The weathering crust is composed primarily of ferruginous quartzite Early Carboniferous rich iron ores. Fine-grade hematite - the smallest crystals of ferrous minerals found in the rich iron ores. It used to be called the previous geologists-researchers hydrohematite. According to the research it is now defined as a normal fine-grade hematite. It is characterized by the size of 100-500 nm, fixed minimum crystal size of 85 nm.