Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
Search
            ×
                        Mining
                        Mining
                            NIOSH
                            All CDC
                    Submit
                For a full list of topics:A-Z Index
                Advanced Search
            Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)





Mining Project: Noise Controls for Jumbo Drills Used in Metal/Nonmetal Mines
Keywords: Jumbo drills Metal mining Noise and vibration control Nonmetal mining
This page is archived for historical purposes and is no longer being maintained or updated.
Principal Investigator
J. Shawn Peterson -  Request informationStart Date
10/1/2013End Date
9/30/2018Objective
To develop durable noise controls that reduce the noise exposure of jumbo drill operators and facilitate the commercialization of the controls to make them available for all miners.Topic Area
Hearing Loss Prevention Overview
Research Summary

Jumbo drill operators are exposed to some of the highest noise levels in metal/nonmetal mining. In the worst cases, operators’ may be exposed to noise levels in excess of 105 dB(A). In such instances, their noise exposure exceeds the MSHA permissible exposure level (PEL) in less than one hour and operators are highly likely to incur permanent hearing loss. Based on data provided by the Parker Bay Company & Raw Materials Group,which does market research on mining equipment, NIOSH estimates that roughly 50% of the jumbo drill machines used in the world do not have enclosed cabs. Therefore, operators are directly exposed to the noise generated by the machine.
This project sought to develop noise controls that reduce exposure while not interfering with effective operation of the jumbo drill. Engineering noise controls were developed to reduce the noise emission of jumbo drills. The effectiveness of these controls was evaluated in laboratory settings and in underground settings to quantify this noise reduction.
The jumbo drill drifter and drill string were confirmed as prominent noise contributors to the sound level at the operator location. Prototype noise controls to address these noise sources were fabricated and tested under laboratory and field conditions. Of these prospective noise controls, the most effective in reducing noise emissions were constrained layer damped drill strings and damped drill string centralizers. Several versions of each of these were tested.
Laboratory testing of constrained layer damped drill strings resulted in a 2-3 dB reduction in the sound power level when compared to drilling with stock drill strings. Field testing of a second set of constrained layer damped drill strings proved to be promising as well. Here, testing results indicated that there was a 2-5 dB reduction in the sound pressure level at the operator location when compared with drilling with stock drill strings. Laboratory testing of damped drill string centralizers resulted in a 2-dB in the operator location sound pressure level. Given a 2-5 dB reduction in noise exposure and a 5-dB exchange rate, an operator’s noise dose would be reduced by roughly 25% to 50%. That is, an operator’s noise dose may be reduced by as much as one half of its baseline value.
Fully enclosing the jumbo drill operator location within a cab is an effective method of reducing noise exposure for the operator. A well-designed cab forms a noise barrier between the operator and the noise sources when the operator remains within the cab with the doors and windows closed. Field testing to evaluate the effectiveness of cabs at reducing the sound pressure level at the operator location were also conducted. Cabs proved to be very effective, reducing the operator location sound pressure level by 35-50 dB when compared to outside the cab.
The impact of this research will be to reduce the likelihood and magnitude of hearing loss for jumbo drill operators. The amount of reduction will vary with operating conditions, but in many instances the use of noise controls should reduce the noise exposure of the operator.

See Also
Analysis of Mine Fires for All U.S. Metal/Nonmetal Mining Categories, 1990-2001
Novel Stopping Designs for Large-Opening Metal/Nonmetal Mines
Propagation of EM Signals in Underground Metal/Non-Metal Mines
Relationship Between Elemental Carbon, Total Carbon, and Diesel Particulate Matter in Several Underground Metal/nonmetal Mines
Risk Profile of Cumulative Trauma Disorders of the Arm and Hand in the U.S. Mining Industry
Silica Dust Sources in Underground Metal/Nonmetal Mines - Two Case Studies
Technology News 491 - NIOSH Releases Two New Safety Training Videos
Technology News 501 - Measuring Very Low Air Velocities in Underground Metal/Nonmetal Mines
Technology News 518 - Super Stopping: A Permanent Solid Stopping for Directing Ventilation Airflows in Large-opening Metal/Nonmetal Mines
Technology News 519 - EZ-Up Curtain Stoppings: A Practical Solution for Directing Ventilation Airflows in Large-opening Metal/Nonmetal Mines
Page last reviewed: January 9, 2020
Page last updated: January 9, 2020
Content source: National Institute for Occupational Safety and Health, Mining Program
Facebook
        Twitter
        LinkedIn
        Syndicate Mining
        Site BrowserSafety and Health TopicsData & StatisticsMethodologyMine DisastersMSHA Data FilesMine & Mineworker ChartsTools & PublicationsTools You Can UsePublicationsNews & ArticlesResearch ProgramNORA Mining CouncilStrategic PlanMining Program, 2019-2023Miner Health Program, 2020-2030ProjectsContractsFunding OpportunitiesMining LinksAbout UsContact NIOSH MiningEmploymentFacilitiesHistoryVisitor Information Hearing Loss Prevention Overview
 NIOSH Homepage
 NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue