Abstract: In order to further explore the crushing behavior of copper ore in Bond work index ball mill，the effects of key parameters such as feed particle size，grinding time，closed-circuit sieve size and cycle times on product particle size distribution，grindability and Bond work index are systematically ana‐ lyzed by batch grinding test and enhancing Bond work index test.The results show that under the condition of narrow size fraction batch grinding，the ore of each size fraction follows the law of geometric decreasing crushing，and the crushing efficiency of intermediate size fraction ore is the highest.In the process of wide grain size grinding，the particle size of the product is continuously refined with the increase of grinding time，and the cumulative pass rate amplificationof the middle grain size is the most obvious，and the parti‐ cle size reduction rate gradually slows down with time.The enhanced Bond work index test shows that with the increase of the aperture of the closed-circuit sieve，the particle size of the feed and discharge shows a coarsening trend，and the grindability of the ore increases accordingly. The grinding system reaches dynam‐ ic stability after 4～5 cycles.In addition，the Bond ball mill work index decreases first and then increases with the increase of the closed-circuit sieve aperture，which provides a theoretical basis and data support for optimizing the Bond ball mill work index test process.

Key words: copper ore, Bond ball mill work index, grinding behavior, particle size characteristics