Skip to Menu Skip to Search Contact Us Finland Websites & Languages Skip to Content

SGS has designed specific comminution tests, such as the Static Pressure Test (SPT), to measure the energy required for High Pressure Grinding Rolls (HPGR). The amount of energy needed for grinding is an important control to the economic viability of your project.


SPT* is used to estimate the energy needed to achieve a specific grain size reduction by HPGR. The test measures the energy consumed when crushing a dry sample of ore in a steel sample container using a hydraulic press. The test is run in closed circuit to generate a product that is 100% passing 6 mesh (3.35mm).

The High Pressure Grinding Index (HPG) is determined from the 80% passing value of the feed and product sizes and energy used in breakage. The HPG Index can be determined at a range of pressures and is used to show the ore body hardness profile. Throughput in commercial units is predicted after plant calibration.

Feed Sample Requirements:
At least 7 kg of passing 3⁄4” ore (with no more than 80% passing 1⁄2”).

SGS's team of experienced engineers will conduct the SPT in combination with other bench-scale tests. These data can then be used to simulate grinding circuits. The use of such methodologies provides you with a bankable solution that is unmatched in its rigor. Contact us to determine your energy requirements.

*Bulled D. and Husain K., (2008) "The Development of a Small-scale Test to Determine Work Index for High Pressure Grinding Rolls", in Proceedings of the 40th Annual Canadian Mineral Processors Conference - 2008.