sag mill balls charge conditions pdf

Measuring ROM at Highland Valley Copper

autogenous (SAG) mill with a standard ball charge. Table 1 shows the range of hardness values (in tph) for each of the rock categories. A considerable variation in throughput is shown for each category due to local ground conditions and the degree of fragmentation.

CALCULATION OF BALL MILL GRINDING EFFICIENCY - Page 1 of 1

calculation of ball mill grinding efficiency. dear experts . please tell me how to calculate the grinding efficiency of a closed ckt & open ckt ball mill. in literatures it is written that the grinding efficiency of ball mill is very less [less than 10%]. please expalin in a n excel sheet to calcualte the same. thanks.

The innovative - Magotteaux

SAG mill operation is "sensitive" to changes in ... helps reducing the occurrence of ball impacts on liners, thereby extending liner and media lifetime. Improve mill efficiency. MagoSense helps the mill operator to decide on the grinding strategy in order to maintain the optimal power and load charge conditions for maximization of the ...

Coarser Grinding: Economic Benefits and Enabling

For the SAG mill, optimization involves finding the operating conditions that would maximize the fresh feed tonnage to satisfy the demand of the ball mill. The same theoretical considerations used for conventional ball milling systems are also applicable to …

Received July 27, 2018; Reviewed; Accepted October 2, 2018 ...

classification conditions and the mill throughput were fixed. Under this condition, the mill speed and ball charge of the SAG mill have the most significant influences on the specific grinding energy. Variable circuit energy distributions were designed by simulating different mill speed-ball charge combinations with Moly-Cop Tools (Table 2).

Industrial Grinding Estimation of Blended Ore from ...

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.

Understanding Size Effects of Semi-autogenous Grinding ...

Although it is well known and easily experienced that the feed size distribution influences the throughput and stability of operation of a semi-autogenous grinding (SAG) mill, the details are poorly understood since it is often only the input and output measurements that are used to identify unfavourable in-mill conditions. Load cells and power monitoring are sometimes …

MODULE #5: FUNCTIONAL PERFOMANCE OF BALL MILLING

If a ball mill contained only coarse particles, then of the mill grinding volume and power draw would be applied to the grinding of coarse particles. In reality, the mill always contains fines: these fines are present in the ball mill feed and are produced as …

A Method to Determine the Ball Filling, in Miduk Copper ...

variation is between 1.2– 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%). In addition, acquired load samplings result for mill ball filling was 1.3%. Keywords: Miduk Copper oncentrator, SAG Mill, Ball Filling Percentage Introduction Semi-autogenous (SAG) mills are

Orway Mineral Consultants Canada Ltd. Mississauga, ON ...

2006). The laboratory bench-scale SAG mill reproduces operating conditions of a commercial SAG mill, in a closed circuit dry grinding environment. The ground product for the laboratory SAG mill is then submitted to the Bond ball mill work index test. The number of SAG mill revolutions required to grind the material to a P

CMP Paper 16.10.09 Final

The method of powering mills such as AG, SAG and Ball has a long and technically interesting history. It can be said; almost every decade in the last half century had its own trend. ... torque that has to be transmitted to the mill through the torque tube at the charge or discharge side of the mill. ... the advantage of having a constant ...

AN OVERVIEW OF SINGLE STAGE AUTOGENOUS AND …

3 SAG mill (8 – 15% ball charge) Variable competency ore 4 High ball charge SAG mill (15 to 25% ball charge) Incompetent ore 5 Low ball charge SAG mill, high mill speed. (4% ball charge, 90% Nc) A cross between AG and SAG for competent, abrasive ores. As typically operated in RSA. 6 SAG mill (configurations 3, and 5 ) with recycle crusher

Care and Maintenance of Bearings - NTN Global

80000 ～ 150000 22, 32 32 Except for thrust ball bearings Except for thrust ball bearings 150000 ～ 500000 10 22, 32 100, 150 Single row radial ball bearings Cylindrical roller bearings Single row radial ball bearings Cylindrical roller bearings ～15000 150 220 100 68 32 All types 15000 ～ 80000 150 All types 60 ～ 100 80000 ～ 150000 ...

White paper, September 2015 SmartMill™: Exceed your ...

small charge of steel balls may be added to aid the process — the mill is then called a semi-autogenous (SAG) mill. AG/SAG mills are often used as the first stage in a two- or multiple-stage grinding process, where the second stage is carried out by the ball mill, but they can also be used as a one-stage grinder. The absence of, or

(PDF) DESIGN AND OPERATION OF VERTIMILL® FOR …

Low capital investment alternatives such as the optimisation of the SAG mills lifter/liner design, pulp lifters, ball charge level and ball size were studied in the SAG mill circuit as well as an ...

STARTLING EFFECT OF BALL SCATS REMOVAL ON SAG MILL …

IV-126 Figure 1 The mill interior and details of the discharge grate Figure 2 Ball scats IV-127 Evidence of Excess Scats Mill charge When inspecting the …

MINE LINERS - Magotteaux

balls on the rocks (SAG mill) or by interaction between rocks on the one side and mill shell and toe of the grinding charge on the other side (FAG mills). The trajectories of grinding media and rocks promote size reduction by im-pacts. This grinding mechanism is required in SAG and FAG mill applications. 2. PERMEABILITY

Optimizing Performance of SABC Comminution Circuit of the ...

and design conditions to improve the comminution process. Modiﬁcations to the SABC comminution circuit included an increase in the SAG mill ball charge from 8% to 10% v/v; an increase in the mill ball charge from 23% v/v to 27% v/v; an increase in the maximum operating power draw in the ball mill

Ball Charge and Grinding Efficiency - Grinding ...

