Mining Project: Develop and Evaluate Engineering Noise Controls for Air Carbon Arc Cutting and Gouging

Research Summary

This project developed and evaluated noise controls and alternatives toward reducing sound pressure levels and personal noise exposures from air carbon arcing applications in the mining industry to below permissible exposure limits.

Collaboration between NIOSH and stakeholders developed during previous NIOSH studies was used to obtain welding shop or other on-site locations. Pre-control sound level measurements were taken to develop a baseline for comparison purposes when noise controls and alternatives were applied. Effectiveness, efficiency, and worker acceptance of the noise controls and alternatives were evaluated. Noise controls and alternatives for reducing sound levels to below the ceiling limit of 115 dB(A) and noise exposures to below the permissible exposure limit of 90 dB(A) TWA per 8-hour shift for workers were transferred to the mining sector.

This project addressed the following four research questions: (1) What are the most significant contributors to the noise generated by air carbon arc cutting (ACAC) and gouging (ACAG)? (2) What noise controls are available or can be developed for ACAC and ACAG that focus on the most significant noise-generating mechanisms and reduce the overall sound levels? (3) Do the available or newly developed noise controls reduce the noise exposures of workers using ACAC and ACAG and are they sufficiently durable in the mining environment? (4) Do substitute or alternative metal cutting and gouging methods reduce worker exposures and do they perform adequately in the mining environment?

Existing and conceptual noise controls and alternatives were designed and rigorously tested to confirm applicability to mining. Successful application of noise controls could significantly reduce workers' exposure to harmful sound levels from air carbon arcing, followed by a significant reduction in noise-induced hearing loss that is currently prevalent in the mining industry. Also, it is hoped that other industries that use air carbon arcing could realize the benefits from this research.