The 'pilot plant' sample, where the ratio of rod mill work index to ball mill work index is more "normal" gives an Optimized Bond/Barratt T 80 prediction of 540 µm which is much closer to the survey than the Lowes West sample. The Raw Bond/Barratt model also gives a very fine T 80 prediction on the Pilot Plant sample.
Read OnBall Mill Work Index has been widely used for ball mill sizing, and is also utilized in computer simulation. BOND ROD MILL GRINDABILITY TEST The Bond Rod Mill Grindability Test is also performed according to the original Bond procedure. It requires 15 kg of minus ½ mesh material that is preferably prepared at the testing facility. The Bond Rod ...
Read OnFIGURE 8: ROD MILL/BALL MILL WORK INDEX RATIO v. UNCONFINED COMPRESSIVE STRENGTH 100 200 300 400 UCS (MPa) 0 0.5 1 1.5 2 WiRM/WiBM (metric) Siddall et al (1996) identified the ratio of Bond rod mill Work Index and ball mill Work Index as being indicative of an ore's compentency. Figure 8 plots this ratio versus UCS; no trend is apparent ...
Read OnThe resultant operating work index of the ball mill will vary according to the ratio of the ball mill, rod mill and crushing work index values and for an Andean copper porphyry is typically in the range of 80% of the measured ball mill work index value. Testwork Required. Bond ball mill work index; Bond rod mill work index
Read On• The Bond Ball Mill Grindability Test determines the Bond Ball Mill Work Index used to determine net power requirements when sizing ball mills. The test is a closed-circuit, dry grindability test. It is run in a standard ball mill and can be performed at mesh sizes ranging from 48 mesh to 400 mesh. Bond Ball Mill Work Index (and modified ...
Read Onthings. It is incorrect to say, for example, "the ball mill work index is 13 kWh/t and the SAG mill SEC is 5 kWh/t, so the total circuit energy is 18 kWh/t." This example is a real discussion that one of the authors had with a flotation engineer who was confused because of the convention of using the same units for both quantities.
Read Onwork index. By running a batch dry-grinding test in a rod mill, an average specific energy of 7.34 kW/STPH was determined using Bond's formula with the reference work index of 11.25 kW/STPH. This specific value is limited to these test conditions:
Read OnBy combining with SAG discharge and screening on the SAG discharge screens, top size control to the ball-mill circuit feed is maintained while still unloading the SAG circuit (Mosher et al, 2006). A variant of this method is to direct pebble-crushing circuit product to the ball-mill sump for secondary milling: while convenient, this has the ...
Read OnA number of samples were taken from the SAG mill feed belt and subjected to SMC Tests and Bond ball mill work index tests. Note that the Bond tests were conducted using 150 microns as the closing screen size so that the final product size from the tests was similar to the 106 microns measured during the survey.
Read OnThis Grindability Test or Bond Ball Mill Work Index Procedure is used to determine the Bond Work Index of minus six mesh or finer feed ore samples. These equation application methods are used to process <1/2″ ore samples in a Ball Mill using a standard ball charge.. Below describes in general terms the Bond Work Index Procedure used by a Professional …
Read OnFirst, a Jar Mill grindability test requires a 5 lb. (2 kg) sample and produces a direct measured specific energy (net Hp-hr/t) to grind from the design feed size to the required product size. The second test, a Bond Work Index determination, results in a specific energy value (net Hp-hr/t) from an empirical formula.
Read Onmill. As such, primary ball mills should be designed with the rod mill work index, and single-stage ball mills should be with both the rod mill and ball mill indices. This is because it is common to observe a difference (sometimes significant) between the rod mill and ball mill index values for a given ore type (McKen, Verret, & Williams, 2006). On
Read OnThe samples, once broken, can be used subsequently for Bond ball mill work index or batch grinding tests, therefore limiting overall sample requirements.The test generates an index (DWi) that can ...
Read On(JKDWT) "A×b" and the Bond ball mill work index. The SAG and ball mills power draw is calculated using semi-empirical equations, as a function of mill geometry, speed and load.
Read On- Bond Grindability Tests 7 - Efficiency Factors 7 - Operating Work Index 8 - Limitations of the Bond Test 9 - Single Particle Tests 9 - Bond Impact Test 9 - Drop Weight Test 10 - Mill Speed 10 - AG Mills 10 - SAG Mills 10 - Rod Mills 10 - Ball Mills 11 - Linear and Speed Effects 11 - Fines Correction 11
Read OnThe crushing-ball milling circuit specific energy was estimated on the basis of the Bond equation and the relevant Bond work indices (Table 4), with the …
Read OnDifferent methods, including point load index, drop weight test, Bond mill work index and abrasion index, were employed to appropriately characterize the entering feed strength to the circuit.
Read Onautogenous mill, with an 8% ball charge. The test is run until a steady-state is achieved similar to the Bond rod mill and ball mill tests. A draft fan supplies the airflow required to remove the ground material from the mill, and a collection system recovers the …
Read OnSee this useful summary Table of Bond Work Index by Minerals. For any circuit, whether a crushing circuit, a rod mill, or a closed ball mill circuit, the Work Index always means the equivalent amount of energy to reduce one ton of the ore from a very large size to 100 um. The sample was received crushed appropriately for the ball mill test.
Read OnReduction ratio = 2 – 20 depending on material. Typically R = 8. Rod Mill Charge: Typically 45% of internal volume; 35% – 65% range. Bed porosity typically 40%. Height of bed measured in the same way as ball mills. Bulk density of rods = 6.25 tons/m3. In wet grinding, the solids concentration 1s typically 60% – 75% by mass.
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