High Pressure Grinding Roll (HPGr) technology has been accepted as an energy efficient alternative to conventional comminution circuits in the mining industry. There are, however, aspects of this technology that can be improved to enhance efficiency. Edge effect is a common problem associated with HPGRs. Edge effect is a general industry term that describes a condition of impaired comminution performance at the edges of the tyres due to a reduction in crushing pressure. In open circuit operations, this effect results in coarser particles reporting to downstream equipment, increasing the demand on these machines. In a closed circuit application, edge effect will result in an increased circulating load and diminished HPGR circuit capacity.
This paper will discuss how edge effect was significantly reduced through innovations in the HrC™ HPGr design, which incorporates an Arch-frame and a flanged tyre solution. Lab scale testing showed flanges provided a more consistent pressure distribution across the width of the tyre, allowing for better particle breakage at the edges of the tyre. Through a series of pilot plant tests comparing a 750×400 mm HPGr with flanges versus the same HPGr with traditional cheek plates, the introduction of flanges reduced the overall specific energy by an average of 13.5% and lowered the circulating load by an average of 24%, while increasing the specific throughput by 19%.