Understanding Iron Ores and Mining of Iron Ore Apr03

Understanding Iron Ores and Mining of Iron Ore...

Understanding Iron Ores and Mining of Iron Ore Iron (Fe) is an abundant and a widely distributed element in the in the crust of the earth, constituting on anĀ  average ranging from 2 % to 3 % in sedimentary rocks to 8.5 % in basalt and gabbro. Its supply is essentially limitless in almost all regions of the world. However, most of this iron is not in a form which can be used in current iron making practices. Hence only that part of the total iron in the crust of the earth which is available to the steel industry both economically and spatially, may correctly be termed iron ore. However, what constitutes iron ore varies widely from place to place and time to time. There are many factors which determine whether iron bearing mineral can be classified as an iron ore, but basically it is a question of economics. Keeping this concept in mind, a logical definition of iron ore for commercial purposes is ‘iron bearing material that can be economically used at a particular place and time under then current cost and market price conditions.’ Because iron is present in many areas, it is of relatively of low value and thus a deposit must have a high percentage of Fe to be considered ore grade. With the advent of improved methods of beneficiation, concentration and agglomeration, the variety of iron bearing materials that can now be used has been broadened and many low grade material types which were once considered uneconomic, are now being considered as iron ore. Typically, a deposit must contain at least 25 % Fe to be considered economically recoverable. Over 300 minerals contain iron but five minerals are the primary sources of iron ore. They are (i) magnetite (Fe3O4),...