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) in diameter, powered by a 28 MW (38,000 HP) motor.

performing SAG mill. It is possible in some cases to modify a SAG circuit to force it to perform better, but this often takes time, much effort and costly modifications. In most cases the capital spent on a properly sized SAG mill may prevent production losses that would be many times greater over the extended start up period. This is the

In this research, the equations governing the motion of grinding media inside a SAG mill and the impact force and stress due to the impact of steel balls onto the liners have been derived. The effect of the different design parameters have also been studied in order to

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.

In the case of the large SAG mill referred to in Fig. 1, the mill’s initial volume is 757m 3 when new liners are installed, with the volume on average increasing to 792 m 3 at the end of shell

1 IMPROVEMENTS IN SAG MILL THROUGHPUT FROM FINER FEED SIZE AT THE NEWMONT AHAFO OPERATION *Adrian Dance1, Sonny Mwansa2, Walter Valery 2, George Amonoo3 and Bryon Bisiaux3 1SRK Consulting (Canada) Inc 22nd Floor, 1066 West

used to balance the rate of impact breakage within the circuit) 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.

SINGLE STAGE SAG/AG MILLING DESIGN ABSTRACT Single stage semi-autogenous / autogenous (S/AG) milling has become a common design for a variety of ore types with the advantages of being comparatively low capital cost and flexible for future expansion. The single stage

The ore in the SAG mill is mainly crushed by impact force, abrasive force and squeezing force between ore particles and grinding balls,through the continuous rotation of the mill, the large ore will be rotated into inner layer (near the center of the mill), and the smaller particles will be the outer layer. Most of the grinding balls for SAG

2019-09-23· SAG Conference 2019. Join us in Vancouver from September 22 to 26, 2019 at the premier global event for Semi-autogenous and High Pressure Grinding Technology.

What Can Go Wrong in Comminution Circuit Design? C Bailey1, G Lane2, S Morrell3 and P Staples4 ABSTRACT The design of semi-autogenous grinding (SAG) mill based comminution circuits for the treatment of competent ores, similar to those at Geita and

What I mean is that volumetric harness should be soft core hardness. As you know these kinds of steel balls are resistant to impact but at a certain radius (worn balls) the spherical shape of balls will be change to irregular shapes which can affect grinding efficiency badly. So the ball size distribution inside SAG mill will be incomplete. For

The patterns of rock comminution within tumbling mills, as well as the nature of forces, are of significant practical importance. Discrete element modelling (DEM) has been used to analyse the pattern of specific energy applied to rock, in terms of spatial distribution within a pilot AG/SAG mill.

AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill. Because of the range of mill sizes available, AG/SAG milling can often be accomplished with fewer lines than in a conventional rod mill-ball circuit. All of the above contributes to

The load movement inside of a SAG mill can be monitored through the audible impacts of the falling stream of ore and grinding media with themselves and with the mill liners. The mill noise is a mixture of many different sound sources. The main source is the large number of small shocks between load components during tumbling of the mill load, audible as a continuous stochastic noise. An

Every mining operation has a unique grinding process. Metso has experience of over 8,000 grinding mills globally, including manufacturing and delivering the largest SAG/AG mills in the world. Our experts welcome the opportunity to assist you with circuit and circuit control design as well as start-up, operation, and optimization of your mill.

2016-03-17· Question what is an Autogenous mill? An autogenous (AG) mill is a grinding mill used in the minerals processing industry. It is shaped like a huge drum on its side and spins rapidly to carry ore to the top using centrifugal force. Gravity assist...

2015-03-11· Gold extraction with BORAX for small-scale miners Rather Rich & Healthy than Poor & Poisoned Duration: 9:49. geusTUBE 997,264 views

The patterns of rock comminution within tumbling mills, as well as the nature of forces, are of significant practical importance. Discrete element modelling (DEM) has been used to analyse the pattern of specific energy applied to rock, in terms of spatial distribution within a pilot AG/SAG mill.

2016-03-17· Question what is an Autogenous mill? An autogenous (AG) mill is a grinding mill used in the minerals processing industry. It is shaped like a huge drum on its side and spins rapidly to carry ore to the top using centrifugal force. Gravity assist...

(SAG) mills. In order to optimize this section, the skills to accurately model and understand its underlying mechanisms are required. The literature exposed a clear lack of previous research on the influence and performance of grate/pulp lifter design in AG/SAG mill discharge. The current understanding from

The IsaMill is an energy-efficient mineral industry grinding mill that was jointly developed in the 1990s by Mount Isa Mines Limited ("MIM", a subsidiary of MIM Holdings Limited and now part of the Glencore Xstrata group of companies) and Netzsch Feinmahltechnik ("Netzsch"),

2015-06-19· Besides dissipating a significant fraction of the total energy consumed by the mill (for example, the outer row of 50 mm diameter balls in a 4 meter diameter mill

The impact of ore variability on process performance was observed at the OK Tedi mine in Papua New Guinea, where the variations in feed ore hardness (Bond work index 5–16 kWh/t) and in feed size distributions caused the SAG mill throughput to fluctuate between 700 and 3000 t/h (Sloan et al., 2001).

with impact, so solid liners begin to squeeze together and become extremely difficult to remove, and can damage a mill shell if the stress is allowed to build up to an extreme level. 2. Low Carbon Chrome Moly Steel (300 to 370BHN): Was generally used for mill liners (AG, SAG and Ball) prior to the movement to higher carbon content steels. It

the ball mill, but they can also be used as a one-stage grinder. The absence of, or reduction in the number of, balls means they can be less costly to operate than ball mills. SAG mills of over 40-foot diameter have been constructed. Like the ball mill, the AG/SAG mill will have a critical rotation speed above which grinding ceases. Mill motor

Every mining operation has a unique grinding process. Metso has experience of over 8,000 grinding mills globally, including manufacturing and delivering the largest SAG/AG mills in the world. Our experts welcome the opportunity to assist you with circuit and circuit control design as well as start-up, operation, and optimization of your mill.

1. IMPACT The mechanism of reducing the big rocks is "crushing" which requires impacts. Either by impacting of grinding balls on the rocks (SAG mill) or by interaction between rocks on the one side and mill shell and toe of the grinding charge on the other side (FAG mills). The trajectories of grinding media and rocks promote size reduction by im-