EXPLORATION OF SOLID MINERAL DEPOSITS (a. mineral exploration; n. Prospektion der Mineralienlagerstatten, Erkundung der festen Bodenschatze; f. prospection des gisements mineraux, exploration des gotes mineraux; i. prospeccion de yacimientos de minerales, exploracion de depositos de minerales) - complex work carried out to determine the industrial significance of mineral deposits that have received a positive assessment as a result of prospecting and appraisal work.

The reserve for replenishment of reconnaissance objects are also previously explored, but for various reasons included in the balance sheet. Their repeated revision (re-evaluation), carried out on the basis of new geological and genetic concepts, changes in market conditions, the emergence of more advanced means of exploration of deposits and new technological schemes and processing of mineral raw materials, sometimes makes it possible to justify the transfer of some of these previously studied objects under preliminary exploration of deposits without carrying out additional field work. During exploration of deposits, the geological and industrial parameters of deposits are established, necessary for their industrial assessment, design of construction of mining enterprises, provision of operational work and processing of extracted minerals. For example, the morphology of mineral bodies is determined, which is of paramount importance for choosing a system for their subsequent development . The contours of mineral bodies are established taking into account geological boundaries (contacts of lithologically different rocks, fault surfaces, etc.) and according to sampling data (see), the average content of main and associated components, the presence of harmful impurities, the nature of the distribution of minerals, etc.

Methods for field exploration are determined by a set of appropriate technical means that ensure obtaining the most complete information on the exploration intersection or the geological volume as a whole. During preliminary exploration, the main type of work is drilling: impact (during exploration of placers), core (core and coreless), deep; in particularly difficult cases (as a rule, when exploring deposits of non-ferrous and rare metal ores), deep pits, shallow shafts, and adits are used. Their purpose is to confirm exploratory drilling data, clarify the structure of the most complex sections of the field, and collect technological samples. Detailed exploration and additional exploration of deposits is carried out, as a rule, on the basis of drilling; At some sites, deep exploration and exploration and production mines are also being drilled. The main types of work during operational exploration are mine workings (horizontal, vertical and inclined) and underground (usually short-length) wells - core and perforating (coreless). To obtain maximum information about the structure of deposits and the patterns of distribution of minerals with a minimum expenditure of funds, exploration mine workings are located in such a way that they intersect the entire thickness of the promising zone (horizon, structure), and exploration profiles (groups of exploration intersections) are located primarily across the strike of the latter.

The set of technical means for exploration of deposits is determined by the type of work: these are trenchers and multi-bucket excavators for digging ditches and trenches, bulldozers for clearing and opening bedrock outcrops, as well as trench exploration of placers, sets of self-propelled equipment for digging pits and mapping and prospecting wells, tripping mechanisms for sinking deep holes and mines, various types of drilling rigs for drilling exploratory wells, automated devices for sampling and analysis, field geophysical equipment with a computer for rapid processing of received data, etc.

An indispensable component of geological exploration work at all stages is desk processing of materials. Based on the materials of primary geological documentation and sampling, consolidated horizontal plans and sections are drawn up - the basis for calculating mineral reserves. The same data is used to compile detailed geological and structural maps, on the basis of which forecast maps are constructed, which are the basis for drawing up projects for further work.

The main volume of work on preliminary and detailed exploration of deposits, as well as, if necessary, additional exploration, is carried out by organizations of the Ministry of Geology of the CCCP at the expense of the state budget. Exploration of some deposits, mainly local construction materials, is carried out under economic agreements with interested organizations. Operational exploration is carried out by industrial organizations; The main amount of costs for its implementation falls on the cost of manufactured products. When developing deposits, there is a partial refund of funds previously spent on exploration by the Ministry of Geology (at reimbursement rates approved for each type of mineral separately).

Requirements for the work performed at each stage of field exploration are formulated in the relevant guidelines approved by the Ministry of Geology of the CCCP. The results of exploration work (information about the reserves of the deposit, the quality and degree of manufacturability of the minerals composing it, the technical and economic conditions of development, the results of economic calculations for the infrastructure of the designed enterprise, the cost of production, etc.) must guarantee the justification of the costs of the industrial development of the deposit and the return on investment. When large and rich deposits are discovered, especially scarce types of mineral raw materials, it is allowed to combine individual stages of exploration work. In mineral deposits that are very complex in their geological structure (piezo-optical raw materials, ores of noble and some rare metals, etc.), exploration of deposits is carried out with the associated development of identified mineral bodies. In this case, reserves are usually calculated only in low categories.

Methodological methods for exploring deposits of new types of solid minerals (for example, located on the bottom of seas and oceans) have their own specific features (see Marine exploration of deposits).

