rod mill Work Index test for these purposes. Chose a o closing screen for the ball mill test one (standard square root of 2 series) mesh size coarser than the plant ball mill circuit P80. If between standard mesh sizes, the finer of the chose two. Results of Bond ball mill tests conducted with closing
mill. 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
Single stage SAG mills, SAG mill aspect ratio, simulation, modelling ... the SAG mill and ball mill depends on the energy requirement between both duties. ... The Bond rod work index in kWh/t .
1.27 for the rod mill and 0.67 for the ball mill. The particle size distributions reported are shown in Figure 1. It follows that the No 1 rod mill/ball mill circuit was operating very ef ciently when comparing the combined operating work indices for both mills with the rod mill and ball mill laboratory work indices.
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 m 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.
Rod Mill Batch Process . The mill dimensions, (D L), are 0.204 0.3 m and it is loaded with 8.55 kg steel rods 14 to 20 mm diameter. The mill rotates on rolls and its frequency is set to 70 RPM corresponding to 85% of the critical frequency. The mill power is 22.5 Watts, calculated by (6). Fi- P
the final product size. The prediction of the SAG mill transfer size used in the formula is made by comparison with pilotplant data and operating plant data for similar ore types (Barratt, 1989). The approach acknowledges grinding efficiency as the ratio of operating work index to that for a single-stage ball mill.
developed specifically for rod, ball and ag/sag mills. This presents problems for High Pressure Grinding Rolls (HPGR) circuit designers as, ... Bond ball work index) P 80% passing size for the ...
Wi Bond Work Index for rod and ball compartments F 80 80 % passing size of the circuit feed, m P 80 80 % passing size of product, m EF 1-8 Correction factors To estimate power draw in the rod and ball compartments, Equations 3 and 4 were used 6 7.
dimensions, ball load, ball size, grate/pebble port size, trommel aperture and pebble crusher configuration. However, the SCSE is an effective tool to compare in a physically meaningful manner the expected behaviour of different ores in AG/SAG milling in exactly the same way as the Bond laboratory ball mill work index can be used to compare the ...
In conjunction with the Bond ball mill work index they can be used to accurately predict the overall specific energy requirements of circuits containing AG and SAG mills, Ball mills, Rod mills, Crushers, High Pressure Grinding Rolls (HPGR).
comparison of hpgr - ball mill and hpgr - stirred mill circuits to the existing ag/sag mill - ball mill circuits by chengtie wang b.eng., university of science and technology beijing, 2009 a thesis submitted in partial fulfillment of the requirements for the degree of master of applied science in the faculty of graduate studies
Reduction 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.
The ball mill designs also follow the Bond/Rowlings method with comparison with other methods. Again the method of use is the same ... rod milling work index kWh/t. The 110 is replaced ... For SAG mills the equation becomes Power(5.6115%balls*0.1438)*D24. 6* L Mill Critical speed Crit
FIGURE 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 ores compentency. Figure 8 plots this ratio versus UCS no trend is apparent ...
The SAG mill specific energy consumption (E SAG) is calculated using the 1979 Barratt equation and the ball mill specific energy consumption (E bm) This model includes a phantom cyclone effect in the equations due to the ball mill being calculated by difference and not being calculated by the normal Bond equation. The resultant operating work index of the ball mill will vary according to the ratio of the ball mill, rod mill and
AG/SAG Wio, AWio (kWh/t) 28.5 Ball Mill Wio, BWio 8.6 Circuit Wio, OWio 14.6 Bond Ball Mill Work Index, BWi, kWh/t 13.4 Bond Rod Mill Work Index, RWi, kWh/t 18.1 Table 1. Example of AG/SAG Ball Mill Circuit Wio Calculations 1 2 ABstrAct Optimum use of power in grinding, both in terms of grinding efficiency and use of installed capital, can have
2. SAG-Ball Mill Circuit SAG-ball mill circuit F80 165,000 m P80 125 m W 14.6 kWh/t . 16.8 kWh/t . Bond Test WIs (kWh/t) Crushing16.0 Rod Mill 14.5 Ball Mill 13.8 . Bond Standard Circuit Work Index kWh/t . W Total 0.9 3.4 8.0 12.3 kWh/t 14.1 kWh/t . Note, 14.1 kWh/t is also the combined Cr-Rod-Ball test WI of the ore.
