According to the Mine Safety and Health Administration (MSHA), “noise is one of the most pervasive health hazards in mining.” The agency goes on to say that occupational noise-induced hearing loss is one of the 10 leading work-related diseases/injuries, and that prolonged exposure to hazardous noise levels can cause permanent, irreversible damage to hearing. MSHA’s metal/non-metal mine noise standards (30 CFR 56.5050 and 57.50501) define the noise exposure “action level” as an “eight-hour, time-weighted average sound level of 85 dBA integrating all sound levels from 80 dBA to at least 130 dBA.” A high level of noise, if left unabated, not only has a negative impact on employees, it can affect the surrounding community as well.
“When we hire employees, they go through audiometric testing to get the baseline of where their hearing is so we know if there are issues,” says Brian Dillard, area production manager for Rogers Group, Inc. in northern middle Tennessee. “We then train them on hearing loss and hearing conservation, how to properly wear earplugs, the importance of wearing earplugs or ear muffs to reduce the noise, and how hearing loss happens.”
Oldcastle Materials takes a slightly different approach by identifying and marking where the noisiest areas in the plant are located. “We conduct noise mapping within our facilities,” says Chris May, director of environmental, health and safety for the company. “In addition, we seek to provide enclosed cabs for our employees that are operating equipment, so we aren’t exposing them to an all-day noisy environment.”
Dave Iddings, owner/operator of Iddings Quarry, Inc. in Mifflinburg, Pa., agrees that having insulated cabs on the equipment helps him control how much noise his employees are exposed to, but he has another trick up his sleeve. “Everybody does everybody else’s job,” he says, explaining that he limits the amount of time any one of his employees is exposed to noise by having them trade positions during the day. “One guy may be running the crusher in the morning, and after lunch he’ll crawl into the excavator.”
As for the community, it’s best for an aggregate operation to be out of sight and out of mind, or in this case, out of earshot. The noisy processing plant consisting of screens and crushers, the worst noise offenders, can sometimes be located down in the pit. The walls of the pit provide a natural noise barrier and also remove the plant from sight. In cases where this is not possible, a noise barrier can be constructed, or planted, in the form of a dirt berm or a thick row of trees. The old saying “Good fences make good neighbors” rings true for aggregate operations.
Brian Dillard, area production manager for Rogers Group, Inc. in northern middle Tennessee, has been with the company for 10 and a half of his 19 years in the industry. He received a mining engineering degree from Virginia Tech.SA regulations. He holds a bachelor’s degree in biological anthropology from Harvard University.
Chris May, director of environmental, health and safety for Oldcastle Materials companies, has been with the company for 18 years. She is chairperson of the of NSSGA’s Sustainability Committee, chairperson of NAPA’s Safety and Health committees, and a member of ARTBA’s Safety Committee. She holds a master’s degree in science in environmental health with a specialty in health and safety from East Tennessee University and is a Certified Mine Safety Professional.
Dave Iddings is the owner/operator of Mifflinburg, Pa.-based Iddings Quarry, Inc., which was started by his father in 1932. After high school, Iddings attended Penn State and served in the U.S. Navy. After that, he went to work for his father and has been there ever since. The quarry has received several NSSGA Sterling Safety Awards.
Voices of Experience
“From the employees’ perspective, there are a lot of things that we can do,” says Brian Dillard, area production manager for Rogers Group, Inc. in northern middle Tennessee. “When we hire employees, they go though audiometric testing to get a baseline of wher their hearing is. We ensure that they are wearing ear plugs out in the plant and on the equipment by doing safety audits. A general rule of thumb is that any time you have to raise your voice to communicate, you have the potential for hearing loss, so you need to use earplugs.”
Every year, at most of their locations, an occupational health specialist is brought in to sample the noise the employees are exposed to in the plant and mobile equipment. If overexposure is detected, the employee is automatically enrolled in a hearing conservation program.
Screens can be one of the worst offenders in an operation, but Dillard says rubber greatly reduces the noise. “The rubber on the top and middle decks of our scalping screens has a huge impact on noise reduction,” he says. “We also use rubber in some of the chutes on our screen towers to reduce the noise made by larger size rocks. Rubber truck bed liners help reduce the noise of the initial dump from a loader bucket into the truck.”
According to Dillard, berms create the best buffer between the operation and the community. “Berms are your best bet, if you have the room and the infrastructure,” he says. “If not, you can plant evergreen trees or anything else that will buffer the noise. We also enclose a lot of our screening and crushing towers to minimize the noise.”
Dillard says that prevention and doing things to minimize the noise to start with can help in the long run. “If we can minimize the noise on the front end, then we don’t have to worry about hearing loss, and we don’t have to wear ear plugs,” he says.
“For employees, we conduct annual surveys, or audiograms, to see if they have any changes in their hearing,” says Chris May, director of environmental, health and safety for Oldcastle Materials companies. “We’re constantly monitoring that. We provide employees with different types of hearing protection. Some employees prefer to use ear muffs, some prefer ear plugs. For those who prefer ear plugs, there’s a wide variety. We offer them different types because we want them to be comfortable, and we want them to use them.”
Oldcastle helps reduce the impact of noise on its employees by providing equipment with enclosed cabs, but it also does noise mapping. “We take a noise monitor around the facilities and to different parts of the plant so we can understand where the noise issues are and define those areas,” May says, explaining that the noise mapping creates awareness and helps identify areas where hearing protection is required, as opposed to areas where it is just a good thing to do. Labels in different colors and shapes allow employees to easily identify whether the area requires no hearing protection, requires hearing protection, requires specialized hearing protection (NRR 30 and above), or requires dual hearing protection and limited exposure time.
“We do several things in the plant to protect the surrounding community from noise,” May says. “Where possible, we try to surround the properties with trees. We plant fast-growing trees to form a noise barrier, which is also aesthetically pleasing.”
Kinder, gentler noise from the equipment is important, too. “If we do night work, we use back-up alarms that have narrow bands, so it’s very specific to what’s behind that equipment, rather than having a wide band that goes everywhere,” May adds. “You have to be directly behind it or in the path of it to hear the alarm. That way, it reduces the noise impact on the surrounding neighborhood.”
Dave Iddings, owner/operator of Mifflinburg, Pa.-based Iddings Quarry, Inc., goes about noise reduction from a different angle. “Workers are allowed to have so many decibels for so many minutes before they have to go into the hearing conservation program,” he says, explaining that his employees are cross-trained to do every job in the quarry, so that someone working in an extremely noisy area in the morning can work in a different area in the afternoon. “One guy may be running the crusher in the morning, but after lunch he’ll crawl into the excavator. Everybody here just alternates around to do different jobs. By alternating drivers, I’ve eliminated the problem.”
Newer mobile equipment is well engineered when it comes off the assembly line, so the operating noise has been greatly reduced. “You can put an operator into an excavator or a haul truck and have them there for eight hours, and the exposure will not be in excess,” Iddings says. “With some of my older equipment, I have to be very careful. If I put a driver in an older haul truck for eight hours, we’d probably be exceeding the allowable amount. I watch that, so it doesn’t happen.”
Iddings says the only other place he might have a borderline noise issue would be at the crusher. There, he has put in a sound-proof booth with windows all the way around, so that the employee can see everything, but is protected from the noise.
With only a few farms and ranches in the area, there are no issues with the community, but Iddings is still aware of his neighbors. “I’m working into the side of a hill on a limestone ridge, which is a natural noise barrier,” he says.
“My crushers are on the west side of the hill, and the prevailing wind is out of the west,” he adds. “The noise from the crusher blows into the side of the hill, and then up and over. So nobody else is exposed to that noise.”