The amount of costs for exploration of deposits depends on the scale of the deposits, the degree of their geological complexity, the type and type of minerals, the economic development of the area and other factors and can reach many tens of millions of rubles. In general, exploration works account for no more than 40% of allocations for geological exploration, incl. for preliminary exploration of deposits - more than half.

For the first time, a course of lectures on exploration of deposits ("exploration business") was given in 1924 in Petrograd by K. M. Markov. In the 30s N.V. Arsenyev, N.V. Baryshev, I.S. Vasilyev, S.V. Kumpan and others, and in the 50-60s. V. M. Borzunov, A. B. Kazhdan, I. D. Kogan, K. V. Mironov, E. O. Pogrebitsky, A. P. Prokofiev, V. I. Smirnov, P. A. Shekhtman, A. A. Yakzhin and others published a number of educational and methodological manuals, as well as monographic works. The course on deposit exploration techniques is taught in many geological universities, and in a number of them departments of the corresponding profile have been created. The deposit exploration methodology synthesizes the experience of related geological sciences (mineral geology, structural geology, etc.), and makes extensive use of modern research methods, in particular mathematical ones (using a computer).

Geological exploration, prospecting work for the exploration of rock deposits, both centralized and near-route, with a preliminary assessment of their quality and reserves.

Construction dictionary.

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Books

• Structural geology, A. K. Korsakov Category: Textbooks for universities Publisher: KDU, Manufacturer: KDU,
• Structural geology. Textbook. Grif UMO Ministry of Defense of the Russian Federation, Korsakov A.K. , The textbook discusses the main forms of occurrence of sedimentary, intrusive, volcanic and metamorphic rocks. The morphological characteristics of the bodies formed by them and their elements are given... Category: Textbooks: basic Series: Publisher:

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GEOPHYSICAL EXPLORATION, exploration of the earth's interior using physical methods. Geophysical exploration is carried out primarily in the search for oil and gas, ore minerals and groundwater. It differs from geological exploration in that all information about search objects is obtained as a result of interpretation of instrumental measurements, and not through direct observations. Geophysical methods are based on the study of the physical properties of rocks. They are used either to identify mineral deposits (for example, magnetic properties are studied to find iron ores), or to map geological structures such as salt domes and anticlines (where oil accumulates), as well as to map the topography of the ocean floor, oceanic and continental structure the earth's crust, determining the genesis and thickness of loose sediments and bedrock, the thickness of ice sheets and ice floating in the oceans, during archaeological research, etc.

Geophysical methods fall into two categories. The first includes methods for measuring natural earth fields - gravitational, magnetic and electric, and the second - artificially created fields.

Geophysical methods give the best results when the physical properties of the studied and mapped rocks differ significantly from the properties of the adjacent rocks. Geophysical research of all types includes the collection of primary material in the field, processing and geological interpretation of the data obtained. Computers are used at all stages.

The origins of geophysical exploration methods are associated with the beginning of the use of magnetic compasses to search for iron ores and electrical measurements to identify sulfide ores. The use of geophysical techniques expanded in the 1920s as gravimetric and seismic surveys proved effective in locating salt domes and associated oil deposits along the Gulf Coast of the United States and Mexico.

Seismic exploration.

In a solid body, when a force is suddenly applied, elastic vibrations or waves, called seismic waves, arise, spherically propagating from the source of excitation. Information about the internal structure of the Earth is obtained from the analysis of the travel times of seismic waves from the vibration source to the recording devices (the travel times of the waves depend on the density of the medium along their path).

Seismic waves are generated either by artificial explosions in shallow wells or by mechanical vibrators. In marine seismic, an air gun is used to generate seismic waves. Echo-sounding emitters of high-power elastic vibrations, electric spark discharges and other means are also used.

The downward generated waves, reaching a geological boundary (i.e. rocks whose composition differs from the overlying ones), are reflected like an echo. The recording of this “echo” by detectors is called the reflected wave method. Waves refracted at the geological boundary also propagate horizontally (along its surface) over long distances, then refract again, follow to the earth's surface and are recorded far from the seismic source.

Seismic waves are recorded by sensitive instruments, seismic receivers, or geophones, which are located on the earth's surface or in wells at a certain distance from the point of wave excitation. Geophones convert mechanical ground vibrations into electrical signals. In marine exploration, pressure detectors called hydrophones are used to record seismic waves. Elastic vibrations are recorded in the form of a trace on paper, magnetic tape or photographic film, and more recently, usually on electronic media. Interpretation of seismograms allows one to measure the travel time of a wave from the source to the reflecting layer and back to the surface with an accuracy of thousandths of a second. The speed of seismic waves depends on the elasticity and density of the medium in which they propagate. In water it is approx. 1500 m/s, in unconsolidated sands and soils containing air in the pore spaces - 600-1500 m/s, in solid limestones - 2700-6400 m/s and in the densest crystalline rocks up to 6600-8500 m/s (in deep layers of the Earth up to 13,000 m/s).

