The single-stage SAG mill circuit was shown to efficient operate ly on primary crushed, Wallaby Deeps underground material. With relatively coarse, competent feed and a reasonable ball charge, the variable speed SAG mill generated a product with sufficient fines content that the cyclones could manage without excessive recycle.
The SAG mill circuit also includes a single-deck screen and a cone crusher while the ball mill circuit utilizes hydrocyclones. Currently, the grinding circuits are inefficient in achieving the aspired product fineness of xP,80 = 125 μm even at low to normal throughputs (450-600 t/h).
Simulation work was carried out to analyze how feeding a finer size distribution to a single stage SAG mill in closed circuit with hydro cyclones at Freda Rebecca Gold Mine would affect through put and specific energy consumption using an Excel based milling process simulator developed by Hinde, a comminution specialist who has worked for Mintek for many years. Other …
CIRCUIT PERFORMANCE INTRODUCTION . As the SMC Test ® produces the JK parameter values A and b as well as estimates the JK parameter ta and crusher model energy matrices, the SMC Test ® can be used to conduct AG/SAG mill and crusher circuit simulations through the use of JKSimMet. Independent
"Among the new solutions acquired is LoadIQ, for monitoring and optimising the performance of semi-autogenous (SAG) mills," he says. "The SAG mill is a key element of many milling circuits today, usually located between primary crushing and ball milling phases."
Optimising mill circuits for best efficiency impact. By Guest Contributor. Oct 26, 2021. Wireless LoadIQ system installed on the mill shell from which it gather mill mechanical and operational data for enhanced decision making on the mill performance and depicting the compact size of the unit. Decades of product evolution have given FL a ...
best performance. Results of using this advanced controller on a ball mill circuit operation in a copper concentrator are presented. The controller stabilized the mill operation and resulted in a 4.18% throughput increase in ground ore that is finer than the desirable size. INTRODUCTION
index by using values from an operating circuit. Its value is only valid at the stated SAG product size. • Transfer size (T80) is the term used to describe the SAG mill product that is sent to the ball mill. For peak performance and balancing the power available in the SAG mill and ball mill, the transfer size must be measured and controlled.
Using a power modelling approach, different mill sizes are selected to meet the power requirements that achieve the design tonnage. In the figure below, the range of expected throughput for different ore types are plotted for a fixed grinding circuit; each ore type can process between 80% and 120% of the design throughput.
The work involved participating in and overseeing the redesign of the SAG mill liner systems and developing operational strategies for maximising throughput through to the end of mine life. Ausenco's comminution optimisation tool, Ausgrind, was used to benchmark and analyse plant data with empirical models, predict circuit performance for ...
The circuit comprises a SAG mill, 12 m diameter by 6.1 m length (belly inside liners, the effective grinding volume), two pebble crushers, and two ball mills in parallel closed with cyclones. The SAG mill is fitted with a 20 MW gearless drive motor with bi-directional rotational capacity. (Reversing direction evens out wear on liners with ...
CIRCUIT PERFORMANCE INTRODUCTION . As the SMC Test ® produces the JK parameter values A and b as well as estimates the JK parameter ta and crusher model energy matrices, the SMC Test ® can be used to conduct AG/SAG mill and crusher circuit simulations through the use of JKSimMet. Independent
approach was demonstrated by a global mine-to-mill operations review in 2009, incorporating circuit sampling and standard ore characterisation testwork to facilitate the assessment of circuit performance efficiency and increased circuit productivity. This effort, and an ongoing commitment to performance analysis, has resulted in
by the installation of a 12MW SAG mill with a diameter of 10.97m (36ft). The mill, when built, was the largest SAG mill operating at any existing Australian mine. To aid in commissioning and optimising the mill, the Julius Krutt- schnitt Mineral Research Centre (JKMRC) and plant staff con- ducted extensive surveys of the grinding circuit.
It is commonly referred to as a SABC circuit, for Semi-Autogenous Ball mill Crusher (SABC). This circuit shows a semi-autogenous grinding (SAG)/ball mill circuit where both grinding mills are in closed circuit, with the SAG mill closed with a crusher to control the amount of 'critical size' material in the circuit.
SAG circuits may employ low to relatively high ball charges (ranging from 2% to 22%, expressed as volumetric mill filling) to augment autogenous …
optimization of sag mill circuit · optimized the oper ating strategies for the SAG mill circuit at Paracatu op eration in Bra zil. The focus of this project was to reach design t hroughput and final grinding product size, conditions . Mar 21, 2007· The optimal performance of AG/SAG mills is the key to successful plant operation.
