The purpose of the article is to present the history of activities and conditions of formation of the depository collection of the Central Scientific and Technical Library (CSTL) of the Institute of Scientific and Technical Information (ISTI) of the Donetsk People’s Republic, to substantiate the necessity of research on the thematic direction "Coal Industry of Donbass" and to develop the methodological approach to its monitoring, scientific and thematic structuring. CSTL is the oldest and the only specialized scientific and technical library in Donbass, which has the collection, related to the industrial specifics of the region. The library activity during the military conflict practically stopped since 2014 and resumed only in 2022 with the transition of the Donetsk People’s Republic to the Russian Federation. Due to the need to integrate CSTL into the library space of Russia and improve the efficiency of the library work with users, a set of works on accounting, preservation, scientific and thematic structuring of collections, as well as digitalization of the library resources is in demand. The article describes the history of the formation of CSTL depository collection and the peculiarities of the library activity. The methodical approach to monitoring, scientific and thematic structuring of the collection on the direction "Coal Industry of Donbass" is proposed and the results of the work done are presented.