Case Study

A major iron mining company in Colima, Mexico, faced challenges with their ball mill operation. The mill, a massive 16.15 ft diameter, 35 ft long rotating cylinder weighing 907 tons, is a critical component in grinding iron ore into fine particles for further processing.

However, the existing motor control system presented significant safety risks and maintenance challenges:

• Safety Hazards: The traditional inching drive system, used for slow rotations during maintenance and liner replacement, relied on a complex mechanical clutch and gearbox. This posed a risk to workers, as unexpected movements could occur during maintenance procedures.
• Maintenance Downtime: The liner replacement process required a complete shutdown and cooldown of the mill, leading to substantial production downtime and lost revenue.
• Energy Inefficiency: The fixed-speed motor operation led to excessive energy consumption during periods of lower demand, impacting the mill's overall efficiency.

 Solution

To address these issues, the mining company partnered with Invertek Drives to implement the Optidrive P2 variable frequency drive (VFD). This advanced VFD solution offered precise motor control, enhanced safety features, and energy optimization capabilities.

The Optidrive P2 VFD was integrated with the ball mill's existing motor and gearbox system, providing:

• Automatic Inching Drive: The VFD replaced the mechanical inching drive, enabling smooth, controlled slow-speed rotations during maintenance. This eliminated the safety risks associated with the previous system and facilitated faster, safer liner replacements.
• Hoist Brake Control: The VFD's integrated hoist brake control function ensured secure holding of the mill at any position, further enhancing safety during maintenance.
• EthernetIP Communication: The VFD's EthernetIP capability allowed for seamless integration with the mill's existing control system, enabling remote monitoring and control for improved operational efficiency.
• Energy Optimisation: The VFD's variable speed control optimised energy consumption by matching the motor's speed to the grinding requirements, resulting in significant energy savings.

Overview

The implementation of the Invertek Drives Optidrive P2 VFD transformed the ball mill operation. This included enhanced safety through the elimination of the hazardous mechanical inching drive and the addition of hoist brake control significantly improved worker safety during maintenance.

In addition, the streamlined liner replacement process, facilitated by the automatic inching drive, minimised production downtime and maximised throughput.

The VFD's variable speed control also optimised energy consumption, leading to substantial cost reductions and a smaller environmental footprint. The EthernetIP communication enabled remote monitoring and control, providing operators with real-time insights and improved decision-making capabilities.

By addressing critical safety concerns, reducing downtime, and optimising energy consumption, the Optidrive P2 VFD proved to be a valuable investment for the Colima Iron Mill.