Reflection.

When using the reflected wave method, registration is carried out by a set of geophones uniformly located on the earth's surface in line with the excitation source. Typically 96 geophone groups are used, each of which has from 6 to 24 devices connected together.

Since the distance to the geophone and the speed of propagation of seismic waves in the rocks under study are known, the depth of the reflecting boundary can be calculated from the travel times of the waves. The wave path can be described as two sides of an isosceles triangle (since the angle of incidence is equal to the angle of reflection), and the depth of the reflective layer corresponds to its vertex. The total length of the sides of such a triangle is equal to the product of the wave's travel time and its speed. Reflection surface depths are calculated over a large enough area to trace formation configurations and identify and map salt domes, reefs, faults, and anticlines. Any of these structures could be an oil trap.

Refraction.

The refracted wave method is used to study the lithology and depth of rocks, as well as the configuration of deposits and geological formations. It is also used in engineering geological surveys, hydrogeology, marine and petroleum geology. Seismic waves are excited near the earth's surface, and detectors that record refracted waves are located on the earth's surface at some distance from the vibration source (sometimes many kilometers away). The first to reach the detector is the refracted wave that followed the shortest path from the source to the receiver. Using the hodograph (graph of the time of arrival of the first wave pulse to geophones located at different distances from the source), the speed of wave propagation is determined, and then the depth of the refractive surface is calculated.

Gravimetric survey

widely used for reconnaissance of poorly studied areas. In these studies, the force of gravity is measured with such high precision that even small changes in it, due to the presence of buried rock masses, make it possible to determine the depth and shape of their occurrence.

Gravimetric instruments are among the most accurate; they can measure variations in the gravitational field with an accuracy of one hundred millionths. The most typical of these instruments, the gravimeter, uses a horizontal balance bar (pendulum) that deviates from its equilibrium position with the slightest change in the force of gravity.

The Earth's gravitational field is determined by the density of its constituent rocks. Gravimetric reconnaissance does not operate with absolute measurements of the gravitational field, but with the difference in the acceleration of gravity from one point to another. During the gravimetric survey, horizontal changes in the gravitational field due to differences in the composition and density of rocks are recorded. With depth, their density changes in the range from 1.5 g/cm 3 (loose sands) to almost 3.5 g/cm 3 (eclogite). The gradient is even ok. 0.1–0.2 g/cm 3 leads to the occurrence of recognizable anomalies (deviations from the standard value of gravity) if the body under study is large enough, shallow and the noise is not too great, i.e. interference from external sources.

Gravimetric surveying is used to identify salt domes, anticlines, buried ridges, faults, shallow bedrock, intrusions, ore bodies, buried volcanic craters, etc. see also GRAVITY.

Magnetic prospecting

is based on measuring small changes in the geomagnetic field associated with the presence of magnetic minerals in surface sediments or in the geological basement - igneous and metamorphic rocks underlying sedimentary strata. Magnetic variations caused by magnetic minerals are used to search for deposits of iron ores and pyrrhotite, as well as associated sulfide ores. Studies of magnetic variations created by basement rocks make it possible to study the structure of the overlying layers of the earth's crust. When searching for oil and gas bearing strata, magnetic prospecting methods determine the depth, area and structure of sedimentary basins.

The magnetic susceptibility of rocks is measured using the magnetic method. The important iron ore mineral magnetite is characterized by the highest magnetic susceptibility (2-6 times higher than that of two other also highly magnetic minerals - ilmenite and pyrrhotite). Since magnetite is quite widespread, changes in the geomagnetic field are usually associated with the presence of this mineral in rocks. Magnetic minerals associated with igneous basement rocks have a much higher magnetic susceptibility than rocks of the sedimentary cover. This determines the contrasts in their magnetization.

In recent years, based on the study of the magnetization of rocks of the ocean floor, much new information has been obtained about the history of the Earth, especially about the formation of ocean basins and the position of continents in the distant geological past. Rocks often retain residual magnetization corresponding to the geomagnetic field at the time of their formation. Thus, remanent magnetization is a kind of “record” of changes in the Earth’s magnetic field throughout its history. Based on magnetic studies, it has been confirmed that as mid-ocean ridges grew, ocean basins expanded. see also OCEAN .

Magnetic surveys are usually carried out from aircraft using magnetometers. The first aeromagnetic instruments used instruments developed during World War II to detect submarines. see also GEOMAGNETISM.

Electrical or electromagnetic reconnaissance

(electrical prospecting) is intended to study the internal structure of the Earth and the geological environment, search for minerals based on the study of various natural and artificial electromagnetic fields. Electrical prospecting is based on the differentiation of rocks by electromagnetic properties. The nature of electromagnetic fields caused by both artificial and natural sources is determined by the geoelectric structure of the study area. Some geological objects, under certain conditions, are capable of creating their own electric fields. Based on the identified electromagnetic anomaly, conclusions can be drawn aimed at solving the assigned problems.

