Data & statistics

Noise Exposure and Hearing Conservation in US. Coal Mines - A Surveillance Report (PDF, 1021 KB, 2007)
This study examines the patterns and trends in noise exposure documented in data collected by Mine Safety and Health Administration inspectors at U.S. coal mines from 1987 through 2004.

Software

Determination of Sound Exposures (DOSES): Software Manual and Implementation Guide (PDF, 1001 KB, 2009-05)
The Determination of Sound Exposures (DOSES) software was developed by NIOSH specifically for use by mine management and safety personnel to simplify the record-keeping and analysis associated with time-motion studies and worker noise exposures, making it easier to identify and solve noise problems.

Development of the NIOSH Determination of Sound Exposures (DOSES) Mining Noise Exposure Management Software (PDF, 346 KB, 2012)
To help manage noise exposures, the U.S. National Institute for Occupational Safety and Health (NIOSH) developed the Determination of Sound Exposures (DOSES) software and implementation guide for use by mine management and safety personnel.

Technology News 536 - NIOSH Develops New Software to Analyze and Reduce Noise Exposure (PDF, 140 KB, 2009-07)
NIOSH has been performing research to analyze and reduce hazardous noise exposure in mines.

DOSES - Determination of Sound Exposures
The Determination of Sound Exposures (DOSES) software was developed by the National Institute for Occupational Safety and Health (NIOSH) specifically for use by mine management and safety personnel. DOSES simplifies the record-keeping and analysis associated with time-motion studies and worker noise exposures, making it easier to identify and solve noise problems.

Models

From Development to Evaluating Effectiveness in Industry: Building a Research Model for Noise Control Technology Efforts (PDF, 163 KB, 2010)
As a way to focus on the direct impact of NIOSH-developed control technologies on reducing noise induced-hearing loss (NIHL), a structured research model was developed to include metrics that help to more accurately evaluate and measure the effectiveness of noise control technologies. This research structure can serve as a model for researchers and academics to assess the development, dissemination, and evaluation of noise control technologies.

Measurement & analysis

Acoustic Assessment of Pneumatic and Electric Jackleg Drills used in the Mining Industry (PDF, 435 KB, 2010)
This paper presents an acoustic assessment of pneumatic and electric jackleg drills that involved Noise Source Identification (NSID), penetration rate measurements, operator´s cumulative noise dose measurements, and the determination of sound power levels.

Analysis of Nonstandard Noise Dosimeter Microphone Positions (PDF, 618 KB, 2008-03)
This study, conducted as part of a project involving the evaluation of a new type of noise exposure monitoring paradigm, showed the effects of dosimeter microphone placement in a diffuse field were found to be minor for most of the test microphones/locations.

Application of a Microphone Phased Array to Identify Noise Sources on a Horizontal Vibrating Screen (PDF, 2397 KB, 2008)
This paper provides detailed information on the findings of NIOSH research measuring the sound power level generated by a horizontal vibrating screen with the screen either directly on the floor or on rubber isolation pads.

Application of a Microphone Phased Array to Identify Noise Sources on a Roof Bolting Machine (PDF, 3036 KB, 2007)
This paper discusses the methods NIOSH used to identify noise sources on a roof bolting machine while drilling.

Application of Phased Array Technology for Identification of Low Frequency Noise Sources (PDF, 427 KB, 2008)
NIOSH is conducting research to identify and control dominant noise sources in Continuous Miners. The objectives of the work presented in this paper were: 1) To rank the noise radiated by the different sections of the conveyor, and 2) to determine the effect of a urethane-coated tail roller on the noise radiated by the tail-section.

Assessment and Evaluation of Noise Controls on Roof Bolting Equipment and a Method for Predicting Sound Pressure Levels in Underground Coal Mining (PDF, 3609 KB, 2006)
A research program was implemented to: 1) determine, characterize and to measure sound power levels radiated by a roof bolting machine during differing drilling configurations (thrust, rotational speed, penetration rate, etc.) and utilizing differing types of drilling methods in high compressive strength rock media (>20,000 psi); 2) distinguish and correlate the empirical data into one, statistically valid, equation, in which, provided the mining industry with a tool to predict overall sound power levels of a roof bolting machine given any type of drilling configuration and drilling method utilized in industry; 3) provide the mining industry with several approaches to predict or determine sound pressure levels in an underground coal mine utilizing laboratory test results from a roof bolting machine and 4) describe a method for determining an operators' noise dosage of a roof bolting machine utilizing predicted or determined sound pressure levels.

