The work index covering grinding in tumbling mills of coarse sizes is labelled M. ia. The work index covering grinding of fine particles is labelled M. ib (Morrell, 2008). M. ia. values are provided as a standard output from a SMC Test ® (Morrell, 2004. a) whilst M. ib. values can be determined using the data generated by a conventional Bond ...
The work index tests, developed by Fred C. Bond, are conducted in various test devices at a size range for which the material will be processed in the various crushing and grinding ranges. The bench scale test data that can be used for selection of cone crushers, rod mills and ball mills can be obtained as part of either:
Bond's work index is one of the mostly widely used metrics of mineral grindability. In spite of its ubiquity, users are often not aware of the nuances of the work index family: what …
A primary gyratory crusher was required to crush iron ore at the rate of 3000 t/h. The largest size of the run-of-mine ore was 1000 mm. The required product size was less than 162 mm. Manufacturer's data indicated that the nearest size of gyratory crusher would be 1370 mm × 1880 mm with a cone angle of 18°.
The Bond crushing work index test (sometimes called the "impact work index" test) is noisy, and the difference you observed is perfectly reasonable. ... (1997) reports a standard deviation in crushing work index tests across laboratories as 4.5. The laboratory CWi value of 27.4 (metric) is almost within 4.5 units of the 22.4 value I calculated ...
Characterization of rocks for selection of crusher can be done in different ways, and the most commonly used is Bond work index (Tavares and Carvalho 2007). Holmes (1957) proposed a modification ...
The Bond work index most commonly referred to is the BBM work index. This value is obtained in a 12" 12" laboratory mill running at 70 rpm, with rounded inner edges and without lifters. The grinding charge is comprised of a distribution of steel balls with several diameters. Table1shows the original Bond proposal [13], while the last Bond
The reason for this variation in ball mill work index is because the ore at Mt. Milligan has an intrinsic exponent of –0.45 in the 100 µm to 200 µm size range, not the –0.50 exponent empirically measured by F. Bond. The work index increase between 100 µm and 76 µm is due to a porphyritic grain size that causes a spike in energy
The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to evaluate the grinding efficiency and to calculate the required grinding power. ... Modified Bond method for the evaluation of crusher efficiency. Min., Metallur. Explor., 6 (1989), pp. 14-17, 10.1007/BF03402519. ... grindability index and …
The results showed that using the non-standard mills (between 20 and 35 cm in diameter), the Bond´s model constants (α=0.23; β= 0.82, and γ = 44.5), are unable to predict the Work Index ...
Also, values of crushing work index (CWi) increased inversely with the A*b breakage index, as commonly observed (Napier-Munn et al., 1996; Tavares and Silveira, 2008). In order to demonstrate the ...
Currently, the dimensions of the largest Blake-type jaw crusher in use are 1600 mm × 2514 mm with motor ratings of 250–300 kW. Crushers of this size are manufactured by Locomo, () and others. The crusher is the C 200 series having dimensions 1600 mm × 2000 mm driven by 400 kW motors. Table 4.1.
Once the Bond Work Index is known for a specific material the equation can be used to calculate the energy requirements for various ranges of input and output sizes. Bond's work index is given below: The indices derived by Kick, Bond and Von Rittinger all assume a constant energy requirement per unit of
For A; values > 0.15 non-autogenous impact crushers are considered uneconomic and for A, values > 0.7 double toggle jaw crushers are preferred to single toggle crushers. Bond developed a number of …
The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to evaluate the grinding efficiency and to calculate the required grinding power. Although considered an ...
Rowland, C.A., 1973, "Comparison of work indices calculated from operating data with those from laboratory test data," Proceedings Tenth International Minerals Processing Congress, The Institution of Mining and Metallurgy, London, UK, pp. 47–61.
Introduction. The specification for the apparatus to determining a "Bond" rod mill work index is first described in Bond & Maxton (1943). It states that the apparatus is a tumbling rod mill to be operated in a locked cycle test at a fixed circulating load. The geometry of the grinding chamber is described as:
The self-grinding work index is an extension of the concept of Bond work index. It generally refers to the work index calculated by using Bond's fracture theory on …
crusher and roll crusher in a closed cycle with screening to size -3,327mm. The samples of pure andesite and pure limestone are separated from the ground material for ... Table 1 The Bond work index values obtained by standard the Bond procedure and values calculated according to the mass fraction of the sample components Sample i …
The final form of Bond's equation can be written as [4]: (2) E = 10 C W i 1 P 80 − 1 F 80 kWh ton where C = a tabulated constant depending on type and condition (wet or dry) of comminution equipment, F 80 = 80% passing sieve size of the feed, μm, P 80 = 80% passing sieve size of the product, μm, W i = Bond work index: the work required …
P80 = 25400 x Oss x (0.04Wi + 0.40) P80 = 25400 x Css x 7Ecc x (0.02Wi + 0.70) / (7Ecc – 2Css) Where Oss = Open-side setting in inches. Css = Closed-side settings in inches. Ecc = Eccentric throw in inches. P80 = Aperture through which 80% of the …
The Bond (impact) crushing work index is given as 27.7 based on a laboratory determination. Use the circuit survey data to compare the operating work index to this laboratory determination. The reported power draws of these MP 1000 crushers were 460+554+583+581 for a total of 2178 kW at the DCS.
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 …
The Bond work index most commonly referred to is the BBM work index. This value is obtained in a 12" × 12" laboratory mill running at 70 rpm, with rounded inner edges and without lifters. The grinding charge is comprised of a distribution of steel balls with several diameters. Table 1 shows the original Bond proposal [13], while the last ...
PDF | The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value... | Find, read …
When we apply the Bond Equation we found that CWi (Calculated) = 21,54 Kwh/t. And the CWi (lab test) = 27,4 Kwh/t. My question is: there is same correction factor that we must …
According to the Bond standard procedure, the work index is determined by simulating a dry grinding in a closed circuit in the Bond ball mill to achieve 250% circulating load (Bond, 1949, 1952 ...
The self-grinding work index is an extension of the concept of Bond work index. It generally refers to the work index calculated by using Bond's fracture theory on the principle of ore crushing energy consumption according to the W, F, and P data of a small or semi-industrial or industrial self-grinding test. In this kind of test, McPherson …
Progression of mining into the deeper and harder B2 ore necessitated the installation of Plant 2 in 2008 to meet throughput requirements. This plant contains an in-pit MMD crusher and a SAG mill in circuit with four ball mills and has a nominal plant capacity of 41 Mt/a for a Bond work index (BWI) below 8.7 kilowatt hours per ton (kWh/t).
In addition, the value of the BWi determines the energy required for crushing and milling (depends on the BWi type, e.g., crushing work index, Bond ball mill work …
BOND WORK INDEX. The Bond Work Index is a factor that measures the energy consumed in size reduction operation of the ore. The Bond's Work Index equation is: W=WI* (10/√P80 -10/√F80) where. W= the energy input (Work input) per ton, kwh/metric ton. WI= Work Index= specific energy per ton, kwh/metric ton (characterizes the ore)