Electrical prospecting has more than 50 methods. This variety of methods is explained by the fact that it uses natural fields of cosmic, atmospheric and electrochemical nature; artificial fields with various methods of their creation and measurement (galvanic, inductive and remote); harmonic fields of a wide frequency range; pulsed fields of different durations; signals of different frequency (from millihertz to hundreds of terahertz) and dynamic ranges are recorded. In addition, electrical prospecting uses the latest advances in electrical engineering and radio electronics. During electrical prospecting, the amplitudes of the electric and magnetic field components, as well as their phases, are measured. Registration is carried out in analogue or digital form. Modern computer technology is widely used in measurements, processing and interpretation of results.

Nuclear geophysical methods

are based on the study of natural radioactivity of rocks or secondary radioactivity arising from neutron or gamma irradiation of rocks. There are gamma, neutron activation, and X-ray radiometric methods. The most widely used method is the gamma method, which measures the intensity of gamma radiation from natural radionuclides contained in rocks. Changes in radioactivity depend on the composition and properties of rocks, which makes it possible to use these methods to study the geological structure of the territory, the processes occurring in the subsurface, and to identify mineral deposits in them.

Constantly evolving based on many years of experience of courageous and tenacious practitioners. Since ancient times, they laid the foundation for the craft of extracting minerals from the bowels of the earth, gradually exploring new resources and discovering methods for their production. Contemporary geologists have gone far ahead in terms of knowledge and technology. However, with all the current progress, this work still requires considerable mental, physical and financial costs.

Extensive set of works for strategic purposes

Searches, discovery and complex technical preparation for the further development of mineral deposits - this is the most capacious description of the entire complex of geological exploration work, the complex and multifaceted structure of which makes this area quite closed to those who do not have the slightest specialized knowledge.

The main goal of geological exploration is to study methods of exploration and extraction of mineral resources with the most effective and economically rational results. At the same time, the state of the environment must be taken into account - the rules of geological exploration work reduce the harm caused to it to a minimum.

In addition, geological services and organizations often provide related subsoil study services for the construction of various underground structures, conduct engineering-geological studies of individual territories on a private basis, and prepare sites for the harmless disposal of hazardous industrial waste.

Brief historical sketch

The search and exploration of minerals (in particular, precious and non-ferrous metals, and later ferrous metals) has been carried out by man since ancient times. The earliest and most complete experience in conducting geological exploration on the lands of medieval Europe was presented in his works by the German scientist Georg Agricola.

The first documented geological exploration in Russia was carried out on the Pechora River in 1491. The most powerful impetus for the development of this industry in domestic practice was given only a couple of centuries later, in 1700. This was facilitated by the publication of the “Order of Mining Affairs” by Peter I. A further shift towards a more scientific basis for Russian geological exploration was laid by Mikhail Lomonosov. In 1882, the first state geological institution of Russia - the Geological Committee - was created. Ten years later, in 1892, his employees managed to create the first geological map of the European part of the country on a scale of 1:2,520,000. Around the same period, the theory of exploration for oil, groundwater, hard rock minerals and placers began to take shape.

With the advent of the Soviet period, the geological service underwent significant changes. State priorities shifted more towards the search for oil, as a result of which not only the old oil and gas-bearing areas were expanded (in particular, the North Caucasus), but also new fields were explored. So, in 1929, geological exploration was deployed in the Volga-Ural region, widely known among the people as the “Second Baku”.

By the beginning of 1941, Soviet geology could boast of quite impressive results: deposits of most known minerals had been explored and prepared for exploitation. During the years of the Great Patriotic War (1941-1945), geological exploration was abruptly transferred to accelerated searches and development of areas with the most strategically important resources (in particular, in the Urals, Siberia, Central Asia and the Far East). As a result, reserves of oil, iron ores, nickel, tin and manganese were significantly replenished. In the post-war years, depleted deposits were compensated for by intensive exploration of new ones.

In modern Russia, the state emphasis on exploration has shifted more to private investment. However, the budget share also makes it possible to build long-term strategic programs for the development of the country’s domestic mineral resource reserves. Thus, for the period 2005-2020, revenues from the treasury for geological research are expected in a total amount of 540 billion rubles. Almost half of them will be allocated to hydrocarbon exploration.

Stage one - initial preparation

All stages and phases of geological exploration work in total consist of three sequential sets of actions.

The initial - first stage - includes only geophysical work on the ground with geological surveys of the territory. In this case, reference wells are often drilled. The entire region under consideration is under close monitoring, including the possibility of earthquakes and other factors negative for exploration.

