These are empirical indices determined by close circuit grindability tests developed by F.C.Bond in the mid 1930’s. They require a specific 305mm diameter x 305mm long (inside dimensions) horizontal axis ball mill without lifters operating at 70 rpm to perform grindabilities from 28 to 500 mesh and a 305mm diameter x 610mm long rod mill with a wave type liner operating at 46 rpm to perform grindabilities from 4 to 65 meshes.
Essa's ball and rod mills can be supplied as complying machines with the appropriate barrels and ball or rod charges. As with our standard range of ball and rod mills, the Essa bond index ball mill and bond index rod mill are supplied standard with a barrel and rotating yoke assembly and the electric motor drive mounted on a stand alone bench, funnel and screen. These machines will be of essentially the same physical arrangement and size as our standard range but with the customised features required to meet the Bond specifications.