Harrowing statistics from the European Agency for Safety and Health at Workstate that quarry workers are twice as likely to be killed in an accidentthanconstruction workers, and thirteen times more likely than those workingin manufacturing.There’s no doubt the industry can be dangerous, but how can mechanical automation support health and safety in the sector?Here David Strain, technical director at integrated automation systemexpert, Technidrive,explains. 

Data from the Health and Safety Executive (HSE) shows that over 3,500 quarry workers have suffered an injury reportable to HSE since 2000, with 31 of those being fatal. There are several initiativesto improve safety in the sector, this includes Target Zero, a Quarries National Joint Advisory Committee (QNJAC) scheme that has helped to reduce quarry accidents by over 80 per cent since 2000.

While this invaluable scheme — which includes training conferences and the creation of informative material — hasachievedgreat things for the industry, the most effective way to minimisehuman risks in quarrying is to remove them from the most dangerousaspects. Automation is key to achievethis. 

Automated equipment is alreadywidely used to perform drilling, blasting, loading, hauling and sorting of materials. In addition to increasing speed and accuracyin these processes, automationcan remove the need for operators to work intimately with dangerous equipment.

However, one area that oftenrequires human intervention is the unblocking of jaw crushers. By nature, a jaw crusher must be incredibly strong. Rock enters the crusherfrom the topof the machine and gets compressed between two surfaces — the fixed and moveable jaw. The rock will continue to be crushed until it is small enough to fall through the opening. Unfortunately, these crushers occasionally get blocked by the rocks and stones. 

Naturally, prevention is better than cure. Every effort should be made by the quarryteam to prevent blockagesoccurring, for instance: designing quarry blasts to achieveoptimum rockfragmentation, reducing oversize material, and ensuring that filler buckets are appropriatelysized for the capacity of the crusher. However, occasional blockages are still inevitable.

In the past, operators have succumbed to dangerous methods of removing blocked stones. Questionable tactics include using a tooth on chain to get the jaw to bite — creating the possibility for the tooth to be ejected at high velocity. Or,using brute forcewith a jack hammer, sledgehammer or similar tobreak the stones or pry them from position. If you’ve ever seen a sling give way in this situation, you’ll think twice about this method.

Technidrive had witnessed these risks first hand and wanted to develop a system to remove human intervention in this dangerous job.The vision was an automatedsystem that unblocks a crusher using mechanical forward and reversing actions to shift the stones. The system would sense when the blockage had been freed and give anautomated signal to notify operators that the process was complete. 

Technidrive developed its innovativejaw crusher unblock systemin 2015, and it has since been deployed at quarries across Europe. The team began its design by carrying out torque and speed calculations to determine whatdrive system was needed. In addition to the motor, we needed a variable speed drive (VSD) that could control the speed and torque.

Crucially, the system couldoffer startupwhen starting the jaw crusher from full.To achievethis, the team developed its own innovativesoftwarewhich ensuredthe VSDcould be remotely activated in unblock mode and operators would be kept out of harm’sway.

Since theinitial development, Technidrive has created similar equipment for several other businesses in the quarrying industry. Treating each project on an individualbasis, the organisation has been able to design, manufacture and deliver bespoke turnkey systems to a number of different sites. 

When workingalongside earth-moving equipment, removing operators from the most hazardousaspects should be a nobrainer. While the quarrying industry will always be among the world’s most dangerous sectors, mechanicalautomation can play a crucialrole in reducing risk and supporting the industry’s efforts towards Target Zero.

For more information on Technidrive and the systems integrator’s jaw crusher unblock, visitwww.technidrive.co.uk or contact the team atsales@tec>hnidrive.co.uk. A video of the jaw crusher unblock system can also be found on the Technidrive YouTube channel.