Jul 13, 2016 As indicated by Kapur et al. (1992), high-pressure roll grinding is likely to replace ball mills in increasing numbers in the near future. Polycom Amenability Tests for Gold Ores. Krupp Polysius has developed a rapid and effective test for evaluating a Kppern Specialists in High-Pressure Comminution 7 Improved Cost-Efficiency High-pressure grinding roll presses (HPGRs) are emerging as an important comminution technology in the minerals processing industry. The technology has found its key application in the liberation of diamonds and also in primary comminution.