significant) between the rod mill and ball mill index values for a given ore type (McKen, Verret, Williams, 2006). On average, the rod and ball mill indices are essentially equal, but the ratio between the two can be quite variable. High RWI/ BWI ratios indicate competent ores with low ball mill hardness, while low ratios represent friable or coarse-grained ores. Fine and ultra-fine grinding, also more
The Bond equation is used to calculate ball mill specific energy from T 80 to the final product P 80 size. The total circuit specific energy is the sum of the SAG mill and ball mill specific energies. W SAG R.(Ms16000)/(Ms.447.3) (4) W T K a.K b.W SAG.10.BWi.(T 80-0.5-1700-0.5).EF5 W BM.K BM (5) Where W SAG SAG mill specific energy from F
Oct 24, 2018 However, Bond Work Indeces are related to the type of equipment to be used (rod mill, ball mill, SAG uses Drop Ball parameter-Kwhr/m3-, so it is more complex than just specific energy consumption ...
WiBM Bond Ball Mill Test Work Index (kWh/t) Wic Bond Impact Crushing Test Work Index (kWh/t) WioACT Actual Operating Bond Work Index determined from measurements on the circuit (kWh/t) WiRM Bond Rod Mill Test Work Index (kWh/t) WiSTD Standard Circuit Bond Work Index (expected or designed) used for circuit design. Specific energy requirement at ...
The SAG mill comminution (SMC) test is a smaller scale test than the JKTech drop weight test. The lithological weighted average value of Axb was 33.4 Bond Rod Mill Work Index was determined to be 14.86 kWh/t Bond Ball Mill Work Index was determined to be 13.33 kWh/t ...
The mill product can either be finished size ready for processing, or an intermediate size ready for final grinding in a rod mill, ball mill or pebble mill. AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill.
Rock Mechanics (ISRM). The Bond crushability index, uniaxial compressive strength, elasticity modulus and dry density of the rocks studied are shown in Table I. Generally, there are three Bond indices ball, rod and crushability. The Bond ball and rod indices are determined using
The results obtained from this work show, the ball filling percentage variation is between 1.2 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%). In addition, acquired load samplings result for mill ball filling was 1.3%. Keywords Miduk Copper oncentrator, SAG
LAB/PILOT PLANT EQUIPMENT LAB/PILOT PLANT EQUIPMENT - MILLS Ball, Rod, and SAG Lab Mills. Specifications Sizes 12 and 16 diam., up to 48 long Mild steel
Dec 12, 2016 Ball Mill Power Calculation Example. A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80% passing inch (6350 ...
Bond abrasion index Bond ball mill work index Bond impact crushing work index Bond rod mill work index Comparative work index High pressure grinding rolls (HPGR) up to 10tph Inferred work index JK drop-weight test Levin open circuit grindability Pilot SABC (AG/SAG) up to 4tph Point load test
The ratio of reserve de nition samples ... Bond rod mill work index (RWi) X X X X Bond ball mill work index (BWi) X X X X SAG milling tests JK Tech drop weight test (DWi) ...
May 15, 2014 Wi The Bond Ball Mill Work index ( 1952 )- is a measure of the resistance of the material to crushing and grinding . A Bond Ball Mill Work Index test may be required for the design of a new mineral processing plant . It is determined by Bond Ball Mill Grindability test in a lab using a Bond Mill.
(1961) and is given in equation 1 and was originally developed for use with crusher/rod mill/ball mill circuits. W 10 x Wi x (P-0.5 F ) (1) where W Specific energy Wi Work (hardness) index P 80% passing size for the product (P80) F 80% passing size for the feed (F80)
Figure 4 shows the schematic of the closed circuit tests and the sampling points. Material used in the testwork was obtained from a local quarry. The rock had the following breakage properties Drop Weight Index, DWi 3.2 kWh/m3, Bond Rod Mill Work Index RMWi13.1 kWh/t, Bond Rod Mill Work Index BMWi18.1 kWh/t.
Aug 21, 2021 The guideline reviews the data required for the analysis, including hardness characterization data generated from the SMC Test and Bond Ball Mill Test Work Index, presents the Morrell equations and their applications, and provides a worked example.
B ball size (inch) If a power loss was in deed occurring in the manner indicated above, then. given a typical ball size of 65mm (2.5inch), such power loss would only. be noticeable in mills with ...