Technique of prospecting works at various stages of geological exploration process
The methodology for prospecting for minerals includes search methods and the sequence of their conduct in ore-bearing areas for the identification and preliminary evaluation of manifestations and mineral deposits. The main features of the search methods are the characteristics of geological, mineralogical, geochemical, geophysical anomalies that are created by minerals or their host structures (Aristov, 1975). Such anomalies are identified and delineated by studying geological, mineralogical, geochemical and geophysical fields, the nature of which is related to the geological structure of the region under study. The study of fields and delineation of anomalies is performed by individual methods or their complex by means of an area survey or by route crossings. At the same time, the search network is a set of observation points made by this or that search method for revealing ore occurrences, possible industrial deposits of minerals or their attributes. Parameters of the search network are the frequency of observations and their orientation. The parameters of the search network grow according to the specific geological and geomorphological structure of the particular site, the possibility of finding the expected industrial facilities, the scale of the prospecting works and the stage of their implementation. In the design methodology of the search network, there are two areas: geological and mathematical. The geological direction is based on the nature of the manifestation of the elements of the geological and geomorphological structure of the area under study. Mathematical modeling is used when the volume of such data is very limited or some of them (for example, data on the size and nature of the location of the expected objects) are absent. More detailed information on the method of designing a search network can be found in the training manual. Aristova  and in the corresponding methodological manuals and instructions on geological survey and mineral prospecting.
Search methodology accompanying geological surveys
The searches that accompany regional geological research have the task of developing the prerequisites and signs of search forecasting of all types of minerals and delineating ore-prospecting zones and areas. The solution of these problems is accomplished by studying and outlining geological, mineralogical, geochemical and geophysical fields and isolating anomalous zones and areas on their background. As a result, in addition to geological maps, maps of minerals and forecast-mineragenic schemes are drawn up with the identification of structures, zones and areas that are promising for mineral resources, recommended for further prospecting.
The technique of prospecting works in this case is determined by the geological survey technique of scales 1: 200000 ... 1: 50000, which are performed by way of polystyrene, group geological surveys, geological additional studies, deep geological mapping [Methodic Manual ..., 1978; Prognozno-metallogenicheskie ..., 1985]. For regions with different geological structure and mineral assemblages, specialization of prospecting works is necessary. It includes a certain set of research methods, necessary and sufficient to identify the prospects of the given region for its characteristic minerals. This set of methods includes: interpretation of aerospace photographs, aeromagnetic, gravimetric and aerogamming, seismic profiling, aerovisual and ground-based geological observations, geochemical surveys with schlich testing of alluvial deposits. Also, fragments, boulders, and pebbles are studied in loose sediments. Initially, aerial methods and ground geophysical observations are carried out, then all the exploratory work that accompanies the geological survey.
The main means of accelerating the work and increasing their effectiveness in group geological surveys are the use of helicopters, aircraft for landing geological survey and prospecting. Broad aerospace images are used. Detailed geological survey and prospecting work is carried out using ground geophysical and geochemical methods in perspective areas.
Interpretation aerokosmofotosnimkov geological aerovisual and ground-based observations reveal the search criteria, the direct and indirect signs of all possible kinds of minerals. The most expedient methods of geochemical prospecting are testing of bedrock, loose and vegetative cover, river sediments, natural waters through a network of search observations. They provide identification of industrially significant bodies of a mineral. Shlykh methods are carried out in areas promising to accumulate minerals that are stable in the oxidation zone, for example, gold, platinoids, cassiterite, tantalo-niabats, ilmenite, titanomagnetite. scheelite, wolframite, diamond, corundum, spinel, etc. Geophysical methods - radiometry, magnetometry, electrical prospecting, gravity prospecting, seismic exploration allow to solve three types of search problems: 1) verification of geochemical anomalies, 2) detailed anomalies of physical fields detected by aerogeophysical survey, 3) search for sections of ore-prospecting geological structures, covered with loose sediments, excluding the effective use of geochemical methods. The final method of prospecting is the penetration of surface mines or boreholes for the discovery of geological, geophysical, geochemical anomalies and evaluation of mineral occurrences. All wells perform geophysical and mineralogical logging.
The choice of this or that search method or complex of methods is dictated by the features of the geological and geomorphological structure of the region under study.
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