Laserfiche WebLink
6.5 Hz <br />100- <br />---------- ------------ ------ <br />Log(/) <br />01 <br />Figure 1 - Amplitude spectrum of vibrations generated at the Benson quarry 0.67 mile <br />away during ripping of bedrock. The peak frequency is at about 6.5 Hz and is about 100 <br />to 1000 times larger than the background amplitudes. The high frequencies roll off above <br />10 Hz due to a high-cut filter with slope of 20 db/octave out to the Nyquist frequency of <br />25 hz. <br /> <br />IIII <br />.01 <br />------ -------- ------ ------ ---- <br />4-4 Hz <br />:resonance <br />------- ------- ----- ------------------ <br />.Ohl Log(Q <br />o.l <br />Figure 2 - Amplitude spectrum of vibrations generated at the Benson quarry 0.67 mile <br />away when only the crusher is operating (no ripping). Note the very different character of <br />the spectrum and the strong resonance at a frequency of 4 Hz. This corresponds to the <br />fundamental mode of a standing wave between the crusher and the cliff face.