The highest risk of exploration operations and exploration investment is usually at the prospecting stage in depth. At this stage, with regard to the results of evidences, which come from the surface and their promising conclusions, decisions are made in order to examine the depth and further exploration. This phase is one of the other properties of the abandoned mines. Thus, if these mines are introduced properly, they will have lower risks and more attraction for the investors.
3. Abandoning process of mine:
In foreign countries, each index passes different stages to reach a definite reserve.
From passing a stage to another, a process may be occurred to make a mine abandoned. The mentioned stages are as follows;
For each stage of exploration operations, which results to gain data from a mineral producing region, a definition is available. The last definition, which explains different stages, is Jorcdiagram.
In the above-mentioned diagrams, with regard to the exploration operation, minerals are divided to two main groups;
Mineral resources group: This word is used for discovered reserves and materials that the exploitation of them is uneconomic at this stage and mineral masses were not discovered there.
Mineral reserves group: This word is used for mineral masses that the existence of them is proved by excavation or other exploration methods or mineral masses that the availability of them is guessed in a particular region via high percentage are called mineral reserves.
Considering the performed exploration operation type and the available data, each group is divided to several sub-groups as follows;
Inferred Mineral Resources: This word is used for resources that one part of mineral mass does not have outcrop or it has an outcrop in one dimension, therefore, the reserves are determined by geological analyses. On the other hand, if only a few samples are available from a mass, it is possible to guess the grade and amount of reserve through geological evidences and comparison with other ore-deposits. This mineral mass is called inferred mineral resource (the error rate for these reserves is about 30% to 95%). Because of the high error rate of this mineral, it will not be exploited. Meanwhile, it is essential to obtain accurate data and to do exploration operation on mineral mass.
Indicated Mineral Resources: If one part of a mineral mass is opened from 2 or 3 directions by tunnels, wells or superficial excavations, the reserve which is determined by these data is called indicated mineral resource. Sampling for all these excavations must be accessible. On the other hand, at this stage sampling is not complete. It means that sampling has not been done in four directions. The level of geological data is sufficient to guess the tonnage and grade of mineral mass, rationally. If political, economic and technological situations are suitable, exploitation of this mineral mass will be possible. This indicated mass is changed to a probable mineral reserve.
Measured Mineral Resources: If sampling is complete and from four directions of the mass, accurate form, tonnage and grade are determined via the obtained data. This resource is called �measured mineral resource�. If it is exploited under mining conditions (technologic, economic, etc.) it will change to proved mineral reserves. To change a mineral resource to a mineral reserve, certain factors are considered which are as follows;
Metallurgical, economic, marketing, environmental laws, social and governmental factors etc.
Discontinuation of operations among the stages of indicated, measured and probable will cause a reserve to be abandoned. In this project, these reserves are examined parallel to the abandoned mines.
With regard to the governing economy conditions and available technology, in the developed countries, abandoned mines are called the mines that the economic part of their reserves can be exploited. The availability of other conditions has caused that the definition of abandoned mines becomes vaster. One of the first and fundamental issues is the ignorance of the systematic exploration in Iran, and there is no definite boundary between reserves and mineral resources. Many a mine that few exploration data respecting them are available, and as a result no definition about mines is presented. Some of the mines are not presented as mines, and sometimes some of the indices or ore-deposits, which were not under exploration process for minerals and regardless of their economic conditions are presented as mines. As a result, there is no definite and standard process for abandoning the Iranian mines.
In Iran, different issues have roles in abandoning the mines, which are political, cultural, industrial, technological and economic etc. On the other hand, most of the mines which are abandoned now, because of running out of their reserve and mining process did not close. It is possible to be hopeful that reserve is still available in some parts of them.
4-1. The significance of abandoned mines studies:
The study and re-examination necessity of these mines is hidden in their properties. As it has been mentioned in the abandoned mines properties section, it is possible to realize that these mines are unused assets of the country. These assets are capable to bring a large amount of benefits to the community economic body. Besides economic point of view, environmental issues and health of the local residents are the other important reasons for this purpose. Each healthy person in the community is an asset for the country. Without safety measures in mines, many lives are subject to danger. In sum, this situation is important from two points of view, 1.economic and 2.environmental issues. On the other hand, opening the mines and recruitment of people in the deprived areas of the country and thrive the mentioned regions prevent from migration of local people to the cities