sag mill feed size distribution

Control of Size Distribution of the Ore Feeding a Semi ...

A control strategy for the ore feed size distribution is assessed using a simulator of the ore stockpile operation.INTRODUCTIONThe popularity of autogeneous (FAG) and semi autogeneous (SAG) grinding mills has been increasing over the last 20 years (Napier Munn et al., 1996).

PARTICLE SIZE DISTRIBUTION ANALYSER

• Monitoring the feed to a SAG or AG mill (e.g. to ensure sufficient proportion of large particles to assist in grinding). • Assessing crusher output (e.g. to ensure crushing / screening is working as expected). • Monitoring the product. • Optimising raw material mix for downstream processing. • Monitoring HPGR feed to ensure fraction

AG - Autogenous & SAG Semi-Autogenous Mill Design Calculations

Apr 17, 2018· A typical calculation is given in the following example: Product Size: All passing 6 mesh with 80% passing 20 mesh. Mill, gear and pinion friction multiplier: 1.025. Mill Power required at pinionshaft = (240 x 16.5 x 1.025) ÷ 0.746 = 5440 Hp. 5440 Hp ÷ 0.98 = 5550 HP (required minimum motor output power).

Development of a Multi-Component Model Structure for ...

mill contents of an autogenous industrial mill was measured in terms of size and mineral distribution, during a survey conducted at LKAB operations in Sweden. The breakage and transport in AG/SAG mills was found to depend on the physical properties and proportion of the different components in the mill feed.

Mine-to-Mill: The influence of feed size on AG/SAG milling ...

In this presentation an historical perspective of the origins of Mine-to-Mill is described and is followed by a discussion of how AG/SAG feed size affects throughput and specific energy and the factors that in turn influence AG/SAG feed size, such as ore hardness, Run of Mine (RoM) size distribution …

IMPROVEMENTS IN SAG MILL THROUGHPUT FROM …

study focussed on ball mill limited material from the Apensu open pit. Following a benchmarking study of all blasting, crushing and grinding practices in January 2009, PTI recommended changes in both blasting and crushing conditions in order to generate a finer feed size to the SAG mill.

O. I. SKARIN N. O. TIKHONOV CALCULATION OF THE …

Distribution of energy between WAM and CDBM mills In 1989, within the framework of the conference on SAG milling, Barratt presented another formula for SEC required for WAM comminution of minerals from F 80 to the size T 80 [9]: E WAM = (6) where T 80 is the size of 80% content of ball mill feed in WAM — CDBM circuit (typically 1000–3000 ...

Modelling SAG milling power and specific energy ...

Specific energy model on data of four SAG mills. ... but adding a variable that represents the feed size distribution. Operational data from 4 grinding circuits corresponding to 3 Chilean copper concentration plants are used and the % −6″ +1″ (−152 +25 ...

Throughput optimisation in milling circuits

Rock Size Distribution. Rock Distribution of bulk material ie. mineral ore. ... SAG Mill Discharge. Controlling the feed and discharge of a mill is mostly a stabilisation exercise – you need to be able to quickly and accurately control the mill feed rate. If the mill feed setpoint is changed, then the actual feed rate needs to stabilise at ...

Modelling SAG milling power and specific energy ...

Jan 01, 2015· The feed size distribution is also the implicit result of the ore competence (affecting blasting and crushing performance). This distribution affects the SAG mill load and the load affects directly the mill power and the efficiency of the mill operation (Van Nierop and Moys, 2001). If a SAG mill has been designed with a conventional power or ...

Ø Effect of SAG Mill Feed Size Distribution and Ore ...

Ø Manipulation of SAG Mill Operating Parameters (eg. load, ball charge, speed and density) Ø Maximising Pebble Recycle Load and Crusher Interaction With the SAG Mill I-12 Ø Effect of SAG Mill Feed Size Distribution and Ore Variability Ø Mill liner design modifications, and Ø Circuit Design Considerations That Influenced Throughput

Chapter - M MODELLING, SIMULATION, OPTIMIZATION

operation fluctuations. To sample SAG mill fresh feed, belt conveyor was stopped and a sample was taken by removing material over a two-meter length. Operating condition during sampling was recorded. Particle Size distribution of all samples except mill fresh feed and scats reject was determined using 6730 to 38 µm screens.

Inferential measurement of sag mill parameters IV ...

Oct 01, 2009· The oversize crusher feed size distribution (oscf) and the primary cyclone feed size distribution (pcfd) are estimated utilising the SAG mill grate size and discharge screen aperture sizes and the Rosin–Rammler size distribution function, which has been selected for its convenience and since it "has been found to fit many size distributions ...

feed size for sag mill - stomatologie-dentalnihygiena.cz

The capacity of the SAG mill is related to lots of factors such as feed size, size distribution, discharge size and grindability, etc., and it should be confirmed according to the actual situation. SM40*14'——means it is a dry mill. Read More Mine-to-Mill: Changing AG/SAG feed size through . 2021-4-27 Mine-to-Mill: Changing AG/SAG feed ...

