Mill Power required at pinionshaft = (240 x x ) ÷ = 5440 Hp Speed reducer efficiency: 98% 5440 Hp ÷ = 5550 HP (required minimum motor output power). Therefore select a mill to draw at least 5440 Hp at the pinionshaft. Based upon the pilot plant test results, the volumetric loading for the mill can be determined.
SAG power draw survey tabulation This LibreOffice spreadsheet contains the raw data used to create Table 1 and Table 2 of the paper "An updated data set for SAG mill power model calibration", presented at IMPC 2016 in Quebec City, Canada in September, 2016. Refer to the paper for the definitions and meanings of the different columns.
These factors often translate to a higher unit power input (kWh/t) than an SAG circuit milling the same ore. but at a higher power efficiency (often assessed by the operating work index OWi, which if used most objectively, should be corrected by one of a number of techniques for varying amounts of fines between the two milling operations).
However, when combined with an accurate SAG mill powerdraw model, total charge volume and ball load can be estimated with reasonable accuracy. ... Mill Weight (t) Mill Power (kW / 10) Mill Speed ...
Bond rod mill work index (Wi RM) SAG Grindability index (SGI) or SAG Power index (SPI™) Drop weight test, both JK and SMC (A×b, DWI, Mia, etc) Bond rod mill work index versus A×b Only considering rod mill work index tests performed in laboratory mills equipped with wave liners. This is the standard specified by F. Bond and is typical of ...
Methods to Estimate AG/SAG Mill Grinding Power Requirements. (1) Using the results of SMC data. (2) Using SAG Power Index (SPI) data. (3) Using the 1989 Barratt method updated on Alex Doll's Web site (February 16, 2015) (3) Using Don Burgess' method (11th Mill Operators Conference 2012) They seem to give very different predictions for ...
where m p is in kW; D is internal mill diameter (meters), L is internal mill length (meters); J is total fractional charge loading of the mill; J B is the fractional mill filling by balls; ε B is the effective porosity of the charge, taken as ; ρ s and ρ b are true densities of rock and balls (tons per cubic meter), respectively; w c is the weight fraction of rock in water and rock in ...
operation of SAG mills. SAG mills are currently the technology of choice in hard rock milling operations for reducing primarycrushed ore to ball mill feed. In recent years, the trend has been towards largersized SAG mills with diameters of m (34 ft) and above, with the largest being m (40 ft) in
To date, CITIC HIC has cumulatively produced and delivered over 1,550 mineral grinding mills, with a total installed power of 3,900MW. Our largesize grinding mills hold a market share of 85% in the domestic mining market, and have been exported to more than 50 countries and regions. This means that we are a world's leading manufacturer and ...
SAG Mill Process Control What do you prefer? Controlling Weight (within a range) by manipulating mill speed and keeping a constant feed rate? Controlling weight by manipulating feed rate? Oberstorm 8 years ago Like Where do you see maximizing throughput subject to load maximum and upstream/downstream process constraints? Marshal Meru 8 years ago
Tracking the mill performance showed that the mill power consumption decreased from to kWh/t (a nearly 30% reduction), P 80 of the mill product decreased from 611 to 355 μm, and the mill fresh feed flow rate increased from 511 to 521 t/h by decreasing the feed ore hardness from 112 min to 58 min based on SAG power index (SPI ...
Control of SemiAutogenous Grinding (SAG) mill weight is an example of an important process that exhibits many of these aspects. Maintaining the SAG mill weight at the optimum value is critical for achieving maximum grind rate efficiency and mill production (Powell,, van der Westhuizen,, Mainza, 2009).
m length (190) single SAG mill equipped with a 20 MW electric motor. The SAG mill product flows to two m (120) by m (240) horizontal screens, whose combined oversize (pebbles) is diverted to two Metso MP 800 cone crushers. The crushed product returns to the SAG mill feed, closing the primary grinding circuit. The horizontal screen ...
parameters used by the AG/SAG mill model in JKSimMet which permits prediction of the product size distribution and the power draw of the AG/SAG mill for a given feed size distribution and feed rate. In a design situation, the dimensions of the mill are adjusted until the load in the mill reaches 25% by volume when fed at the required feed rate.
Inferential measurements of SAG mill discharge and feed streams and mill rock and ball charge levels, detailed earlier in the series, are utilised in a simulation environment. A multivariable ...
A generalized SAG mill power draw equation developed by Austin, is given by: where the parameters used in the model are defined as: mp= net mill power (kW) K = a constant (kW/ton ) D = mill internal diameter (m) L = mill length (m) J = fractional volume of mill filled by total charge. εB = effective porosity of the total charge.
SAG mills are the main workhorses in the majority of comminution circuits globally. They need to be fed and kept working round the clock. ... analyse incoming information from LoadIQ as well as ore properties and internal mill dynamics together with board power usage, mill weight and bearing pressure. It can then automatically take corrective ...
The correlation between the AG/SAG and ball mill circuit data is also very poor. Use of equation 2 shows a very different picture, the results being illustrated in Figure 7. This shows that on average the "M" operating work indices of AG/SAG and ball mill circuits are very similar and hence energy utilisation efficiencies are similar. Also
The variation of feed particle size significantly affects the overall process control, product quality, and economic performance of the mill [2] [3] [4]. Poor product quality from the AG/SAG mill ...
As one of the machines widely used in mining, a semiautogenous grinding (SAG) mill can significantly improve the roughing efficiency of rock. But the SAG mill still faces the obstacles of significant energy consumption and empirical operation parameters. In order to obtain the optimal operation parameters of a SAG mill, in this paper, the discrete element method (DEM) is used to simulate the ...
% solids by weight of discharge slurry 0 77 0 78 . It should also be remembered that power draws indicated in the control room of a concentrator may not ... Slurry pooling causes the power draw in AG and SAG mills to be lower than a mill without a slurry pool. This phenomenon results in overflow mills usually drawing less power than grate discharge
Figure 7: SAG mill power consumption as a function of the proportion of 152 +25mm in the fresh feed for SAG mills of different diameters (after Casili A. and Silva N.,2015) The equation developed ...
Ball mill is a fine grinder. A horizontal or vertical rotating cylinder which is filled partially with. the balls of ceramics, small rocks and balls made from stainless steel. The ball charge of a SAG. mill is about 29% to 30%. By friction and influence of tumbling balls inside rotating cylinder.
The SAG mill power draw model of Austin (using the calibration by Doll, 2013) is used to predict the process power draw at the mill shell, P shell, and the efficiency losses for the drive's ...
Published in MATERIA 2021;23:6366 The idea of minetomill optimization has been tested in various mines in last decades, resulting in higher mill throughput in many mines, but also ...
To achieve this purpose, a total number of 186 fullscale SAG mill works were investigated and the most effective parameters on SAG mill power,, feed moisture, mass flowrate, mill load cell weight, SAG mill solid percentage, inlet and outlet water to the SAG mill and work index were measured and utilized to develop the GEP model.
The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between and kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 percent of the ...
The AdaBoost algorithm begins by training a decision tree in which each observation is assigned a weight equal to ... A Mill Power Equation for SAG Mills. Min. Metall. Explor. 1990, 7, 5763. [Google Scholar] Moys, A Model of Mill Power as Affected by Mill Speed, Load Volume, and Liner Design. J.
This variation comes generally at a sacrifice in motor efficiency because the reduced power demand from the mill is lost in the speed control circuit. As mentioned above if the power is approximately 6000 horsepower or less a single pinion can be used, allowing the use of a synchronous motor and air clutch for low inrush applications.
Ball mill： Ball mills are the most widely used one. Rod mill： The rod mill has the highest efficiency when the feed size is <30mm and the discharge size is about 3mm with uniform particle size and light overcrushing phenomenon. SAG mill: When the weight of the SAG mill is more than 75%, the output is high and the energy consumption is low ...
The purpose of the primary crusher is to reduce the ROM ore to a size amenable for feeding the secondary crusher or the SAG mill grinding circuit. The ratio of reduction through a primary crusher can be up to about 8:1. Feed: ROM up to m. Product: 300mm (for transport) to 200mm (for SAG mill) Feed Rate:
SAG mill water flow rate SAG mill power vs. wear geometry maximizing kWhr/ton tons/hour in combination SAG mill liner changeout life/cycle vs. tons/kg consumed. Ball mill liner efficiency based on liner geometry and its influence on kWhours/ton, total tons/life cycle, and P80 transfer to cyclones. Ball mill grind is based on different ...
With our SAG mill running at % critical speed (mill RPM), the SER motor speed reference is 850 RPM or 85% of 1000 RPM. We are recovering approximately MW of slip energy; the power ...
The control strategy for the SAG mill is fairly basic. Parameters which can be adjusted are feed tons per hour and mill speed. The combination of the two are used to maintain a target feed trunnion bearing pressure of 520 psi, and power draw between 95% and 105% of available current (2,620 amps).
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