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In most mines, the grinding circuit is either the largest or second largest capital investment.


With the emergence of low grade – high tonnage operations, this is especially true because economics dictate the use of the largest milling equipment to maximize economy-of-scale. It is important to be confident in your grinding circuit design, without arbitrary safety margins, to ensure positive project economics.

SGS has a proven solution for grinding circuit design, optimization and production forecasting during development or operations.

In the early stages of a project, bench scale tests are used to characterize ore samples.

Bench Scale Tests

  • Modbond Grindability Test
  • Abrasion Test
  • Bond Ball Mill Grindability Test
  • Bond Low Energy Impact Test
  • Bond Rod Mill Grindability Test
  • High Pressure Grinding Rolls (HPGR)
  • Isamill Evaluation
  • JK Drop-weight Test
  • Laboratory Comparative Work Index
  • MacPherson Autogenous Grindability Test
  • Point-load Test
  • Rock Quality Designation (RQD)
  • SAG Mill Comminution (SMC) Test
  • SAG Power Index (SPI) Test
  • Static Pressure Test (SPT)
  • Triaxial Test and Uniaxial Compression Test

For subsequent design simulations, the Comminution Economic Evaluation Tool (CEET®) and JK SimMet are used.

At the bankable feasibility stage, or for production forecasting, a more rigorous model of the orebody is created using the geometallurgical methodology pioneered by SGS. Design uncertainty is quantified using statistical techniques.

Pilot Plants

Due to size, complexity, or desire for absolute minimum start-up time or maximum operational efficiency, there is no substitute for pilot testing. The best pilot programs are supported by thorough, bench-scale orebody characterization and circuit simulation.

Beneficiation Process

SGS provides a comprehensive range of test work services for the coal and iron ore industries. Our extensive global network of laboratory and metallurgical testing facilities support most of the processes that are used in the exploration and treatment of iron ore and coal globally. All physical separation techniques can be tested at SGS, both on the laboratory and pilot plant scales. We have expertise with beneficiation techniques including:

  • Scrubbing
  • SAG Power Index (SPI) Test
  • Bond Tests
  • JK Drop Weight Test
  • Gravity Separation
  • Magnetic Separation
  • Flotation

Our Experience

SGS mineral processors have operated many SAG plants and have conducted over 500 SAG pilot plants. We have designed the largest installation base of advanced control (expert systems) for comminution circuits in the world. Our reference list speaks to our global experience and includes grinding circuits, both large and small, including the largest operating grinding circuit in the world – Collahuasi Rosario’s 40-foot SAG mill.

SGS’s philosophy is to understand the variability in your ore and then design, optimize, or forecast from this knowledge. We bring proven technology from the geological and processing disciplines, relying on not just one methodology but several, to provide a bankable solution that is unmatched in its rigor.