Application of Operating Work Indices in Autogenous ...

AG/SAG mill product that needs additional grinding in the ball mill, or "Corrected Ball Mill Feed." T2' is the 80% passing dimension of the Corrected Ball Mill Feed. Figure 1. Comparison of the Particle Size Distribution Slopes Figure 2. Relationship Between the Transfer Size Distribution Slope and T 80 or AWi0/BWi Figure 3.

A General Model for Semi-autogenous and Autogenous …

an 8 m diameter SAG mill with LID = 0.5 grinding a copper ore, and predicted maximum capacity and minimum kWh/ton at about 6070 ball load at 25070 ... complex function of the feed size distribution and specific rates of breakage. However, it is still convenient to define a mean residence time by solid hold-up W divided by solid feed rate, ...

MILLING CONTROL & OPTIMISATION - MINTEK

• Stabilise the mill feed. ... feeder to determine the size distribution of feed material. ... Figures 8 and 9 on the right show results from a gold plant's SAG mill achieved with MillStar's Segregated Ore Feed Controller combined with the Power Optimiser:

t10 (%) Weighted Fit 63 x 53 - SMC Testing

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 . 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 4 t10 (%) Ecs (kWh/t) Weighted Fit 63 x 53 45 x 37.5 31.5 x 26.5 22.4 x 19 16 x 13.2

Taking Control of the Mill Feed R2 - Orway

The effect of feed size in AG/SAG milling has been studied extensively with an early review presented by Abel (1997), whilst the relationship between changes in feed size and comminution has been covered by a number of authors under the banner of "Mine to Mill" (Morrell and Kojovic, 1999).

A Neural Network Model for SAG Mill Control

SAG specific power range of about 3 to 9 kWh/t for this site. The design of the ore stockpiling and conveying system contributes to fluctuating size distribution with significant short-term segregation occurring under certain operating situations. Depending on ore type and feed size distribution, each SAG mill will process between 700 and 3000 tph.

SIMPLIFIED GRINDING MILL CIRCUIT MODELS FOR USE IN …

3.3 Cumulative distribution for solids feed, mill charge and sump charge represented by 25, 9, 5 and 3 size classes. (Ref - the reference size class set, l - size classes are log-linearly separated, c - separation between size classes is chosen.) . . . . . . . . . 35 3.4 Manipulated variables MFS and MIW for each controller of the seven size ...

AN OVERVIEW OF SINGLE STAGE AUTOGENOUS AND …

efficient, single stage SAG milling is likely to be the most profitable grinding circuit design. 2. Medium Grind – 80% passing size between 106 and 75 µm. To mill in single stage SAG configuration, the feed must be consistent, not too coarse or too fine. The downstream process must be able to handle fluctuations in the grind size. If these

THE OPTIMAL BALL DIAMETER IN A MILL

in a mill should be proportional to grain number N having the definite diameters which they can grind: N b ~ N. (7) The number of grains of the material with determined diameters depends on the grain size distribution. For a great number of materials the grain size distribution at the ball mill feed has been described by Gaudin-Schumann's ...

The SAG grindability index test - ScienceDirect

Jan 01, 2014· The mill reportedly rotates at 70% of critical velocity (Verret et al., 2011), or 54 rpm (Gonzalez, 2000).There is controversy surrounding the mill rotational speed. The calculation of mill critical velocity (V c) is derived from the balance of gravitational force and the centrifugal force acting on a ball, and is given by Eq., after Austin and Concha (1994) (1) V c = 42.2 (D-d) where D is the ...

Multi-component AG/SAG mill model - ScienceDirect

Apr 01, 2013· The breakage rate distributions are affected by a number of operating conditions. Morrell and Morrison (1996) modelled the effect of ball charge, mill filling, feed size distribution and mill speed on each breakage rate. The resulting 5 empirical equations are embedded in the current JKSimMet Variable Rates AG/SAG model.

SAG Mill Grinding Circuit Design - 911metallurgist.com

Jun 06, 2016· By combining with SAG discharge and screening on the SAG discharge screens, top size control to the ball-mill circuit feed is maintained while still unloading the SAG circuit (Mosher et al, 2006). A variant of this method is to direct pebble-crushing circuit product to the ball-mill sump for secondary milling: while convenient, this has the ...

Blasting design for increased SAG mill productivity ...

Nov 01, 1993· SAG mill throughput is often a bottleneck to increasing plant productivity. Improved size distribution control in the mill feed can be used to increase mill production. This can be accomplished by controlling blast fragmentation as a function of energy input and rock characteristics. Such an approach requires the integration of rock fragmentation and comminution modeling.

SAG Mill Feed Particle Size Analyser - 911metallurgist.com

Mar 30, 2018· We describe here one of the very first pioneering SAG Mill Feed Particle Size Analysers: A set of preliminary experiments was carried out in order to assess the hardware-software's behaviour.Static ore was used to obtain the right sequence of image processing algorithms. The camera was installed 3 mts away from the commercial sizer over the feed conveyor of the SAG Mill.