A design for fixed-speed or variable-speed operation is presented, and the capital and operational cost factors that influence design are considered. The choice of a drive system is independent on the size of the mill, its critical speed, and the horsepower required. Several areas of concern are outlined for each drive-system design.

Sales Online2014-10-1 · 4 High ball charge SAG mill or ROM Ball mill (15 to 25% ball charge) Low competency ore Hidden Valley, Nzema, Sepon, UG2 ores (South Africa), Yanacocha 5 Low ball charge, high speed SAG mill (4% ball charge, 90% Nc) A cross between AG and SAG for average competency, abrasive ores. Typically operated in RSA on Witwatersrand Gold Ore Driefontein ...

Sales OnlineAn electrical impact study between variable speed dual pinion mills and gearless mill drives Abstract: Conventional mining process circuits use both Semi-Autogenous Grinding (SAG) and Ball mills. It is very common that the SAG mills are operated with adjustable frequency drives (AFDs) and the Ball mills are operated at fixed speed [1].

Sales OnlineThe four identical variable speed drives (VSD) operating all four mill motors are Sinamics Perfect Harmony GH180 units. Service Online; Automated SAG Mill Speed Control Using On-contact . Therefore the SAG mill speed could not be controlled using the microphone based signal and instead was manually controlled/set by the control room operator.

Sales OnlineMany grinding mill owners choose a variable speed drive for their mill to cope with variations in or e har dness... [↓ read more ↓] Alex Doll & Kurt Tischler: testwork: Effect of core diameter on the Bond impact crushing work index test

Sales Online2016-1-1 · The mill speed is 70% of the critical speed. 9.4. 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 an 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 …

Sales OnlineThe Juniper mill consists of a variable speed SAG mill operating in closed circuit with a discharge screen. SAG mill product is fed to a ball mill operating in closed circuit with cyclones. 1.5 MW installed power;18 ft x 6.5 ft (6 m x 2 m) 900HP SAG (Variable speed drive), turns both directions, 11.5 ft x16.5 ft (3.8 m x 5.5 m) 1150 HP ball mill.

Sales Online2017-12-14 · the SAG mill critical speed; Pc = SAG mill power consumption (kW); % 600 +100 = % of the fresh feed in the size range 152 +25 mm. M. Silva, A. Casali/Minerals Engineering 70 (2015) 156–161 157 In fact the later can be modelled as a function of the others.

Sales Online2020-3-22 · Mill criteria SAG mill: 24 foot nom diam by 12 foot effective grinding length (EGL) ball mill: two 11 foot nom diam by 17 foot (assumed to be EGL) SAG mill single variable speed motor 4500 HP; Ball mill single fixed speed motors 1000 HP (each mill) assume rubber liners in SAG…

Sales OnlinePebble crushing is widely practiced because of its known to have a 15-50% impact on mill throughput (Johnson et al., 1994), while rejecting the pebbles or forward-feeding crushed pebbles to the ...

Sales Online2010-3-24 · mill trunnions provides a very low cost solution for variable speed mill operation. Since the mill and its power unit are supplied as a module, the mill can be supplied, erected and commissioned very quickly without the need for highly skilled technicians. Outside of traditional hard rock mines, these mills offer an attractive, economic alternative

Sales Onlinethe mill speed as a fraction of the critical speed, ϕC, can be observed by plotting the process power and torque draw superimposed on the relevant motor capability curve. Such plots for an example mill, the SAG mill at Cadia (described by Dunne et al., 2001) is shown in Figure 3.

Sales Online2020-7-18 · Each SAG primary mill (Boliden-Allis) operates with two 5.000 HP. Ball Mills as secondary grinding stage. The Electric Drive (SIEMENS) consists a 11.000 HP synchronous motor of variable speed. General Description of the Drive. The SAG Mill Drive is mainly formed by a 11,000 HP.

Sales Online2018-7-9 · Variable speed was required for the SAG mill. Various options were considered to meet the specified speed range of 65 to 85% of mill critical speed, and the final selection was the IES Hyper-Synchronous drive Slip Energy Recovery (SER), in conjunction with …

Sales Online2018-3-4 · Therefore the SAG mill speed could not be controlled using the microphone based signal and instead was manually controlled/set by the control room operator. Thus operation/speed of the mill could and would change significantly based on a particular operator running the mill and their overall level of mill operation experience and skill.

