Comminution is an essential component of mineral processing operations and its proper operation and design is vital to ensure that the plant operates efficiently. In recent years, there has been a shift of emphasis on ball mill optimization to semi-autogenous grinding (SAG) mills. In order to optimize this section, the skills to accurately model and …
The finding in this research is to reveal the condition in which a reliable DEM solution is achievable in the appli-cation of a SAG mill. The DEM result sheds insight to the design of the grates like the size and total opening area of the slots. It also provides structural optimization on a new type of grate used in a SAG mill.
This mill has curved pulp lifters fitted to a curved drilling pattern. It uses bridging grates. A curved pulp lifter and curved composite cantilever grate system was retro-fitted to the Northparkes 24 ft SAG Mill (the Bradken "Vortex" design). The principal process objective with this mill was to provide a capability "to pump rocks".
1. Installation of new liners reduce the internal mill volume. 2. Possible packing of material in between lifters. 3. Decrease in grate open area if discharge grates …
Comparison of different pulp lifter designs (pilot mill data at 15% charge, 7.05% grate open area and 70% critical speed, pulp lifter size — 6.7%). ... The spilling of the sag mill over the feed trunnion indicates that the volume of slurry inside the mill (hold-up) has increased so much that the mill starts to operate similar to an overflow ...
It should be noted in this study only data from the 32 ft SAG mill is analysed. Metallurgical Plant Design and Operating Strategies (MetPlant 2011) 8 - 9 August 2011 Perth, WA 195 Fig. 2- Throughput over liner life for 32 ft case study SAG mill. The project work forming the basis for this paper is scheduled for two full liner life cycles.
How a Grate Discharge Ball Mill Works. Here I try to explain how ground slurry is discharged from a grate ball mill (or SAG). How it works is, the slurry flows across the grate as it would a screen panel. On the other side of the grate/screens are veins like …
The SAG Mill has a "small" circulation load of oversize given be the 3/8″ trommel screen and the 1/2″ x 1 1/4″ discharge grates. The load of 4″ balls in this SAG is "good" but un-measured. SAG Ball consumption is "average" at 400 g/t while Ball Mill grinding media (3″ balls) usage in 550 g/t. Yet, you add steel and nothing ...
SAG mill geometry and operating conditions. To explore three dimensional slurry flow in a SAG mill, including discharge through the grates and flow in the pulp chamber, we use a pilot scale Hardinge 6 ft (D) × 2 ft (L) (1.8 m × 0.6 m) mill. The model contains the complete mill geometry including the feed end, the …
The most important one is that its performance does not get affected due to variations in: ♦ grate open area, and ♦ volume of grinding media (charge) inside the mill. 179 S. Latchireddi, S. Morrell / Int. J. Miner. Process. 79 …
Apron feeders draw the crushed ore from a coarse ore stockpile to feed two parallel primary grinding lines. Each line consists of a variable speed SAG mill measuring 28 feet in diameter by 11 ft long. The mill motors are rated at 5,500 HP. At the discharge of each SAG mill is a pair of vibrating screens.
A number of optimizations and improvements were adopted over the 10 years of operation of the semi-autogenous mill, including changes in the grates open area, size and arrangement of aperture, liner profile and the mine's rock blasting plan. The next section describes the main aspects of the circuit design and the improvements introduced over ...
In a way, the media size should be selected based on feed size and grate opening. Finer feed (i.e. secondary crushed) justifies a 4" ball but if the grate opening is 60 mm x 100 mm slots then a 4" ball won't last very …
Decrease in grate open area if discharge ... and Newcrest Mining Limited conducted an extensive study of the effect of liner wear on mill performance of a 32 foot SAG mill at Newcrest's Cadia ...
No pebble ports in the grates (SAG circuit). b) Semi autogenous grinding in which the pebble fraction of mill discharge (+½ in.) is taken out through pebble ports for separate crushing and ball milling. The minus ½ in. fraction of mill discharge is recycled to the SAG mill through a classifier.
Based on experience, mill liner designs have moved toward more open shell lifter volumetric capacity and a grate design to facilitate maximizing both pebble-crushing circuit utilization and SAG mill capacity. Mill throughput is maximized with shell lifters between ratios of 2.5:1 and 5.0:1.
Grate aperture size and open . area of first half and then all of the outer grates wa s increased from . ... Large fluctuations in SAG mill throughput (Sloan et al., 2001), ...
SAG Mill Discharge Grates main function is to discharge minerals with qualified particle size and refractory stones. Therefore, if there are many stubborn minerals in the mineral, two different Grates are installed at the discharge head of the mill. The discharge Grates must ensure that there are no casting defects such as shrinkage holes and shrinkage in …
** Percentage of the mill's discharge section A detailed description of the modifications introduced in the SAG mill grates during this period can be found at Delboni Júnior et al. (2006). Such ...
SAG mill liner development draws primarily on practical experience from SAG milling operations supported by computer-based modeling of charge motion in SAG mills and on established good design practice. Liner design needs to respond to the process aspects of mill liner action that are critical to good SAG mill performance, i.e.,
SAG mill throughput as a function of grate open area As shown in Figure 2 the grate open area has a strong effect on Sossego SAG mill throughput. The nominal capacity of the circuit should be achieved with a combination of 13.5% ball charge and 10.8% open area with 3 and 3.5 inch apertures.
The most challenging task in the simulation of granular flow inside a SAG mill is the grates filtering the ore particles. The grates consist of many small slots and is placed in the …
A SAG mill, or semi-autogenous grinding mill, operates on the principle of autogenous or self-grinding. It uses a combination of ore and grinding media to break down larger rocks into smaller pieces. Understanding the working principles of a SAG mill is crucial for anyone involved in the mining industry. In this section, we will delve deeper ...
Maintenance-related events such as insurance and warranty inspections, alignment checks, lubrication system troubleshooting and many service and repair tasks require a clean gear set. When a large, conventionally geared …
< 5% for a mill run "Perfectly" between 10 and 20 % for normal operation > 20% for a mill run poorly > 90% during grind-outs. Observing the density of impact marks per given area, you could figure out how it happens. You may also observe variation of intensity along the mill shell, usually less at F/E and more at D/E, this is a different story.
The role of SAG mill grate open area and aperture was evaluated in detail. This paper describes the main aspects of designing the circuit, as well as the work carried out at the industrial ...
Contribute to chengxinjia/sbm development by creating an account on GitHub.
The mill discharge flowrate Q (m 3 /h) for a grate discharge mill is equal to the product of the flowrate through the mill charge, Q m (m 3 /h), and k g, a scaling factor that accounts for coarse particles (Napier-Munn et al., 1996): (20) Q=k g Q m (21) Q m =6100J pm 2 γ 2.5 Aφ −1.38 D 0.5 where A is the total discharge grate open area (m 2 ...
Contribute to legaojm/m development by creating an account on GitHub.
The Discharge End (DE) pulp lifter is a critical component of autogenous (AG) and semi-autogenous (SAG) grinding mills, having a significant impact on the throughput, efficiency and performance of mills. Underestimating the importance of an optimised liner design in a mill can lead to back-flow and carry-over processes which can ultimately ...
