The SAG test reproduces commercial SAG mill grinding conditions on L of ergy to grind ore from 80% passing 152 mm to 80% passing mm (WSDT), mill product is then crushed to passing mm and is subjected to the t to provide the total pinion energy at the specified grind size for mill design.
Download chapter PDF Introduction to Crushing and Grinding of Bauxite. The most common initial process step to feed an alumina refinery with bauxite is the crushing or sizing of the raw bauxite material that is extracted from the mine. ... The SAG mill can handle very course and variable feed sizes while the closedcircuit ball mill helps ...
Common convention generally refers to highaspect ratio mills as SAG mills (with diameter to effective grinding length ratios of 3:1 to 1:1), lowaspect ratio mills (generally, a mill with a significantly longer length than diameter) are also worth noting.
Early SAG mill designs using gear drives were limited in the amount of power that could be applied to the pinions, MPa (5000 hp). The exception to this design was the Hibbing taconite operation. It used MPa (6000 hp) motors to drive a 1Imdiam x long (36ftdiam x 15 ft) autogenous mill. However, recent SAG mill designs now ...
Due to its strong lifting capacity and excellent grinding performance, the trapezoidal liner is widely used in the SAG mill. The structure of the trapezoidal liner is shown in Fig. 1, the main dimensions are: dip angle (tau), length of the top edge (L) and height (h).Dip angle (tau) determines the trajectory of the mediums in the SAG mill, which directly affects the impact speed and ...
drive application is a dualpinion SAG mill driven by two 5,000 kW wound rotor induction motors (WRIM). Two TMdrive10SPRs control motor speed by recovering rotor current and returning the power to the utility supply. Configured in a twin motor arrangement, the motors share load in the tandem mill. The Customer Need
On Mill Installation and Maintenance. Before starting the erection of the mill, adequate handling facilities should be provided or made available, bearing in mind the weights and proportions of the various parts and subassemblies. This information can be ascertained from the drawings and shipping papers.
Plant Concept SAG Circuit HPGR Circuit Equipment 1 x SAG Mill MW 1 x Secondary Crusher 750 kW 1 x Pebble crusher 450 kW 1 x HPGR MW 2 x Ball Mills MW each 2 x Ball Mills MW each Screens and conveyors MW Screens and Conveyors MW Total drive capacity installed MW MW
Analysis of typical SAG mill installations in the copper industry indicates that typically less than 90% of installed motor power is used on average. Therefore, the installed SAG motor power was determined to be kWh/t (/90%). Checks were carried out to ensure that the SAG mill could utilise this power within a reasonable envelope of ...
Decisionmaking on selection of SAG mills increasingly uses the methods of sizing the milling power based on laboratory tests on grindability of minerals. This article considers one of such methods allowing determination of mill characteristics based on the Bond work indexes of crushing, rod milling and ball milling.
A SAG mill is an excellent BrainWave appli cation because the improved control perfor mance translates directly into higher profits for customers. The diagram shows the BrainWave user interface from the Los Pelambres installa tion. In the trender area on the right side, the
> Mill throughput and efficiency gains are iterative over time > Mill trajectory modelling based on bar heights, angles, spacing and speed is very predictive > Field trials are the acid test operator, designer and vendor > Optimisation strategy: Maximise impact grinding AG/SAG mills Avoid impact on the shell rather the toe of the charge
The apparent inefficiency of SAG mills when using Bond analysis is widely understood to be due to the difference in the slopes of the size distributions. In contrast, when the SSE75 was calculated, it showed the SAG mill consumed 20% less energy to produce final product material than the ball mill. Since the aim of a comminution circuit is to ...
In order to obtain the optimal operation parameters of a SAG mill, in this paper, the discrete element method (DEM) is used to simulate the breakage process of the particles by controlling three parameters,, the mill speed ratio, the mill fill level ratio, and the steel ball ratio.
Based on experience, millliner designs have moved toward more openshell lifter spacing, increased pulp lifter volumetric capacity, and a grate design to facilitate maximizing both pebblecrushing circuit utilization and SAG mill capacity. As a guideline, mill throughput is maximized with shell lifters between ratios of :1 and :1.
LG A mill power equation for SAG mills. Minerals and Metallurgical Processing. Feb 1990 pp5762. Gross power No load power Net power drawn by the charge () The net power is calculated from Net power e! c./ Watts () In equation, D is the diameter inside the mill liners and Le is the effective length of the mill including the ...
bling mills (AG/SAG, rod, and ball mills) involved in reducing the size of the primary crusher product to that of the final product (usually the cyclone overflow of the last stage of grinding prior to flotation/leaching). 2. Feed rate to the circuit (dry tonnes/h) 3. Power draw of the comminution equipment (kW)
Mill in Brazil and Lumwana having a 38ft, 18 MW SAG and one 26ft, 16 MW Ball Mill in Zambia, all three mills put in operation in 2008, as well as Los Bronces, Confluencia in Chile equipped with one 40ft SAG Mill of 22 MW and two 26ft Ball Mills of MW commissioned in 2011. In the light of increasing interest in that technology various ...
The breakage rate function shape of the SAG mill is largely governed by the mill load particle size distribution and mill speed. The feed in the mill contains fractions of ore that serves as the grinding media. Larger ore fractions break the smaller particles but also breakdown themselves and exit the mill as a product.
1. SAG mill is the primary tool for grinding. SAG mill is used before the other mills. Ball mill is a secondary, and it is used after the SAG mill. 2. SAG mill breaks the raw material into pieces for the further grinding. Ball mill is used to grind the pieces of raw material into. powderlike structures. 3.
The author has developed a simple and sound approach to determine the preliminary SSSAG mill aspect ratio before conducting population balance model simulations. The approach developed takes into ...
You may find more information regarding the SAG discharge if you search them as "scats" (broken ball chips). Safety Notes; they result from internal stresses in the balls impact and heat energy in the SAG mill causing a Martensite transformation in the ball (Crystals form in the metal) and they have a potential to rupture with very sharp edges.
Product Size: All passing 6 mesh with 80% passing 20 mesh. Net power from pilot plant: KWH/ST. Mill, gear and pinion friction multiplier: Mill Power required at pinionshaft = (240 x x ) ÷ = 5440 Hp. Speed reducer efficiency: 98%. 5440 Hp ÷ = 5550 HP (required minimum motor output power).
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.
PDF | On Sep 7, 2015, Paul Toor and others published Understanding the effects of liner wear on SAG mill performance | Find, read and cite all the research you need on ResearchGate
To predict the power of the SAG mill, Hoseinian et al. proposed an analytical model based on gene expression programming. To develop their model, they employed several tests by varying the SAG mill parameters such as the moisture of charge, mass flow rate, cell weight of mill load, solid percentage and inlet and outlet water to the SAG mill.
2006 DEPARTMENT OF MINING ENGINEERING This paper addresses two major issues: the influence that the lifter profile has on the charge behaviour within an industrial mill and the development of a structured methodology to evolve lifter profiles within the framework of the DEM. UNIVERSITY OF BRITISH COLUMBIA
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