ASSESSMENT OF THE ACOUSTIC MICROCLIMATE AND RATING OF NOISE HAZARDS IN THE INNER TRANSPORT SYSTEM OF A BUCKET WHEEL EXCAVATOR: A CASE STUDY

Abstract

Noise and acoustic microclimate have an important influence on working conditions in industry. However, there are many sources of noise in machinery that create occupational hazards. In particular, these problems occur in belt conveyors, which are components of integrated continuous material handling systems. In large heavy-duty machines used for surface mining (bucket wheel, bucket chain excavators, and stackers), the most acoustically active areas are located in the zones of conveyor lines. For this reason, the present article presents the results of comprehensive research of noise in a transport system in a bucket wheel excavator operated in a surface mine. The most significant sources of noise were tested. Two analysis approaches (deterministic and probabilistic) were applied. Lower values of permissible exposure time were obtained using the latter method. This approach should be selected, as it takes into account the real conditions of operation of the tested object. The research and analysis showed that in real operating conditions of large working machines (multi-bucket wheeled excavators), the noise level cannot be treated in deterministic categories. This is due (among other factors) to the fact that the working loads are randomly variable in various operating conditions, which also causes the nature of noise in the area of these machines and their surroundings to change randomly. For this reason, the acoustic climate and the assessment of the level of noise hazards in such machines should be analyzed by taking into account the random nature of noise.