### A Method of C alculating Autogenous/ Semi

SAG mills mimic the same shortcoming. It follows that in order to obtain the speciﬁ c energy (SE) to achieve a certain transfer size, based on the 80 per cent passing value, an inefﬁ ciency factor must be applied to the SE of single stage ball mills, rod mills or AG/SAG mills when calculating power according to the Bond Third Theory method.

feeders to the SAG mill by conveyor 02-CVR-01. The ore is milled in a 6 MW, semi-autogenous grinding (SAG) mill in open circuit. The pulp exits the mill over a trommel screen. Tailings Storage Oversize from the trommel screen is crushed in a pebble crusher and is returned back to the SAG mill. Trommel undersize is pumped from

The key additions were a secondary crusher to reduce the semi-autonomous grinding (SAG) mill feed size and tertiary grinding for reduction in flotation feed size to maintain recovery. The Cadia East mine, which consists of two large block caves, became the sole feed source for

Debottlenecking of the Ridgeway Concentrator at Newcrest’s

Specific energy model on data of four SAG mills. consider explicitly the effect that the feed particle size has on the mill performance, particularly on the power and on the specific energy consumption of the mill. To address this fact new models are developed in this work able to predict power or specific energy consumption, including the

### Grinding Circuit - an overview | ScienceDirect Topics

The crushed pebbles fall directly onto the SAG mill feed belt and return to the SAG mill. SAG mill product feeds two parallel ball mills of 6.6 m 11.1 m (internal diameter length), each with a 9.7 MW twin pinion drive. The ball mills are operated at a ball charge volume of 30–32% and 78.5% critical speed.

Ball mill Wi test closing screen size, umclosing, m; Ball mill Wi test product size, P 80, m; Ball mill Wi test feed size, F 80, m; Ball mill Wi grams per revolution at test conclusion, gpr; Required parameters. F 80, m is the 80% passing size of the fresh feed to the circuit (expected to be a Bond-compatible size distribution). P 80

The software uses the particular power model (Bond/Barratt, Morrell Mi, etc.) to determine what is the transfer size where the ratio of E SAG to E ball matches the ratio of mill power (1:1.5 in this example). This is the 'maximum efficiency' transfer size where the mills will both operate at full power.

Jan 11, 2019 The SAG mill feed particle size distribution shape can be used to reduce the variation of the SAG mill feed disturbances by manipulating the stockpile feeder to achieve a better distribution shape by taking the segregated material as necessary to blend on line the material.

Grinding and Flotation Optimization Using Operational

### Optimization of a SAG Mill Energy System: Integrating Rock

Jul 01, 2019 The analysis is expanded to consider the case where stockpiles are used to manage the grindability of the SAG mill feed, and also by assessing potential changes in the solar energy available based on a forecast of the solar availability out to 2030. Figure 1 shows the energy sources involved in the optimization problem. The photovoltaic (PV

Water is added to the SAG mill to produce a slurry and the ore feed size is reduced as it traverses the SAG mill. The SAG mill discharges onto a double deck screen with 6.35 mm bottom openings. Screen oversize is recirculated to the SAG mill feed chute by a series of conveyors. Screen undersize flows by gravity to the cyclone feed pump box.

targets by lowering the throughput. Further, the SAG mill circuit was characterized by fluctuating feed size of between x. F, 80 =102 to 185 mm. A need for control of the feed size as well as blending ratios was recommended for an efficient operation in terms of throughput and final product size. This could be achieved through closer monitoring of

Feed size effects what size is important? historically, Mine-to-Mill has – focussed on blasting alone – generation of more fines • pass through SAG mill onto ball mill circuits • higher throughput (e.g. 10% to 30%) • coarser grind size (possibly) fine 25mm medium 25 - 75mm coarse 75mm

### Modelling SAG milling power and specific energy

Jan 01, 2015 In Fig. 3, Fig. 4 the data is presented in order to show the effect of the fresh feed size, particularly the % −6″ +1″ (−152 +25 mm), on the SAG mill power consumption (Pc) in kW and on the SAG mill specific energy consumption (Ecs) in kW h/t, obtained by dividing the power consumed (kW) by the fresh feed rate (t/h).

Modelling SAG milling power and specific energy

Mill Weight Power Top Size Figure 4: Feed Top Size vs. SAG Mill Performance 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 13:00 14:00 15:00

AG/SAG mill feed, trommel screen undersize product (-5.00 +0.00 mm), ball mill discharge and cyclone feed, overflow and underflow have been conducted in order to characterize the particle size distribution in the products and to carry out mass balancing of grinding circuits.

