A landmark improvement has been made to JKTech’s JK Drop Weight Test and SMC Test® by enhancing the usefulness of the A and b parameters and converting them to a more meaningful specific energy value.
For over 20 years, the results of JK DW and SMC tests have been reported as A and b parameters which have been universally accepted as representing an ore’s resistance to impact breakage. These parameters however have no physical meaning in their own right, but are ore hardness parameters used by the AG/SAG mill model in JKSimMet which permit the prediction of the product size distribution and the power draw of the AG/SAG mill for a given feed size distribution and feed rate.
Using A*b as the single parameter to describe the impact resistance of a particular ore has been shown to have dual drawbacks. Firstly, A*b is inversely related to impact resistance, which adds unnecessary complication. Secondly, A*b is related to impact resistance in a non-linear manner.
Thus, to give a more intuitive parameter, JKTech Pty Ltd and SMC Testing Pty Ltd have developed a “standard” simulation methodology to predict the specific energy required for a particular tested ore when treated in a “Standard” circuit comprising a SAG mill in closed circuit with a pebble crusher.
The specific energy value for the “standard” circuit, SAG Circuit Specific Energy (SCSE), will be included in future JKTech Pty Ltd reports of JK Drop Weight and SMC Test® results in addition to the traditional A, b, ta and crusher parameters.
Of course, the SCSE quoted value will not necessarily match the specific energy required for an existing or a planned AG/SAG mill due to differences in the many operating and design variables. SCSE will be an effective tool to compare in a relative manner the expected behaviours of different ores in AG/SAG milling.
Manager - Metallurgical Solutions
JKTech Laboratory Services
T: +61 7 3346 5883