Mill Grinding Balls, Grinding Cylpebs and Grinding Rods
Grinding Media for Copper Mining
Copper porphyry ore is typically medium-hard but very abrasive because of the silica content. SAG mills in copper concentrators run large balls at high impact, and the ball mills that follow need media that keeps its hardness as it wears down.
Recommended media
| Mill | Ball size | Material | Why |
| SAG mill | 100-150 mm | Forged B2 / B3, HRC 58-62 | Survives high-energy impact, low breakage |
| Ball mill | 40-80 mm | Forged B3 or high chrome cast Cr18-26 | Abrasion resistance in silica-rich slurry |
| Regrind | 25-40 mm | High chrome cast, HRC 60-65 | Long life in fine grinding |
Selection notes
- Larger SAG balls (125-150 mm) suit coarse feed and hard ore; 100-110 mm suits finer feed or softer ore
- High chrome cast media works well in the ball mill when impact is moderate; forged is safer if the mill sees broken balls
- Wear rate should be reviewed every quarter against g/t, not against a fixed replacement schedule
Typical consumption is 0.7-1.6 kg per tonne of ore. Copper circuits with very abrasive ore often move to high chrome in the second ball mill and keep forged media in the SAG.
Related: SAG mill grinding balls | high chrome cast grinding balls | ball mill liners
