How is the large limestone crushed & screened ?

Aggregates - National Lime & Stone natlime.com Drive by it every day, have bought some 2" over sized for a small job. It's just a depot though, no crush nor screen. One large stock pile has stone that must be 18" or bigger. Just how is it crushed, screened, and handled ? Conveyors ?

Being new to crushing in general all I can offer is the quarry I purchased has a tower style crusher about 2.5-3 stories high. Trucks can dump directly into the mouth and it tapers down from about 9ft wide to 4ft at the jaws. Jaws chew the rock up to roughly 9" before it makes it through the grate the way I have it set up. I can run a larger grate if needed. The 9" minus runs out on a conveyor to trommel that allows anything under 1" to sift out onto another conveyer to the side and the rest, just rock over 1" to 9" runs out the front conveyer. Finished product is 1" minus gravel and 9" minus stone. Simple setup but much more can be added to refine the stone into more products.

I worked a couple of mom and pop crushers. Both started with a jaw and then a cone and screen and wash screw for sand. anything big you wanted to save, you can run across a big static grizzly like this. you can put a guy on a machine picking out the bigger stuff and sorting it too. It has to pay.

Got a shop-built version.

This video shows the basic function of a rock crusher. As mentioned the plates can be adjusted to different widths to give you different sized material. This second video show a good sized stone quarry in operation. The rock is first blasted and loaded to trucks that feed a crusher. Oversized stone may be broken with a hydraulic hammer mounted to what looks like an excavator arm. A stone may go through several crushers to get to the desired size. The crushed stone then goes through several different screen plants according to size and may be washed to give clear stone. Road base, we call it Item 4 here, is a mixture of stone and fines that compacts well. We have several stone quarries within 30 minutes of me, they're quite an operation and have been digging for over 100 years at each of them.

I have a Crushtek impact crusher waiting on time and money to get working. Here is how they work. I don't see how they stay together very long. We run a smaller Komplet 6040 asphalt machine that will handle concrete. It's a jaw crusher like Steve posted the works on. The plates on the jaw crushers are high manganese steel and are fairly expensive to replace. Some build them up, but after trying that on one set of plates (perhaps too far gone), decided it was not practical.

Tony Wells said: I have a Crushtek impact crusher waiting on time and money to get working. Here is how they work. I don't see how they stay together very long. We run a smaller Komplet 6040 asphalt machine that will handle concrete. It's a jaw crusher like Steve posted the works on. The plates on the jaw crushers are high manganese steel and are fairly expensive to replace. Some build them up, but after trying that on one set of plates (perhaps too far gone), decided it was not practical. Click to expand... Some guys around here have used an impact with limited success on rock. They work very well for concrete, the trick (or so I've been told) is they have to be stuffed as full as you can run them, basically get the chamber packed full of material, using it against itself. You still wear the hammers out, but they aren't so bad to change compared to the plates. It works better to run most of your material through a jaw first, screen off your fines, then you can feed the crusher a steady diet of whatever size you need as fast as you need to keep it full.

The one I have has had the chamber liners (for lack of the right term), which are supposed to be spring loaded, all adjusted back to be rigid. The blow bars are supposed to fling the material against the liners and fracture. The liners take a beating. This machine has been ridden hard and put up wet, and it will be a major project to get it to work correctly again.

That's all well and good. This riprap is 18"-24" approx. How do you convey it ?

Thicker belt on the conveyor. The plant im selling to right now is mixing my 9" minus stone with their 12" plus to make modified riprap. They told me they'll belt out up to 36" if a large stock pile is needed, otherwise they let the 18" plus usually fall out the bottom of the crusher after going across the shaker deck and have a loader pick it up and bring it to where it needs to be piled.

We used to have a scalper. Basically a power grizzly. It sat close to the muck pile. You fed it with an excavator. It had a vibrating feeder. Oversized went off the top off the end. What you want, fell through and came off the front, and under sized went off the back. No belts just a lot of shaking. Full time job for a welder. We just sort it out with the excavator now. The excavator has to dig out from the face anyway.