In 2012, Patching Associates was retained by a leading global resources company to conduct an engineering noise assessment at a mine located in the Northwest Territories.
The Northwest Territories Mine Health and Safety Act requires managers to take all reasonable measures to ensure that work sites in a mine do not exceed a specified noise exposure level limit. A process plant and power plant operator must be in a working environment of 83 dBA or less during a 12 hour shift in order to stay within the 85 dBA noise exposure limit.
The main objectives of the project were to:
Using a Sound Pressure Level sound meter, a large sample of noise measurements were taken inside each subject area at high-traffic, key working locations. The measurements were used to produce a birds eye view noise map of the plants, showing the noise contours at different working floors. The noise contours highlighted the locations where the occupational noise levels exceeded the noise exposure target level.
The next step of the project was using a Sound Intensity Level sound meter to take close proximity measurements from the noise-emitting equipment. These were used to quantify the noise emissions of each noise source within the plant. A detailed 3D noise model was then created for each plant based on structural drawings and the quantified noise emissions. This step of the assessment resulted in noise maps like the image to the right.
The model calculated the noise propagation at desired locations, and the modeled levels were compared to measured levels to calibrate the model. Using the model, noise control measures were developed and were designed to be a close as practically achievable to the noise exposure target level.
The noise assessment of the process plant determined that the average occupational noise levels at key working locations would meet the noise exposure target levels after implementation of the recommended noise control measures.
The recommended measures were as follows:
The engineering noise control measures were developed into specifications which allowed the facility owner to obtain competitive bids on noise control equipment.
Patching Associates provided important insight and analysis need for the operations team to implement specific noise control measures and assess the cost and benefit of specific solutions.
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