# Study of Noise Effect of Slag Storage Technology on Surrounding Environment
## 2 Materials and Methods
### Methods  
#### 2.2.1 Design of a Methodology for Minimizing the Effects of Slag Storage Technology  
The most significant effect of the slag storage technology complained about by residents from surrounding populated areas is noise. Excessive, annoying, disturbing noise, often exceeding permissible levels, has been a long-standing problem in the assessment area. The problem extends several kilometers from the source of the noise--the slag landfill, which is the waste material from the iron production technology. The immediate source of noise is the deskulling of slag pots near the metallurgical plant. The slag generated during iron production is loaded into slag pots; see Figure 2a,b. The critical activity that produces the highest noise levels is the deskulling of slag pots. This involves the bounding of a steel hammer weighing several tens of kilograms against a steel pot weighing several tons, in which slag is transported. In addition, the high noise levels generated during the discharge are of an impulsive nature. The proposal of a methodology for solving the noise problem of slag dumping and its validation in practice is the basis of the present paper. To develop this methodology, an analysis of all available methods that would be able to meet the measurement requirements was carried out. Subsequently, real measurements were carried out to validate the methodology itself and to assess the range and suitability of the results obtained. The measurements were carried out in such a way that their results were also relevant to the requirements of statistical processing. The detailed methodology is shown in Figure 3.  
Figure 2: (**a**) The process of discharging the slag pot. (**b**) Slag transport pot and hammer for deskulling the slag pots. 2.2.2. Theoretical Basis for the Calculation and Prediction of Noise Propagation Modeling of Industrial Noise Noise  
Noise from industrial sources can vary in terms of the sizes/dimensions of the sources. An appropriate modeling technique must be established for the individual sources that are the subject of the assessment. To calculate sound propagation using noise mapping methods, an input dataset is required that contains the following information:  
* source type (point, area, and line);
* frequency spectrum of acoustic power in octave bands;
* operating time composed on the basis of the annual average;
* positioning using orthogonal coordinates;
* directional characteristics of the source;
* dimensions and spatial orientation;
* operating conditions of the source [18,19]. The calculation of sound attenuation in the path of its propagation in the external environment makes it possible, thanks to the knowledge of the physical properties of a specific source, to predict the sound pressure level at the point of reception. The calculation is based on two special types of atmospheric conditions:  
* a decrease in the bending conditions of sound propagation (positive vertical gradient of the effective speed of sound propagation) from the source to the receiver;
* homogeneous atmospheric conditions (zero vertical gradient of sound propagation speed) in the entire calculation area of propagation [20]. Figure 3: Design of the noise assessment methodology of a metallurgical plant. Tone components or impulse sounds emitted by industrial sound sources within the meaning of ISO 1996-2:2007 [21] are not included in this method. Temperature and humidity due to atmospheric absorption are calculated according to ISO 9613 1:1996 [22; 23]. The calculations are given in octave bands ranging from 63 Hz to 8000 Hz. However, based on methodological research, the authors consider the possible deviations of the numerical model. The paper [24] by authors [PERSON], [PERSON] et al. compared the numerical simulations of the noise propagation of wind towers to the experimental measurements performed inside houses, applying the ISO 9613. The results revealed that the application of the numerical model underestimated the actual measured value.