JOHANNESBURG (miningweekly.com) – Global construction and mining equipment manufacturer Caterpillar (Cat) has launched the first continuous mining and hauling system for underground hard rock applications, now commercially available.

The new Cat Straight System features a hard rock shearer that uses Cat-activated undercutting technology specifically designed for the extraction of bedded hard rock deposits.

A low-profile hard rock chain conveyor and hard rock hydraulic roof supports complete the system, which delivers simultaneous cutting, loading and hauling—controlled by the Cat longwall automation system.

The system is designed to replace conventional drill-and-blast operations in low-heights environments, ranging from 1.3 m to 2 m, as well as in bedded deposits such as certain types of platinum, copper and gold deposits.

Additional benefits of Cat’s Rock Straight System include reduced health and safety risks. The electrically powered rock cutter and hard rock conveyor have no exhaust emissions, and there is no need for explosives use in the production cycle.

Further, compared with conventional hard rock mining, fewer people are needed underground, while remote control places the operator in a climate-controlled cabin.    

Meanwhile, the undercutting machine, the HRM220, which depends on this Cat-activated technology, enables picks to attack the rock from an improved angle to exploit its tensile strength. The activation movement improves the velocity, momentum and impact of each pick while moving the pick away quickly to decrease wear and heating.

The result is reduced energy consumption and the replacement cost of cutting tools.

The HRM220 incorporates electronic modules that enable control, monitoring and protection of the miner.

Remote operation and diagnosis of major components can be done from the operator cabin through on-screen information.

Cat’s HRC30 hard rock conveyor’s newly developed apron face conveyor is low profile and designed to transport rock in low cutting heights.

A single flight bar chain moves the apron pans across the length of the cutting face as they ride on the line pans. The apron pan system ensures reduced wear when moving abrasive rock.

The durable conveyor uses high-strength steel for long service life and reliable operation. Its haulage capacity is 160 t/h.

Meanwhile, Cat engineers designed the HRS1220 hard rock roof support specifically for the Rock Straight System.

Based on proven longwall roof support designs, the two-legged shield incorporates a solid base connected with an advancing mechanism on each side of the base.

The supports feature a working range of 1060 mm to 2155 mm with a yield load of as much as 2599 kN.

Cat’s PMC-R electrohydraulic control system provides advanced roof support automation. It has proven to be flexible, reliable and productive in mines worldwide. In addition to improving productivity, the system also provides equipment monitoring and remote diagnostics.