جستجوی مقالات مرتبط با کلیدواژه "کانسنگ های آهن" در نشریات گروه "زمین شناسی"

Investigation of effective parameters on mechanical and physical properties of ore deposits is very important in determination of their rock mechanic and failure properties. This investigation can be suitable in different mining operations such as drilling, blasting, comminution and mine planning. In this paper, at first, microscopic sections were studied under different lights in Chadormalu iron ore mine. Then geomechanical and seismic properties as well as failure behaviour of the oxide ores (magnetite and hematite) were studied. The results demonstrated that the percentage of magnetite has a direct relationship with uniaxial compressive strength, tensile strength, Young modulus and P and S wave velocities; and the magnetite percentage has an inverse relationship with Poisson's ratio, porosity and saturation. Finally, the relation between magnetite percent and blast-induced preconditioning was investigated. The results showed that increasing the percentage of magnetite will increase the blast-induced preconditioning and increasing preconditioning decreased comminution processes in the Chadormalu iron ore mine. Also increasing the percentage of magnetite in feed of process factory from 25 to 50% decreases the power consumption from 70 (KWh/t) to 40 (KWh/t).

Neyzar iron deposit is located about 50 km southwest Mashhad, northeast Iran. It was developed as layered and discontinuous lenses in a fault zone within quartz-arenite and sub-litharenite sandstones of Lalun Formation (Lower Cambrian).  Mineralographical studies show that hematite is the principal iron ore mineral accompanied by goethite and lesser amounts of pyrite. Microscopic examinations confirm the presence of skeletal, relic replacement, marginal replacement, and pseudomorphic textures within the ores. Based on petrographical data, two series of alteration minerals, hypogene (sericite, pyrite, pyrophyllite, barite, chalcedony, and calcite) and supergene (goethite, jarosite, gypsum, limonite, and hematite) were developed in this deposit. Based on the results obtained from field works, mineralographical and geochemical studies, it appears that the evolution of the studied ores is genetically related to the host rocks.  Both hydrothermal processes and fault systems (existing in the host rocks) played important roles in leaching of elements and depositing of the ores. Results of chemical analyses show that the REE values vary in the iron ores from 6.97 to 18.26 ppm. Eu and Ce anomalies in the ores are within the ranges of 0.01-1.36 and 0.28-1.89, respectively. Geochemical considerations reveal that distribution of rare earth elements within Neyzar iron ores was controlled by pH, abundance of complex-forming ions (CO32-, F־, Cl־, PO43-, and SO42-), scavenging processes, and fixation in neomorph mineral phases.