Assessment of Engineering Noise Controls at a Talc Processing Plant (PDF, 592 KB, 2009-04)
This report describes an investigation by NIOSH researchers to quantify sound levels and to determine the amount of sound reduction provided by engineering noise controls installed in a talc processing plant.

Assessment of Equipment Operator´s Noise Exposure in Western Underground Gold and Silver Mines (PDF, 516 KB, 2010-03)
This report contains the description of studies conducted at U.S. western hard-rock mines to determine the levels of noise exposure of the miners.

A Comparison of Beamforming Processing Techniques for Low Frequency Noise Source Identification in Mining Equipment (PDF, 437 KB, 2009)
The implementation of an adaptive beamforming algorithm (RCB) and a post-processing technique (CLEAN-SC) on the results obtained from a VS machine using a 3.5-meter array were studied as a mean to improve the resolution and thus the accuracy of the NSI process at low frequencies, i.e., from 200 Hz to 1000 Hz.

Design and Instrumentation of a Large Reverberation Chamber (PDF, 563 KB, 2003-06)
Documents the refurbishing and instrumentation of the PRL reverberation chamber to bring it up to compliance with the ISO 3743-2 standard for engineering grade measurements for broadband noise.

Estimated Sound Power Radiated by Surfaces on a Continuous Miner Tail Section Using Vibration Measurements (PDF, 1208 KB, 2003-06)
Identifies the most significant noise-radiating surfaces on a continuous miner tail section and examines the effects of three engineering noise controls.

Evaluation of Engineering Noise Controls for a Continuous Miner Conveyer System (PDF, 327 KB, 2003-06)
An analysis of extensive noise and urethane durability testing on a Joy 14CM9 continuous miner's conveyor assembly, tail roller, and bottom plate and a discussion of the initial underground testing results for the urethane-coated conveyor flights and tail roller.

Flammability of Noise Abatement Materials Used in Cabs of Mobile Mining Equipment (PDF, 626 KB, 2003)
Describes the flammability tests conducted on 15 to 20 different noise abatement materials of various chemical compositions and thickness.

Hearing Protection and Air-Rotary Drilling - Part 2 (PDF, 151 KB, 2005-11)
The results from the sound level measurements, the dosimeter recordings and the time-activity studies on four different air-rotary rigs indicate a wide variation of operator noise exposure during hole development. These variations appear to be dependent on the cab design and the operator's drilling behavior.

Heavy Construction Equipment Noise Study Using Dosimetry and Time-Motion Studies (PDF, 1552 KB, 2007-07)
The focus of this research was to determine the noise exposures of heavy construction equipment operators while documenting the workers' tasks, (i.e. hauling, moving, and/or pushing construction material). The types of construction equipment studied included asphalt pavers, backhoes, bulldozers, compaction equipment, excavators, haul trucks, telehandlers, and wheeled loaders.

Heavy Construction Equipment Noise Study Using Dosimetry and Time-Motion Studies (PDF, 65 KB, 2005)
The focus of this research was to determine the noise exposures of heavy construction equipment operators while documenting the workers´ tasks, (i.e. hauling, moving, and/or pushing construction material).

Identification of Noise Sources on Longwall Panels Using Multiple Time-Synchronized Dosimeters (PDF, 501 KB, 2007)
This paper describes research designed to develop guidelines and test procedures for identifying all noise sources that are major contributors to the underground noise exposure of longwall coal mining system workers.

Lower Respirable Dust and Noise Exposure with an Open Structure Design (PDF, 988 KB, 2006-11)
NIOSH performed an evaluation to determine to what extent building types could impact respirable dust and noise levels. This report discusses the evaluation of three different types of product sizing silica sand structures: a masonry design, a steel-sided design, and an open structure design. The data obtained in this study indicate that the open structure design (no walls) was superior from both a dust and noise (health) standpoint compared to the other two structures.

