CMD Gears enables mills to operate under challenging conditions

The mining industry relies heavily on efficient and reliable equipment to process large volumes of ore and mineral resources. One critical component in this ecosystem is the grinding mill, which plays a pivotal role in comminuting materials to prepare them for further processing. Grinding mills, particularly the large semi-autogenous (SAG) and ball mills, often operate under challenging conditions that demand precision, durability, and adaptability. A key technology enabling these mills to operate safely and efficiently is the hydraulic inching drive system.

“Hydraulic inching drives are auxiliary systems that provide precise, low-speed operation of large grinding mills during maintenance, inspection, and troubleshooting activities. They complement the primary mill drive systems, which are typically designed for normal operations,” said Victor Manoury, sales engineer at FCMD North America, a company of Groupe CIF along with CMD Gears & Ferry Capitain.

Why Are Inching Drives Necessary?

Grinding mills in the mining industry are massive structures, with diameters that can exceed 40 feet and weights reaching hundreds of tons. Operating and maintaining these mills present unique maintenance challenges.

“Tasks such as replacing liners, repairing internal components, or inspecting the mill require precise positioning and rotation of the mill shell. For safety, inching drives allow controlled movement of the mill, minimizing the risk of accidental overspeed or uncontrolled rotation during maintenance,” Manoury said. “During initial installation or post-maintenance alignment, inching drives enable precise positioning of components such as pinions and ring gears.”

How Hydraulic Inching Drives Work

The hydraulic inching drive consists of several components working together to provide low-speed operation:

Hydraulic Motor: This motor converts hydraulic energy into mechanical motion, enabling the slow rotation of the mill.

Portable Hydraulic Power Unit (HPU): The portable power unit supplied pressurized hydraulic fluid to the motor, controlling its speed and torque.

Gearbox: The inching drive includes a high-reduction gearbox to achieve the necessary torque at low speeds.

Control System: An advanced control panel allows operators to regulate the speed, direction, and duration of mill rotation, either from the main cabinet of the HPU or from a remote control.

Brake System: Hydraulic inching drives incorporate robust braking systems to securely hold the mill in position when not in motion.

Engaging/Disengaging Mechanism: The system is equipped with engaging and disengaging systems, hydraulically controlled and operated, to transition from normal operation to inching mode.