A gold ore was crushed in a jaw crusher down to 3 mm and to 1 mm …
A gold ore was crushed in a jaw crusher down to 3 mm and to 1 mm in a cone crusher and finally in a rod mill to minus 75 mm and sampled at each stage. The standard deviation at the first stage was ±10 ppm, ±1 ppm at the second stage and ±0.1 at the third stage. The confidence level in assaying was 3.0 ± 0.1%.