Comparison of UCS to Bond Work Indices
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 ore’s compentency. Figure 8 plots this ratio versus UCS; no trend is apparent,Application of Operating Work Indices in Autogenous,,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 haveModel:Bond/Barratt SABC Models - SAGMILLING.COM,The ball mill oversize feed factor (EF 4 BM) is always calculated with the rod mill work index for the optimum feed size and the ball mill work index for EF 4 BM. The model assumes that the calculated value of E ssbm + the specified contingency is greater than the sum of E sag + E peb ;AG - Autogenous & SAG Semi-Autogenous Mill Design Calculations,Apr 17, 2018· This meant that Bond Work Indices had to be used for mill sizing which was reviewed with mill manufacturers and other consultants. The SAG mill was sized with 746 kW to give a 25% contingency for power swings on the calculated power. The ball mill was sized at 1120 kW.A Method of C alculating Autogenous/ Semi-Autogenous,,stage ball mills, rod mills or AG/SAG mills when calculating power according to the Bond Third Theory method. Rod mill and AG/SAG mill products are similar and tend to be not as steep as a 0.5 slope when plotted on log-log paper. This is because the particle size distribution (PSD), these millsSINGLE STAGE SAG/AG MILLING DESIGN - Orway,Regardless of the test used each sample should be twinned with a Bond Ball Work Index or, SAG mill (4% ball charge, 90% Nc) A cross between AG and SAG for average competency, abrasive ores., be taken into account when selecting the aspect ratio of the mill. In essence, the diameter of the mill
Bond Work Index - an overview | ScienceDirect Topics
Ball mill design requires a Bond work index, BWi, for ball mills at the correct passing size; SAG mill design requires an appropriate SAG test, for example, SPI (Chapter 5). Flotation design needs a valid measure of kinetics for each sample, including the maximum attainable recovery and rate constants for each mineral ( Chapter 12 ).Bond Work Index Formula-Equation - 911 Metallurgist,conventional crushing and grinding circuits (crusher-rod-ball mill or crusher-ball mill). By the 1970s, the application of conventional tended to be limited to relatively low capacities. circuits The majority of modern grinding circuits include a SAG mill, a ball mill and/or a combination thereof. The use of BondDifference Between Sag Mill vs Ball Mill - mech4study,Oct 12, 2017· SAG mill make use of steel balls included with some large and hard rocks for grinding. These mills utilize the balls in making the large fragments of materials broken into pieces. The ball charge of a SAG mill is about 9% to 20%.This process takes place inside the large rotating drum of SAG mill which is filled with balls partially.Model:Bond/Barratt SAB Model - SAGMILLING.COM,The 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 workBenchmarking: Bond - Kanowna Belle - SAGMILLING.COM,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 aO. I. SKARIN N. O. TIKHONOV CALCULATION OF THE,Decision-making on selection of SAG mills increasingly uses the methods of sizing the milling power based on laboratory tests on grindability of minerals. This article considers one of such methods allowing determination of mill characteristics based on the Bond work indexes of crushing, rod milling and ball
GMSG GUIDELINE: DETERMINING THE BOND EFFICIENCY
Bond Test WI’s (kWh/t): Rod Mill: Ball Mill: 9.5 kWh/t.8 9 kWh/t . Bond Standard Circuit Work Index: Assume the rod mill Work Index of 9.5 applies from the actual rod mill feed sizeof 19,300 mµ (although some of this work might ideally be done by crushers to achieve a rod mill F80 of 16,000 m) to a rod µHow to Size a Ball Mill -Design Calculator & Formula,May 15, 2015· The power calculated on using equation 1, (Bond, 1961; Rowland and Kjos, 1978), relates to: 1) Rod milling – a rod mill with a diameter of 2.44 meters, inside new liners, grinding wet in open circuit. 2) Ball milling – a ball mill with a diameter of20150505 Bond Efficiency-GMG-ICE-v1-r04 Determining the,,Assume the test Wi of the rod mill (9.5) applies from the actual rod mill feed size of 19,300 µm (although some of this work might ideally be done by crushers to achieve a rod mill F80 of 16,000 µm) to a rod mill (circuit) product size of 1,000 µm. 10 10 W1( –––––––－–––––––––) (AMIT 135: Lesson 6 Grinding Circuit – Mining Mill Operator,,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.AMIT 135: Lesson 8 Rod Mills – Mining Mill Operator Training,Rods are placed parallel along the length of the rod mill. Rods are 150mm shorter than the mill length. Breakage occurs more from cascading than cateracting. The product size distribution is narrower than a ball mill but significantly coarser. Most are overflow discharge type. Length-to-diameter= 1.4 to 2.3. Mill length = 7 meters. Rod Mill,What's the Difference Between SAG Mill and Ball Mill,,Nov 26, 2019· Difference Between SAG Mill and Ball Mill, from the working principle, application, structure, etc. Grind and blend solid or hard materials into smaller pieces by means of
Grinding control strategy on the conventional milling,
