SAG Mill Variable Speed Drive. Large scale equipment can reduce both capital and operating costs for concentrators. Large semiautogenous mills can be effectively utilized in big mills but they must be kept fully loaded to take advantage of their great potential. With varying hardness ores, controlling throughput is difficult and careful design ...
WhatsApp: +86 18838072829Figure 5. Highlow wave ball mill liner Materials The selection of the material of construction is a function of the application, abrasivity of ore, size of mill, corrosion environment, size of balls, mill speed, etc. liner design and material of construction are integral and cannot be chosen in isolation.
WhatsApp: +86 18838072829remedial measures [1,2]. The causes of both the SAG and ball mill drive faults were related to the stiffness of the drive components. During this work, the characteristics of the SAG mill system were measured. The resonant frequency of the foundation was determined using an amplitude decay technique. Vibrations in the SAG mill stator
WhatsApp: +86 18838072829At 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 ...
WhatsApp: +86 18838072829This 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.
WhatsApp: +86 18838072829According to Figure 1, the dynamic model of the ball mill is where is the rotation resistance coefficient of the drive motor, is the friction torque, and the rotation direction of the ball mill is determined by the sign function sign().. When the rotational speeds of the clutch are synchronised,, =, the clutch no longer slips. The dynamic model can be written as follows:
WhatsApp: +86 18838072829Ball mill with ring motor drive. Brake of a ring motor drive. 8 Flotation Wet grinding Grinding is one of the most energyintensive production stages and therefore has ... SAG and ball mill for the wet grinding of gold ore in the Dominican Republic. 10 Flotation All around the world, mines are having to work ore ...
WhatsApp: +86 18838072829Proposed 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
WhatsApp: +86 18838072829An unplanned stop must be avoided at almost any cost. Many years ago, SPM Instrument installed a VCM system on the mill gearbox and motor. Image 1. The ball mill at Orcem Netherlands. Image 2. The gearbox, just renovated, with the shock pulse and vibration sensors. Image 3. A principal overview of the ball mill. 4 System setup. Measuring ...
WhatsApp: +86 18838072829Grade control during ore haulage delivery to die mill 28 Coordination with mill 29 Metallurgical balance 30 References 30 PART II. PROCESSING TECHNOLOGY 33 CHAPTER 3. PROCESSING CONCEPTS 35 References 37 . CHAPTER 4. ORE PREPARATION 39 Introduction 39 Crushing and grinding 39 Introduction 39
WhatsApp: +86 18838072829HPGR test results published by Grier (1992) on gold ores from the Mt. Todd project showed significant energy savings for a HPGR/Ball Mill circuit as compared to a SAG/Ball Mill plant. By adding a Polycom highpressure grinding roll, the throughput of existing plants can be increased by as much as 150% while simultaneously reducing the power ...
WhatsApp: +86 18838072829Fig. 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).
WhatsApp: +86 18838072829Drive system for Single and Dual Pinio n Mills In case of a high speed solution, AC induction motor an d for low speed solution a brushless synchronous motor are fed by
WhatsApp: +86 18838072829Effective preassembly. There are two things to consider for effective preassembly: the speed at which operators can work and the weight of the tool. Of course, the power of the tool is essential to enabling operators to complete tasks at a faster rate, thus reducing downtime. For example, the use of an impact wrench for pretightening bolted ...
WhatsApp: +86 18838072829• 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
WhatsApp: +86 18838072829Different configurations of SAG, ball and rod mill occur but in general a SAG mill can be considered an intermediate stage in breaking down rock from the crushing plant, and feeding to ball or rod mills for further size reduction. Types of mill Different types of mill are in operation rod or ball mills, so
WhatsApp: +86 18838072829As 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 ...
WhatsApp: +86 18838072829Ball Mill SAG Mill Figure 2 Core pressing system with spring plate/washer and retightening statistics in a typical installation Access to the inside of the motor and the cooling system The easier the access to the inside of the motor is, the more convenient and efficient is the work on the motor.
WhatsApp: +86 18838072829Go 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 ...
WhatsApp: +86 18838072829the 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
WhatsApp: +86 18838072829The use of VSDs makes it very easy to set the mill speed by just modifying this value on a touchscreen. But this is not only an option for new installations. In installations where SAG and Ball mills have been working for several years at fixed speed, but the speed regulation has been observed to be necessary VSDs can also be integrated very ...
WhatsApp: +86 18838072829During the last decade numerous protocols have been published using the method of ball milling for synthesis all over the field of organic chemistry. However, compared to other methods leaving their marks on the road to sustainable synthesis ( microwave, ultrasound, ionic liquids) chemistry in ball mills is rather underrepresented in the knowledge of organic chemists.
WhatsApp: +86 18838072829This Table is based on normal design parameters which need to be included in the selection of SAG and ball mills and the drive motors for each mill. For good SAG operation, the SAG mill D/L ratio should not be less than 2 in normal circumstances. Similarly, the ball mill L/D ratio should not exceed
WhatsApp: +86 18838072829High 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.
WhatsApp: +86 18838072829Larger 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 ...
WhatsApp: +86 18838072829— Ball/SAG mills with up to 8'000 kW per motor, typically geared solutions ('highspeed') using asynchronous motors with 68 poles and rated speed 1'000 1'800 rpm ... (FIT = failure in time) which tells about the number of device failures in 10 9 device hours. v. Weak grid. ... ball mill conveyor drive applications dusty ...
WhatsApp: +86 18838072829Megaliner is now available for all sections of horizontal mills: the head, the shell and the discharge system. The concept is best suited for large AG, SAG and ball mills with large trunnions and where modern liner handlers are available. Unique attachment system: the liner bolts are inserted and removed from the outside of the
WhatsApp: +86 18838072829When future tonnage needs to be increased, the SAG Mill can feed downstream ball mills to boost capacity. When it comes to the biggest of the big, FLSmidth has experienced a great deal of success with SAG and ball mills. "We just sold our 27 th 40ftdia. SAG mill," said Anthony Filidore, head of GPLMMining Comminution for FLSmidth. "Of ...
WhatsApp: +86 18838072829Horizontal Ball Mill Drives. We can provide all elements of a mill drive system as a fully optimised solution to suit your process exactly, or individual components as required. Book an appointment. Find out more about David Brown Santasalo. David Brown Santasalo A Global Gear Engineering Leader. Watch on.
WhatsApp: +86 18838072829This 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 ...
WhatsApp: +86 18838072829The power the mill consumes is a function of the ore and/or ball charge geometry and the mill speed. The motor only supplies the amount of power (or torque really) that the mill demands, and we add some extra power to the motor to deal with 'upset' conditions like a change in ore density or a surge in ore level inside the mill.
WhatsApp: +86 18838072829Ball Mill Sole Plate. This crown should be between .002″ and . 003″, per foot of length of sole plate. For example, if the sole plate is about 8′ long, the crown should be between .016″ and .024″. Ball Mill Sole Plate. After all shimming is completed, the sole plate and bases should be grouted in position.
WhatsApp: +86 18838072829mills in the older plants that had many mills in parallel. In fact this is generally still the case in the multistream plants, where mill liner design and selection is only tackled on a cost consumables basis. However, the gains to be had through good liner design and selection are just as great as on the large SAG mills.
WhatsApp: +86 18838072829