In multi-stage ABC/SABC circuits, the AG or SAG mills are in closed circuit with screens and pebble crushers. The mill discharge from these mills consists of slurry, which goes to the ball mills for further grinding, and coarse pebbles/rocks, which are crushed and sent back to …
The paper proposes a novel performance audit report for a SAG Mill Circuit. The audit report is demonstrated on a validated run-of-mine ore grinding circuit model, which the authors have captured in a simulator, using Simulink. The elements of the report combine established statistics and views with specific mill control context.
Optimization of mill performance by using online ball and pulp measurements Soon after a stop, a mill is a dangerous place to enter for the personnel tasked with taking measurements or samples. Crash stops are difficult to handle. The mill and all feed streams should be stopped simultaneously but, often, they are stopped around about the same time.
The survey data collection included the power draw of the single-stage SAG mill, the fresh feed rate, particle size distributions for circuit feed and product, and the pebble rejection rate (pebbles are discarded from the SAG circuit and treated elsewhere). Grindability testing for SGI and/or a
The "Mill Redesign Project" at INCO's Clarabelle Mill Design, Construction, and Start-up of Stillwater Mining's Ea Grinding Circuit Improvements at Barrick Goldstrike's Roaste Brunswick Mine SAG Mill Liner Design and Wear The use of wetlands for effluent polishing at Placer Dome, C
mill circuit. • Define and calculate the grinding efficiency of the ball mill in a ball mill circuit. • Relate overall ball mill circuit output and circuit efficiency to specific design and operating variables. • Compare sets of circuit survey data in terms of the elements of the functional performance equation.
SAG mill circuit example for gold processing [image: (135-6-3)] AG/SAG Mill AG/SAG mills are normally used to grind run-off-mine ore or primary crusher product. Wet grinding in an AG/SAG mill is accomplished in a slurry of 50 to 80 percent solids. 2D and 3D simulations of particles in a SAG Mill red=fastest, blue=slowest moving particles
"Performance characteristics and optimisation of the Fimiston (KCGM) SAG mill circuit", Proc SAG '96, Vancouver, Vol 1 pp233-248. Tracking Hardness and …
2 AG mill + a recycle crusher Competent ore - relatively homogenous (the recycle crusher is 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.
The SAG Power Index (SPI) test (Starkey & Dobby, 1996) uses a benchscale SAG mill test to - determine the specific energy of an industrial SAG mill. The test is operated in closed circuit and the time required to grind the material to a P 80 of 1.7 mm is used to predict AG/SAG specific energy using Equation
Amelunxen SGI Model. This is a model that estimates the specific energy consumption of a SAG or AG mill plus ball mill circuit using the equation by Amelunxen (2014) for E SAG and the classical Bond work index equation for E ball substituting CF ball in the place of the Rowland efficiency factors.. The model requires manual calibration factors for both equations (CF SAG …
The Ball Charge in SAG and Ball Mills, in other words, the fraction of the mill volume constituted by balls, has a significant impact on the performance of a mill and the greater Grinding circuit. Running at the wrong Ball Charge adversely impacts not only throughput but the consistency of the product particle size (P80) as well.
Single stage SAG Mills are very beneficial in reducing CAPEX for plants with a staged throughput approach. When future tonnage is to be increased, the SAG Mill can feed downstream ball milling to boost capacity. Amstar SAG/AG Mills range in size from 4.3m through 12.2m in diameter with powers as high as 28,000 kW.
Where the SAG mill/ball mill circuit is the bottleneck in the processing plant the pebble circuit can be a significant factor in limiting overall plant capacity. The pebble circuit recirculating load can be very significant (depending on the ore characteristics and SAG mill operating dynamics).
The range of mill sizes and versatile applications allow SAG milling to be accomplished with fewer lines than conventional set-ups. This, in turn, contributes to lower capital and maintenance costs for a SAG mill circuit. Versatile applications . SAG milling extends itself to many applications due to the range of mill sizes available.
Case Study #1 – Improving Circuit Stability OMC have been assisting an African gold mine in optimising the comminution circuit, with a focus on operations practices and plant utilisation. The original circuit configuration consisted of a primary crusher followed by a SAG mill with a pebble crusher and a ball mill (SABC).
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