What is the difference between CWi and DWi: WiC measures fracture strength in coarse rocks, DWi measures matrix competence in medium-size rocks.
Commentary on the apparatus of the Bond rod mill work index
by Alex Doll
The Bond “Third Theory” of comminution was originally divided into three size classes reflecting the varieties of comminution equipment common during the time period when Bond (and his collaborators) were gathering the information to
These notes are based on observations made while on a recent trip through the West, for the purpose of studying the practical operation of the ball-mill. The writer takes this opportunity to express his thanks for courtesies extended at the many plants visited as well as for the valuable data received.
While there are several types of ball-mill on
Rittinger’s theory and law of the energy expended in crushing of rock is that the work of crushing is proportional to the reduction in diameter; or, as I have more fully expressed it:
“The work done in crushing is proportional to the surface exposed by the operation; or, better expressed for this purpose, the work done on a given mass of rock
The drop weight test is a common laboratory measurement used to determine the comminution characteristics of rock samples. A common metric derived from a drop weight test is a value “A×b”. Another common metric that is derived from the SMC Test™ variant of a drop weight test is a “Drop Weight Index”, abbreviated as DWi. This work looks
Here is the old Allis-Chalmers Bond Work Index Grindability Test Procedure.
The standard feed is prepared by stage crushing to all passing a 6 mesh sieve, but finer feed can be used when necessary. It is screen analyzed and packed by shaking in a 1000-cc graduated cylinder, and the weight of 700 cc is placed in the mill and ground dry at 250 per cent
A linkedin.com group was recently discussing this by asking: I’ve tried to estimate AG/SAG Mill power requirements using several different methods:
(1) Using the results of SMC data
(2) Using SAG Power Index (SPI) data
(3) Using the 1989 Barratt method updated on Alex Doll’s Web site
The Bond Abrasion Test determines the Abrasion Index, which is used to determine steel media and liner wear in crushers, rod mills, and ball mills. Bond developed the following correlations based on the wear rate in pounds of metal wear/kWh of energy used in the comminution process.
Here is an illustration of the typical relationship between the Mohs Mineral Hardness Scale and their corresponding Bond Abrasion Index.