Measurement Method for Determining Absorption Coefficients for Underground Mines (PDF, 230 KB, 2007-11)
Mine workers are exposed to additional noise levels underground due to the reflection of machine generated noise that would otherwise dissipate in an above ground setting. This paper presents a method using a ray-tracing technique to determine absorption coefficients, for octave bands from 63 Hz to 8 kHz, for underground mines.

A Measurement Method for Determining Absorption Coefficients for Underground Mines (PDF, 162 KB, 2006)
This paper will present a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients will be essential for determining and predicting potential noise overexposure to machine operators in different mine environments.

Mining Machine Noise Contour Plots (HTM, 9 KB, 2010-01)
Mining Machine Noise Contour Plots show the noise patterns NIOSH researchers measured around a variety of surface and underground mining machines. The patterns around many of the machines show "hot spots" of hazardous noise that should be avoided.

Noise Assessment of Stone/Aggregate Mines: Six Case Studies (PDF, 1694 KB, 2007-08)
NIOSH is conducting a cross-sectional survey of equipment sound levels and worker noise exposures in the stone/aggregate mining industry. Six stone/aggregate mines (three surface and three underground) were recently surveyed. The findings identify the equipment and machinery that are likely to cause worker overexposures and the workers found to be experiencing overexposures. In addition, the benefit of cabs in reducing mobile equipment operator noise exposure is discussed.

Noise Source Identification on a Continuous Mining Machine (PDF, 759 KB, 2008)
In the Hemi-anechoic chamber of the Pittsburgh Research Laboratory noise source identification on a continuous miner was performed using phased array measurements and a frequency domain beamforming algorithm with Diagonal Removal.

Noise Source Identification on a Horizontal Vibrating Screen (PDF, 344 KB, 2009-07)
This paper presents the results of a study conducted by NIOSH in collaboration with the Acoustical and Vibrations Engineering Consultants Inc. (AVEC) to determine the most dominant noise sources on a VS machine at low frequencies, i.e., 250 to 1,000 Hz.

Results of Noise Measurements from Underground Testing of a Roof Bolting Machine Duty Cycle (PDF, 353 KB, 2007)
This paper presents the results of an evaluation of the duty cycle of a typical roof bolting machine operation at two coal mines. The evaluation entails a time motion study of an operators´ shift, logging each activity for time and the noise levels associated with each task. The results provide insight into which portion of the operators´ duty cycle is the most prominent contributor to noise exposure.

Snapshot of Noise and Worker Exposures in Sand and Gravel Operations (PDF, 951 KB, 2008-03)
This paper presents research examining noise on dredges used in several surface mine sand and gravel operations and in the processing facilities.

Sound Power Level Study of a Roof Bolter (PDF, 1717 KB, 2006)
NIOSH initiated a study of a roof bolter to reduce noise exposure to mine roof-bolter operators. An important segment of this research entails determining the affect of various drilling configurations on the performance (penetration rate) and sound power emissions when drilling into granite.This paper details the effects of each of these variables on the performance and sound power level emission. When drilling into granite, it was found that wet drilling generated lower sound power levels and performed better than vacuum drilling.

Sound Restoration Hearing Protection: Genesis of a Standard Test Method (PDF, 75 KB, 2008)
Issues related to testing the performance of sound restoration hearing protectors are outlined within this paper, and possible solutions are discussed.

Structural Vibration as a Noise Source on Vibrating Screens (PDF, 1451 KB, 2009)
NIOSH is actively developing noise controls to reduce noise generated by horizontal vibrating screens. Testing described in this paper indicates the screen sides and feed box are dominant noise sources for the 250 Hz through 800 Hz one-third-octave bands whereas the electric motor appears to be the most significant source for the 1 kHz band.

