Crushing is a dangerous business. Every year there are serious accidents on the job site and some are fatal. Nearly all could have been avoided with better safe work practices. Just this past June, the Mine Safety and Health Administration (MSHA) issued a Serious Accident Alert after a worker was trying to unplug a portable crusher. He attempted to turn the crusher rotor using a pry bar and his foot got caught in the moving part.
Safety is more than a list of instructions or better guards. Safety needs to be a big part the workplace culture – always on everyone’s minds so its second nature.
Safety is also a numbers game. The more risk your workers are exposed to, the greater the probability you or your staff will be hurt. The more nails you need to pound in a day, the better the chances you will hit your thumb!
Don’t just mitigate risk. Eliminate risk.
Using work arounds such as PPE or Safe Work Practices reduce risk but some risk remains. The smart question is “can we completely eliminate this risk?” This means taking an engineering or design approach to the elimination of risk in crushing equipment. Before the risk elimination question can be asked, it is important to understand that repairs, maintenance, relocating crushing spreads and unplugging crushers are major causes of injuries and death. Very few are hurt sitting in a centralized control tower or loader cab.
The questions are:
- How can we eliminate or reduce the amount of required maintenance on a machine? Reduction of the number of moving parts and using better components reduces the frequency of maintenance operations. How can we make repairs and maintenance easier and safer? When designing a machine, you can make it easier and safer for people to conduct the maintenance that can’t be eliminated and the inevitable repairs that come with crushing.
- How can we reduce the risk of plugging a crusher in the first place and make unplugging a crusher safer? Preventing plugging improves productivity and improves safety and there are simple ways to do this. For example: the tipping hydraulic grizzly is one of the simplest ways there is to prevent plugging on a jaw plant. There are also design improvements that make unplugging a machine less dangerous and the cleanup less back breaking.
- How can we make moving a portable crushing spread safer? Plenty of people are hurt relocating crushing spreads every year. The simple way is to reduce the number of loads, reduce the number of loose conveyors and reduce or eliminate the number of crane lifts.
Here are some examples of how design can impact safety1. Common Level Design
Equipment with common level design means there are fewer conveyors to move and maintain. This reduces the amount of direct contact workers have with the conveyor and the belts, and reduces their risk of injury around them. It also means fewer loads to move and fewer crane lifts when relocating a spread.
2. Centralized Control
Centralized control means there is one button in the control tower that the operator can push to stop the entire plant. This eliminates what we call the “Crusher Olympics”. When everything needs to stop, your operator isn’t sprinting from one machine to the next to shut it down. This is hazardous to the machinery as well as to the operator and other workers.
With centralized control, options such as Emergency Radio Shut down can be implemented. Workers are issued two way radios that have a special emergency button to shut down the whole spread if a worker is in danger.
“0 Speed Switch,” This means that if a belt stops moving, the 0 Speed Switch will shut down the system which prevents the piling up of materials, another hazard to workers. Hydraulically adjustable conveyors are safer as workers don’t have to manually lift conveyors.
Tag Lines - a pull cable goes the full length of the conveyor, so if pulled, the tag line kills the power and stops the crushing spread if a worker detects a dangerous situation.
4. The Hydraulic Grizzly & Jaw Safety
Hydraulic grizzlies help crushing operations become more efficient when handling large material at the beginning of the crushing process. But what is often overlooked is how they also contribute to the overall safety of the plant. Because the grizzly removes larger unwanted material from reaching the jaw, the probability of plugging a jaw is reduced. For workers, unplugging a jaw is very dangerous. The grizzly removes the hazards before they become a problem for the jaw crusher, and by doing so, it is improving safety for the workers on site.
5. Less Maintenance
Plants with centralized control and one generator require less maintenance than plants with individual motors for every piece (tracked equipment). Reducing maintenance also reduces workers’ risk as in the example mentioned at the beginning. Many workers are injured while trying to repair the equipment or unplug it when somewhere on the crushing spread. Reducing the need for maintenance then reduces their exposure to risk.
Next Generation Screen Plants which don’t require daily greasing. The bearings require grease only once or twice a year which reduces the maintenance time, cost, and risk to workers of being around the equipment.
6. Moving a spread
Moving a common level design crushing spread is a much simpler, easier, and safer process. With the common level design, there is no need for independent conveyors to tie machines together into a crushing operation. The tear down/moving process is easier for workers and reduces their exposure to risks associated with moving and placing independent conveyors. It also reduces the cost of moving as it reduces the number of loads that need to be hauled and speeds up the moving process.
7. Air Quality & Noise Reduction
Air quality and noise control are important for safety as well. Optional dust and noise control features that should be considered.
A cone bottom is dust shield to reduce the amount of silica there is in the air.
• Having a pressurized control tower to keep particulate out of the air.• Having the Genset is in its own room in the control van. Putting a fire-rated wall between the Genset and the operator room reduces noise in the control van and also improves the chances for escape in the event of an engine fire.
Good design improves both safety and productivity. For more information about ELRUS equipment and our safety features, contact us.