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 ...
WhatsApp: +86 18838072829The minus 152 mm (6 in) product is conveyed onto a 29,940 Mt (33,000 st) crushed ore stockpile, reclaimed by three vibrating feeders, and then conveyed to the SAG feed chute at a targeted rate of 136 Mt/hr (150 st/hr). The control strategy for the SAG mill is fairly basic. Parameters which can be adjusted are feed tons per hour and mill speed.
WhatsApp: +86 18838072829When the SAG mill feed size ... (1975 mm) from a SAG mill. At the optimum pebble content of 25% by volume, a 25% saving in steel ball consumption and a 15% saving in energy consumption was ...
WhatsApp: +86 18838072829A threedimensional slice of a generic intermediate size m diameter SAG mill is used here. This study was performed using a series of DEM simulations whose details are given in Table 1. ... which achieved tradeoff between impact toughness and strength after the optimal heat treatment scheme (900 °C normalizing → 900 °C quenching → ...
WhatsApp: +86 18838072829Figures 4a and 4b are for the same size mill with a ball charge of 6% of mill volume (290 lbs. per cubic foot). ... Current operational results show that the SAG mill is operating at 5% ball charge level by volume and is delivering a K80 800 micron product as predicted. Power drawn at the pinion is 448 kW, kWh/tonne (SAG mill) and 570 kW ...
WhatsApp: +86 18838072829The operations of AG/SAG mills are known to be sensitive to the changes in feed particle size distributions presented to the mill [].The variation of feed particle size significantly affects the overall process control, product quality, and economic performance of the mill [2,3,4].Poor product quality from the AG/SAG mill poses significant challenges to downstream processes such as flotation ...
WhatsApp: +86 18838072829Generally, grinding efficiency depends on the behavior of the load inside the mill and it determines the share of various breakage mechanisms (Toor et al., 2013). Maintaining an optimum charge height and composition in a SAG mill remains one of the fundamentals for efficient mill processing (Royston, 2007).
WhatsApp: +86 18838072829Grinding Mill Control in Closed Circuit. The principle objective for controlling grinding mill operation is to produce a product having an acceptable and constant size distribution at optimum cost. To achieve this objective an attempt is made to stabilize the operation by principally controlling the process variables.
WhatsApp: +86 18838072829Our system will ensure your mill operates at optimum charge level to save on energy and improve performance. ... You'll be able to reduce energy use while improving throughput at consistent product size. ... The AutoCharge system is primarily suitable for SAG mill balls (100150 mm). As each ball rolls through the counting chute, an electro ...
WhatsApp: +86 18838072829To predict the power of the SAG mill, Hoseinian et al. proposed an analytical model based on gene expression programming. To develop their model, they employed several tests by varying the SAG mill parameters such as the moisture of charge, mass flow rate, cell weight of mill load, solid percentage and inlet and outlet water to the SAG mill.
WhatsApp: +86 18838072829SAG Mill Feed rate, tlh 950 lBall charge, % 81 0 l~vera~e power, kW I~otal charge, % 1 24 1 1 ... Full mass flow and size balance around the SAG and ball mill circuits ii) Power response of the SAG and ball mills ... practicable and the ball and total charge at optimum levels 1070tlh was achieved. A full survey under these conditions was
WhatsApp: +86 18838072829Ball mill: Ball mills are the most widely used one. Rod mill: The rod mill has the highest efficiency when the feed size is <30mm and the discharge size is about 3mm with uniform particle size and light overcrushing phenomenon. SAG mill: When the weight of the SAG mill is more than 75%, the output is high and the energy consumption is low ...
WhatsApp: +86 18838072829Tracking the mill performance showed that the mill power consumption decreased from to kWh/t (a nearly 30% reduction), P 80 of the mill product decreased from 611 to 355 μm, and the mill fresh feed flow rate increased from 511 to 521 t/h by decreasing the feed ore hardness from 112 min to 58 min based on SAG power index (SPI ...
WhatsApp: +86 18838072829Relation between Sag mill solid and product P80! Both are dependent on feed size. Dependent on Volume % solids in SAG mill. Dependent on ball charge volume. Hardness of ore. Recirculation load. Dependent on P80% size. All other parameters are secondary. In general Sag mill solids are kept at 70% by wt. Operating grinding circuit is an art.
WhatsApp: +86 18838072829In a largescale operation, feed ores are introduced into the AG/SAG mill in a continuous mode at a given flow rate to replace the discharging slurry. Nonetheless, the variations in the feed characteristics, typically hardness and size distribution, could cause sudden disruption to the mill operation. This would be challenging to detect in practice, owing to the hostile environment of the mill.
WhatsApp: +86 18838072829control the weight in the SAG mill to promote optimum grinding. This strategy has been demonstrated to improve mill throughput by as much as 3%. When copper prices are high, producers look to increase production by eliminating process bottlenecks. At Minera Los Pelam bres, as at many mines, SAG mill through put limits overall production.
WhatsApp: +86 18838072829by volume load. Recent studies in the threefoot diameter SAG mill are instructive. The following graph shows the relevant facts as Figure 2. Figure 2: Pilot Plant kg/hr Vs Charge % by Volume This data is indicative of trends that were happening in the 3ft. diameter SAG pilot mill. They have not been proven in large commercial scale mills.
WhatsApp: +86 18838072829Depending on the mill size the SAG mills draws between 2 MW and 17 MW. The product from the SAG mill is further reduced in size using pebble crushers and ball mills. Hence, typical gold or copper ore requires between and kWh per ton of energy to reduce the particle size.
WhatsApp: +86 18838072829In semiautogenous grinding (SAG), the grinding mill inventory, ( volume of total charge, volume of ball charge, etc.) is important in determining the optimum operating condition for maximum production (tph), minimum specific energy (kwh/t) or lowest cost (/t). A twodimensional graphical method is presented for determining the actual ball charge within the total charge when parameters ...
WhatsApp: +86 18838072829According to available literature, the operating speeds of AG mills are much higher than conventional tumbling mills and are in the range of 8085% of the critical speed. SAG mills of comparable size but containing say 10% ball charge (in addition to the rocks), normally, operate between 70 and 75% of the critical speed.
WhatsApp: +86 18838072829mill with a 30 mm graded ball charge and a 30% filling degree. The mill discharge pulp density was increased from % to % solids. The data is summarized in Table III. The example in Table III illustrates that the density has a large influence on the grinding efficiency. In this case, the optimum %<75 µis in the region of % or kg/l
WhatsApp: +86 18838072829To obtain the optimal rotation speed of the SAG mill, we must calculate the motion of the particles ... [23] in the fields of charge motion and power draw, e ects of grinding media shape, breakage of particles, and so on. ... the size and number of particles in the SAG mill was mainly investigated based on discrete element method. For optimal ...
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