The Inversion Method in Measuring Noise Emitted by Machines in Opencast Mines of Rock Material

Abstract

The inversion method was used to test vibroacoustic processes in large-size machines used in opencast mines of rock material. When this method is used, the tested machine is replaced with a set of substitute sources, whose acoustic parameters are determined on the basis of sound pressure levels and phase shift angles of acoustic signals, measured with an array of 24 microphones. This article presents test results of a combine unit comprising a crusher and a vibrating sieve, for which an acoustic model of 7 substitute sources was developed with the inversion method.

Underground Gold Miner Exposure to Noise, Diesel Particulate Matter and Crystalline Silica Dust

“…The bagged dust and DPM samples were transported to an accredited laboratory for analysis. The NIOSH analytical method 7500 (Chapter Q) was used for analysis of silica and dust samples and analytical method 5040 by NIOSH reported by Pleban et al 13 was used for analysis of DPM. The requisite quality control and quality assurance systems were employed for analytical methods.…”

“…10 Noise measurements were taken 1.0-2.0 m above the floor level and 3.5 m away from sound reflecting structures (same day the measurements for the silica, DPM and dust were taken) at the target zones using the American National Standards Institute (ANSI) Type 2 sound level meter and dosimeter. 13,14,15 The survey results were then transformed to the equivalent noise levels. The workers were categorized according to the following job titles and descriptions (Table 1).…”

Quietness in the Soundscape of the Białowieża National Park

“…Taking into account merely the most common source of noise which is the road traffic, analyzing the data included in the acoustic maps and measurements performed by the Chief Inspectorate of the Environmental Protection in the year 2013 [2] in Poland we can state that 66% of the examined roads are characterized by the level of noise emission above 65 dB L AeqD in daytime, and on 78% of roads the noise level exceeds 56 dB L AeqN during night time. Additionally, the sonic environment includes also the noise generated by industry [3][4][5], aircraft, wind turbines [6,7], railways, craft services, farms, playgrounds, municipal facilities, renovations, and household appliances [8]. What is more, the presence of noise from several sources makes segregation of sounds by the ear difficult [9].…”