In the paper, there are presented the consequences of incorrect values of estimated maximal dust suspended' emission - Ep on the results of dust pollution concentration calculations. Wrongly estimated value of dust concentration in the area of dust pollution emitter - dumping side of fine-grained materials, conveyor belt, waste-tip - cause incorrect estimation of the environmental effects, induced by the activity of such type of structures, which are, for example, the part of the mineral resources processing factory. In the paper there is a comparison of estimated dust concentration values according to the ministerial directives, for determined Ep values in the base of dust concentration measurements and for adopted estimated Ep values. The comparative calculations were done by using, as the real value, the dust concentration measurement in automatic monitoring stations - "Rudna" and "Tarnówek" - of flotation waste dumping-side of copper ores "Iron Bridge" (Żelazny Most").