Industrial noise studies in quarries and neighbouring communities. – M. U. Onuu and A. N. Tawo
The study involved wide-range acoustical and social surveys in five quarries and two neighbouring communities. Results show that measured maximum noise levels, Lmax., were as high as 128 dB(A) at drilling blasting point 1 m away. Acoustical energy in the quarries even at low frequencies (32-63 Hz) are high (86.0-104.0 dB(A)) and between 90.0 and 106.0 dB(A) at 1-4 kHz where the normal ear is very sensitive. Noise levels at the facades of houses in the communities and schools and noise exposure levels range from 59.8 to 68.0 dB(A) and 53.0 to 70.2 dB(A) respectively, implying that only about 45% sentence intelligibility is achieved in the classrooms. Workers in the quarries have zero permissible occupational noise exposure time per day and percentage of overexposure per day that exceeds 33798. It is very worrisome that between 28.5 and 37.6% of the workers reported that they enjoy working in the quarries irrespective of the high noise levels.
Keywords: Industrial noise studies, quarries, neighbouring communities, noise levels and acoustical survey.