The SAG mill feed conveyor is fitted with a belt scale, providing plant feed tonnage control through the variable speed capability of the apron feeders. Grinding Circuit The grinding circuit is in a single-stage SAG mill configuration. One of the Kemess ball mills was modified to function as the SAG mill in the Young-Davidson grinding circuit.

### Throughput optimisation in milling circuits

The feed rate setpoint can then be tied into a SAG mill power optimisation strategy. SAG Mill Discharge. Controlling the feed and discharge of a mill is mostly a stabilisation exercise – you need to be able to quickly and accurately control the mill feed rate. If the mill feed setpoint is changed, then the actual feed rate needs to stabilise

size depending on the required mill feed rate and ore hardness. Figure 3 – Meadowbank milling flowsheet . Crushed ore is conveyed to a covered stockpile with an 8,500 t live capacity. Two variable frequency drive pron feeders reclaima the stockpiled material to a conveyer belt feeding the SAG mill in the primary grinding circuit.

Grinding Circuit Final Grind Control at Agnico Eagle

After closed-circuit secondary crushing, the SAG mill feed 80% passing (F80) size was 25 mm to 30 mm. Installed grinding power is split equally between the two mills with the SAG mill fitted with a variable speed drive (VSD). SAG discharge screen oversize (‘pebbles’ or ‘scats’) was

Jan 27, 2020 SAG mills usually have a larger diameter than length and are used to reduce large feed size ore (typically ~300mm) down to ~3mm, often for further grinding in a secondary process. Ball mills are smaller in diameter than length and can be used in either primary, secondary or tertiary grinding applications to reduce material from ~20mm to very

### SAG Mill Optimization using Model Predictive Control

For SAG mill control, expert systems are often used as they are able to detect the rapid increase in mill weight and anticipate an imminent overload using combinations of rules. However they often reduce the feed rate more than necessary in some situations, and require time to return the feed rate to maximum

Ball mill Wi test closing screen size, umclosing, m; Ball mill Wi test product size, P 80, m; Ball mill Wi test feed size, F 80, m; Ball mill Wi grams per revolution at test conclusion, gpr; Required parameters. F 80, m is the 80% passing size of the fresh feed to the circuit (expected to be a Bond-compatible size distribution). P 80

targets by lowering the throughput. Further, the SAG mill circuit was characterized by fluctuating feed size of between x. F, 80 =102 to 185 mm. A need for control of the feed size as well as blending ratios was recommended for an efficient operation in terms of throughput and final product size. This could be achieved through closer monitoring of

Optimization and Performance of Grinding Circuits: The

Metso’s AG/SAG mills accomplish the same size reduction work as 2 or 3 stages of crushing and screening The feed size for these mills is limited to the maximum size that can be practically conveyed and introduced into the large mill feed chutes. And the product of the large AG/SAG grinding is either a finished size ready of processing, or an

### Grinding Mill Computer Model

Fo - Optimum Feed Size for rod mills F o W r =16 000 size and power relationships For SAG mills the equation becomes Power=(5.6115+%balls*0.1438)*D24. 6* L Mill Critical speed Crit Crit D = 42.3 n - revs per min nC= s*Crit Cs is the fraction of the critical speed

The SAG mill pinion energy, W SDT (kWh/t) and SAG discharge Bond ball mill work index, S d-BWI (kWh/t), are then used to calculate the total energy to grind the ore from 80% passing 152 mm to 80% passing the client specified final product size P 80.This information, along with the ore specific gravity, is used to calculate necessary mill sizes and motor power in industrial applications.

The oversize crusher feed size distribution, oscf, and the primary cyclone feed size distribution, pcfd, are estimated utilising the SAG mill grate size and discharge screen aperture sizes and the Rosin-Rammler size distribution function, which has been selected for its convenience and since it

bling mills (AG/SAG, rod, and ball mills) involved in reducing the size of the primary crusher product to that of the final product (usually the cyclone overflow of the last stage of grinding prior to flotation/leach-ing). 2. Feed rate to the circuit (dry tonnes/h) 3. Power draw of the comminution equipment (kW)

20150821 Morrell Method-GMG-ICE-v01-r01 Morrell

### Molycop Training- SAG Milling Fundamentals - Credly

Molycop Training- SAG Milling Fundamentals. Issued by Molycop. This course explores and explains a SAG Mill’s operational variables, providing participants practical operational advice to effectively operate and manage a SAG Mill Operation. Practical in scope, this course identifies and explains a SAG Mill’s operational variables, providing

feeders to the SAG mill by conveyor 02-CVR-01. The ore is milled in a 6 MW, semi-autogenous grinding (SAG) mill in open circuit. The pulp exits the mill over a trommel screen. Tailings Storage Oversize from the trommel screen is crushed in a pebble crusher and is returned back to the SAG mill. Trommel undersize is pumped from