A 40 per cent increase in production of half-inch gravel

For 40 years Gravicon has been dedicated to manufacturing and marketing stone aggregates. It supplies raw material for the production of concrete for road engineering works and infrastructure in Colombia. Its biggest challenge was increasing its market share while providing its clients with a higher quality gravel.

To meet this challenge, the plant’s conditions were studied in a joint effort with Metso and Gecolsa, a Metso dealer for the aggregate market in Colombia. It was determined that Metso’s Nordberg HP4 cone crusher would lead to a 40 per cent increase in production of ½’’ gravel and a 35 per cent increase in the plant’s total production (due to its high crushing capacity), plus improvements in the percentage of long and flat particles in conformance with ASTM standards.

This radical change in the final product’s size would accommodate the new and demanding requirements of the Bogotá market, the capital of Colombia.

The aggregate market in the Bogotá metropolitan area – where Gravicon is the main source of materials for the most important concrete and construction companies operating there – is primarily distinguished by the lack of sources of good quality material within a short distance. In the case of concrete materials, production zones are between 80km and 220km away, so freight charges are a significant factor in the final cost of materials during construction.

{{quote-A:R-W:300-Q:"Crude material is extracted from the Guayuriba River banks by beach refill excavators and transported by trucks to the crushing plant."}}There has also been a rise in industrial-type construction requiring concrete mixes of fine granulometry, where ½’’ gravel and sand dominate, and with strict shape requirements to improve how concrete is pumped. In terms of quality and price, the demands are high for aggregate producers, and not many companies have managed to succeed in the market.

The process began in 2011 when Gravicon decided to initiate tertiary crushing in its main plant. Metso recommended installation of a Nordberg HP300 cone crusher, which included a lung stack feeder, to ensure a full cavity and thus better shaped material and higher production.

Several years later, the increase in demand for material and the need to go from 1’’ (25mm) gravel as the main product to ½’’ gravel made it necessary to pursue an optimal solution that would adapt well to Gravicon’s requirements.

“Metso and Gecolsa recommended the switch to a new, state of the art HP4 cone crusher with a high crushing force that perfectly fit the client’s needs,” said Diego Pulido, Metso’s Andean area dealer distributor manager.

The suggested change was based on a complete analysis of the plant’s production performance and the mass balances examined by Metso specialists with the help of Bruno process simulation software.

The 298kW HP4 is the first of its type in Colombia. With the HP4 set up, Gravicon increased the production of ½’’ gravel by 40 per cent and improved the quality of the product shape.

Meanwhile, it increased the total production of the plant by 35 per cent compared to the previous HP300, thanks to the HP4’s ability to process up to 340 tonnes per hour.

Gravicon uses the Guayuriba River as its source of crude material, with a maximum size of 50cm and about 40 per cent natural sand content. It is a hard and abrasive material, with 16 per cent wear and tear, and a top quality raw material for the production of sand and concrete gravel.

Crude material is extracted from the Guayuriba River banks by beach refill excavators and transported by trucks to the crushing plant.

The plant has a primary crusher with a 610mm x 914mm jaw, a 108mm secondary Simmons cone, a closed circuit, a tertiary fine HP4 cone worked with a lung stack feeder in a closed circuit, two 6m x 2m sieves and a hydrocyclone for sand washing. The quality and quantity of the final product is highly dependent on the performance of the HP4.

“After switching to Metso’s HP4 cone crusher, Gravicon is now the biggest and most reliable high quality gravel producer – with the highest installed capacity – in the Meta region, and is becoming a key player in the Bogotá aggregate market,” Gravicon general manager Hugo Baquero said.

Source: Metso

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