## STARTLING EFFECT OF BALL SCATS REMOVAL ON SAG MILL

The only noted work related to worn balls was the study of effects of scats removal on SAG mill performance (Powell & Smit, 2001). This work does not give insight into what the effects

## effect of balls charge on sag mill performance

The Effect of the Grinding Charge Trajectory on the . and optimal grinding charge trajectory for the SAG Ball and Rod Mills. • Identified potential benefits could be obtained with an ideal grinding media charge mill speed as well as optimisation of lifter profile (specialty lifter face 20 angle) which is directly related with mill power draw internal motion of mill charge

## STARTLING EFFECT OF BALL SCATS REMOVAL ON SAG MILL

Mill grind out In order to measure the ball load in the mill, the feed to the mill was stopped and it was ground out to a ball charge only. As a result of slurry pooling in the mill, the surface of the charge could unfortunately not be inspected, and the 9.7% ball level was measured relative to

## Optimization of mill performance by using

charge motion. It is well known that ball milling efficiency varies during the lifetime of the shell liner. For instance, the mill performance could become worse or better by putting in a new shell liner. Data from pilot plant test work illustrates the influence of the shell lifting effect on

## Ball Charge and Grinding Efficiency - Grinding ...

SAG lifter and end cone geometry - can change SAG mill performance more than 20%-50% depending on P80 transfer size and Axb, some of which is published and some will be published at SAG 2015. SAG mill wear rates and performance changes with wear morphology, grate details, mill speed changes and optimization with speed control Ball feed size SAG ...

## effect of balls charge on sag mill performance

SAG mills are autogenous mills that also use grinding balls like a ball mill. A SAG mill is usually a primary or first stage grinder. 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 ...

## Factors Affecting Ball Mill Grinding Efficiency

Oct 25, 2017 · The following are factors that have been investigated and applied in conventional ball milling in order to maximize grinding efficiency: a) Mill Geometry and Speed – Bond (1954) observed grinding efficiency to be a function of ball mill diameter, and established empirical relationships for recommended media size and mill speed that take this factor into account.

## SAG Mill Grinding Circuit Design - 911metallurgist

Jun 06, 2016 · Ball charge (fraction of volumetric loading and ball size) Mill operating conditions including mill speed (for circuits with variable-speed drives), density, and total mill load; The effect of feed hardness is the most significant driver for AG/SAG performance: with variations in ore hardness come variations in circuit throughput. The effect of ...

## (PDF) Influence of feed size on AG / SAG mill performance

Influence of feed size on AG / SAG mill performance. January 2001; ... with sag mills being increasingly less so as the ball charge is increased. ... 00 fraction that shows a positive effect on ...

## (PDF) Understanding the effects of liner wear on SAG mill ...

Understanding the effects of liner wear on SAG mill performance. ... significantly affect the trajectory of the charge are ... mill power requirements based on the A*b and Bond ball mill work ...

## The Effect of the Grinding Charge Trajectory on the ...

SAG Mill 2 Ball Mill Simulations of the Mill Power Effect on the Throughput Conclusions. ... zone from ball charge in the mill. - Also they allow to determine the single energy at impact, ... The Effect of the Mill Power on the Throughput 8200 8300 8400 8500 8600 8700

## Optimization of the make-up ball charge in a grinding mill

The −20 + 10 mm fraction pebbles are compared with steel balls as media for grinding of a copper concentrate in a vertical stirred mill, which obtained from a 7.0 m diameter × 3.5 m SAG mill at ...

## SAG Mill Grinding Circuit Design - 911metallurgist

Jun 06, 2016 · Ball charge (fraction of volumetric loading and ball size) Mill operating conditions including mill speed (for circuits with variable-speed drives), density, and total mill load; The effect of feed hardness is the most significant driver for AG/SAG performance: with variations in ore hardness come variations in circuit throughput. The effect of ...

