types of charges in sag mill

The charge level of a mill can be described as the volume occupied by the grinding media (including empty spaces) as a fraction of the total volume available inside the equipment. Assuming this definition, other measurements may be taken considering the total charge that includes the rock charge; in this case, applicable to SAG and AG mills.

The grinding plant consists of an SAG mill of 10 4 m diameter x 5 18 m length with a 12 000 kW dual COMBIFLEX drive and a ball mill of 7 3 m diameter x 10 5 m . Ball Mill And Sag Mill tivlabs Ball Mill Manufacturer Germany Grinding Capacity Plants Mesin Model Predictive Control for SAG Milling in Miner SAG and ball mills are generally accepted as .

Peripheral and trunnion discharge – For cylindrical mills which are continuously fed, the discharge of the ground product can be either through the periphery of the mill (peripheral discharge) or through the far end of the mill (trunnion discharge). Tumbling mills

In Mineral Processing Design and Operations (Second Edition), 2016. 8.3.1 Rod Mill Charge. Rod mill charges usually occupy about 45% of the internal volume of the mill. A closely packed charge of single sized rods will have a porosity of 9.3%. With a mixed charge of small and large diameter rods, the porosity of a static load could be reduced even further.

The Ball Mill, the Pebble Mill and the SAG Mill are 3 of the most popular types of mills on the industrial market. They are primarily used for the Mining industry, but they can also be used in the Chemical & Processing industry which has it's own category page for those listings here: Ball, Pebble, SAG Mills for Chemical Use .

For example, the SAG mill may have 10 MW of power draw available and the two ball mills each of 7.5 MW of power draw available for a total of ratio of 10:15 (1:1.5). The software uses the particular power model (Bond/Barratt, Morrell Mi, etc.) to determine what is the transfer size where the ratio of E SAG to E ball matches the ratio of mill ...

Ore hardness plays a critical role in comminution circuits. Ore hardness is usually characterized at sample support in order to populate geometallurgical block models. However, the required attributes are not always available and suffer for lack of temporal resolution. We propose an operational relative-hardness definition and the use of real-time operational data to train a …

Even though Semi Autogenous Grinding (SAG) and Autogenous Grinding (AG) mill charges contains less balls and no steel balls respectively, their large mill volumes can become quite heavy as well. In all three cases (Ball, SAG or AG mill), when the equipment is stopped, the material inside can dry up over time to form a solidified charge.

The effect of mill charge is primarily through the shifting of the center of gravity and the mass of the charge. As the ... Figures 8.5 for the popular mill types. 3 c is the mill ... LG A mill power equation for SAG mills. Minerals and Metallurgical Processing. Feb 1990 pp57-62.

The slurry and ball charge adheres to the walls of the mill before cascading off at a given angle causing impact and fragmenting the ore (Nunez F, 2011). There are different types of SAG mills; low aspect, medium aspect and the high aspect. The aspect ratio here refers to the ratio of the mill diameter to length.

Principle of SAG Mill operation. 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%.[6][7] The largest SAG mill is 42′ (12.8m) in diameter, powered by a 28 MW (38,000 HP ...

Attrition mill is a type of grinding mill by kinds of media to crush lump to powder-like substances. The impact can be rock on rock such as in an Autogenous Grinding (AG) mill, rock and a small ball charge (~10%), used in Semi Autogenous Grinding (SAG) mills, balls of various sizes in Ball Mills and less commonly these days, steel rods in Rod Mills.

