grinding refers to both FAG and SAG grinding. In the last 10 years, smaller-scale tests have been developed to further address the variability of ore types, most notably the MinnovEX SAG Power Index (SPI) test [2], and more recently, the SAG Mill Comminution (SMC) test [3], developed by Steve Morrell. These constitute the third

Assuming a test size of between 31.5 mm and 26.5 mm, 30 kg of ore is generally sufficient. SAG-mill Power Index® (SPI) Test. The SPI® test is carried out in a standardised mill under set conditions, with the output being the time to reach a given size, which can be converted to a SAG mill specific energy input (in kWh/t).

However the SAG route is more power-intensive and, for very hard ores, comes with some process risk in predicting performance. More recently, a hybrid solution has become available in the form of high pressure grinding rolls (HPGR's), which can replace the third stage of crushing and also the SAG mill.

The purpose of the primary crusher is to reduce the ROM ore to a size amenable for feeding the secondary crusher or the SAG mill grinding circuit. The ratio of reduction through a primary crusher can be up to about 8:1. Feed: ROM up to 1.5 m; Product: -300mm (for transport) to -200mm (for SAG mill) Feed Rate: 160 to 13,000 tph

Hardest measurements were used to allow any blend of feed to be treated at design t/h. A total of 9 kWh/t of grinding energy was indicated and this could be provided either in a single stage SAG mill to produce the P80 200 micron product, or a two stage circuit with equal power on the SAG and ball mills using the design Bond Wi of 11.5 kWh/t.

A cable hangs between two power poles whose bases are on the same level, similar to the photograph below. The sag in the middle of the cable is and the towers are 100 ft. apart. Find the length of the cable in terms of the quotient, where is the lowest point of …

head of the SAG mill (kPa). The relation between trunnion pressure and consumed power in the SAG mill was also obtained and explained in Equation 2[3]. where, p is SAG free trunnion pressure (kPa) and P is consumed power at the SAG mill (kW). The surface changes of liner during its life due to abrasion were examined and its consumption

8.3.2.2 Ball mills. The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 1–1.5 times the shell diameter ( Figure 8.11). The feed can be dry, with less than 3% moisture to minimize ball …

SAG mill fractional total filling (J t) and ball filling (J b) are determined by solving the powerdraw or mill weight residuals given mill power draw or weight process measurements as inputs. SAG mill fractional rock charge filling (J r) is calculated by difference of the total and ball charge fractions, see Equation (11). J r J t J b (11)

Sag and Tension: Sag is an interesting topic to discuss.We generally see a lot of overhead lines on our way.Sag in general words can be said that distance between the highest point of electric poles or towers and the lowest point of a conductor connected between two poles or towers.You will know how to calculate sag and sag formula.

This can improve mill power efficiency and reduce energy wastage, increasing throughput, and operational revenue. 5. Recycled. A worn-out metallic liner can be recycled and sent back to the foundry and used to produce new liners. An added sustainability benefit is that our metallic mill liners are not painted. 6.

Relationship between SAG mill power draw, bearing Download scientific diagram Relationship between SAG mill power draw, bearing pressure and feed rate from p +86 21 33901608 [email protected] Home

In these circuits the conveying power is limited to the transport of material from the primary crusher to the SAG mill and pebble recycle stream. Based on experience and the energy curve database, a typical primary crusher and the SAG mill can be assumed to be 1 km apart, consuming about 0.40 kWh/t in conveying power.

The control of autogenous and semi-autogenous mills: the relationship between measurements of bearing pressure and parameters describing the …

Fig. 1. SABC A/B milling circuit. Scw = solid concentration by weight fraction in the SAG mill feed; Jb = balls charge (bulk fraction of the SAG mill volume); N/Nc = fraction of the SAG mill critical speed; Pc = SAG mill power consumption (kW); % 600 +100 = % of the fresh feed in the size range 152 +25 mm. M. Silva, A. Casali/Minerals ...

A clear example is the work of Hadizadeh et al. (2017), who classified the mill power draw and bearings pressure in levels such as very low, low, good, high, and very high. Between levels, a ...

SAG mills have a higher installed power density for a given plant footprint relative to AC mills. With the combination of finer grind and a lower installed power density (based on the lower density of the mill charge), a typical AG mill has a lower throughput, a lower power draw, and produces a finer grind.

The power draw of the SAG mill has room for significant improvement. As ball filling in the SAG mill is quite low, additional grinding media would likely increase the processing capacity of the SAG mill; however, the capacity of the ball mill, with installed power for the required product size of 170 µm, has reached its limit.

other methods. The ball mill correction factor (CFnet) is empirical and one way of estimating it was presented by Amelunxen at the Procemin 2013 Short Course by Doll & Amelunxen. The SGI equation uses a transfer size between a SAG and ball mill; it is proposed that a synthetic transfer size of 2100 µm be used to model single-stage SAG mills. 5.9ˇ

The behaviour of SAG mill itself is very complicated due to time delays and variations in ore characteristics. There are interactions between SAG mill operating parameters (bearing pressure, mill load weight, power draw and motor torque).

A SAG mill with a 44′ (13.4m) diameter and a power of 35 MW (47,000 HP) has been designed.[9] Attrition between grinding balls and ore particles causes grinding of finer particles. SAG mills are characterized by their large diameter and short length as compared to ball mills.

• Manage power and torque limits to prevent mill overload SAG MILL CASE STUDIES Location: Minera Centinela Mine • Reduced feed variability by 18% • Increased SAG mill throughput by 13.5% and reduced energy consumption per tonne by 9.3% Location: Minera Los Pelambres Mine • Reduced feed variability by 5.6%

The SAG mill was fitted with a gearless drive with a power rating of 24 MW and the ball mills were also fitted with gearless drive systems, each providing 16.4 MW.

LG A mill power equation for SAG mills. Minerals and Metallurgical Processing. Feb 1990 pp57-62. Gross power No load power Net power drawn by the charge (8.13) The net power is calculated from Net power KD2.5L e! c./ Watts (8.14)

Ball Mill Power Calculation Example #1. A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80% passing ¼ inch (6350 microns). The required product size distribution is to be 80% passing 100 mesh (149 microns). In order to determine the power requirement, the steps ...

Mill power Usually, plant operators use mill power readings as an indicator of ball filling degree and, often, try to keep it at the maximum level. It is well known that the mill absorbed power depends on operating parameters other than ball level, such as pulp density and liner configuration. Figure 2 shows that there is no linear relation between

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 0.1 mm. The calculation shows that the crushing ratio can reach 3000 ~ 4000, while the ball mill's ...

Ball 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 ...

1. SAG mill is the primary tool for grinding. SAG mill is used before the other mills. Ball mill is a secondary, and it is used after the SAG mill. 2. SAG mill breaks the raw material into pieces for the further grinding. Ball mill is used to grind the pieces of raw material into. powder-like structures. 3.