Vertical Impact Crusher In High-grade Chippings Production

The production of technical stone, gravel and sand for the building industry is a very important part of the mining production regarding volume and the financial value as well. The most demanded classes are with grain sizes &#8211 ; 4 and &#8211 ; 2 mm but their production is not always simple. In addition to volume, the specific grain size composition, grain shape and minimal portion of the particles &#8211 ; 0, 09 mm (filler) usually are demanded. Until about ten years ago the portion of the impact and hammer crushers, less often cone crushers were used in the production of these classes. Nowadays the vertical impact crushers (rotor mills) are mainly applied for this purpose. In the paper are presented some of these crushers used in the quarries and gravel-pits in Croatia. Their efficiency (capacity, grain size composition, grain shape, filler portion) depending on the influence of the some technological parameters, as for example grain composition of the feed material, physical-mechanical rock properties, moisture content and etc. are analysed.