Medium Hard Rock Crushing Impact Machine Two

On the day of the blast, the explosives are delivered and taken to the site of the blast. Detonator cord is placed in each hole and the holes are then loaded with high explosives to within a few metres of the top. The remaining depth is “stemmed” with quarry dust or fine aggregate. The site is cleared. Sirens are sounded to make sure that everyone nearby is warned. The detonators are connected to the electric trigger wire and the circuit is checked. A final safety check is carried out and only when the final all clear is given does the shotfirer set off the explosives. A single blast can fragment up to 20,000 tonnes of rock.

After the blast, the face and shotpile (sometimes called the muck-heap) are inspected to check that all the shot holes have fired correctly. The face shovel or loader then tidies up the shotpile and starts to load the dumper trucks that take the rock to the crusher. Boulders which are too big to go through the crusher are set to one side for secondary breaking at a later date. Secondary breaking is typically done using a hydraulic digger fitted with a rock hammer, though crawler cranes with steel drop-balls may be used in some quarries.

Crushing can be done in three or four stages, primary (first stage), secondary (second stage), tertiary (third stage) and, in some quarries, a quaternary (fourth stage). Crushed rock, or product, is transported along the process line on conveyor belts or down chutes.

The primary crusher is fed via a chute and vibrating feeder . The base of the feeder is made of steel “grizzly” bars and it is here that the first screening operation is actually done. Fine material and dust produced by the blast, along with any remaining subsoil or weathered rock from the top of the quarry face, drops through the bars onto a separate conveyor belt and onto a stockpile. This screened material is called scalpings and is used as rock fill.

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转载于:https://www.cnblogs.com/liajones/archive/2012/02/25/2367759.html