This option comprises an open circuit SAG mill followed by a closedcircuit ball mill. Due to the high throughputs associated with this circuit, the ball mill is most often closed with a hydrocyclone classifier. The course material is returned to the ball mill feed and the fine overflow product reports to the downstream process.
Siemens' gearless drive technology of to % as confirmed by real operational data from the Antapaccay mine in Peru. It was the first plant worldwide to use gearless drives for both applications. KEYWORDS Gearless Mill Drives, Gearless Conveyor Drives, Availability, SAG Mill, Ball Mill, Overland Conveyor, Antapaccay 15
Proposed algorithm was evaluated using field records of an MW semiautogenous (SAG) mill drive confirming its ability to handle startups with different charge conditions. View Show abstract
Go gearless to meet your business objetives by exceeding standard availability targets in your grinding operations. ABB's GMD is the most powerful mill drive system in the market to power semiautogenous (SAG), ball and autogenous (AG) mills, This 'workhorse' for grinding operations combines a robust, servicefriendly and fit for purpose ...
Firstly, there was a serious flaw in the power configuration of the SAG mill and ball mill (both rated at 6000 kW with a single pinion drive). The capacity of the SAG mill was not fully utilized, as the actual operating power draw was only 3358 kW. This meant it was only operating at 56% of its maximum power, providing large room for improvement.
Ball and SAG mills work with material of different sizes and densities, and both take a lot of power to do their jobs. ... A single overload could cause a fracture or complete failure of critical drive components. Damaged equipment means less uptime, lower productivity, and increased maintenance costs. Torque Limiters: Protecting the System ...
It is not unusual to find SAG mills up to 40 feet in diameter and Ball mills of 26 feet. Motor power is ever increasing with current designs producing upwards of 20MW. ... Such designs however, whilst giving great flexibility in the control and drive system, do limit the options for safety and static control in the event of total power failure ...
The biggest characteristic of the sag mill is that the crushing ratio is large. The particle size of the materials to be ground is 300 ~ 400mm, sometimes even larger, and the minimum particle size of the materials to be discharged can reach mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mill's ...
At present, the removal of the bolts which fasten the liners should be carried out manually as part of the maintenance procedure SAG mills should be subjected to. The disadvantage of this procedure is the fact it should be carried out manually which makes the system to lose efficiency due to the high maintenance periods. Due to the above, a robot system and method have been developed to carry ...
SAG Mill vs Ball Mill. ... Design Drive Power. C. Total Feed Conditions, including total mill volumetric flow rate; ... First evidence of grate failure occurred at 678 000 tonnes throughput, and at 850 000 tonnes, after three grates had been replaced on separate occasions, the remaining 25 were renewed. ...
This lack of movement towards larger mills is somewhat surprising since in the same period the drive rating of ball mills for similar duties such as ore grinding has shown an increase in drive ...
As well as ever larger SAG mills, ball mills are also expanding in size. In the late 1990s the trend moved towards using GMDs to power these larger ball mills, as well as using the drive to vary the speed. GMDs quickly moved from 20' ball mills, expanding to 24, 25 and then 26' mills. In early 2010 ABB commissioned the first GMDs for two 27 ...
Fig. 1 shows the grinding circuit of a modern copper concentrator with rated capacity of 110 000 tonnes per day (MTPD) with four gearless mill drives (GMD), comprising one SAG mill of HP and three ball mills of HP each one. Slurry pumps with a rating near 2000 HP with gearless lowspeed motors fed by frequency converters are applied (Bergholz et al., 2003, Rotella et al., 2003).
components having bushings, on which the mill rotates. The components of the mill that rotate on bearings are the trunnions. The trunnion is a kind of cylindrical and tubular shaft with thick walls, wherein the ore passes through its inner diameter, both in the feed and in the mill discharge. Engineering Failure Analysis 61 (2016) 2836
Larger ball and SAG mills, with higher installed power ratings relative to the mill diameter, offer higher efficiency and throughput, roundtheclock reliability and the opportunity to mine in remote areas. ... Two 28 MW gearless mill drive systems (GMDs) are operating in the mine's 40 foot SAG mills and four MW GMDS are employed in 26 ...
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High temperature of the ball mill will affact the efficiency. 3 For every 1% increase in moisture, the output of the ball mill will be reduced by 8% 10%. 4 when the moisture is greater than 5%, the ball mill will be unable to perform the grinding operation. 5. The bearing of the ball mill is overheated and the motor is overloaded.
the AG/SAG mill (because there is no recycle), but loads the ball mills instead. Often an existing plant that observes their SAG mill is limiting throughput, but the ball mills are underloaded can opencircuit the primary mill to better balance the grinding load with the secondary mill. The coarse transfer size to the ball mill makes this circuit
• 22 MW GMD for 28' ball mill • 28 MW GMD for a 40' SAG mill • 28 MW GMD for 42' SAG mill Whether it is size or an installation at the highest altitude (4600 ), ABB's GMDs are well positioned to contribute to the building of larger and ever more powerful mills. — Leading the gearless mill drive evolution
Ignoring mechanical losses in this drive train, the power transmission at each stage, defined as torque x speed, is constant. The typical mechanical inching drive motor speed is around 1500 to 1800 RPM while the mill inching speed is in the order of to RPM. Thus, the gear reduction ratio between the inching drive motor and the mill is ...
As well as ever larger SAG mills, ball mills are also expanding in size. In the late 1990s the trend moved towards using GMDs to power these larger ball mills, as well as using the drive to vary the speed. GMDs quickly moved from 20' ball mills, expanding to 24, 25 and then 26' mills. In early 2010 ABB commissioned the first GMDs for two 27 ...
Ball Mill Wi test on SAG ground ore from the first or SAG stage of the test. The SAG stage therefore had to use enough material to do the Bond Wi test. To ensure this, the SAGDesign SAG mill was designed to be 488 mm (") in diameter and 163 mm (") long (EGL). Other design parameters for the SAGDesign SAG mill were selected to
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pressure grinding rolls, SAG and ball mills, and exha ust and dryer combustion fans are the major load types [8, 11, 31, 32] . Induction and DC motors are used to drive t hese loads using
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