(EGL) SAG mill driven by a 24,000 kW gearless drive. The SAG mill feeds two FL 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]).
Semi-autogenous 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. …
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 …
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 ...
SAG MILL TESTING - AN OVERVIEW OF THE TEST PROCEDURES AVAILABLE TO CHARACTERIZE ORE GRINDABILITY. AUTHOR: F.O. VERRET, G. CHIASSON AND …
SAG Mill Charge. Defining the charge weight and height for fully autogenous grinding mill requires allowance for the ore specific gravity (and its variations) and …
However, the performance of a SAG mill changes rapidly in response to conditions such as feed size and hardness as well as longer-term variability due to liner wear – something no instrumentation can directly observe. Mill Filling Tool Dashboard. The new Mill Filling Prediction (MFP) tool is a soft sensor (a mathematical model that act as a ...
* SAG mills are the machines with the highest reduction rate which performs crushing, grinding and washing together. It offers a much higher reduction ratio than 3-stage crushing and screening system. * Feeding material in the dimension of 200-300 mm, is reduced to d100: 2 mm and below. This capability increases the efficiency of the ball mill ...
SAG mills contain balls of up to 150mm in diameter that occupy 5%-18% of mill chamber volume. Ball mills, conversely, contain grinding media up to 50mm in diameter, occupying between 25% - 40% of mill chamber volume. To effectively reduce material size, each type of mill needs to generate different charge load actions, or the type of motion ...
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 6-10 hours. The achievement of steady-state is desirable in a grinding test, because harder components may build up over time. For AG/SAG mills,
Ball mill: When the particle size of the product is less than 0.5mm, 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.
Then, in the late 1980s when the price of copper rose quickly from a low of $0.62/lb to a high of $1.62/lb, this substantial increase in price further fuelled the industry demand for larger diameter SAG mills, with mill power quickly doubling from 15,000hp to 30,000hp (11,000-22,000kW). As SAG mills grew in size and number, so did the size …
The behavior of the SAG mill circuit is multivariable i.e. exhibit complex interactions and nonlinear behavior between the process variables. It is also dynamic i.e. delay times between variables within the process need to be considered before control actions are executed. Given these challenges, the objectives for acceptable SAG mill operation ...
5 to 50 TPH SAG Mill. Starting as small as 13 feet (4 m) in diameter on 330 HP and as large as 24′ (14.5 m) in diameter on 3,300 HP, the 911MPE Semi & Fully Autogenous Mills tumble crushed ore without iron or steel grinding media. They are used when the crushed ore pieces are hard enough to perform all the grinding.
Sag Mill Maintenance. Minding the Grind: Maintenance Options to Keep SAG Mills Turning When the largest machine in the plant stops working, the silence that follows typically isn't golden – just expensive By Russell A. Carter, Contributing Editor. Purpose-built structures such as the Skyway system from Russell Mineral Equipment can provide ...
TABLE 1 Comparison of RoM and SAG mill operating regimes AG/SAG South African RoM Speed, % critical 70- 80% 75 -90% Charge Filling, % total mill volume 20 - 30% 35 - 45% Bali filling, % total mill volume 4-15% 15 - 35% Internallength 3-5m 5 -12m Aspect ratio, diameter/length 0.7 -2 0.5 - 0.8 Recycle stream Trommel oversize Cyclone underflow ...
SAG Mill Circuit Sampling. Many mills have been built based on data from inadequate sampling or from insufficient tests. With the cost of many mills exceeding …
The LSTM network shows great results on predicting the relative operational hardness at 30 min time support. On SAG mill 1, using a lambda value of 0.5, the obtained accuracy was 77.3% while increasing the lambda to 1.5 led to an increase in accuracy of 93.1%. Similar results were found on the second SAG mill.
This paper presents the technical details of the world's first 42 foot diameter 28 MW gearless SAG mill, installed at the Conga copper-gold 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.
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To date, CITIC HIC has cumulatively produced and delivered over 1,550 mineral grinding mills, with a total installed power of 3,900MW. Our large-size grinding mills hold a market share of 85% in the domestic mining market, and have been exported to more than 50 countries and regions. This means that we are a world's leading manufacturer and ...