milling circuit consists of a rod mill followed by a ball mill in series. Crusher product (-9 mm) is fed to the rod mill, and the water is fed in ratio to the ore feed mass. The rod mill discharge is pumped, without any further water addition, to the first ball mill. The ball mill discharges to a sump where water isBENCHMARKING COMMINUTION CIRCUIT PERFORMANCE,expected from their Bond ball milling work indices. In fact, the average ratio of DWi to Bond ball mill work index was at the 90th percentile of a much larger database. This result indicates that the SAG milling power requirements for these ores is likely to be much greater than what would be expected from the Bond ball mill work index.Comminution testing - JKTech - University of Queensland,Jul 30, 2020· An improved method using less mass compared to the Bond Ball Mill Work Index test. The JK Bond Ball Mill (JKBBM) test, is a locked cycle grindability test conducted using a standard laboratory Bond Ball Mill with the same steel ball charge and material feed size (100% passing 3.35 mm) as the Bond Ball Mill Work Index test.Autogenous and Semi-Autogenous Mills - ScienceDirect,Jan 01, 2016· According to Smith , an option to install an AG/SAG mill in preference to a normal tubular ball mill may be considered when the unconfined compressive strength of the ore is less than 180 MPa, the Bond crushing work index is less than 20 kWh/t and the Bond rod mill work index is not significantly higher than the Bond ball mill work index and,SAGMILLING.COM .:. Articles,Correction of Bond Ball Mill Work Index Test for Closing Mesh Sizes It is commonly known that one must run the Bond ball mill work index test such you pick aBenchmarking: Bond - Kanowna Belle - SAGMILLING.COM,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
Comparison between bond crushing energy and fracture,
applied to ball mills4–7, SAG mills8–10 and centrifugal mills11,12., Generally, there are three Bond indices: ball, rod and crushability. The Bond ball and rod indices are determined using standard ball and rod mill, respectively, and are, Parallel-bond stiffness ratio ( K,BENCHMARKING COMMINUTION CIRCUIT PERFORMANCE,expected from their Bond ball milling work indices. In fact, the average ratio of DWi to Bond ball mill work index was at the 90th percentile of a much larger database. This result indicates that the SAG milling power requirements for these ores is likely to be much greater than what would be expected from the Bond ball mill work index.Energy Benchmarking - SMC Testing,A 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 toSMC Test® Minerals Processing Comminution Testing - SMC,,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).20150821 Morrell Method-GMG-ICE-v01-r01 Morrell method,Wi Bond Work Index Ws Specific energy correction for size distribution (kWh/t) WiBM Bond Ball Mill Test Work Index (kWh/t) 3. KEYWORDS Autogenous Grinding (AG), Ball mill, Bond Work Index (Wi), Comminution circuit, High Pressure Grinding Rolls (HPGRs), Rod mill, Semi-Autogenous Grinding (SAG), Spe-cific energy (W) 4. INTRODUCTION AND BACKGROUNDCORRELATION BETWEEN BOND WORK INDEX AND,3- STANDARD BOND TESTS The Bond's standard ball mill is used to determine the work index value of differ ent samples. The Bond work index is defined as the kilowatt-hours per short ton required to break from infinite size to a product size of 80% passing 100 µm. If the breakage
A New Approach to the Calculation of Work Index and the,
The mill power is = 22.5 Watts, calculated by (6). Fi- P nally the product is wet screened to find the size d80. 2.4. Rod Mill Semi Continuous Process The same mill is used for the semi continuous grinding tests which is similar to the Bond test but with the exist- ing mill of known power. After time the millSampling and analysis for feasibility studies and mineral,,Mar 30, 2015· GRINDABILITY TESTS Bond Rod mill work Index • The rod mill work Index is also normally distributed with and average and median of 14.8kWh/t • It is common to observe difference between the ball and rod mill caused by variation in ore hardness • The test has been mainly used for the design of rod mill or primary ball mills. http,Geometallurgy - Wikipedia,The Bond ball mill work index test is thought to be additive because of its units of energy; nevertheless, experimental blending results show a non-additive behavior. [18] The SPI(R) value is known not to be an additive parameter, however errors introduced by block kriging are not thought to be significant .A Method to Determine the Ball Filling, in Miduk Copper,,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 Mill, Ball Filling PercentageRod Mills for coarse grinding | FLSmidth,Our Rod Mills are available in multiple diameters to fit the needs of your operation. Grinding, primarily by attrition, Rod Mills require comparatively low levels of power to operate. Rod Mills can be either wet or dry designs. Once replaced by AG and SAG mills, Rod Mills have hadRod Mills, How Do They Work? - Mine Engineer.Com,Rod mills are very similar to ball mills, except they use long rods for grinding media. The rods grind the ore by tumbling within the the mill, similar to the grinding balls in a ball mill. To prevent the conditions leading to rod charge tangling, the length to diameter ratio is maintained at 1.4 to 1.6.
efficiency calculation of rock grinding mill
calculation of ball mill grinding efficiency - page 1 . by Erdem (2002) for dry multi-component cement grinding ball mills, using the results of the Bond ball mill grindability test. For all model based methods, a reliable method to calculate mill power draw for a given mill is required for the calculation . Get Price,,,,,