The result is a preliminary identification of promising deposits. In this case, a set of maps of the captured area is necessarily created for various scales and purposes. The state of the surrounding geological environment is also assessed for stability and its possible changes.

The second stage is the search for deposits and their assessment

A deeper and more detailed collection of information on mineral deposits on the scale of a certain territory begins precisely from this stage.

Stage 2 consists of exploratory work in areas that are promising based on the results of the first stage: identification of specific mineral deposits, a more accurate assessment of their volumes. A complex of geological, geophysical and geochemical work is being carried out, aerospace materials are being deciphered, and surface workings are being constructed (or simply made) for a detailed study of deep rocks. As a result, another set of geological maps is compiled (on a scale of 1:50000 - 1:100000), and geologists receive detailed statistical reports.

At the third stage of geological exploration, the feasibility of further exploration of the found deposits is determined. The next stage, during which the extraction of the required resources begins, will depend on the results obtained. Geologists evaluate the economic potential of all deposits found, rejecting all non-valuable accumulations.

It is equally important that after this complex of work is carried out, the values ​​of the considered deposits are compiled. And only with positive results is the object finally transferred for further exploration and exploitation.

The final (third) stage - mastering

That is why the painstaking collection of geological information on discovered deposits is carried out. As in the case of the previous one, the rules of geological exploration work divide this stage into two stages.

Stage 4 (exploration) begins exclusively on assessed deposits (those whose development is recognized as economically feasible). The geological structure of the object is clarified in detail, the engineering-geological conditions for its further development are assessed, and the technological properties of the minerals located in it are determined. As a result, all assessed deposits must be technically prepared for further exploitation. It is equally important when exploring a field to take into account in detail the resources that fall under categories A, B, C2 and C1.

Finally, at the fifth stage of geological exploration, operational exploration is carried out. It occupies the entire period of development of the deposit, thanks to which specialists have the opportunity to have reliable data on the existing deposits (morphology, internal structure and conditions of occurrence of minerals).

In search of underground waters

By analogy with the extraction of solid minerals, geological exploration for water is carried out in exactly the same four stages (regional geological consideration, a complex of prospecting works, assessment and exploration of the field). However, due to the specifics of this resource and the conditions for its formation, extraction is carried out with a considerable number of nuances.

In particular, operational water reserves are calculated and approved in completely different units of measurement. They display the volumes of this resource that can be extracted under given conditions per unit of time - m 3 / day; l/s, etc.

Modern instructions for geological exploration work distinguish 4 types:

1. Drinking and technical - they are used in water supply systems, they irrigate the soil, and water pastures.
2. Mineral waters with medicinal properties - this type is used in the manufacture of drinks and also for preventive purposes.
3. Thermal power (this subtype also includes steam-water mixtures) - are used for heat supply to industrial, agricultural and civil facilities.
4. Industrial water serves only as a source for the subsequent extraction of valuable substances and components from it (salts, metals, various chemical microelements).

High risks of incidents, complications and sometimes catastrophic consequences always force us to be especially careful about the safety of geological exploration work aimed at searching for groundwater. Open-pit mining can often be accompanied by suffusion, landslides, collapses and collapses. Underground mining can always be associated with sudden water breakthroughs, floats and flooding. In addition to the obvious danger to humans, nearby accumulations of other minerals are also subject to negative effects - they simply become wet.

Exceptional nuances for oil and gas exploration

The extraction of these resources is divided into two stages. The first - search - is aimed at obtaining data on fossils falling under categories C1 and C2. At the same time, a geological and economic assessment of the feasibility of developing certain deposits is also given. The stage itself is carried out in three successive stages:

1. Regional geological and geophysical work includes small-scale surveys of the study area. A qualitative and quantitative assessment of oil and gas prospects in the study area is carried out. Based on this information, priority targets for oil and gas exploration will be determined.
2. Preparing the basis for deep exploratory drilling - sites for laying exploratory wells are selected in the agreed order. Includes detailed seismic surveys, and in some cases also gravity/electrical surveys.
3. Exploration work - during drilling and testing of exploratory wells, prospects and oil and gas characteristics are also assessed, and reserves of open deposits are calculated. In addition, the geological and geophysical properties of adjacent horizons and layers are determined.

Any geological exploration project also implies the possibility of drilling in already developed fields. This allows you to find more deposits at the exploited site, which during the exploration stage for many reasons could remain unnoticed.

The next stage is exploration. It is carried out with the aim of preparing all found promising gas and oil fields for further development. The structure of the discovered deposits is examined in detail, productive layers are marked, and indicators of condensates, groundwater, pressure and many other parameters are calculated.

The result of the exploration stage is the calculation of oil and gas reserves. On this basis, the economic feasibility of further exploitation of the deposits is decided.

A hopeless bottom or prospects for geological exploration?

