Mobile crushers remove mountains.

Montrond Quarry in the French Jura Mountains has an estimated raw material capacity of approximately 10 million m³. Between 1,500 and 2,000 tons per day of Jurassic limestone are processed here into concrete aggregate and road construction materials. As the rock is contaminated with clay and soil, it is particularly important to separate these materials from the limestone material during the processing operation. In order to be able to produce high-quality concrete aggregate, the quarry operator decided to use mobile crushing and screening plants from Kleemann. Because of their highly effective pre-separation prior to crushing, these plants fully meet the special requirements placed on the processing technology in Montrond Quarry.

The material is quarried by blasting and is then screened and cleaned from impurities in the heavy-duty double-deck screen of the Mobicat MC 120 Z primary crusher The grain sizes 80 to 150 mm are directly forwarded to the crusher and onto the main discharge conveyor. The 0 to 80 mm pre-screened material is stockpiled via a lateral discharge conveyor and is either used as subgrade material for local forest paths or also fed into the secondary crusher. The bypass material and the crushed rock of a size up to 200 mm is transported from the mobile primary crusher to a secondary crusher type Mobirex MR 130 Z. Here, the size 0 to 31.5 mm is separated on the pre-screen of the secondary crusher and sold as subgrade material for road construction.

In the second crushing stage of the processing operation, the pre-crushed material ranging from 31.5 to 200 mm in size is transported to the Mobirex MR 130 Z impact crusher, where it is reduced to grain sizes of between 0 and 40 mm. The grain sizes 0 to 20 mm and 20 to around 40 mm are separated by the single-deck secondary screen mounted on the Mobirex plant.

The grain size 20 to 40 mm – the so-called oversize material – is fed back into the crusher, while the grain size 0 to 20 mm is separated further into its individual aggregate fractions on the high-performance screen of the Mobiscreen MS 20 D. In this final processing stage, the 0 to 20 mm grain size is separated into the four high-quality aggregate fractions 0 to 4 mm, 4 to 6 mm, 6 to 10 mm and 10 to 20 mm.

Operating site: Montrond Quarry near Champagnole, France
Feed material: Jurassic limestone
Daily processing rate: 1,500 to 2,000 t
Final aggregate fractions: 0-4 mm, 4-6 mm, 6-10 mm, 0-31,5 mm, 0-80 mm, 0-150 mm
End products: concrete aggregate, road construction materials, foundation material
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