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Eagle Mountain Major Gravel Operations <br />High Level HSE Review <br />Table 3 below provides theoretical noise levels for the intermittent backup alarms, and the <br />resulting additive peak levels at various distances. The theoretical intermittent noise is added to <br />the total noise levels from Table 2 to arrive at the Theoretical Sound Level at Receiver Location <br />(using appendix for adding sound levels). For the purpose of this study, the assumption is that the <br />backup alarms are at 102 dB. It should be noted that the overall impact of intermittent backup <br />alarms will be dependant upon the number of vehicles operating at one time, the frequency (hz) <br />of the alarms, and the number of times that the backup alarm is activated. <br />Table 3 - Theoretical Intermittent Noise from Backup Alarms <br />Case ? 1 2 <br />Receiver/Receptor distance from 70 100 <br />plant fence line € <br />_ r <br />Base sound level assumed at fence 102 { 102 <br />line for Intermittent noise (back-up <br />alarms) <br />Attenuation due to distance <br />{AAttenuation due to grass absorption 5 _ 5 <br />(2.00 dB/30m) I <br />eoi cfi- F Peak-, Sound t?e? e6 <br />4 i? r Location (rising <br />f <br />3t 4" 5` 6` <br />_.__._._ •200 - 300 400 ' 500 <br />•102 , 102 102 ? 102 <br /> 62_I <br />5 5 5 5: <br />fi 51'.3. 44,.9 ? ?? _ 10 K`' 3!{ $ ? 36.8: . <br /> <br />It should be noted that theoretical sound calculations are based on various assumptions that are often difficult to <br />quantify. Calculations should be considered to be within +/- 10%, 3 - 5 dB. <br />-5-