The rapidly developing mining industry poses the urgent problem of increasing the energy efficiency of the operation of basic equipment, such as semi-autogenous grinding (SAG) mills. For this purpose, a large number of studies have been carried out on the establishment of optimal operating parameters of the mill, the …
Highlights Circulating load and classification efficiency effect on ball mill capacity revisited. Relative capacity model introduced and validated. Relationship between circulating load and classification efficiency verified by industrial data. Existing fine screening technology could increase ball mill circuit capacity 15–25%.
The instrumentation installed on a SAG mill is integral to control. For example, the mill load and noise sensors are instruments that provide essential information for an optimized SAG mill operation. Insufficient understanding of the ore characteristics and feed composition can result in an ineffective SAG mill operation.
The model output variables are: power-draw, load level, ball load, mineral discharge rate and size distribution, water discharge rate, ball throughput, bearing pressure, pebble throughput, and toe and shoulder angles of the internal load. 2.1 SAG mill model The particles fed to the mill are ground in the milling chamber and subsequently
SAG Mill process control classically maintains the SAG mill volumetric filling within a set operating range. Typically a SAG mill weight measurement, by either bearing pressure transducers or load cells, is used as an inferred measurement of volumetric filling. To maintain volumetric filling within a set operating range the SAG weight setpoint use for …
The lifter face angle is the main factor when the SAG mill is running at low speed. ... Hlungwani et al. [8] studied the influence of square and trapezoidal lifters on mill power and load by combining DEM simulation and experiment. Delaney et al. [9] predicted the performance of the SAG mill based on the DEM. Kiangi et al. [10] studied the ...
SAG mill power draw models are used in mill design and grinding circuit modelling to predict how much power will be consumed by a particular mill geometry and operating …
If crop load =ore + grinding mill media +waterBut usually, it was used in a percentage formation. ... And this generally depends on the type of mill you are using (i.e. ball, rod, SAG, AG, UFG, etc…), although there are some overlaps between. ... The 60% "packing factor" for the balls is pretty close to our average for a seasoned charge. Maya ...
While the VSI Mill may have some benefits in certain applications such as tertiary crushing or producing sand for construction purposes, it still remains a relatively niche technology within the mining industry. SAG Mill. A SAG mill, also known as a semi-autogenous grinding mill, is one of the essential equipment used in copper ore mining.
Difference Between SAG Mill and Ball Mill, from the working principle, application, structure, etc. Grind and blend solid or hard materials into smaller pieces by means of shear, impact and compression. ... The pressure indication of the high pressure oil circuit can be used to reflect the load of the mill indirectly. When the mill stops ...
The second major factor which has impeded the development of more advanced and effective SAG mill control procedures is the lack of available instrumentation to measure important SAG mill process variables. For example, the volumetric load level within a SAG mill is perhaps the single most important factor which characterizes the …
MILL FILLING AND LOAD As already discussed, SAG mill filling is a critical parameter for SAG mill performance. Yet, no percentage mill filling indications are present in
The specific energy does not just depend on ore competence but also on factors such as feed size and ball load (Morrell, 2004). The ore competence is usually characterised by pilot plant testing, lab testing an even plant testing and its nature is considered in SAG mills design and optimisation. ... SAG mill specific energy …
Sag Mill is a kind of heavy duty equipment used in the ore crushing and grinding industry. Its working principle is to utilize the impact and grinding effect of a small amount of steel balls and the material itself to crush the ore Through the rotation of the cylinder, large pieces of ore are gradually broken into smaller particles in the collision …
developing a pilot-scale SAG mill facility that will imitate a full-scale operation. It will have sensors for on-line mill load, power, flow and other measurements. This research will lead to an understanding of the individual effect of design and operating variables on power draft. Researchers will mimic the operation of participating mine sites.
It was known then to be the best and proper load at which to run a SAG mill and this has not changed. The Pilot SAG mill had a fixed speed drive and ran at 75% of critical speed. ... the latter is the internal size of the Starkey SAGDesign test SAG mill. The A factor equation, W = f (D 2.5) has also been found to be valid for all sizes ...
The proportion of grinding media is another factor affecting mill operation. It has undergone an important evolution lately. Originally it was considered that a SAG mill should work at 8–10% ball content. Later-on, larger mill sizes and larger processed tonnages have led to operations at 10–14% level.
