Kopalnie Dolomitu has installed a washing plant at Jurkowice Quarry near Sandomierz in the South of Poland which is processing heavily claybound limestone and producing a range of washed sand and aggregates. The new plant was delivered by CDE in conjunction with the company’s sales partners in Poland, Biuro Handlowe Ruda.
In order to effectively tackle the clay present within the feed material CDE introduced two AggMax modular logwashers. “In the majority of instances one AggMax will effectively deal with the clay contamination but in this instance we needed two” explains Eoin Heron, CDE Sales Manager for Europe.
“It was not only the amount of clay present but the nature of the clay which ensured that scrubbing through two AggMax systems was required.” The highly plastic nature of the clay at Jurkowice quarry means that it is extremely hard to break down. The result of this was that without the introduction of the CDE washing plant the resource at Jurkowice would have been sterile.
“There was just no business case for trying to process the material without looking at a washing plant that would deliver the required levels of attrition to the material” explains Mr Przemyslaw Bokwa, Managing Director, Kopalnie Dolomitu.
The company extracts limestone and dolomite in four mines in the Sandomierz area. The job of sourcing potential suppliers of the new washing plant fell to Mr Sebastian Zajac of Kopalnie Dolomitu and this involved a detailed appraisal of the various options that existed.
“At an early stage CDE demonstrated previous experience dealing with the kind of material we were faced with at Jurkowice and this gave us the confidence to choose them as the supplier” says Mr Zajac.
Kopalnie Dolomitu is one of the largest suppliers of aggregates in Poland and their focus on a sustainable approach to mining is evidenced by the equipment specified on this plant. In addition to the AggMax logwashers the plant includes a full closed circuit water recycling system including the Aquacycle Thickener and GHT Filter press.
“As a company we are driven to ensure that we utilise the resources under our stewardship in the most sustainable way possible” explains Mr Przemyslaw Bokwa.
“We achieve this at Bokwa by extracting maximum value from the material through the introduction of the most efficient processing system available while also minimising environmental impact through efficient use of the water used to wash the material.”
The washing plant operates at 150 tons per hour and has two different feed materials, 0-8mm and 0-63mm. The material is loaded by dump trucks into two feed L55 feed hoppers specifically designed for the sticky nature of the feed material. Material is discharged from the feed hoppers onto a feed conveyor before being sent to the first AggMax 151S Modular logwasher.
A CDE vibrating finger Grizzly screen removes any +80mm material that could be present before the feed material enters the first Rotomax RX150 logwasher where attrition is delivered by 120 paddles mounted in a spiral arrangement on the dual shaft machine.
“The spiral arrangement eliminates intermittent shock loading on the shafts, motor and gearbox, minimises contact between the material and the shafts and ensures the material in the RotoMax receives constant attrition” explains Mr Eoin Heron. “This not only maximises the effect that the attrition has on the material in terms of the ability to break down the clay and liberate the sand fraction but also means that the RotoMax is designed around maximising plant life.”