Case Study: Fan silencer for mine ventilation system addresses unique installation and transportation challenges

Problem:

A nickel mining operation was in need of fan silencers for two extremely large axial fans used for mine ventilation and cooling. Not only did the fan silencers have to meet the application requirements, but they needed to be designed to overcome inherent installation and transportation challenges.

Nickel mining is performed by excavating nickel-containing ores from a series of deep subterranean man-made tunnels, called mine shafts. In order to mine safely and economically at depth, a number of issues must be addressed. One such issue involves having access to an adequate air supply within the mine. Related to this involves controlling the ambient temperature within the mine to make it comfortable for the workers. Both of these issues are addressed using mine ventilation systems. To ensure the safety of workers, these mine ventilation systems must be running at all times while the mine is populated. Large axial fans are employed to push fresh outdoor air into the mine; on its way inside, heater houses condition the air to the appropriate temperature for optimum worker comfort. Due to the enormous size of the ventilation fans, noise is an issue not only for the workers, but also for compliancy with local and environmental regulations.

The dB Noise Reduction team was enlisted to develop custom fan silencers for two heavy duty axial fans designed to deliver a total of 800,000 ACFM directly into the mine shaft. Trusted not only for their quality industrial silencers, dB Noise Reduction is also known for its capability to engineer custom noise control solutions to meet the specific needs of a project. This was especially important for this project, as the required size of the fan silencers presented unique transportation and installation challenges.

Solution:

In order to design a product to meet all of the requirements for this project, dB Noise Reduction utilized a combination of classical engineering, acoustic analysis, 3D modeling and finite element analysis (FEA).
The result of this design work produced two silencers weighing nearly 19,000 lbs per silencer.

A two part modular design was employed for each silencer, with each section weighing approximately 9,300 lbs. This design allows the silencers to be efficiently shipped on a flatbed truck, without the need for any special travel accommodations beyond that of a standard wide load. A uniquely beneficial aspect of the dB Noise Reduction design approach was in the special structural considerations given to the mechanical and installation constraints of the site. To facilitate an efficient installation, the two sections of each silencer were engineered so that they could be bolted together on-site, and then lifted by crane as a single piece for final installation. This was done to avoid the difficult and complicated process of attaching the two sections together after installation, when areas on the sides and bottom of the silencer would not be accessible.

Loading a unique fan silencer for a mine ventilation system.

Ready for transporting a unique fan silencer for a mine ventilation system.

The final result was a turnkey installation and commissioning of the fan silencers and associated mine ventilation systems. The completed ventilation systems not only met all noise requirements, but was successfully operational three weeks ahead of schedule.

The dB Noise Reduction difference:

We understand the need for focussed, cost efficient retrofits on noise abatement projects. Projects must be carried out quickly, with an eye to economy and a minimum amount of paperwork. The dB Noise Reduction team was able to carry out this particular project over a twelve week period within very tight budgetary constraints.