The waters of the seas and oceans, despite their relative lack of exploration in our time, are also being widely developed. First of all, the underwater shelf presents quite impressive prospects for the extraction of various mineral salts (in particular, sea salt, amber, etc.), oil and gas. All minerals in such an area are divided into three types:

1. Contained in sea water.
2. Solid resources that are located on the bottom/bottom layer.
3. Fluids (oil and gas, thermal waters) lying deep in the continental and oceanic crust of the Earth.

Based on their location they are classified as:

• Deposits of the near and far shelf.
• Deposits of deep-sea depressions.

At the bottom, offshore geological exploration for oil and gas production is carried out exclusively by drilling wells. Typically these resources are located at least 2-3 kilometers deep into the shelf. Taking into account the distance to the deposits, various types of sites are used from which geological exploration will be carried out:

• At a depth of up to 120 meters there are pile foundations.
• At a depth of 150-200 meters there are floating platforms on an anchor system.
• Hundreds of meters/a couple of kilometers - floating drilling rigs.

Western practice of private business

Abroad, geological exploration of mineral resources is carried out mainly on the initiative of private firms, leaving only systematic geological surveying and prospecting work at the regional level to the needs of the state. The vast majority of processes to prepare deposits for their further development begin only after receiving the first positive results from exploration workings (artificially created cavities in the earth’s crust formed as a result of geological exploration).

They, in turn, subject the largest deposits to detailed drilling and tapping, the industrial development of which will require significant financial investments. When conducting operational exploration, high-category minerals are increased exclusively in those volumes that are required to ensure current production. The depth at which work is carried out, in such ordinary cases, does not exceed 2-3 operational horizons (a set of exploration workings at the same level).

However, for the sake of reliability, it is worth noting that such a practice does not at all guarantee insurance against serious miscalculations and errors when searching for minerals. The Western approach to geological exploration largely boils down to the extraction of information, on the basis of which the discovered deposits will be assessed for their economic feasibility and, if the results are successful, immediately put into operation. In this regard, identifying the fullest possible volume of all types of minerals at an object, as well as predicting the resource for explored reserves, is a rather problematic task.

geological exploration in the Russian Federation

The Russian practice of searching for mineral resources can be carried out both with government support and through private investment. In cases related to government needs, all geological exploration work is provided in the form of orders. Depending on the direction and volume, contractors receive funds from the appropriate budget level: federal, regional or local.

Before the start of geological exploration in any area at the expense of budgetary funds, the state selects applicants on a competitive basis. The process itself is quite simple:

1. Each territory where the state plans to conduct geological exploration work is put up for an appropriate competition. In this case, the customer (government entity) develops a geological task and a starting price for the results of geological exploration expected from the project. It takes into account both standard production costs and the planned level of profit.
2. The winner, who proposed the most suitable execution option for the most reasonable price, in accordance with the established procedure receives a license to carry out work within the specified facility.
3. During the issuance of the permit, the customer also signs a contract for geological exploration with the winner of the competition. The period for completing the work is determined either based on the results of the competition, or through additional negotiations and agreements with the contractor.

The main points in the scheme under which the geological exploration project is financed at the government level are arranged as follows:

1. The Ministry of Natural Resources receives annual allocations from the Ministry of Finance of the Russian Federation with a quarterly breakdown and plans their distribution among government customers. After this, the Ministry sends the relevant information to the Main Directorate of the Federal Treasury.
2. The Federal Treasury notifies its respective territorial divisions of approved funds for the customers they serve.
3. The Ministry of Natural Resources thus sends the approved amount of finance to the customer, while simultaneously presenting him with the “Agreement on the transfer of functions of the state customer” in accordance with established standards.
4. The funds and the contract communicated to the customer are the basis for immediate geological exploration planning.

The contractor receives payment for geological exploration work quarterly (the possibility of paying advances is also provided). And only if the report on the completed geological task fully satisfies the subsequent state examination, then it is successfully accepted into the repository of the territorial geological fund and the geological exploration is considered completed.

Lecture No. 17

Objectives, methods of prospecting and exploration of mineral deposits

Plan:

I. Stages of search work.

1. Regional geological study.

2. Geological survey work.

3. Search work.

4. Search and evaluation work.

II. Stages of exploration work.

1. Preliminary reconnaissance.

2. Detailed reconnaissance.

3. operational reconnaissance.

4. Additional exploration.

Keywords: Survey, prospecting, exploration, regional, stage, scale, geophysical, research, assessment, elements of geological bodies, prospecting prerequisites, prospecting signs, criteria, predicted resources, reserve categories.

Geological structure of territories (region). Deposits are determined in the process of geological exploration. Geological survey and search are an integral part of these works, which, for the purpose of rational and economical conduct, are carried out in 8 stages.

1) Regional geological study

a) regional geological and geophysical studies on a scale of 1:1000000

b) regional - geophysical, geological surveying, hydrogeological and geotechnical work on a scale of 1:200000.

