The SAG mill's steel liners were failing to meet the required service life. To remedy the problem, the supplier had added more material to the liner design. But this created its own challenges, reducing the effective grinding volume and adding weight to the mill that was pushing bearing pressures dangerously close to limitations. Peening liners.
Different combinations of SAG mill ball charge and grate open area were tested until 2006. A higher load level was achieved after several changes in the grate design that prevented both liner and grate breakage. Upon resolution of issues related to the mill grate design, the project achieved the target throughput of 41 kt/d. Phoenix
These SAG milling plants (Fig. 1) are designed with few pieces of equipment having a large processing capacity, replacing advantageously a large battery of traditional crushers and rod and ball characteristics make SAG mills an excellent example of critical equipments whose continuous and stable operation is essential to guarantee mineral processing plant profitability (Concha et ...
SAG Mill Circuit Example — Gold Processing SAG mill circuit example for gold processing [image: (13563)] AG/SAG Mill. AG/SAG mills are normally used to grind runoffmine 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
The model has been assessed using data obtained from milling tests performed on a pilot mill in which grate design, slurry flowrate and slurry viscosity were varied. ... The SAG mill model ...
For large mills, using 125 to 140 mm (5 to 51/2 in.) feed ball size, conventional new lifterliner dimensions are around 300 to 350 mm (12 to 14 in.) overall height above the shell, with around 100 mm (4 in.) plate thickness and around 150 mm (6 in.) top width. Detailed design depends on individual mill circumstances.
The flow of water to the mill was regulated using an adjustable valve and measured using a rotameter. The grinding media within the mill comprised 6 mm diameter steel balls occupying 30% of mill volume. For a given grate design, the mill was fed at a variety of flowrates for each of three rotational speeds.
The support of the grate wall is critical in any mill liner design. There are a variety of designs on the market now ranging from cast iron to molded rubber. A basic design is a fabricated metal structure with a protective coating of abrasion resistant rubber. The pulp lifters have three main functions.
In its original form Morrell's model used a different media charge shape to that in Fig. 1 (Morrell, 1992) and was configured to consider the cases where slurry was contained within the grinding charge as in a typical grate discharge AG/SAG mill (Fig. 2a) or where it additionally formed a large slurry pool as occurs in all overflow ball mills ...
Pulp lifters, also known, as pan lifters are an integral part of the majority of autogenous (AG), semiautogenous (SAG) and grate discharge ball mills. The performance of the pulp lifters in conjunction with grate design determines the ultimate flow capacity of these mills. Although the function of the pulp lifters is simply to transport the slurry passed through the discharge grate into the ...
The amount of pebbles passing through the grate increases with the angle of the grate. It is imperative to ensure the efficient removal of both slurry and coarse pebbles (critical size) in order to ensure the efficient operation of AG/SAG mills. Elimination of the above mentioned material transport problems will allow the mill to respond truly ...
The design of grate/pulp lifters in SAG mills has a substantial impact on the behavior of the mill. If sufficient grate open area and pulp lifter capacity is not available, they will provide a high resistance to flow of slurry resulting in excessive amount of slurry resulting in slurry pool formation inside the mill. If the amount of slurry ...
The discharge grates of the SAG mill were identified as a key component in the SABC circuit, and their design is a crucial factor in the mill's performance [17,18,19,20,21]. The initial design of the grate section caused a serious accumulation of pebbles within the SAG mill which contributed to a decreased grinding efficiency.
angle increases the mill's outlet flow. Keywords: grate, SAGMill, DEMSimulation, flowback, carryover 1. Introduction Size reduction of ores has an important role in the process of obtaining various metals. For example, for copper the ore must be separated from the mineral and must reach sizes smaller than 50 m, and this
The design of mill liners and SAG mill discharge grates will have a large effect on how efficiently the mill operates and the circuit throughput. All models generally assume that a mill is fitted with "efficient" liners and that the grate design neither limits passage of pebbles (and pulp) nor permits recirculation of pulp back into the mill.
Grate discharge mills are used when the grinding energy shall be concentrated to the coarse particles without production of slimes. In order to get a steep particle size distribution curve, the mill is used in closed circuit with some kind of classifier and the coarse particles known as classifier underflow are recycled. ... SAG Mill vs ...
estimated utilising the SAG mill grate size and discharge screen aperture sizes and the RosinRammler size distribution function, which has been selected for its convenience and since it "has been found to fit many size distributions very well" (NapierMunn et al.,1996).
The structural design of the SAG mill allowed for a ball charge filling of . 15% by volume. ... new feed and 70% of the mill charge was between the grate and trommel . aperture sizes. The size at ...
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A vibrating screen was used to provide a mill discharge product separation at 19 mm (¾ in.). The minus 76 trail (3 in.) plus 19 mm (+¾ in.) screen oversize product, which are the "pebbles", were then crushed to essentially 100% minus 19 mm (¾ in.) in a crushing circuit. This product was returned to the feed end of the mill.
In this training module, we'll cover the workings of a semiautogenous grinding mill, or SAG mill, that's designed to be the first stage of a grinding circui...
Yanacocha gold single stage sag mill design, operation and optimization. Proceedings SAG 2015, Vancouver, British Columbia, Canada. Paper #127. ... Grate design considerations ...
The usefulness of the SDV is that for a possible open area dictates the amount of pebbles from the mill. An optimal grate design with pebble ports at 65% of the open area was found to allow area and engineering design parameters, the likely maximum flowrate high mill throughput (over 400tph) and to limit pebble production to the out of the mill ...
** 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 ...
Key considerations. Numerous factors must be considered when selecting a mill liner design, including required grinding action, mill size as well as ore and grinding media characteristics, among others. These considerations will help determine the best liner material and geometry. Depending on the mill size and material being ground, a lining ...
6 6 Feed Trunnion Mill Shell Grate Pulp Lifter Discharge Trunnion Figure : Schematic of a typical SAG mill. Field of breakage: The motion of charge or rocks and balls in SAG mils can be viewed as a field of breakage generated as a result of the internal profile of the lifters and the rotational speed of the mill shell.
Citic SMCC's slurry flow model for AG/SAG mills (grate discharge mills) was constructed using the approach originally adopted by Morrell and Stephenson (1996) who related the volume of slurry heldup in the mill to its rate of flow out of the grates. Morrell and Stephenson incorporated the effects of grate design, mill speed and charge volume.
Semantic Scholar extracted view of "Slurry flow in mills: grateonly discharge mechanism (Part1)" by S. Latchireddi et al. ... A Discrete Elements Method (DEM) study of load movement within a SAG mill 12,192 × 7620 (40′ × 25′) in normal operating conditions is performed. ... The effect of grate design on the behaviour of gratedischarge ...
In a SAG mill the dimensions of the mill were m × m and the specific gravities of the mineral and that of the balls charged were and respectively.. The mill was rotated at 75% of its critical speed when 8 % of the mill volume was charged with grinding :1. The mill power drawn, 2. The maximum mill filling possible.
which relates the holdup of slurry, grate design, grate open area and mill speed to the volumetric discharge rate through the grate ... In SAG mills running with higher ball charges, the rock
High costeffectiveness CITIC HIC grinding mills are recognized as China's Manufacturing Industry Single Champion Product. CITIC HIC is responsible for setting the national standards of semiautogenous mills (SAG mills) and ball mils, supported by powerful database, optimized process technology, cuttingedge design concept, and 60 years of experience in developing and nurturing innovative ...
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