Survey of Noise in Coal Preparation Plants (PDF, 545 KB, 2007)
Noise surveys were conducted in eight coal preparation plants. The research consisted of worker dose monitoring, task observations, and equipment noise profiling. Results indicate that only workers who routinely spend a significant portion of their shift in the plants (away from the control rooms) are susceptible to overexposure from noise. Certain pieces of equipment (screens, centrifuges, sieve bends) are the loudest primary noise sources responsible for the worker noise exposures.

Engineering controls

Analysis of a Mechanism Suspension to Reduce Noise from Horizontal Vibrating Screens (PDF, 606 KB, 2011)
The National Institute for Occupational Safety and Health (NIOSH) is developing noise controls to reduce noise generated by horizontal vibrating screens.

Assessment of Noise Controls Commonly Used on Jumbo Drills and Bolters in Western United States Underground Metal Mines (PDF, 1102 KB, 2005-01)
The noise-control treatments most commonly observed on drills and bolters during this study were evaluated on machines at underground metal mines to determine the amount of noise reduction achieved by each control.

A Control Suite to Reduce Roof Bolting Machine Drilling Noise (PDF, 898 KB, 2010)
NIOSH conducted research to reduce the noise emission of various underground coal-mining equipment and developed a suite of controls to reduce drilling noise.

Development and Evaluation of a Urethane Jacketed Tail Roller for Continuous Mining Machines (PDF, 549 KB, 2007)
This paper details the Laboratory noise testing results of a continuous mining machine conveyor system which uses a coating for the tail roller component designed to help bring the continuous mining machine into compliance with federal noise regulations.

The Development of a Damped Drill Steel to Reduce Roof Bolting Machine Drilling Noise (PDF, 509 KB, 2010)
The paper documents NIOSH research to date of a damped drill steel on a roof bolting machine.

Development of Roof-Bolting Machine Bit and Chuck Isolators for Drilling Noise Reductions (PDF, 368 KB, 2009)
NIOSH is developing bit and chuck isolators to reduce vibration, and thus noise radiation of the drill steel, with the longer-term goal of reducing roof bolting machine operator noise exposure.

Dial Down Dust and Noise Exposure (PDF, 1541 KB, 2007-07)
Although structure type and building material were not viewed as significant factors affecting the health of employees in mineral processing facilities when they were built, NIOSH has found that building type can impact respirable dust and noise levels. NIOSH performed a study in which it evaluated three building types: masonry, an open-structure design, and a steel-sided design.

A Dual Sprocket Chain as a Noise Control for a Continuous Mining Machine (PDF, 371 KB, 2007)
This paper describes a noise control for reducing the noise overexposures of continuous mining machine operators.

A Dual Sprocket Chain as a Noise Control for a Continuous Mining Machine (PDF, 162 KB, 2009-09)
A dual sprocket conveyor chain for a CMM was examined both in the laboratory and in underground field studies to test the influence on lowering the sound power emissions of the chain conveyor of a CMM when compared to a standard chain.

Evaluation of Stiffeners for Reducing Noise from Horizontal Vibrating Screens (PDF, 575 KB, 2010)
NIOSH is developing noise controls to reduce noise generated by horizontal vibrating screens. This paper documents testing of the stiffeners.

The Evolution of Drill Bit and Chuck Isolators to Reduce Roof Bolting Machine Drilling Noise (PDF, 2012)
This paper documents the evolution of the bit isolator and chuck isolator. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB.

In-Cab Noise Reduction on an Air-Rotary Drill Rig (PDF, 3828 KB, 2007-05)
The National Institute for Occupational Safety and Health (NIOSH) has investigated engineering noise controls to reduce sound levels in cabs on air-rotary drill rigs. A recent investigation revealed that some drillers are exposed to A-weighted sound levels exceeding 85 dB even though a cab is used. NIOSH studied the in-cab sound levels of one such rig. Next, field tests were performed in a production environment to evaluate noise controls to reduce in-cab sound levels.

Less Sound Underground: Reducing Roof Bolting Machine Drilling Noise (PDF, 194 KB, 2010)
This article presents the most significant findings from NIOSH research to develop noise controls that reduce the sound at the operator´s position of mining machinery.