CHARGE LEVEL. Maintaining an optimum charge in a SAG mill remains one of the fundamentals for efficient mill processing. If the charge level or the ball to charge ratio is incorrect, breaking liners and/or increasing power consumption is inevitable and can only result in degraded mill efficiency.

secondary mill power that permits the range of vari- ability samples to be processed according to whether a "SAG Mill limiting" condition, i.e., harder ore, or a "Ball Mill limiting" condition, i.e., softer ore exists. For example, a ratio of 1:1.5 or up to 1:2 would indicate a trend away from processing harder ore types and

A SAG mill is generally used as a primary or first stage grinding solution. SAG mills use a ball charge of 8 to 21%. The largest SAG mill is 42' in diameter, powered by a 28 MW (38,000 HP) motor. A SAG mill with a 44' diameter and a …

An optimization is carried out to minimize the yearly cost of energy for the operation of the SAG mill. This cost includes the energy consumption cost in $/kWh and the capital cost for the PV-BESS infrastructure, prorated over the life of the battery system, accounting for the discount rate through an annuity factor (Pamparana et al. 2019a, b).The energy requirements …

The SAG mill was installed with a low ball charge, no variable speed and a fine grind was targeted (P80 106 µm). High circulating loads and difficulty achieving the target grind size were experienced. This type of ore should have been treated in a high ball charge SAG mill with variable speed capability.

Semi-Autogenous Grinding (SAG) Mill Wet or dry Higher capacity than A-G mill grinding Primary, coarse grinding (up to 400 mm feed size) Grinding media is grinding feed plus 4-12% ball charge (ball dia.100- 125 mm) High capacity (short retention time) Less sensitive to feed composition (critical size material) Semi-Autogenous Mill

Ball-limited circuits (where the T 80 hits the lower limit) will result in the charge level in the SAG mill dropping until its power draw matches the throughput limit dictated by the ball mill. It is important to realize that once the SAG mill charge level drops to be equal to the ball charge, the model will be operating "out of range" and the ...

between this type of primary grinding mill and AG/SAG mills. Keywords: surface vibration, AG/SAG mills, primary grinding, instrumentation, process control INTRODUCTION . Plant operators are increasingly reliant on instrument measurements to gauge the real time operational status of critical plant equipment.

The SAG mill had a 6–8% ball charge and the power consumption was 8 kWh/t, which agreed well with the expected value. 9.6. Problems. 9.1. In an SAG mill the dimensions of the mill were 9.75 m × 3.5 m and the specific gravities of the mineral and that of the balls charged were 4.1 and 7.9, respectively.

The mill design allows the rate of generation of fine material to be measured in close to real time for autogenous and SAG mill charges. The updated simulation model estimates mass loss …

To calculate grinding media charge for continuous type ball mill, M = 0.000676 x D2 x L Example … how to calculate cement grinding mill balls charge – Mining FLshanghai ball mill for cement grinding. cement mill is a corrugated …

In addition to high impact SAG mill grinding, media is used in other types of milling such as the finer grind of ball mills, tower mills, vibration mills and regrind mills. Many variables influence the size reduction performance in a mill, including the media size, shape & quality, the properties of the incoming ore feed, the ratio of feed to ...

SAG mills of comparable size but containing say 10% ball charge (in addition to the rocks), normally, operate between 70 and 75% of the critical speed. Dry Aerofall mills are run at about 85% of the critical speed. The breakage of particles depends on the speed of rotation.

3 SAG mill (8 – 15% ball charge) Variable competency ore 4 High ball charge SAG mill (15 to 25% ball charge) Incompetent ore 5 Low ball charge SAG mill, high mill speed. (4% ball charge, 90% Nc) A cross between AG and SAG for competent, abrasive ores. As typically operated in RSA. 6 SAG mill (configurations 3, and 5 ) with recycle crusher

The biggest characteristic of the sag mill is that the crushing ratio is large. The particle size of the materials to be ground is 300 ~ 400mm, sometimes even larger, and the minimum particle size of the materials to be discharged can reach 0.1 mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mill's ...

ear for the mill and has the ability to accurately detect ball-to-liner impact occurrences. By quantifying the charge toe angle, or the media angle (βdynamic), on each rotation, a precise control strategy based on the internal dynamics and volumetric loading of a SAG mill is now possible. Also, by

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 …

Implementation of the new design in the SAG mill was carried out, resulting in increase in daily throug hput from 6 to 12%. Further, the time spent in liner change was. reduced by 47% given the ...