“You’re never standing still. You’re either falling backward or moving forward.” – Unknown
That quote is generally offered in the context of personal growth. But it’s true in almost any context – maybe especially the context of a crushing site.
Crushing operations are dynamic. Material characteristics in the same quarry can be vastly different. Crushing and screening equipment installed at most sites was engineered to produce common finished products. With today’s various asphalt and concrete mix designs, customers now require a variety of different finished products.
In the midst of this, optimization is important. Plant optimization will allow you to produce more in no matter what mode your plant is operating in and do it more efficiently. And since crushing plants are either operating inefficiently or optimized to perform better, it’s important for the sake of your bottom line that your plant is doing the latter.
There are countless optimizations to make, and, of course, what they are will vary depending on the product you’re working with and the nature of your crushing site. However, there are certain optimizations that are most likely to apply broadly across a variety of crushing sites. And there are general frameworks to use to introduce optimizations, too.
With that in mind, here are five ways to optimize your crushing site.
1. Adjust the closed side settings of the primary, secondary, and tertiary crushers.
One common area for optimization at crushing sites is the utilization of respective capacities for each crusher as influenced by the closed side settings. Often, the primary crusher may be at less than capacity, but the secondary crusher may be overloaded. Or the secondary crusher may be choke fed, but the tertiary crusher isn’t. You may have the closed side settings set too tight or too loose, depending on the situation – and if you’re off, you won’t be able to achieve full production down the line.
While perfect balance can be difficult to maintain, an optimized plant should have all crushers functioning at close to 100% capacity. After all, if one crusher is at 50%, your plant isn’t being as efficient as if all crushers were at 100%. So, adjust the closed side settings to effect throughput rates that makes this possible.
2. Provide proper quantity of material to each crusher.
Another common area for optimization is in the quantity of material being provided to each crusher. Down the line, this can be affected by closed side settings, but another important factor to consider is the use of surge piles and bins. These type of feed systems can ensure a more consistent rate of feed material to each crusher, enabling a consistent flow of material being feed to the crusher so that fluctuations (or worse, stops and starts) can be avoided.
3. Check crusher speeds and manganese.
It may seem straightforward, but a common area for optimization in a crushing plant is in aligning crusher speeds with manufacturer recommendations. A manufacturer may recommend a speed between 800 and 1,100 RPM. If your crusher is set to speeds above or below that range, you’re likely compromising your productivity. If you’re operating within that range, consider adjusting, too – depending on material and site, slowing the speed of the crusher can actually increase throughput, but increase crusher amp draw.
When making manganese selections for cone crushers, make sure that material is being crushed all the way down through the crushing chamber, and isn’t being crushed only at the bottom.
And of course, keep a watchful eye as manganese wears out, to avoid wear on critical parts on the crusher protected by the manganese, and be ready to replace as needed to maintain efficient production.
4. Ensure screening units are functioning properly.
Believe it or not, we’ve witnessed crushing sites where substantial section of screens weren’t being used – material wasn’t reaching all surface area, and production efficiency was reduced.
So, be sure to check the feed location of the material on all shaker screens. Make sure the material is being fed properly on the center of the feed plate, and that it’s being spread evenly across the width of the entire screen so that every square foot of the screens open area is being used to capacity.
At the same time, make sure that the depth of material on the screen isn’t greater than four-to-one. Too much bed depth, and material simply won’t get through the open area. To reduce bed depth, you can increase the speed of the screen or the throw of the screen. Again, operate the screen within the manufacturer recommended parameters.
5. Determine what the bottleneck is and work your way backward or forward from there.
Finally, a practical word of advice when it comes to optimizing crushing sites: determine what the bottleneck is, and work from there.
Is production declining because of crushing inefficiencies between the secondary and tertiary crushers? Start at the tertiary crusher and work back from there. Set the tertiary crusher so there is a 15% and 25% recirculating load going back to the crusher. Set the standard crushers close side setting so it is running close to choke feed and still sending the proper quantity of material to the tertiary crusher to keep it constantly choked.
If the tertiary is being fed more material than it can handle causing the plant to be shut down so the tertiary can empty out, tighten the standard cone’s closed side setting until it is crushing the proper amount to feed the tertiary crusher.
Once this balance is achieved, set the primary crusher’s closed side setting, so the secondary crusher is being close to choke feed. The same goes for anywhere throughput drops – identify the bottleneck, and you’ll be on your way to optimization so that all crushers are choked.
Once the entire plant’s crushing and screening equipment is properly balanced, perform preventative maintenance to properly maintain the plant so it can perform at maximum capacity during the entire shift, which will help increase the bottom line.
One final tactical tip: don’t be afraid to do belt cuts. Checking the material on the belt can help you to determine if everything is in working order in the preceding crusher, and help you identify potential issues more quickly.
Get Your Crushing Site Running at Full Steam
So, there you have it: five ways to optimize your crushing site. Hopefully, this information has given you a few tactical steps to take to ensure that you’re increasing the productivity of your site and not falling behind. Want to talk more about optimization?
At Mellott Company, we’ve been ensuring top productivity at crushing sites for decades, and we can work with you to identify areas for improvement at your site. Crushing is dynamic, and change is constant. Let’s make sure your crushing site is moving forward toward peak capacity.