Mining Haul Truck Cab Noise: An Evaluation of Three Acoustical Environments (PDF, 424 KB, 2009-10)
This study examines noise exposure inside haul truck cabs experienced during a typical workday with normal operator practices, the effect of noise-reduction features inside the cab, the consequence of disabling noise controls (unnecessary open doors/ windows) and the significance of haul truck and cab maintenance factors.

Modified Tail Section Reduces Noise on a Continuous Mining Machine (PDF, 805 KB, 2011)
Overexposure to noise remains a widespread, serious health hazard in the U.S. mining industries. Most other categories of illnesses and injuries associated with mining have improved, with the exception of hearing loss.

MultiFit4: An Improved System for Insert-Type (PDF, 498 KB, 2010-09)
This paper describes the results of initial testing of the NIOSH Multifit4 system that was designed to be used as a tool by qualified researchers to evaluate hearing protector training and fit interventions at worksites.

Noise and Vibration Reduction of a Vibrating Screen (PDF, 2170 KB, 2005)
Presents detailed results of a cooperative study of vibrating screen noise conducted at a coal preparation plant. Rubber isolators reduced sound levels by 1 dB. Urethane screen panels did not reduce sound levels in this case. Drive noise was determined to be the dominant noise source on the screen. Damped side plates reduced vibration levels on the screen sides by 1 to 7 dB(A).

A Noise Control for A Roof Bolting Machine: Collapsible Drill Steel Enclosure (PDF, 459 KB, 2008)
This paper describes and evaluates an engineering noise control for the roof bolting machine, namely the collapsible drill steel enclosure.

Noise Control in Underground Metal Mining (PDF, 2291 KB, 2009-12)
This document is for operators, safety personnel, and mechanics in the mining industry who are not specialists in noise control engineering or acoustics. Once personnel understand the guidelines and principles of noise control, they will be able to (1) evaluate the extent of a noise problem; (2) determine the best approach to the problem; and (3) apply the most appropriate solution.

Noise Controls For Roof Bolting Machines (PDF, 381 KB, 2009-01)
This paper describes the procedure used by NIOSH researchers to evaluate noise generated by a roof bolting machine and its components, and results are given for two engineering noise controls for the roof bolting machine: a bit isolator and a drill chuck isolator.

Noise Controls for Vibrating Screen Mechanisms (PDF, 5889 KB, 2011)
NIOSH is currently developing noise controls for horizontal vibrating screens.

A Technique for Estimating the Sound Power Level Radiated by Pneumatic Rock Drills and the Evaluation of a CSIR Prototype Rock Drill with Engineering Noise Controls (PDF, 194 KB, 2009-05)
This report describes research by NIOSH to reduce the noise exposures of jackleg drill operators and to prevent additional cases of noise induced hearing loss (NIHL) by developing and evaluating low-cost retrofit noise controls for equipment.

Technology News 527 - The Partial Cab: A New Noise Engineering Control for Surface Drill Rigs (PDF, 286 KB, 2007-08)
NIOSH, in partnership with stakeholders in the mining and surface drilling industries, conducted research to develop engineering control technologies that reduce workplace noise exposure. The result of this research partnership is the development of a partial cab.

Technology News 531 - Engineering Controls for Reducing Continuous Mining Machine Noise (PDF, 124 KB, 2008-09)
Research conducted by NIOSH, with stakeholder involvement, has focused on producing noise treatments to reduce noise generated by the CMM conveyor system. Two engineering noise controls have been developed: the urethane-coated flight bar chain and the dual-sprocket chain.

Technology News 532 - Collapsible Drill Steel Enclosure for Reducing Roof Bolting Machine Drilling Noise (PDF, 313 KB, 2008-09)
Research conducted by NIOSH has focused on producing noise treatments to reduce noise generated by the Roof Bolting Machine. A drill steel enclosure for reducing roof bolting machine drilling noise has been developed as an engineering control.

Technology News 538: Acoustic Enclosure to Reduce Noise From Vibrating Screen Mechanism Housings (PDF, 161 KB, 2009-11)
NIOSH has been performing research to reduce operator exposure to noise from vibrating screens at coal preparation plants.

