involves replacing the mill charge several times throughout the test. The Bond tests are typically run for a minimum of seven cycles, while the MacPherson and pilot plant tests are operated for about 610 hours. The achievement of steadystate is desirable in a grinding test, because harder components may build up over time. For AG/SAG mills,
Modern SAG mills are considered to be the modern process route for bauxite processing and have minimal down time. The installation of a pulp lifter at the rear of the SAG mill are recommended for bauxite processing. This unit may consume over < 50 cm of the width of the mill yet justifies its installation as it enhances the ability of the mill
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...
Semiautogenous grinding mills play a critical role in the processing stage of many mining operations. They are also one of the most intensive energy consumers of the entire process. Current forecasting techniques of energy consumption base their inferences on feeding ore mineralogical features, SAG dimensions, and operational variables. Experts recognize their capabilities to provide adequate ...
The various options available for largehorsepower semiautogenous grinding (SAG) mill drive systems are examined, together with their impacts on mill design and relative capital and operational costs. A brief history of largemill drive systems is given. Stateoftheart mill design and mechanical design considerations are also discussed. A design for fixedspeed or variablespeed operation is ...
services to drive your mill's performance Introducing a new name Metso Outotec is proud to announce the launch of our new rebranded offer: Metso Outotec Gears and Pinions. You ... • AG and SAG mills • Ball and FGD mills •Pebble and rod mills • Multicompartment mills • Rotary kilns and dryers • Mixers and other equipment
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 ...
Semiautogenous grinding mills (SAG mills) are tumbling mills that most commonly have a shell diametertolength ratio of around two. With this high aspect ratio, SAG mills generate both thrown and cascading ballmilling actions with shell linings shaped to lift and to throw alloy steel grinding balls of up to 150 mm (6 in.) in diameter. These
In a largescale operation, feed ores are introduced into the AG/SAG mill in a continuous mode at a given flow rate to replace the discharging slurry. Nonetheless, the variations in the feed characteristics, typically hardness and size distribution, could cause sudden disruption to the mill operation. This would be challenging to detect in practice, owing to the hostile environment of the mill ...
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 ...
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.
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).
1. The possible position (H) of the charge below the central axis of the mill, 2. Determine the relation between H, radius R and fraction fillings, and 3. The maximum fractional volume of mill filled by the total charge. A 13 m × 6 m meter SAG mill had a cylindrical feed chute 1 meter in diameter.
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.
SAG Mill Crushability The comminution dataset consisted of57 drill core composites representing material from production periods across the life of mine. This data showed a wide range in both crushability (=impact resistance) and grindability. • Impact resistance as measured by the JK parameter A*b ranged from a very hard 25 to a soft 118,
(EGL) SAG mill driven by a 24,000 kW gearless drive. The SAG mill feeds two FLSmidth ball mills each 26 ft. in diameter × 40 ft. long (EGL), each driven by a 16,400 kW drive. The SAG mill is one of the largest volumetric capacity SAG mills in the world and represented the first 40 ft. SAG mill in Peru (Garcia Villanueva, 2013 [1]).
state of the medium and its grinding performance on the SAG mill [3, 4]. Hlungwani used the DEM to study the effect of the number and the shape of liners on the power consumption of the SAG mill, and predicted that the trapezoidal lifters draw more power than the square lifters at the normal operating speed of production mills [5]. J. T.
Ball mill: When the particle size of the product is less than, the grinding effect of the ball mill is greater than that of a rod mill of the same specification. SAG mill: The SAG mill has a wide range of feeding particle sizes and can process larger minerals, but at the same time, its output particle size is relatively larger.
This paper discusses a case study application of inferential measurement models for semiautogenous grinding (SAG) mills and is the fourth paper in a series of five papers on Inferential Measurement of SAG Mill Parameters.
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
can improve and optimise SAG mill grinding performances via realtime monitoring technology [15]. In addition, the measurement of vibrationacoustic emission signals has emerged as a promising tool to understand the state of the mill (AG/SAG mill and ball mills) [1628]. Notwithstanding, more accurate and precise prediction is a topical subject
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.
The SAG mill grinding circuit includes a 34 ft x ft SAG mill operated with a MW variable speed drivetrain. SAG mill product is screened at ~12 mm; oversize is conveyed to the pebble ...
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.
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 ...
one SAG mill ( dia.(m)* length(m)) following two parallel ball mills (5dia.(m)*7lenght(m)). The aim of this research work was to investigate on the ball filling estimation of Miduk semiautogenous (SAG) Mill via an utilized method. Miduk SAG Mill circuit is shown in Figure 1. Figure 1: Diagram of Miduk Copper Complex
This paper presents the technical details of the world's first 42 foot diameter 28 MW gearless SAG mill, installed at the Conga coppergold project in Peru. It explains the challenges and solutions for designing and operating such a large mill, and how it delivers high efficiency and low maintenance costs.
iii ores containing clay. Previously, HPGR was considered only suitable for very hard ores and the technology was rejected for other cases. A unique pilotplant
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.
SAG mill A SAG mill is almost always a highimpact application. Hence, it is wise to use tough, impactresistant materials that are somewhat softer but less brittle to avoid cracking, chipping, or breaking. Rubber/steel composite liners are often a good choice as is the range of more impactresistant cast alloys. Rod mill As there should be very
Improving Energy Efficiency in SAG Mills PilotScale SAG Mill Facility Will Help to Optimize Charge Motion and Slurry Flow in PlantScale SAG Mills Reducing Energy Consumption The mining industry operates approximately 80 semiautogenous grinding mills (SAG) throughout the United States. Both mine and mill site variables determine SAG ...
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 100% passing mm and is subjected to the t to provide the total pinion energy at the specified grind size for mill design.
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 ...
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