimization Program

Chamber Optimization is a long-term development program with proven results. The outcome is improved plant performance through crusher wear part development. Our global team of experts utilizes Metso’s unique simulation software and laboratory crushing capabilities to continuously design new, improved wear parts that truly match your ore, performance targets and current process circumstances.