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Eagle Mountain Major Gravel Operations <br />High Level HSE Review <br />x a k 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 <br />Receiver/Receptor distance from <br />plant fence line <br />Base sound level assumed at fence <br />line for Intermittent noise (back-up <br />alarms) 1 2 <br />70 1 100 ; <br /> <br />102 102 3 4 5 <br />200 300 400 <br /> <br />- 102 102 102 6? <br />500 <br />_ <br />102 <br />Attenuation due to distance 45 48 54 58 60 62 <br /> <br />Attenuation due to grass absorption <br />5 5 <br />5 5! 5 f <br />5 <br />(2.00 dB/30m) <br />IFi r at?Pµeai.?a ii?ifl c v:c tT: , `?t _ 7 _S l " 4,g» >>'G 1118 ,. 38, $ { 36:R <br />Recover.<t?ocationb(usina; 1 <br /> <br />It should be noted that theoretical sound calculations are based on various assumptions that are often difficult to <br />-nntifv ralenlationa shnnld he considered to be within +/- 101/o. 3 - 5 d B. <br />-5-