For my diploma paper I have done research as to what extend the earthquake of 1998 really affected the amounts of transported sediments of the Tolminka River, as compared to estimated figures. Since later on, i.e. after the earthquake an additional rock fall occured in the upper part of the valley and, in light of the fact that its material has significantly contributed to the amount of the transported sediments, I have taken pains in order to precisely establish the extent of its contribution. Based upon two sediment samples, along with two samples of rock fall material I have, not only on the basis of granulometric and petrographic composition but also having taken into account the hydrologic processing, established the possibility to tell the sediments apart in accordance with their origin. The geological chart reveals the difference between the composition of the rock fall and other erosive sources which largely contribute to the amount of rainfall. The above said fact has later on been applied in order to establish the differences as regards the share of the sediments of various origins, based upon the three samples of deposited river sediments taken from the sediment traps at the town of Tolmin which had been excavated at three different points of time, i.e. a year before the rock fall, the year after the rock fall and eleven years after the rock fall. The sediments have been excavated in order to be used at a separation plant, the product of which is a certified aggregate for various concretes and tampons. I have, due to various types of lithology and with regard to the origin of sediments, established the annual share of rock fall in the total bed-load, in that I have, having applied the findings of the study on granulometric properties of ground samples, considered the oscillation of the index of the shape of grain during the time period from the occurence of the rock fall and up to 2015. Part of the diploma paper also deals with the separation plant itself and I have found that the origin of the sediments and their consecutive properties have also played an important role as regards the quality of aggregate as well as the profitability of the separation plant, both of which have also been affected by the sleet catastrophe of 2014.