Crushing has its Goldilocks problem – manufactured fines or MF for short.

When it comes to M.F., it seems that everyone has either too much or too little, but never the right amount. I intend to lay out practical ways to increase MF in this post.

Creating More MF

There are several methods to create more MF. I’ll start with the least expensive and move to the most expensive methods. Creating more MF will almost always cost more money or time in crushing.

1. Planning ahead

MF is valuable and gives you flexibility as a rock supplier. When producing road base or concrete stone, you may be able to steal MF and stockpile for future use. Stealing MF and stockpiling for later use can prevent specific production runs to create MF.

2. Choosing the Correct Crushing Chamber

High-quality manganese suppliers will have software that can help you select the correct cone crushing chamber to get the MF you need. The selection of available cone crushing chambers is also important; some crushers have a broader selection of chambers that will allow you to better dial in MF production.

3. Adjusting the Crusher Throw

If you have a cone crusher where the throw is adjustable, you can create a more violent crushing action, increasing the content of manufactured fines. Increasing throw generally increases production. Beware that a high throw with a tight liner configuration can lead to premature failure of some parts in a cone crusher.

 4. Cone Crusher Automation

Some brands of cone crushers have very advanced automation packages that when combined with the correct liner configuration allow you to optimize MF by automatically adjusting the closed side setting and using closed side setting patterns to create different particle shapes and sizes while “staying in the zone” while the manganese is wearing.

5. Recirculation Load

Setting up your system to recirculate a portion of cone crusher discharge back through the cone crusher will create more MF. This method will slow down production and decrease the percent of the top sized rock in your final output but is an effective method to create MF. 

6. Impactors vs. Cones

Autogenous Vertical Shaft Impactors (VSI) can create more MF than a cone crusher. The challenge is the cost of wear parts vs. a cone crusher if you are in a high abrasion environment. A VSI with the ability to bypass some rock is the most desirable, and having the VSI on a variable frequency drive allows you to dial in the MF production.

 7. Adding a crushing stage

The added capital and operating cost of adding another crushing stage are not attractive. However, the economics of asphalt can justify adding a crushing stage. Depending on your needs, you may not have to add a full crushing stage. Several operations bleed a small amount of the Jaw or Cone discharge to a third crusher; either a small VSI or Cone Crusher with a fine chamber.

8. Using a Screen-Jaw Plant 

A screen-jaw plant allows you to separate natural sand and rounds before the jaw crusher. The natural rounds can then be stockpiled and crushed separately by feeding into a small cone crusher or VSI and fed back into the circuit before the second screen. If you have a three-deck jaw screen plant, you can steal ¼” to 1” rock off the bottom deck.

In the next post we’ll explore the other side of the Goldilocks problem – too much MF and what to do about it.

Learn how the Screen Jaw Plant can help turn unwanted fines and small natural rounds into
valuable M.F., while increasing the fracture rate and removing flats and elongates, at the same time.