All about Aggregates
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Manufacturing process

Aggregates are the most widely used products resulting from extracting and processing non-metallic construction materials.
The apparent simplicity of aggregates production, which involves rock crushing, is misleading, because contemporary production technologies for construction materials and the products based on them continuously set higher demands for the quality of aggregates used, for the most part, as filler in the production of concretes, asphalt-concretes, and road surfaces.

Step 1. Developing deposits and extracting rubble stone

Aggregates production technology includes two main stages. The first stage is extracting stone rubble. The second stage is processing the rubble into aggregates (via crushing and screening).


Primary raw material

 

There are four main types of raw material used for producing aggregates:

  • Hard (magmatic) rock (granite, basalt, etc.);
  • Sedimentary rock minerals (limestone, sand gravel and pebble);
  • Secondary aggregates acquired in the process of crushing construction wastes, such as concrete, bricks and asphalt;
  • Slag crushed stone obtained from crushing heaped metallurgical slag or by the special fire-liquid slag melt treatment (molten slag aggregate).

Deposits of sedimentary non-metallic materials, in particular the alluvial types (pebbles, gravel and sand) that get deposited in permanent water currents (rivers and streams), are rarely seen because they are almost completely exhausted. Gradually they have been substituted by sea gravel deposits, which became an excellent alternative material. Its geological nature is the same as river gravel's. Sea gravel can serve as a raw material for high quality concrete and is good for making innovative concretes.

 

Klesiv quarry of nonmetallic minerals "Technobud"

Mining wokrs ar Koschiivka quarry. Hydrohammer

Mining is conducted in compliance with actual mining work plans and annual planned work schedules, in the framework of mining and land allotments and of special permits for subsoil exploitation.

 

When rubble stone (granite or gravel) is extracted using the open-pit method, a quarry is created. In the first stage of its formation an enterprise conducts so-called overburden works resulting in removal of the top fluffy layer of sedimentary minerals.

 

Overburden without useful components is transported to external and internal dumps or used as a mineral construction raw material (for example clay, sand, limestone, chalk, etc.).

 

Afterwards, the substantially large oversized blocks of stone that were gradually separated from the body of stone prepared for extraction undergo further processing. Special prospect holes (small in diameter) are usually drilled to effect their separation - explosives are embedded in these holes. A well-calculated and competently directed blast separates a block of the required size without damaging its quality. Traditionally, such blasts are carried out at a precisely set time at Ukrainian quarries.

 

Stone block loading is carried out by excavating machines. The transportation of mineral resources to the charging hoppers set in crushing and screening facilities, as well as the transportation of the productive stripping solids, is carried out by dump trucks.

 

Step 2: Reprocessing rubble stone into crushed stone

Upon extraction, raw materials are transported to the processing plant for their further processing.

 

The technological process of crushed stone production can be conventionally divided into three stages:

  • primary crushing stage,
  • secondary crushing stage,
  • screening of the crushed rock according to its grain-size category.

At stage 1 the rubble stone is loaded into charging hopper of the feeder (loader); the feeder steadily feeds the rock into primary crusher; the crusher crushes the rubble stone into average-sized pieces.

 

At stage 2 the rock that has been crushed into average-sized pieces is fed by the belt conveyer into the secondary crusher. The rock is now crushed into smaller pieces.

 

At stage 3 the crushed rock is fed to screen for screening. Screening separates the screened rock into tradable fractions, and remote belt transporters pool each fraction of crushed stone separately.

 

Certain types of raw material, such as sand and gravel, are subject to additional processing, which includes washing and purifying.

 

Employee at Koschiivka quarry

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High quality product

Being one of the biggest aggregates producers in the Ukrainian market Lafarge in Ukraine ensures the high quality of its product.

Aggregates from the sites possess conformity certificates according to the State Standardization System of Ukraine (ДСТУ), all required passports of quality and are permitted for use in residential, industrial and road construction.

LafargeHolcim. Cement, aggregates, Concrete.