Product category:
Concrete, Cement, Admixtures
News Release from: Extec Screens and Crushers | Subject: Screening and crushing equipment
Edited by the Buildingtalk Editorial
Team on 13 July 2006
Extec machines for limestone processing
Bolinches selects Extec machines for limestone processing
In today's highly competitive marketplace, one of the key decisions that cement producers must get 100% right is the plant that will be used in the quarrying and processing of the virgin limestone This is particularly true for the screening and crushing equipment
This article was originally published on Buildingtalk on 11 Aug 2005 at 8.00am (UK)
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The crushing and screening stage is the single most economical segment of a limestone manufacturing process after the original reduction of material in the quarry shot, and thus integral to the profitability of the entire operation.
Progressive companies have been quick to see the advantages of modern mobile screening and crushing equipment as traditional static plant relies on material being brought to the machinery; a process that has proved to be both expensive and inflexible.
Thus, new solutions have been devised as the increasing need to process limestone more cost effectively has incentivised companies to use the most up to date equipment in order to maximise their competitiveness.
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One such company is Bolinches.
Established in 1957, Bolinches operates as one of Spain's leading limestone producers.
The company is rightly renowned for its high standards of customer service and environmental management.
They currently operate from a high production limestone quarry situated on the outskirts of Valencia, delivering thousands of tons of limestone to cement manufacturing companies on a daily basis.
A key element of the company's success is the recognition of the need to exploit the competitive edge provided by new technology.
Bolinches decided to consult with a technical field consultant from the Intermop Company of Madrid.
Bolinches selected Intermop to supply the mobile crushers and screeners based on the company's favourable reputation, not just for offering quality Extec products, but also its excellent 'before and after sales' service.
Bolinches discussed with Joe Barrett, the Movoequip Technical Field Consultant, the size and type of units to purchase so they would match the production requirements and working conditions of the limestone quarry.
During a demanding selection process Bolinches worked closely with Intermop to identify the duties that were required for the chosen mobile screener and crusher.
The factors considered by Bolinches as vital in the selection of crushing and screening equipment can be summarised as:.
1.
The maximum feed size the crusher is expected to accept.
2.
The product size allowed to be fed to the Impactor crushers.
3.
The production rate required yielding the correct product size.
4.
The abrasive content and general analysis of limestone to be crushed/screened.
5.
The availability of maintenance for the crusher/screener.
Intermop matched the machinery to the tasks and to Bolinches' required specifications.
The screening and crushing plants selected were the Extec C-12 Jaw Crusher, Impactor Crusher, E-7 and S-3 Screeners.
The E-7 was chosen, as the first step in Bolinches' limestone quarrying process begins when the 'overburden' is removed.
Once a suitable 'face' has been established a selected blast site in the quarry area is drilled to create multiple bore holes and filled with explosive materials.
The E-7 is manoeuvred to any position from an excavator or loader at the quarry face, where the recently blasted limestone is piled.
The E-7 is a heavy duty track mounted, self propelled, open flow screening and stockpiling system, purpose built for screening heavy over-burden at the quarry face, or pre-screening/scalping prior to being fed into a crusher.
Thus perfect for the role Bolinches required.
Material is loaded by excavator into the feeder where it is transferred towards the screenbox.
The limestone passes over the screenbox where smaller material will fall through the top deck and onto the bottom deck.
The smaller material (0-27mm in size) that has fallen through to the bottom deck is transferred to the fines conveyors and is stockpiled at either side of the machine.
The larger material, approximately 550mm-650mm, that has stayed on the top deck is fed to the tail conveyor and is stockpiled at the rear of the machine.
The tail conveyor is supported by an impact bed which prevents roll-back or lateral movement of material.
The 550-650mm material is fed to the jaw crusher direct from an excavator where the vibratory feeder transfers the material towards the C-12 1200 x 750mm jaw crushing plant.
As the limestone advances downward into the crushing chamber it is crushed between the wear plates and deposited on to the main conveyor.
Each rock is crushed an average of 2/2.5 times, as it passes through the jaw with a reduction ratio of approximately 6:1.
Crushed limestone, roughly 100mm in size, is then fed from the C-12 to the Extec Impactor.
The incoming feed direct from the C-12 is fed over a vibratory grizzly feeder that evenly separates the material as it enters the Impactor.
As the material drops vertically through the crusher chamber it strikes the rotating blow bars and is impacted against the breaker plates within the chamber.
The limestone is then transferred to the Extec S-3 singlescreen two deck screener, which separates the material into 0-6mm, 6-12mm, 12-24mm sizes.
The S-3 screener is a self contained, tracked machine built to withstand the rigours and conditions of operating in Bolinches' quarry.
The S-3 utilises a diesel engine to provide the power to the hydraulic power pack to generate electricity for the electrical system of the machine.
The tracks, hopper, conveyors and all other working parts of the machine are all hydraulically driven.
Screening is undertaken by throw back onto the screenbox with sorting taking place by size and product shape.
Material is loaded into the hopper where material falls onto the hopper conveyor, it is then fed onto the main conveyor where at the top it is transferred onto the screenbox.
The material passes over a series of screen meshes which separate the limestone into three grades.
The larger and medium grades are separated on to the side conveyors, leaving the fines to travel up the tail conveyor.
Each grade of limestone then falls on to three separate stockpiles around the machine.
After processing, the limestone is trucked off to a combination of cement manufacturing facilities within the region.
Materials tested to date have all met with the required specifications to satisfy customer demands.
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