Conduct and precision of bond grindability testing

Evaluating the comminution energy requirements of ores using traditional Bond work index testing is well established; such testing is conducted on essentially all development properties, and is widely used as a benchmark for plant performance. Use of the Bond tests to describe ore hardness is so widespread that Bond work indices are often discussed as an ore property. In spite of widespread use for over 70 years, there is often great confusion about how to conduct Bond tests accurately and precisely. Round-robin testing between laboratories often reveals variations in procedures, and makes assessment of test accuracy difficult. This paper details test methodology and procedural closing criteria for conducting Bond tests, discusses precision of test series conducted in a single laboratory with a single procedure, and details typical pitfalls encountered in testing.