Considering the continuous increase in production costs and resource optimization, more than a strategic objective has become imperative in the copper mining industry. In the search to improve the efficiency in the use of resources, the present work develops models of a semi-autogenous grinding (SAG) mill using statistical analysis …
1. Introduction. Mill filling has a dominant effect on grinding mill performance (Apelt, Asprey and Thornhill, 2001), and therefore, its accurate measurement is vital for modelling grinding mill performance.Measuring filling is also necessary to estimate the composition of the load for mill modelling: rock and slurry for AG mills; rock, balls and …
This guide will refer to the two most common varieties: Semi-autogenous (SAG) and ball mills. Key considerations. Numerous factors must be considered when selecting a mill liner design, including required grinding action, mill size as well as ore and grinding media characteristics, among others.
For SAG Milling, optimizing the throw and converting the available electrical energy (installed motor power) to potential energy (height of throw, trajectory) to kinetic energy …
A SAG mill consists of a rotating drum filled with steel balls or rods, and the rock that needs to be ground. The drum is mounted on a stationary structure, which houses the motor, gear, reducer, and bearings. ... The mill weight is measured by load cells or a strain gauge, and the controller adjusts the feed rate accordingly. SAG mills can be ...
SAG mill feed, grate size, open area, classification size, ball diameter or ball charge, total mill load, mill speed, etc. can be investigated at pilot plant scale. All tests are evaluated based on: • Feed rate • Power consumption • Product size analysis Unless single-stage autogenous grinding is considered, we recommend that the
Semi-autogenous grinding (SAG) mill key performance indicators (KPI), such as throughput, specific-energy consumption, and product size, are sensitive to the total …
AG & SAG Mill Grinding Compared – Which is Best. ... however, if economics, location, costs or other factors justify further study, pilot plant autogenous and/or semi-autogenous pilot plant tests should be run to further explore the possibility for this type of grinding. ... Crushing the coarse circulating load, which can be a critical size ...
On the other hand, the filling, distribution, and composition of the load can influence an overload, which can be determined, for example, by confirming the decrease in the moment of inertia of the mill, because under this condition the torque required to turn decreases the power consumed, however, this behavior is observable only at the …
Cytec Handbook. Why have a large circulation load:. If a product all finer than a certain critical size is required, the capacity of the ball mill is increased considerably by using it in closed circuit with a classifier and this increase is made still greater by increasing the circulating load in between the ball mill and the classifier (Fig. 70).
To a more significant degree than in other comminution devices, SAG Mill Liner Design and Configuration can have a substantial effect mill performance. In general terms, lifter spacing and angle, grate open area and aperture size, and pulp lifter design and capacity must be considered. Each of these topics has had a considerable amount of …
Stable mill load translates to consistent product size, a crucial factor for achieving maximum recovery in flotation. The best part? Well-designed and …
Model predictive control is able to optimize the control of processes that exhibit an integrating type response in combination with transport delays or variable interaction, …
Ball load is also a factor, as you can operate with a higher ball load of smaller media without risking high ball wear and/or liner damage. So going to a larger 5" ball is a good idea for primary crushed feed with a relatively large grate opening if there's evidence the 4" ball is not enough to break the coarse particles.
The JKMRC has been studying and modelling industrial AG and SAG mills for over 40 years, but the ability to simulate the effects of blending hard and soft components on mill performance remains quite limited.In an effort to quantify these effects for modelling purposes, a series of laboratory, pilot scale and full scale tests, using multi-component …
Benefit from AG and SAG Mill in many drive arrangements, sizes and bearing designs. Your operation requires a Semi Autogenous Mill (SAG mill) or Autogenous Mill (AG Mill) that is flexible, durable, cost-efficient and tailored to your specific needs and use cases. ... Single or dual pinion drives (with load sharing technologies) Wrap around ...
The methodologies outlined all allow analysis of real-time data and large data sets spanning months and years of operation, thus facilitating identification of optimum …
One such example by the authors is the study on varying the mill filling, and how this contributed to modifying the load relationship in the JKMRC SAG mill model, Powell et al. (2001). ...
Provide a motor with the capability to deliver design power on a continuous basis by including a suitable service factor, usually 15% to cover any drive losses and …
When the normal operating horsepower has been defined. It can be related to a design drive horsepower. If the mill operating horsepower is defined as "net at the shell", then the appropriate losses for trunnion bearings, pinionshaft bearings, and gearing must be accounted for to compute …
For the high tonnage tests feed rates should be increased to meet or exceed the normally acceptable load on the SAG mill motor, or load in the mill, whichever has been identified as the primary constraint. An example of the relationship between mill motor current, power draw and SAG mill feed rate is given in Figure 2.
2. Background. The SAG grinding process has been modeled by various authors, either generating explanatory models of the grinding process, with the aim of modeling, simulating, and optimizing the individual process, as well as integrating it into aggregate processes, such as the mine-to-mill (M2M) paradigm, a practice that has …