2) Geological survey work on a scale of 1:50000-1:25000

3) Search work

4) Search and assessment work

5)Preliminary reconnaissance

6) Detailed reconnaissance

7) Operational reconnaissance

8) Additional exploration

9) Operational reconnaissance

The last 4 stages concern exploration work. The main task of geological surveying of any scale is to compile a geological map that graphically displays the elements of geological bodies recorded on the earth's surface or a certain depth section. The latter may coincide with the base or roof of a stratigraphic horizon or the surface of some geological formation.

In the process of geological surveying and analysis of compiled geological maps, factors favorable for ore formation are identified, which are used as prospecting prerequisites. These include climatic, stratigraphic, geophysical, geochemical, geomorphological, magmatic and other indicators. All this indicates the possibility of discovering mineral deposits.

Search signs- these are local factors that directly or indirectly indicate the presence of minerals. Geological mapping at a scale of 1:50,000 is accompanied by a general search for minerals, which can be expected based on favorable geological conditions. The general objective of the search is the discovery and geological and economic assessment of mineral deposits.

Search methods are varied and must be used in combination, taking into account landscape and other conditions and types of minerals. The possibilities of their use are determined by the location of the search in relation to the earth's surface. They can be conducted from space, air, wells and the horizons of underground mine workings.

Ground methods are the most reliable, diverse and widespread in the practice of geological exploration. These include large-scale mapping, geochemical, geological-mineralogical, geophysical and mining-drilling methods.

Mining and drilling methods the most reliable of other search methods. They allow a geologist to determine, to a first approximation, the structural conditions for the localization of mineral bodies, their morphology, size and material composition, to trace the variability of these parameters, to assess predicted resources and calculate reserves in category C 2.

Search work are carried out in promising areas within known and potential ore fields, as well as basins of sedimentary minerals. Exploration work is carried out using a complex of the listed methods, based on the landscape and geological features of the location of the deposits, the type of minerals and its industrial and genetic type. As a result of the work, sections are compiled on a scale from 1:25000 to 1:5000, assessing the predicted mineral resources according to the P 2 category, and in well-studied areas - according to the P 2 category. Exploration and assessment work is carried out in areas that have received a positive assessment during general searches or prospecting work and at the request of discoverers. At this stage, the geologist determines the industrial type of the deposit, approximately its contour in plan - with extraction to depth, which makes it possible to calculate reserves of category C 2 and estimate the predicted resources of minerals according to category P 2.

As a result, the manifestation is either rejected, or technical and economic considerations are presented about the prospects of the identified deposit, allowing an informed decision to be made on the feasibility and timing of preliminary exploration

Mineral exploration. The purpose of exploration is to identify industrial mineral deposits, obtain proven reserves of mineral raw materials and other data necessary and sufficient for the rational and subsequent functioning of mining and processing enterprises.

This goal is met by common objectives at each stage of the country’s economic and social development.

Stages of exploration. Exploration work is more labor-intensive and costly than prospecting work. There are 3 stages of exploration: 1) preliminary; 2) detailed 3) operational and 4) additional exploration(after operational reconnaissance). Preliminary exploration is carried out after the prospecting and exploration stage and continues at a higher level to obtain reliable information that can provide a reliable geological, technological and economically sound assessment of the industrial significance of the deposit. At this stage, the geological structure of the deposit, its general dimensions and contours are clarified. Large-scale (up to 1:500) geological maps are compiled.

The main direction is field exploration to the depth of horizons accessible for development (by laying boreholes, geophysical research through underground mine workings, and selecting technological rocks for laboratory testing). The morphology of mineral bodies, their internal structure, conditions of occurrence and quality are determined. In addition, hydrogeological, engineering-geological, mining-geological and other natural conditions affecting the opening and development of the deposit are studied. Such knowledge should provide the possibility of calculating reserves in categories C1 and C2. Based on the results of preliminary exploration, temporary conditions are developed, and a technical and economic report is drawn up on the feasibility of industrial development of the deposit and detailed exploration of it.

Detailed reconnaissance carried out on deposits that have been positively assessed by preliminary exploration and are scheduled for industrial development in the next 5-10 years. It prepares deposits for transfer to industrial use in accordance with the requirements for the classification of deposit reserves and predicted resources of solid minerals. Based on the results of detailed exploration, a feasibility study of permanent conditions is drawn up. According to the approved standards, mineral reserves are calculated and submitted to the State Commission for Reserves under the Ministry of Geology of the Republic of Uzbekistan.

