Metso is set to provide an HRC-3000 for Freeport-McMoRan Copper & Gold's Morenci copper mine in Arizona, USA. This HRC™, which will be the world's largest machine of its kind, is Metso's new concept in high pressure grinding roll (HPGR) technology. The HRC-3000 will perform tertiary crushing in the comminution circuit, which includes crushers and ball mills (also supplied by Metso) and will provide a highly efficient solution for this application. The HRC's ability to meet the demands of this application is a result of its innovative design, which improves throughput and efficiency of the existing HPGR technology. Over 8000 hours of testing including 4000 hours in a pilot plant operating at Morenci have proven the design and efficiency of the HRC.
Design features include patented arch frame to eliminate downtime and flanges to maintain wear and increase throughput. Metso's patented arch frame creates an even gap setting across the width of the tires, limiting skewing that results in downtime for mining operations. This anti-skewing arch frame also prevents damage to the roller bearings (caused by misalignment) that often occurs with the traditional HPGR design. Used in place of spring-loaded cheek plates, flanges help maintain even pressure while crushing ore. This even pressure minimizes the amount of material that bypasses the crushing zone, enabling greater circuit capacity and increasing overall crushing efficiency. Addition of the flanges also distributes even wear on the surface of the tires, providing an increased life for the machine's most significant wear part. The above design changes were implemented precisely for the type of application in which the HRC-3000, scheduled to be online by early 2014, will be operating: high-tonnage tertiary crushing of hard rock. And the incentive for operators – thanks to improvements in efficiency at increased throughput – is cost savings.