Sales Online2009-8-26 · conduct plant surveys on a large scale mill equipped with a variable speed drive to validate this work. The influence of pulp density Pulp density has a large influence on the grinding efficiency. In this case, the optimum is in the region of 73.4% or 1.989 kg/l.

Sales Online2015-1-1 · Two new SAG milling models are developed in this work, able to predict power or specific energy consumption, including the usual design variables such as mill size; balls charge level, solids concentration in the SAG mill feed and % of critical speed, but adding a variable …

Sales Online2010-4-13 · In this case, mill speed is the primary manipulated variable used to control mill load. While there is no generic control strategy for SAG milling there is a considerable amount of reusable engineering. In contrast to an expert or black box system, the control loop approach was built using standard blocks, connected as shown.

Sales OnlineVariable speed was required for the SAG mill. Various options were considered to meet the specified speed range of 65 to 85% of mill critical speed, and the final selection was the IES HyperSynchronous drive Slip Energy Recovery (SER), in conjunction with Wound Rotor Induction motors (WRIM).

Sales OnlineVariable Speed . Single or double pinion driving systems. Designed to drive and control the speed of the medium voltage motors coupled to the SAG/AG, ball and HPGR mills with single or double pinion, the MVW01 frequency drive uses state of the art technology through a multilevel structure with medium voltage IGBTs, reducing the harmonic currents on the motor to extremely low levels.

Sales Online2017-4-10 · 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 …

Sales Online2020-10-19 · The SAG Mill is a machine added by Ender IO.It uses Micro Infinity (µI) to grind (or mill) items into their crushed variants, like Ores into Dusts.The SAG Mill has four output slots; recipes can have 1-4 different outputs, with different chances of obtaining those outputs. Uniquely, the SAG Mill can use Grinding Balls made from various materials to increase energy efficiency (resulting in ...

Sales OnlineThe design of the 12 m diameter SAG mill installed at the Cadia Hill Mine in New South Wales followed after two years of extensive laboratory and pilot plant testwork. The testwork showed the Cadia ores to be hard and competent necessitating the use of both a variable speed SAG mill drive and pebble crushing.

Sales Online2020-11-7 · Table of ContentsComminution Circuit DescriptionMill Availability and MaintenanceAdvantages and DisadvantagesVariable Speed SAG Mills Motor Capability vs Mill Capability The single line grinding circuit at Bond Gold’s Colosseum mine consists of variable speed drive semi-autogenous (SAG) milling and secondary grinding with a fixed speed ball mill. There are several …

Sales Online2020-11-3 · with the ball mill (6.71 × 9.91 m) discharge and sent to the cyclones. The SAG mill in phase 1 uses two 4100 kW synchronous motors and works with a constant 10.5 rpm rotational speed in two directions, and SAG mill of phase 2 uses two 3700 kW synchronous motors and works with variable speed in two directions. Since this

Sales OnlineControl of -SemiAutogenous Grinding(SAG) mill weight is an example of an important process that exhibits many of these aspects. Maintaining the SAG mill weight at the optimum value is critical for achieving maximum grind rate efficiency and mill production (Powell, M.S., van der Westhuizen, A.P., & Mainza, A.N. 2009).

Sales Online2020-3-22 · The model assumes all SAG mills are variable-speed; if a fixed-speed mill encounters this condition, it will completely grind out and operators will probably be forced to stop the SAG mill. Pick your mills sizes to avoid secondary mill limited conditions. This transfer size is NOT a prediction

Sales OnlineFixed or Variable Speed Drives. Crusher Drives; Grinding Mill Drive Systems, SagBall etc; ... 1 x 11000kW SAG Mill driven by Dual 5500kW motors, 1 x 5500kW Ball Mill Equipment: 3 x 5500kW 6 pole 11000 volt Wound Rotor Induction Motors Location: Cloncurry, Queensland ...

Sales OnlineThe SAG mill was installed with a fixed speed motor, however the possibility to retrofit a variable speed drive with limited speed adjustment, if it is found to be necessary, was allowed.

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