Grinding

Effect of Regrind on Grade and Recovery

Evaluate the need for regrind

How do you know if or when regrinding and applying further liberation power can improve your metal’s recovery? Below here is data showing what is to be gained by correctly applying regrind to a copper stream. On the graph, the red/white dot points to where the plan currently is light green Grade-Recovery curve VS where is could be on … Read more

SAG Mill Ball Size Evaluator | Evaluation Factors | Calculate Diameter

Are My Balls Big Enough

Lets calculate/select/pick a new ball for your SAG mill.  Now, lets suppose you have a SAG Mill and Ball Mill that are not drawing full kW Power.  The SAG Mill has a “small” circulation load of oversize given be the 3/8″ trommel screen and the 1/2″ x 1 1/4″ discharge grates.  The load of 4″ balls … Read more

Do I Need Bigger and Larger SAG Mill Balls

SAG Balls

How do you know if a larger SAG ball will increase your tonnage and how to select it?  When is it time to change to a larger Ball in your SAG Mill? It’s difficult to generalize on SAG mill ball size selection as it depends on a number of factors: Ore properties Level of impact … Read more

Roping HydroCyclone -Bad Operation

HydroCyclone Roping – Incorrect Cyclone Operation is often caused by too high a volume feeding into the cyclone. If the apex capacity is exceeded a condition known as roping may occur. Normally, the underflow sprays out of the apex. When roping occurs, the air core inside the apex collapses and the spiraling motion is almost lost. … Read more

Hydrocyclone Efficiency Curves

real ideal hydrocyclone classification

The Hydrocyclone Efficiency Curves are affected by many operating factors such as feed density, apex and vortex sizes and feed pump pressure.  These factors will cause your cyclone classification to operate correctly, in roping or spraying mode.  Everyone knows or has seen an “Ideal Cyclone Efficiency Curve” VS an actual real life hydrocyclone Efficiency Curves?  I … Read more

Polyurethane Screen Panels

polyurethane screen panels1

These Polyurethane Screen Panels are often installed on SAG discharge trommel screens or AG vibrating screens and even crusher circuits.   Polyurethane Screen Panels are best when made of low “durometer” Polyurethane to allow a “bouncing” effect for the rocks and reduces wear.

SAG Mill Trommel Screen

Mill Trommels

A SAG Mill trommel screen lets you control the true discharge size of your SAG mill or the transfer size to the downstream Ball Mill circuit. A well sized trommel should not let rocks pass to the Ball Mill if they are to be more than say 5/8″ or 16mm In the image case below, strangely … Read more

Calculate and Select Ball Mill Ball Size for Optimum Grinding

Calculate and Select Ball Mill Ball Size for Optimum Grinding

In Grinding, selecting (calculate) the correct or optimum ball size that allows for the best and optimum/ideal or target grind size to be achieved by your ball mill is an important thing for a Mineral Processing Engineer AKA Metallurgist to do.  Often, the ball used in ball mills is oversize “just in case”.  Well, this safety factor … Read more

Levin Grindability Index Test Method & Procedure

Grindability Index Test Method Procedure

The Ball Mill Grindability of ores is generally determined by the Bond standard grindability index test method.  However, this test and procedure is not applicable to fine materials such as sands; the grindability of fine materials must therefore be determined by a comparative grinding method, for which a reference material of know grindability is required. Suitable … Read more

IsaMill

Look inside an IsaMill and have a look at an installed IsaMill grinding unit. IsaMill Signature Plot