## Modelling SAG milling power and specific energy ...

inside the mill and it is composed of balls, ore and water. The ball charge is a function of the bulk fraction of the SAG mill volume (Jb) occupied by balls; the ore retained in the mill is the result of the volumetric ﬁlling which depends on the ore size distribution (spe-cially the % +600 and the % 600 +100), on the rotational speed (N/Nc)

## FREDA REBECCA SAGMILLING CIRCUIT OPTIMIZATION

respect with SAG mills being increasingly less sensitive as the ball charge is increased (Morrel S and Valery W, 2001). 2.2. EFFECT OF FEED SIZE DISTRIBUTION ON SAG MILLING The qualitative eﬀect of changes in particle size distributions (PSD) on the SAG mill performance can be addressed by using the grind curves.

## (PDF) A comparison of wear rates of ball mill grinding media

abrasive and impact wear due to their large. (75 – 100 mm) dia meters. Ball mill balls. experience a greater number of impacts, but at. lower magnitude than SAG mill balls, due t o. the smaller ...

## (PDF) AG and SAG mill circuit selection and design by ...

The effects on mill performance of a varying ratio of these two components in the mill feed are not well described by the current generation of AG/SAG models (Stange, 1996). ... ball charge or ...

## Effect of operating condition changes on the collisional ...

Mar 01, 2019 · It is common practice to run SAG mills to maximize ball-to-rock ratios to increase the frequency of ball-charge interactions and to thereby improve mill throughput (Royston, 2007). A higher rock fraction usually tends to increase the fineness of the grind due to longer residence times of the rock particles within the mill.

## how does the speed of ball mill affect productivity

The Effect of the Grinding Charge Trajectory on the . Ball Mill Simulations of the Mill Power Effect on the Throughput Conclusions Introduction At the moment the conventional grinding technologies of SAG and Ball The Effect of the Mill Speed on the Charge Trajectory Changing mill speed by 0 8 rpm to 10 8 the motion becomes more

## Size Distribution SAG Mill Balls | Crusher Mills, Cone ...

effect of balls charge on sag mill performance. and the effect of manipulating the feed particle size distribution were of particular SAG mill design,SAG mill for sale for the ball milling process

## Ball Mill Loading - Dry Milling - Paul O. Abbe

The starting point for ball mill media and solids charging generally starts as follows: 50% media charge. Assuming 26% void space between spherical balls (non-spherical, irregularly shaped and mixed-size media will increase or decrease the free space) 50% x 26% = 13% free space. Add to this another 10%-15% above the ball charge for total of 23% ...

## (DOC) Main text | Gurubasayya Swamy - Academia.edu

RESULTS AND DISCUSSIONS Performance of SAG Mill is measured in terms of throughput and energy consumption. Effect of total load and balls load on SAG mill performance SAG Mill total load and balls load have a marked influence on mill performance. The most important factors affecting the breakage efficiency are in fact charge volume and mill speed.

## Investigation of Effect of Number of Lifters on ...

The number of lifters of mill shell liners, mill rotation speed, and filling percentage of grinding media are three of the most important parameters influencing the charge behavior and the trajectory of ball motion inside the SAG mills, and consequently, their performance. In this paper, the milling operation of pilot-scale SAG mills using the discrete element method (DEM) is investigated.

## A method to predict shape and trajectory of charge in ...

Jun 01, 2013 · To explore various charge shapes and trajectories, the model mills were operated at 55%, 70% and 85% of critical speed for five levels of mill filling (10%, 15%, 20%, 25% and 30% by volume). The special design of the model mill which enabled gradual increase of the mill length so as to minimize the impact of the end-wall effect.

## Modelling SAG milling power and specific energy ...

Jan 01, 2015 · The ball charge is a function of the bulk fraction of the SAG mill volume (Jb) occupied by balls; the ore retained in the mill is the result of the volumetric filling which depends on the ore size distribution (specially the % +6″ and the % −6″ +1″), on the rotational speed (N/Nc) and on the solid concentration by weight fraction inside ...

