Influence of feed size on AG/SAG mill performance ... with sag mills being increasingly less so as the ball charge is increased. ... 1 10 100 1000 help reduce the effect of short term non-ag/sag mill production Size (mm) stoppages, using secondary crushing to increase throughput and More intense blast Standard blast modifying blast intensity ...

EFFECTS OF GRINDING MEDIA SHAPES ON BALL MILL PERFORMANCE Niyoshaka Nistlaba Stanley Lameck A dissertation submitted to the Faculty of Engineering and The Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, October 2005

The data indicated that the effect of increasing speed, ball charge or ball size in SAG mills was to increase the degree of coarse particle breakage, often with an associated reduction in the ...

SAG mill. SAG is an acronym for semi-autogenous grinding. 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) …

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 ...

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 ...

Jun 19, 2015 · A Ball Mill Critical Speed (actually ball, rod, AG or SAG) is the speed at which the centrifugal forces equal gravitational forces at the mill shell's inside surface and no balls will fall from its position onto the shell. ... The effect of ball size on mill performance - ScienceDirect. May 01, 1976 · The specific rates of ...

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)

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 ...

In ball milling applications, the diameter of the balls, mill and throw action of the charge provides a low-impact environment– hence maximum abrasion resistance of steel balls is the desired characteristic. CHEMISTRY & HARDNESS High carbon content and high hardness levels affect abrasion resistance in …

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

The final plan was to increase the ball charge in the SAG and ball mill to 10% v / v and 27% v / v, respectively; set the upper limit of the operating power in the ball mill to 5800 kW; use a TRIO TC Series crusher (without a power-/feed rate–controlling device, but with a feed bin) to crush pebbles for recirculation back to the SAG mill feed ...

8-3 Centrifugal force outward Fc mp& 2 Dm 2 (8.1) & is the angular velocity, mp is the mass of any particle (media or charge) in the mill and Dm is the diameter of the mill inside the liners. Gravitational force Fg mpg (8.2) The particle will remain against the wall if these two forces are in balance ie.

effect of ball charge, mill filling, feed size distribution and mill ... Some researches study how feed size affect on the AG mill performance ... the strength properties of the SAG mill feed and ...

This effect would also lead to improved performance. Evidence of this effect of the studs upon the packing of the charge appears in Fig. 6.13b, for the balls are clearly seen to lie in rows in the mill instead of in completely random array. 16 Types of GRINDING MILL Shell Liners & Designs; 16.1 A-C LORAIN SHELL LINERS; 16.2 WAVE BALL MILL SHELL ...

of the SAG mill is transferred onto a vibrating screen. The oversize material is crushed in a pebble crusher, and the undersize is combined with the ball mill (6.71 × 9.91 m) discharge and sent to the cyclones. The SAG mill in phase 1 uses two 4100 kW synchronous motors and works with a constant 10.5 rpm rotational speed in two

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 grinds the raw material to the required fineness.

The effect of circulating load and classification efficiency on the performance of ball mill circuits is compared to the effect on HPGR circuits. The fundamentals of grinding behavior are also ...

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% ...

The shell liner type, rotation speed, and ball filling percent are the key factors influencing the charge behavior inside the SAG mills, and consequently, their performance. In this

The ball-mill may lack sufficient impact energy to effect breakage of these particles, which are referred to as 'scats'. They may find their way into a ball-mill circuit as a result of wear of the trommel or due to a deliberate change of the aperture size, to increase SAG mill throughput. E.g.

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 ...

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.

Based on experience, mill-liner designs have moved toward more open-shell lifter spacing, increased pulp lifter volumetric capacity, and a grate design to facilitate maximizing both pebble-crushing circuit utilization and SAG mill capacity. As a guideline, mill throughput is maximized with shell lifters between ratios of 2.5:1 and 5.0:1.

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 ...

It is possible then to incorporate this information into a grinding model and investigate the effect of the make-up ball size on the mill performance with various feed and product specifications. Concha et al. was the first to combine a grinding circuit model with a ball wear model to optimize the make-up ball charge. With an optimization ...

A laboratory tower mill was used to investigate the effect of some variables on the power requirements of a plant mill. The grinding laws were tested for fine grinding and Charles` law and Rittinger`s law was found to most closely satisfy the experimental data. The effects of ball size, ball charge mass and media type were investigated.

and affect overall mill performance. Using a smaller, not larger, bucket size to focus the impact of the charge at the toe, along with increasing mill speed as shell lifters wear, is a promising current development in shell liner design and SAG mill opera-tion providing the …

Abstract. Ball mills are equipments which has balls as grinding media and used for last step of grinding process. There are many factors which effect grinding performance of ball mills like; liner ...

A laboratory tower mill was used to investigate the effect of some variables on the power requirements of a plant mill. The grinding laws were tested for fine grinding and Charles` law and Rittinger`s law was found to most closely satisfy the experimental data. The effects of ball size, ball charge mass and media type were investigated.

A new ag/sag mill model has been developed which is based on the dynamics of the grinding charge as well as its size distribution and composition. The effects of changes in such operating conditions as feedsize distribution and ball charge level are inherently described within the model as is the effect of changes to the height and shape of the ...

Mining, Metallurgy & Exploration. SAG mill liner development draws primarily on practical experience from SAG milling operations supported by computer-based modeling of charge motion in SAG mills and on established good design practice. Liner design needs to respond to the process aspects of mill liner action that are critical to good SAG mill ...

in AG/SAG mills, which are showed schematically in Figure 1and described below. • Impact, here referred as the action of a falling charge element, including balls or rocks, onto the particles lying on the exposed part of the charge. • Abrasion, which includes the rubbing action of rock particles against each other, against balls or mill lin ...

At 8 – 12 % v/v ball charge volume, and 25 – 35% v/v total charge volume the SAG mill typically draws 10 –. 11 MW. The operating work index for the mill is extremely ore. depe ndent and can ...

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 ...