Rio Tinto - Kennecott Utah Copper

Concentrator Facility
Bingham Canyon - Utah

rio tinto - kennecott copper

The Concentrator facility crushes and processes 144,000 tons of ore per day from the largest open pit mine in the world. The ore is fed to four Semi-Autogenous Grinding (SAG) mills, 36-feet diameter rotating mill, where the ore is crushed with 6-inch diameter steel balls. SSA Acoustics completed detailed noise measurements and mapping to identify mitigation options to reduce the noise dose for the operators and maintenance staff.

We measured the spectral sound level from the four SAG mills and 8 smaller Ball mills, 20-feet in diameter. The average sound levels were documented for each of the three levels of occupied space, each level exceeded 85 dB(A) and contributes to the overall noise dose for all employees working in this facility. The Mills produced sound levels 90 dB(A) in the near field. In addition, our technician accompanied the operators through their normal routine, documenting sound levels and the duration the operator spends in each location. Through this process we identified enclosed pump rooms and electrical rooms that were contributing 94 dB(A) for up to 3 hours a day to the operators noise dose. These locations were added to the top of the priority list for mitigation measures to reduce the daily impact for these operators and effective maintenance staff.

We met with the maintenance manager, process engineers, and facility managers to discuss feasible mitigation options that would not impede on their processes or maintenance. Our recommendations included details on a flexible sound transmission barrier wrap for the Ball Mills that is directly attached to the mill for easy maintenance access. To address the largest sources and reduce the noise dose we provided a detailed timeline for phasing the mitigation measures to maximize the performance as budget becomes available.

The large volume of material being fed through the Concentrator facility requires that mitigation installations be constructed efficiently without impeding the overall operations.  We presented cost efficient solutions, such as absorptive baffles in enclosed hard surface common areas, removable barriers to separate personnel from loud sources, and 2-way in-ear communication headsets.

The first phase of this project is in the bidding and construction detailing process. Our recommendations included drawing details for dimensioning and basic construction, modified photos to present the final product, a clear cost analysis and priority list that compares cost to the dB of reduction.

Noise Control Engineers