Study of spontaneous combustion of the main industrial types of sulphide ores of sulphide- polymetallic deposits of Azerbaijan

The article is devoted to the study of the causes and conditions of spontaneous com- bustion of sulphide ores, which may result in endogenous fires that complicate mining operations in mines, causing enormous material damage to the national economy, and often also leading to human casualties. There are several sulphide-polymetallic deposits in Azerbaijan, the reserves of which were approved back in the days of the USSR. Of these, the Filizchay deposit is the most unique in terms of its reserves and ore composition. The development of other deposits adjacent to the Filizchay deposit, separately, is inexpedient because of their small reserves. However, the development of sulphide-polymetallic deposits in Azerbaijan is complicated by the revealed tendency of industrial types of ores to oxidation and spontaneous combustion. In this regard, there was a need for a special study of the chemical activity of sulphide ores and the phenomena accompanying oxidative processes, taking into account the natural features of the deposits in order to obtain the initial parameters necessary for scientifically based technological solutions for their development. Sulphide ores of sulphide -polymetallic deposits of Azerbaijan significantly differ in material composition, conditions of occurrence and mining technical features of their development from the listed deposits, the issues of spontaneous combustion of which have been studied for a long time. Until now, there are no general criteria for assessing the fire hazard of sulphide ores, suitable for any deposit, since the conditions for the occurrence of underground fires at different deposits are different. It is this circumstance that makes it necessary to conduct special studies for each deposit separately. Therefore, the need for a special study of this problem on the example of the conditions of sulphide-polymetallic deposits in Azerbaijan, which are prone to oxidation and spontaneous combustion, is of great importance. Identification of causes and factors affecting spontaneous combustion of sulphide ores, classification of sulphide-polymetallic deposits of Azerbaijan according to the degree of their tendency to spontaneous combustion by analyzing the collected materials, as well as by the results of studies to determine the oxidative activity of sulphide ores. The article presents the results of experimental studies to determine the oxidative activity and spontaneous combustion of sulphide ores of the Katsdag, Filizchay and Katekh deposits, carried out in laboratory conditions by the method of Institute of Mining named after. A.A. Skochinsky, the basis of which is the determination of the oxygen absorption rate constant. It is known that the susceptibility of ore to spontaneous combustion is determined by its oxidizability at low temperatures and depends on a large number of factors. In this regard, the dependence of the total amount of oxygen absorbed by sulphide ores on time has been studied, it has been established that the rate of oxygen absorption by sulphide ores is long-live and slowly fading, but incessant. On the basis of extensive experimental material, a classification of sulphide ores of Azerbaijan according to the degree of tendency to spontaneous combustion according to low-tempera-ture oxidation is proposed, since it is this that forms the basis of the spontaneous combustion process. The classification is also based on differences in textural and structural features and mineralogical composition of ores. Of great interest is also the influence of the size of the free reacting surface of the ore on the oxidation process. Analysis of ore samples shows that for their spontaneous combustion, the most dangerous are its coarse fractions than the dust. The results of the conducted studies allow a scientifically sound approach to planning the sequence of development and designing mines.