Ball feed size SAG mill water flow rate SAG mill power vs. wear geometry - maximizing kW-hr/ton & tons/hour in combination SAG mill liner change-out life/cycle vs. tons/kg consumed. Ball mill liner efficiency based on liner geometry and its influence on kW-hours/ton, total tons/life cycle, and P80 transfer to cyclones.

Charge behaviour and power consumption in ball mills ...

Discrete element method (DEM) modelling has been used to systematically study the effects of changes in mill operating parameters and particle properties on the charge shape and power draw of a 5-m ball mill. Specifically, changes in charge fill level, lifter shape (either by design or wear) and lifter pattern are analysed.

Choosing the Right Motors for your Mills

Step 1: Mill overload power •Determine a set of operating conditions that reflects the maximum "overloaded" condition that the mill should be able to handle: –SAG mills: 20% v/v ball charge, 30% v/v filling and 78% critical speed with worn liners –Ball mills: 36% v/v filling and 78% critical speed with worn liners

(PDF) Optimization of the make-up ball charge in a ...

make-up ball diameter of about 1.7 inches, that is, a mixture weighted. toward 1.5 inches. (3) An increase of 12% in capacity was predicted with the optimum make-. …

t10 (%) 63 x 53 The "SCSE" Parameter the JK Drop Weight A ...

given A and b when treated in a "Standard" circuit comprising a SAG mill in closed circuit with a pebble crusher (see Figure 2). The specifications for the "Standard" circuit are: SAG Mill. o inside shell diameter to length ratio of 2:1 with 15 ° cone angles. o ball charge of 15 %, 125 mm in diameter. o total charge of 25 %

SAGMILLING.COM .:. tools_millfilling

Enter the number of lifters that are exposed above the mill charge. Fractions are acceptable and should be used in the case where the charge does not sit uniformly in the mill. For example, you may have 29 rows exposed at the discharge end of the mill, and only 28 exposed at the feed end.

Applied with minimal instrumentation for Client: JSC "AK ...

a. Frequent mill overloads b. Reduced throughput 2. Instrumentation on the mills is not su˜cient to run the mill with optimum ball charge and knowledge of the liner state, leading to; a. Frequent mill stops for inspections b. Non-optimal running conditions. 3. Traditional sensors cannot be used within the mill due to the nature of the process.

Steady State Model Development and Validation

Figure 3.2: Simpli ed mill charge cross-section The SAG mill model is comprised of: 1. solids balance 2. water balance 3. ball charge model 4. powerdraw model 5. impact zone model The solids and water balances are inter-related and are integral to the perfectly mixed mill model described below. The ball charge model is independent of these mass ...

Industrial Solutions polysius ball mills

into the mill as recirculating material; this prevents overgrinding of the finished product in the ball mill discharge. Heat generated during the grinding process can be dispersed by good mill ventilation and by injecting water. Layout of a ball mill / …

Small-Scale Continuous SAG Testing Using the Macpherson ...

The mill charge PSA is compared to that of the feed to identify any coarse build-up. The size-by-size density of the rocks constituting the mill charge is also measured, as it can be significantly different from the feed, which could affect the power draw predictions, especially in fully autogenous or low ball charge applications. The mill charge

20150806 Survey Sample Grinding Circuits-GMG-ICE-v01 …

Grinding (AG), Semi-Autogenous Grinding (SAG), rod, and ball mill circuits operating within the normal range of appli-cation. This guideline does not directly address analysis of crushing plants and fine grinding circuits, but it is a useful reference for such endeavors. Applying power-based analysis techniques requires suf-

SAG mill ball charge determination and its influence on ...

In semi-autogenous grinding (SAG), the grinding mill inventory, (i.e. 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 two-dimensional graphical method is presented for determining the actual ball charge within …

SAG Mill Ball Sizing - Grinding & Classification Circuits ...

Optimum ball charge in a SAG mill is a function of many factors. Some are discussed below. For a SAB or SABC circuit. In general, the higher the ball charge the higher the throughput (and fine feed helps as well). Of course, you need a bigger ball mill. But, high ball loads mean higher ball consumption in the circuit.

GrindingExpert™ - WordPress.com

Our SAG mill strategies automatically adjust feed rate, mill speed and water addition to reduce upsets, eliminate grind-outs, protect liners/lifters, and increase tonnage . We maintain desired operating conditions by constantly monitoring bearing pressure, mill power, recycle pebbles, mill density, charge toe and mill acoustics,

EXAM P SAMPLE QUESTIONS - SOA

An urn contains 10 balls: 4 red and 6 blue. A second urn contains 16 red balls and an unknown number of blue balls. A single ball is drawn from each urn. The probability that both balls are the same color is 0.44. Calculate the number of blue balls in the second urn. (A) 4 …

Optimization of mill performance by using

Stresses, generated in the ball charge, increase, which may result in spalling of balls and blocking the grate discharge. Optimization of mill performance by using online ball and pulp measurements by B. Clermont* and B. de Haas* Synopsis Ball mills are usually the largest consumers of energy within a mineral concentrator.

PERI™ AutoCharge Mill Grinding Ball Charging System

The AutoCharge system is primarily suitable for SAG mill balls (100–150 mm). As each ball rolls through the counting chute, an electro-mechanical limit switch is activated, signalling the counter. Each count is added to the last, allowing a continual increasing total count of balls to enter the mill over a set time period.

Table 3 from Optimizing Performance of SABC Comminution ...

JKSimMet simulations were used to test various operating and design conditions to improve the comminution process. Modifications to the SABC comminution circuit included an increase in the SAG mill ball charge from 8% to 10% v/v; an increase in the mill ball charge from… Expand