Quieting of Continuous Miner Scrubber Fan Noise

DESCRIPTION (provided by applicant): This proposal targets a specific mission of NIOSH and the current SBIR solicitation: hearing loss prevention for mine workers. The main objective of this work is to reduce the noise radiated by Continuous Miners (CM). Since CMs are responsible for about 30% of noise exposures above permissible levels [MSHA, 2006], reducing the noise in this machine would have a significant impact on the health of miners. The approach to achieve noise reduction in the CM is to target oneof the major noise sources, the scrubber duct system. Although several attempts have been made over the years to reduce the noise from CMs, the fan noise itself has not been targeted in previous studies. Furthermore, most of these fans have been redesignedfor over 20 or 30 years ago. The main problem with the current design is that it was designed with efficiency, pressure rise and reliability in mind, whil not considering noise as a major design variable. It is our expert opinion that completely redesigning the fan (rotor and stators) using modern computational tools and technologies would have a very significant impact on the noise. In this process, low noise will be considered the major target. This is an approach that we have successfully implemented indifferent military and commercial projects where noise is a major concern, e.g. unmanned air vehicles. Even in these highly-demanding applications we have found that aerodynamic efficiency can be kept high while significantly reducing noise. The objectiveof the Phase I work is to conduct a proof-of-concept design for a particular CM using state- of-the-art computational tools and control technologies. The newly designed fan properties (aerodynamic and acoustic) will be compared to those of a current CM fan to determine the potential of the proposed approach. This is possible due to Joy Mining Machinery agreeing to support our work by providing technical assistance and information about current systems (see letter of support). This early contact with a major mining equipment manufacturer also provides a better chance of success to the project by making sure that any results from our work could rapidly be implemented in the production line and therefore the mines. PUBLIC HEALTH RELEVANCE: Exposure tonoise above permissible levels is a major occupational hazard that results in Noise Induced Hearing Loss (NIHL) in 90% of mine workers by age 50. The continuous miner (CM), one of the most common equipment's in underground mining, has been identified as amajor noise source that exposes 30% of its operators to noise above permissible levels. The goal of the proposed work is to reduce the noise from the CM by redesigning the fan in the scrubber system (identified as one of the major sources) using modern computational tools from the aeronautical industry.