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power draw. The most frequently used power-based methodologies for calculating energy requirements for comminution circuits using AG/SAG mills are concisely presented in the following section. This paper describes the Orway Mineral Consultants (OMC) approach determining power requirements for thto e

A further explanation is required to explain the importance of designing the SAG mill chamber to draw required power at optimum operating conditions of 75% critical speed and less than 30% by volume load. Recent studies in the three-foot diameter SAG mill are instructive. The following graph shows the relevant facts as Figure 2.

The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills.

The no load power is a measure of some of the power losses in the gears, bearings and electrical components and is the gross power draw of the mill when empty, obtained either during commissioning of the mill or when ground out for a mill reline. Morrell [13] developed an empirical expression for the no load power draw of ball, SAG and AG mills as

The U.S. mining industry operates approximately 80 semi-autogenesis grinding mills (SAG) throughout the United States. Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills.

of the energy required by a SAG mill. Put another way, the SAG mill energy required according to this statement, is 2.5 times more than the Ab value to produce the same degree of particle breakage. There is a speci fi c gravity factor that affects AG/SAG power draw. The lighter material, in the 2.5 specifi c .

2. A SAG mill operates with a 10,000 hp motor. Typical power draw is 80% of maximum. The 80 percent passing feed size to the mill is 6 inches and the mill discharge has an 80 percent passing size of 2.3 mm. Calculate the Operating Work Index for this mill if the feed tonnage rate is 1175 tonnes per hour.

SAG mills use a ball charge of 8 to 21%. The largest SAG mill is 42' (12.8m) in diameter, powered by a 28 MW (38,000 HP) motor. A SAG mill with a 44' (13.4m) diameter and a power of 35 MW (47,000 HP) has been designed. Attrition between grinding balls and ore particles causes grinding of finer particles. SAG mills are characterized by their ...

predictions made by two published mill power draw models for SAG mills (Austin's SAG model and Morrell's C-model). A third model (Hogg and Fuerstenau) is fit to each survey and the principal fitting parameter is tabulated. Power measurement The nature of electrical and mechanical networks is that power is lost to various types of inefficiency as

The mill power draw, throughput and product size distribution are used to compute a specific energy input and the MacPherson autogenous work index (AWI). Although the importance to achieve steady-state in a grinding test is widely accepted (Bond tests), the MacPherson test remains the only small-scale AG/SAG mill test that offers this option.

reference and relative power draw formulas presented here will provide you the best overall characterization of the power draw of your SAG mill. 1-1: The Basic or Reference SAG Mill Power Draw Formula The following formula can be used to calculate SAG mill power draw as a function of mill operating conditions.

Kinross – Round Mountain SAG Mill Adaptive Control. In summary, by using the KnowledgeScape SAG mill adaptive control system (GrindingExpert™), we were able to increase production, increase power draw through increasing the grinding efficiency of the mill. These benefits easily justify the low cost of the system and system maintenance.

Using Monte Carlo simulation showed that the mean power draw of the Sarcheshmeh SAG mill is about 9349.75 kW with a standard deviation of 983.2 kW, with the highest frequency occurring between ...

maximum power draw well below the installed power. Typically, at startup post SAG mill reline, the maximum operable speed ranges are reduced to minimise direct shell impacts due to the steeper face angle of the lifters. This operational approach severely limits available power draw by the mill to maintain higher throughputs for competent ores.

operating at 90% of its maximum power. The combined power draw of the SAG mill and ball mill was 8658 kW, which caused partial over-grinding. From experience in processing plants outside of China, the power rating of the ball mill should be higher than that of the SAG mill [5]. The pebble crusher had an over-powered configuration.

Mill power Usually, plant operators use mill power readings as an indicator of ball filling degree and, often, try to keep it at the maximum level. It is well known that the mill absorbed power depends on operating parameters other than ball level, such as pulp density and liner configuration. Figure 2 shows that there is no linear relation between

SAG mills • Determination of your SAG mill's power draw characteristics. • SAG Mill Steel Charge Estimation tool provides an estimate of the percent steel in the charge of your SAG mill based on the power draw and the total charge volume. • Ball impact energy chart to determine the impact energy of balls as a function of mill diameters.

A motor with around 1400 Horse Power is calculated needed for the designed task. Now we much select a Ball Mill that will draw this power.. The ball mill motor power requirement calculated above as 1400 HP is the power that must be applied at the mill drive in order to grind the tonnage of feed from one size distribution. The following shows how the size or select the matching mill required to ...

Grinding mills: how to accurately predict their power draw. ... In total 76 data sets were generated covering the power draws of ball, SAG and AG mills in the range 7 - 7900 kW. ...

SAG mill design CDM Consulting used to test Rocky DEM power draw Empirical Model Rocky DEM Model Figure 1 - Morrell C-model for mill power draw Rocky calculations for power draw were shown to accurately replicate Morrell's C-model for power draw, an increasingly critical component in mill .

Modelling SAG milling power and specific energy consumption including the feed percentage of intermediate size particles ... ables with the dependent variables SAG mill power and specific energy, to assure models with fixed parameters. ... a significant portion of the power draw.

It follows that SAG mill process control systems that target maximum SAG motor power will not necessarily result in the maximum milling rate. Instead, SAG mill process control systems that aim to maximize SAG mill federate should target operation at the optimal volumetric mill filling for .

If the mill feed setpoint is changed, then the actual feed rate needs to stabilise at the new target in a short period of time. The feed rate setpoint can then be tied into a SAG mill power optimisation strategy. SAG mill discharge control is quite involved due to few interactive variables, such as mill discharge sump level, classification ...

For the mill with higher mill load and lower speed, the power draw of the mill differed slightly for the different lifters with the same face angles of 20o. Rail lifter drew higher mill power and lower power for Hi-Lo lifter. The Hi-Lo lifter relatively indicated improvement in the energy efficiency of the mill approximately 22%.
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