Pit & Quarry, June 2014

CRUSHING SECONDARY BREAKING HIGH IMPACT Following these tips and technologies for hydraulic breaking can save producers money and downtime A bout as long as man has known rock people have been designing and perfecting tools to demolish it In recent years hydraulic breaker technologies have evolved rapidly to include advancements that not only optimize breaking efficiency and reduce operating costs in mining and aggregate applications but they help minimize downtime on the job While performance of a breaker has traditionally been measured by the tons of rock per hour says Stephane Giroudon strategic account sales manager for Doosan a breakers cost per ton is quickly becoming the industry standard One of the easiest ways to keep your tools cost per ton ratio low is to identify technologies that help reduce the effects of the constant beating breakers take in the high psi conditions associated with mines and quarries Additionally there are best practices that can contribute to the extended life of your attachment and your excavator High impact technologies The power and versatility of high impact breakers allow operators to perform a growing variety of tasks in mines and quarries Hydraulic breakers can be used for mass excavation or primary breaking Giroudon says They are effective for secondary breaking or oversize breaking of blasted rock to sizes more manageable for crushers Breakers are also on pedestal rock systems typically installed over the crusher for additional safety with rocks that get jammed in feeders A significant technological improvement for breakers in mining and aggregate applications is blank firing protection designed to guard the hammer from extra wear and tear when an operator misfires Standard on leading manufacturers rock breakers the antiblank fire protection employs a hydraulic cushion at the bottom of the cylinder bore to dampen the movement of the piston It also protects the hammer against metal to metal contact decreasing the premature deterioration of the breaker and its bushings retaining pins and front guide Some manufacturers offer an energy recovery valve in the hammer that can add performance in hard material Increasing a tools strike power by using energy generated by piston rebound the valve recycles recoil energy and transfers it to the tools next blow increasing striking power Another key advancement in breaker technology is speed control When a hammers stroke can be adjusted operators can match breaker frequency to material hardness This provides greater productivity and reduces the amount of harmful energy transferred back to the excavator A breakers hammer configuration is important as well Owners should consider an enclosed breaker design one in which the breaker is cradled inside a protective housing Giroudon says noting that the cradle protects the power cell from damage and reduces noise level The suspensions also protect the excavator boom and decrease vibration for enhanced operator comfort BY DEBBIE MCCLUNG Be sure to inspect the key wear points of a hydraulic breaker on a daily basis 42 PIT QUARRY June 2014 www pitandquarry com