Technology News 539 - Identifying The Benefits Of Engineering Noise Controls Through A Business Case (PDF, 162 KB, 2009-12)
NIOSH has been performing research to develop a business case that promotes adoption of noise controls by reducing barriers to industry acceptance and enhancing drivers that foster their implementation.

Technology News 548 - Bit Isolator Reduces Drilling Noise in Underground Coal Mines (PDF, 400 KB, 2012)
To develop an engineering noise control that reduces roof bolting machine (RBM) operators´ exposure to noise in underground coal mines, thereby decreasing the risk of noise-induced hearing loss (NIHL) in RBM operators and other workers in close proximity to RBMs.

Underground Evaluation of Coated Flight Bars for a Continuous Mining Machine (PDF, 371 KB, 2006)
Continuous mining machines rank first among all equipment in underground coal mining whose operators exceed 100% noise dosage. The conveying system is one of the principal noise sources. A highly durable polyurethane coating has been developed for the chain flights to decrease noise generated by these impacts. This paper evaluates the effectiveness of this engineering noise control in reducing the noise exposure of continuous mining machine operators in an underground coal mine environment.

Collapsible Drill Steel Enclosure: A device for reducing roof bolting machine noise exposure
NIOSH has developed a collapsible drill steel enclosure (CDSE) to encapsulate the drill steel of a roof bolter during the drilling portion of the roof bolting machine duty cycle. Underground field tests have demonstrated that it can reduce time-weighted noise exposure from roof bolting machine drilling noise by up to 7 dB(A). In addition, NIOSH is collaborating with J. H. Fletcher & Co. in the continued development of a CDSE.

Administrative controls

Administrative Controls for Reducing Worker Noise Exposures (PDF, 236 KB, 2005)
NIOSH has conducted worker noise exposure surveys in underground and surface coal mines and coal prep plants which have revealed that worker dosimetry, time-motion studies, and equipment noise profiling are important aspects of effectively using administrative controls.

Development of the NIOSH Determination of Sound Exposures (DOSES) Mining Noise Exposure Management Software (PDF, 346 KB, 2010)
To help manage noise exposures, NIOSH developed the Determination of Sound Exposures (DOSES) software and implementation guide for use by mine management and safety personnel.

Personal protective equipment

The Effect of an Insertion Lubricant on the Noise Attenuation of Foam Earplugs (PDF, 117 KB, 2008)
This study examines the use of a commercially-available lubricant for hearing aids to determine whether it would facilitate improved fit and attenuation for earplugs.

An Evaluation of Sound Restoration Hearing Protection Devices and Audibility Issues in Mining (PDF, 542 KB, 2012)
This paper will present the results of testing completed on a selection of four sound restoration hearing protection devices, with the objective of determining if they provide improved speech intelligibility to workers near certain types of mining equipment.

Equipment

Practical Application of a Partial Cab to Reduce the A-Weighted Sound Level at the Operator's Station on Surface Drill Rigs (PDF, 1191 KB, 2007)
This paper discusses the preliminary cab design, the testing of materials for construction of the prototype, and the field test method and results of a collaboration with a local drilling company to design and install a partial cab between the operator and the drill steel in an effort to reduce the sound level at the operator station of a surface drill rig.

Training

Noise Exposure and Overhead Power Line (OPL) Safety Hazards at Surface Drilling Sites (PDF, 2464 KB, 2005-11)
This is a series of 5 separate double sided sheets designed to educate workers about noise exposure and overhead power line safety at surface drilling sites.

Training theory & methodology

An Examination of Antecedents to Coal Miners' Hearing Protection Behaviors: A Test of the Theory of Planned Behavior (PDF, 847 KB, 2008-02)
The motivation behind this investigation was to apply an established theory to better understand three potential antecedents to intentions toward wearing hearing protection among coal miners.

Laboratories

Anechoic Chamber
Provides a reflection free environment for acoustic testing.

Information gateways

MSHA noise information (http://www.msha.gov/1999noise/noise.htm)

Noise and Hearing Loss Prevention

OSHA noise and hearing conservation (http://www.osha.gov/SLTC/noisehearingconservation/)