## Modelling SAG milling power and specific energy ...

inside the mill and it is composed of balls, ore and water. The ball charge is a function of the bulk fraction of the SAG mill volume (Jb) occupied by balls; the ore retained in the mill is the result of the volumetric ﬁlling which depends on the ore size distribution (spe-cially the % +600 and the % 600 +100), on the rotational speed (N/Nc)

## Performance enhancement tools for grinding mills

SAG and ball mills have grown in size and there are now ... Effect of mill speed and lifter profile on load trajectors Figure 2. Schematic view of ball trajectories. ... The varying nature of mill charges is such that there can be many combinations of balls, mineral and water having the same weight but

## effect of balls charge on sag mill performance

Modelling SAG milling power and specific energy. 2017-12-14 inside the mill and it is composed of balls, ore and water. The ball charge is a function of the bulk fraction of the SAG mill volume (Jb) occupied by balls; the ore retained in the mill is the result of the volumetric ﬁlling which depends on the ore size distribution (spe-cially the % +600 and the % 600 +100), on the rotational ...

## Ball Mill Loading - Dry Milling - Paul O. Abbe

The starting point for ball mill media and solids charging generally starts as follows: 50% media charge. Assuming 26% void space between spherical balls (non-spherical, irregularly shaped and mixed-size media will increase or decrease the free space) 50% x 26% = 13% free space. Add to this another 10%-15% above the ball charge for total of 23% ...

## Semi-autogenous grinding (SAG) mill liner design and ...

Mill speed increase (Royston, 2007) can increase both impacts of balls at the toe and charge turnover, improving mill performance through increased 'ball-charge participation' although as mill ...

## how does the speed of ball mill affect productivity

The Effect of the Grinding Charge Trajectory on the . Ball Mill Simulations of the Mill Power Effect on the Throughput Conclusions Introduction At the moment the conventional grinding technologies of SAG and Ball The Effect of the Mill Speed on the Charge Trajectory Changing mill speed by 0 8 rpm to 10 8 the motion becomes more

## High recirculating loads in Ball Mill Circuits - Grinding ...

The ball mill has higher circulation load, it generates only 30 -35% of actual fines you require to be called as product. If your product size needed is 100% passing 45 micron, then the ball mill total discharge material will contain normally 30% of 45 micron. The rest is oversize which has to be ground again.

## The effect of ball size distribution on power draw, charge ...

2014). However, the horizontal planetary ball mill is different than the tumbling ball mill in many aspects. Djordjevic (2005) studied the influence of ball charge size distribution on the net-power draw of tumbling mill based on DEM modeling. Charge of the mill was composed from the spherical balls

## Ball Mill Design/Power Calculation

Jun 19, 2015 · The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating % solids or pulp density, feed size as F80 and maximum ‘chunk size’, product size as P80 and maximum and finally the type of circuit open/closed ...

## FREDA REBECCA SAGMILLING CIRCUIT OPTIMIZATION

respect with SAG mills being increasingly less sensitive as the ball charge is increased (Morrel S and Valery W, 2001). 2.2. EFFECT OF FEED SIZE DISTRIBUTION ON SAG MILLING The qualitative eﬀect of changes in particle size distributions (PSD) on the SAG mill performance can be addressed by using the grind curves.

## The impact of end-wall effect on the charge trajectory in ...

Nov 10, 2015 · When the same experiments were performed using an iron ore instead of balls with the same size range, the impact of end-wall effect was more pronounced. For a mill length of 3.6 cm, an increase of 30% in the speed (from 55 to 85%) with the iron ore charge, the torque decreased by 41% (from 3.7 to 2.2 kgf·m) when mill filling was 30%.

## (PDF) Exploring the effect of blast design on SAG mill ...

Exploring the Effect of Blast Design on SAG Mill Throughput at KCGM S S Kanchibotla 1, S Morrell 1, W Valery 1, P O'Loughlin 2 ABSTRACT Traditionally blasts in mining operations are designed to prepare the in-situ rock mass for excavation and subsequent transport without giving much consideration to the downstream comminution processes.

## How To Calculate Mill Charge Level

Choosing a SAG Mill to Achieve Design Performance - Starkey ... Figure 2: Pilot Plant kg/hr Vs Charge % by Volume. This data is ... load (as determined by a quick measurement of the charge level with the mill stopped), was. ... The effect of mill charge is primarily through the shifting of the center of gravity and ..... by comparison to the ...