Category:P80 adjustment

Grinding parameters, like work index and Morrell Mi values, are sensitive to the particle sizes where the tests were performed. The Bond tumbling tests performed in comminution laboratories are run to generate a test P80 size that is desired by the test operator; this test P80 is supposed to be similar to the P80 observed in the industrial plant that is treating this same ore.

When the test was performed at a dramatically different P80 than what is desired for the industrial plant, then it may be necessary to perform a correction to the measured work index or Mib results.

• Most ores will see small changes in Bond ball mill work index when the test P80 changes
• Most ores will see large changes in Morrell Mib values when the test P80 changes
• The correction is always ore-specific, and requires a "Hukki exponent" to run the correction algorithm.