Pit & Quarry, March 2010

R E C Y C L I N G Crush and run I n the past 10 years crushing and screening recycling plant designs have expanded and there are now a wide variety of equipment choices There are simple single circuit track and wheel mounted plants and there are more sophisticated systems offering a variety of product layout and capacity choices Producers and contractors can choose from a range of crushers jaw cone impact VSI etc With the recent development of new highly portable crushing and screening systems with user friendly controls and interlocks any producer can efficiently operate their own recycling processing system Most producers have found that state and local operating permits are easier to achieve for portable plants than for stationary plants Determining which recycling plant is best for an operation requires a proper review of a companys needs Annual tonnage requirements material type end product and site location are important considerations when making an equipment investment A key decision that impacts most of these issues is chassis type and recent product advancements have changed the approach many now follow Recycling plants are normally rated by tons per hour tph Track mounted recycling systems typically produce in the range of 100 300 tph Moved to a job site by a low boy trailer the self propelled trackmounted system can drive itself to the operating location and be ready to operate This fast setup makes it economically feasible to move for small jobs in the 5000 ton to 10000 ton range Because of this mobility a trackmounted system can move on a job site to the feed stockpile rather than moving the feed material to the unit The set up time may be as little as one hour and the system may be operated with as few as two men Track mounted plants are typically fed by an excavator A small wheel mounted system can also produce work in this tonnage range The wheel mounted system is typically pulled to the job site on its own chassis by tractor truck The wheel mounted system typically takes more time to set up and is not as easy to move around Set up time may be four to eight hours depending on several factors and the system may be operated with as few as two men The wheelmounted system may be customized and available with more options and larger screens or conveyors while the track plant is typically available as a standard package The wheel mounted system can be fed by excavator or a front end loader if the vibrating feeder is large enough Overall track mounted systems provide quick setup and a low profile costeffective solution for efficiently managing small and large recycling jobs profitably The wireless controls are simple to operate and allow the worker who feeds the plant to also control and move the tracked crusher Wireless controls allow the operator to control the feed rate stop the system and move the plant as required from the convenience of the excavator or front end loader cab For higher volume capacity 300 tph to 800 tph wheel mounted crushers and screens are typically used The larger wheel mounted systems are typically set up to operate in one location for weeks months or longer These systems can typically accept larger feed size and produce a wider range of end products if required The largest wheel mounted plants may require four or more men to operate maintain and perform loadout Options After determining the most appropriate chassis configuration for the application the crusher and screen type must then be decided Two of the most common types of crushers used in recycling are jaw and impact crushers although cone crushers play an important role as well If volume reduction is the goal then a lone crusher such as a jaw or impactor may do the job However if a spec product is needed a vibrating screen must follow the crusher to create the desired screened finished product Producers can choose between a wide range of trackor wheel mounted plants for recycling of concrete and asphalt EDITED BY DARREN CONSTANTINO Take note Properly sized feed is one of the most important factors in demolition recycling applications At the end of the day an operator with properly prepared feed will put more finished product on the ground 22 PIT QUARRY March 2010 www pitandquarry com