The solution: Measure. Control. And profit. BrainWave SAG mill is a unique control package using patented model-based predictive adaptive control technology. It is well known …
Semi-autogenous grinding mills (SAG mills) are tumbling mills that most commonly have a shell diameter-to-length ratio of around two. With this high aspect ratio, SAG mills generate both thrown and cascading ball-milling actions with shell linings shaped to lift and to throw alloy steel grinding balls of up to 150 mm (6 in.) in diameter. These
> 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
A SAG mill has low speed and heavy load, which cause the energy consumption of grinding operation to be very high. It accounts for a large proportion of the electrical consumption across the plant . The rotation speed is an important factor related to the operation and grinding efficiency of the mill. Under the traditional operating …
INTRODUCTION . SAG mills are simple and very effective grinding devices. Their operation, control, and modelling however poses some challenges to the operator and …
The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between 2.0 and 7.5 kWh per ton of energy to reduce the particle size. Considering a typical mining operation processes 10,000 to 100,000 tons per day the energy expenditure in grinding is 50 …
ball (IGB) that will allow mill operators to measure the impact spectrum of balls and rocks in grinding mill. Second, to relate the grinding pulse to the operating conditions of the mill. Third, to use the grinding pulse as a diagnostic tool for SAG mill operation. Milestones • Test the IGB in a simulated impact
SAG mill and two ball mills in closed circuit with cyclones. Two pebble crushers treat the SAG mill discharge trommel screen oversize material. The crushed product is combined with the SAG mill feed. Project economics dictated maximum throughput through a single line comminution circuit. Hence the selection of some of the largest
A total of 120 t of Cristalino ore was prepared and sent to CIMM, where it was crushed and screened prior to grinding tests. The processing equipment included a 1.83 m (8′) diameter by 0.61 m (2′) …
semi-autogenous grinding process by dynamically modeling the SAG mill-pebble crusher loop to improve the SAG mill throughput. Cleary [8–10] studied the effect of rock particle shape on the dynamic filling and energy utilization in a SAG mill and analyzed the operation status of a SAG mill under different collision conditions through the coll ...
The three gearless mill drive (GMD) systems are the ABB most powerful ever made. The GMD for the 40-foot SAG mill has a power rating of 28 megawatts (MW), and the GMDs for the two 28-foot ball mills have a power rating of 22 MW. They are the largest diameter and most powerful SAG and ball mills drive systems at the highest altitude installed to ...
Autogenous grinding is favored when the ore is quite competent and a fine grind is required. Semi-autogenous grinding is applied when fine crushing could cause severe problems or when ore is variable in hardness or competency. Figure 2 shows a typical conventional crushing-grinding circuit with three stages of crushing followed by …
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mentioned some case studies of using good liner designs. For example, the initial SAG mill liner was installed using Hi-Hi with a 6. o . contact angle. Mill throughput increased by 11% after the face angle had been altered to a 17. o. angle and then to a 30. o. angle. Currently, the large face angle (typically 20. o . up to 30. o
A high aspect SAG mill had an ID of 6.0 m and the length measured 4.0 m along the central line. The mill was charged with ore having a S.G. of 2.65 and the load was 40% of the mill volume. The grinding media steel balls occupied 12.2 % of the mill volume. The mill was rotated at 75% of its critical speed, which was 12.9 rpm. Estimate:1.
SAG mills can produce a lot of impact if operated with a high ball charge and low filling. Rod and AG mills can produce a lot of attrition and varying amounts of impact and abrasion. Arraying different mills can take advantage of the strengths of …
The ROM SAG mill circuit—a brief description The typical ROM SAG mill circuit is depicted in Figure 1. The circuit is usually closed with either a screen or, more commonly, a cyclone for product size classification. The focus of control can be divided into two parts, viz. the mill and the cyclone. The importance of cyclone performance should ...
The SAG mill was originally operating in a ball mill duty and it has a low aspect ratio (diameter/length) which changes its operation relative to typical high aspect mills (Powell, Morrell and ...
SAG mills grind ore by lifting it and a small amount of grinding media and dropping it inside a horizontal mill. Ball mills are smaller and use a higher concentration of iron balls to pummel the ore. The mills can operate in an open grinding circuit, feeding secondary grinding systems, or in a closed circuit generating a fine product. ...
