Pit & Quarry, July 2015

CRUSHER SAFETY sion When someone is in a rush When someone is simply inexperienced Aggregate producers cant control all of the factors that lead to accidents related to crusher blockages They can however create a work environment and culture that best positions people to return home from work every day Best use of your workforce To Smith one of the key factors that should be addressed related to crusher safety is a companys workforce A number of people operating and working around crushing equipment dont have the adequate experience he says Producers and recyclers sometimes turn to a transient workforce and that can present problems Our industry is so much about tribal knowledge Smith says Were still relying on grandpa to educate a grandson to operate a plant Or were adding crews to do short time jobs and leaning on temporary labor Transient workers might know how to operate loaders Smith says but do they know how to run a crushing plant Are they shoving oversized material into the crusher Are they packing the crusher full Ultimately it still comes back to the person feeding the plant Smith says They need to be properly equipped and understand what we are doing Effective operators and contractors tend to put one of their best teams on crusher duty because they realize production starts and stops with these workers But teams often consist of just two people a loader operator and a plant operator A third person can make a difference in a number of areas Smith says Any good producer Ive talked to will have a loader operator a plant operator and a ground guy he says Their sole job is to keep an eye on the plant and make sure it doesnt have any problems The third person is the one who can prevent unnecessary maintenance For example if a chute is about to plug up this worker can help to Another take Kelly Graves senior technical sales manager at Kleemann offers his thoughts on crusher blockages and some solutions that have helped to minimize the problem over the years Graves P Q How much of a problem are crusher blockages today and how does the procedure of clearing a crusher today compare with clearing one in the past KG Blockages create downtime which lowers production and decreases tons per man hour With the advancement and increased use of hydraulics downtime is greatly reduced Compared to the old style machines utilizing mechanical devices to open the crushing chamber the hydraulic machines are much faster and more importantly safer than machines of the past Clearing blockages on a newer hydraulic machine can be as simple as pushing a button on the crusher control cabinet or remote control or reversing the motion of the swing jaw with the flip of a switch P Q How do you and Kleemann work with customers to address the blockage issue KG We try to teach producers and recyclers the importance of material prep and feeding concepts to minimize crusher blockages For example feeding a portable or track machine in a recycle application is best with an excavator from an elevated position Position the excavator in such a way where you can see into the feed hopper and feeder By using this method you can see material that may be too large for the crusher inlet or perhaps see a non crushable before it enters the crushing chamber P Q Does one application aggregates or recycling encounter more crusher blockages than the other KG Recycling applications tend to create more blockages than aggregate In an aggregate application the material appears more uniformed and provides a more consistent feed to the crusher whereas recycle material specifically concrete with rebar tends to be less consistent in size and shape A recycle application contains material that is not conducive to crushing such as wood steel trash and soils These types of material increase the probability of a crusher blockage Preparation of recycle material is essential to minimize crusher blockages and downtime Removing as much steel rebar and soils prior to crushing will greatly reduce crusher blockages The use of hydraulic processors hammers and shears creates a more consistent feed size and it separates the steel and rebar P Q What other factors have helped to minimize blocked crushers as a health and safety issue KG Machine design has also played an important role in minimizing blocked crushers For example some impact crushers utilize an inlet hood that will rise hydraulically to allow more clearance into the crusher feed opening This feature is especially important in the recycle industry Another design feature is the material flow concept Think of this concept as an upside down funnel The feeder is smaller in width than a pre screen or a crusher with the discharge belt being the widest This feature reduces bridging increases the dimensions of transfer points throughout the machine and increases material flow through the machine 38 PIT QUARRY July 2015 www pitandquarry com