Deposits with approved reserves in the required quantities are submitted for industrial development by the line ministry. Additional exploration of a developed field focuses on less studied areas: deep horizons, bodies or deposits. Operational intelligence begins from the moment of organization of mining and continues throughout the entire period of development of the deposit. In relation to mining operations, it can be advanced or accompanying. Here the contours of mineral bodies, their occurrence conditions, internal structure, qualitative characteristics and quantity of reserves, spatial location of industrial types and varieties, hydrogeological, mining-geological and other factors of deposit development are clarified.

Technical means of reconnaissance. These are ditches, trenches, clearings, pits (surface) and adits, crosscut shafts, drifts, cuttings (underground) and boreholes and geophysical exploration methods. The most informative are mine workings, passed across the strike of ore-bearing structures of bodies and deposits (ditches, pits) and other workings (trenches, drifts, etc.) passed along the strike and dip of ore bodies of deposits, which allows us to trace the variability of their morphology and qualitative composition in these directions. Mines for exploration purposes are rarely used; more often their purpose is combined with the selection of large volume technological samples for factory testing or trial operation. These are the so-called exploration and production mines. Drilling exploration wells are a universal technical means of exploration. Rotary drilling ensures that a core is obtained (an undisturbed column of rock inside the pipe). This type of drilling is called core drilling. What is the main type of exploratory drilling in ore deposits? Core drilling wells can be vertical, inclined and horizontal. The choice of a drilling unit and the design of a drilling rig depends mainly on the projected depth of exploration wells and conditions (300 m rigs, ZiF).

Intelligence system factors influencing their choice. The study of the geological properties of deposits at the exploration stages is carried out using a large volume of boreholes and mine workings.

1. Linear cutting. This is a set of individual interceptions of an ore body by wells and mine workings in one of 3 directions (thickness, strike, dip). The most informative is the direction of strike of the ore body, which coincides with its thickness. Obtaining exploration data in 3 directions allows us to assess the volumetric variability of the geological properties of deposits. Conduct graphical and volumetric modeling by constructing systems of transverse and longitudinal sections, horizontal plans and block diagrams.

2. Drilling systems group is universal, economical and provides complete information on deposits with significant mineral bodies.

3. Group of mountain systems. Here there are systems of ditches, pits, and exploration mines.

4. Group of mining and drilling systems characterized by use in various combinations of mine workings and boreholes.

Factors influencing the choice of exploration systems are divided into geological, mining-technological and geographical-economic: a) The main factor - geological - is the structural and morphological features of the deposit (shapes, sizes, structure); b) mining and technological factors determine the methods of opening and technology for developing a deposit, based on the mining, geological, hydrogeological conditions of the deposit; c) geographical and economic factors have the greatest influence on the choice of exploration systems in working or remote areas with harsh climatic conditions and weak development of productive forces.

Intelligence methods:

The main methods of exploration are:

1. Detailed geological mapping

2. Linear undercutting of mineral bodies by systems of boreholes and mine workings.

3. Geophysical research in mine workings and wells.

4. Geochemical and mineral studies.

Geological mapping is carried out on a topographic basis on a scale from 1:10000 to 1:500, while reference marks are applied to the geological map, exploration wells (using theodolite traverses and geometric leveling) marking horizons, contours of bodies, elements of technological disturbances, etc. are marked.

Linear cutting of bodies mineral exploration is carried out either by exploration systems of boreholes or by systems of mining exploration workings. Valuable for exploration is the geological information obtained in the process of excavation of exploration workings and drilling of wells.

Geophysical research in wells and mine workings are universal in terms of the range of tasks they can solve. They are used to correct geological heterogeneities. “Logging” is widely used, which is based on the influence of local natural and artificially induced physical fields inside wells on a special probe in the sensors of which signals are transmitted via cable to recording and processing ground-based devices. It is determined by spontaneous polarization, apparent resistivity, radioactivity of rocks in the well section (tack logging), vertical magnetic field changes, changes in thermal conditions (thermal logging), etc.

Geological studies are carried out with the aim of linking ore-bearing zones, assessing the ore content of deep horizons, etc. Mineralogical studies are aimed at solving the following problems:

1. Determination of the complete mineral composition of ores and near-ore spaces

2. Identification based on the characteristics of the mineral composition, textures and structures of ores of their natural types.

3. Study of mineralogical zoning in addition to geochemical zoning.

Control questions:

1. What are the tasks of geological surveying of a field?

2. Why is detailed exploration of the field carried out?

3. What is an ore body, an ore-bearing structure?

4. Transverse and longitudinal sections of deposits?

5. What does geological information provide when designing field developments?

Literatures:

1. Yakusheva A. F. “General Geology”. M. Nedra 1988.

2. Milnuchuk V.I. “General Geology”. M. Nedra 1989.

3. Ershov V.V. “Fundamentals of Geology.” M. Nedra 1986.

4. Ivanova M. F. “General Geology”. M. Nedra 1974.

5. Panyukov P. N. “Fundamentals of Geology.” M. M. Nedra 1978.