SU805225A1 - Method of geoelectrical survay - Google Patents

Description

, (54) METHOD OF GEO-ELECTRICAL EXPLORATION

I

This invention relates to prospecting and exploration for solid mineral deposits using electric current.

There is a method of geoelectrical exploration, in which selectively vozno- contact by contact. Electrochemical reactions on ore materials are boosted and measured. The ore bodies entering into the composition of ore bodies 1 /;

In the case of proximity of the measured potential, it is difficult to separate them from each other, and therefore it is impossible to determine the mineral composition of the ore bodies.

The method of geophysical prospecting of ore deposits is known, based on the initiation of electrochemical reactions at the boundary of the ore using an electric current of varying force, which are recorded in the form of polarization curves. The measured values of the potential are compared with the reference values of the potentials of known materials and judge the mineral composition of the ore body 2).

For ore objects (more than 700–1000 m along strike and dip), sources are needed that can generate a constant electric current of several TY1 per hour and tens of thousands of amperes. The creation of such

sources suitable for different geographic conditions and able to move when searching for and exploring mineral deposits, is a difficult and even hitherto-technical problem.

The purpose of the proposed method is to reduce the power of the NS used sources:

The goal is achieved by the fact that in the geo-exploration method, in which a direct current is passed through the surface of the ore Tcvta, linearly increasing in time and the potential of the ore body is relatively measured from the host potential, and the results of measurements are presented in the form of a long-term correlation of the measured dependencies current, judged on the mineral composition and size of the body by comparing the measured values of the potential with the reference many potential potentials of the reaction of known minerals, the current passes a cycle E. In each cell, the current is changed from zero to the limit value, after which it is turned off and the potential of the ore body is measured, and the next cycle starts at a potential value corresponding to the potential of the latter.

electrochemical reaction excited in the previous cycle.

The drawing shows the results of radiation of all cycles in the form of total polarization of the ore body curve.

When electric current passes through the border between BrumatouiHMH and the BrumatouiHMH, electrochemical reactions take place, as a result of which corresponding products arise, which themselves are diverted from the reaction zone by other forces (diffusion, infiltration, etc.). If the rate of removal of the reaction products from the reacting surface is greater than the rate of their formation, then the intensity of the reaction can be enhanced by increasing the strength of the transmitted current. If the rate of withdrawal of the reaction products is less than the rate of their formation, then the appearance of a limiting current strength occurs and, under its influence, a new one is added to the reaction, which ensures a further increase in current.

.After shooting a polarization curve with a change in current strength from zero to maximum current transmission, the resulting products of one or several reactions are removed from the reaction zone by forces of a non-ethical nature (diffusion, etc.) and the physicochemical system under investigation: the breed gradually returns to. initial state prior to passing the current. This depolarization process, depending on the specific physicochemical conditions, has a different duration. With full polarization, a repeated process is initiated by the electric current of electrochemical reactions to reproduce previously recorded processes. However, if you do not wait for the full depolarization and start a new current effect boundary oudney with enclosing

poro from some intermediate intermediate of the physicochemical system under study, between its initial state and that in which it was at the moment of the maximum current, then the processes again will initiate the depolarization process , as well as new reactions that follow the last, achieved by passing the maximum current and the first time. Accordingly, the reactions for which the second did not begin the process of depolarization will not be reflected in the new polarization. curve, which is a portion of the total curve curve. The processes from the physicochemical state of the ore body and the host rocks are reflected in which part of the reactions undergo a polarization process and are not fully polarized to a system state in which a sum of reactions, including previously excited processes and new reactions, occurs due to repeated current flow. The shorter the depolarization time, the higher

along the axis of current strength, the total section along. an operating curve, fixed at

re-passing the current through the ore

body. With a sufficiently large time de. polarization observable curve meets

J is only the initial part of the total polarization curve.

If we introduce the idea of a measurement cycle of polarization curves, with a change in current strength from zero to the maximum possible under specific observational conditions, then the measurement wire in several cycles at the appropriate selected depolarization time can sequentially fix the entire polarization curve. Each cycle will be removed.

5 only a plot of the polarization curve. In each new measurement cycle, the recorded area moves along the current axis. It partially fixes the curve recorded in the previous cycle and adds a new section of the curve. Since for two 0 contiguous cycles, the parts of the sumy curve partially overlap, by imposing them

i Each other (with an offset along the current axis) get the total polarization curve. Establishing on it the elements and the maximum current strength of the reactions, determine the composition and dimensions of the ore bodies under study.

Depending on the specific geological conditions, the depolarization time between measurement cycles may be different and

30 is established experimentally or calculated theoretically in each case specifically.

The number of observation cycles depends on the magnitude of the maximum current in each cycle. The larger the maximum current, the less ibe need dl cycles. registration of the total polarization curve. By increasing the number of measurement cycles, the maximum polarization current can be reduced. As a result, with the selected

40 values of the maximum current can be investigated with the appropriate number of cycles, objects of any size.

The method is carried out as follows. .. Through Two supply electrodes, one of

5 of which can be grounded in the host rocks, and the other in them, or inside the ore body, is passed through an external source from an external source. A gradual increase in current sequentially excites one reaction after another on different minerals. A: Electrical processes are recorded in the form of polarization curves by simultaneously recording graphical dependences of the strength of the flowing current and the electrochemical potential. on the Grade 5J of the Nyce ore object of the containing medium .. Electrochemical technical set-up. using the measurement / potential difference between the receiving electrodes minus the ohmic voltage between them. One of the receiving electrodes is placed in the enclosing pairs at an arbitrary location, and the other at the corresponding point of the profile, or inside the ore body. (In the latter case, the supply and the receiving electrodes can be combined. The ohmic voltage is subtracted automatically with the supply line, the voltage from which is algebraically added to the potential difference between the receiving electrodes at the input of the potential meter. This is how the polarization curve is recorded with the change By turning off the current from zero to maximum, the current is then turned off and the potential meter reads changes in the electrochemical potential during the depolarization process. As soon as the potential reaches the value of the potential of the preceding reaction or transition to it, turn on the current and change it again from zero to a maximum, registering in a new cycle a change in the current of a portion of the total polarization curve located along the axis of the current strength of the first peak. Next, the current is switched off again and the potential changes during the depolarization period are monitored. After reaching the potential of the preceding reaction, the current is switched on again and the next section of the total polarization curve is recorded in the subsequent cycle, etc. The resulting segments of the total polarization curve are connected to each other, combining the polarization steps of the corresponding processes.

In the drawing, curve 1 reflects the registration of two processes at potentials .H = -0.2 V (oxygen reaction) and at-0.5 V (reaction of the cathode in the reduction of pyrite) on the abscissa axis. The potential values are shown, and on the ordinate axis - the current value. The recording of curve 2 was started with a Potential at which the oxygen reaction is recorded in the first cycle. Curve 2 shows the transition from the registration of the oxygen reaction to the pyrite and the transition to the recording of the reaction on chalcopyrite at a potential of 0.62V, detected at current 200. After completing the second cycle of observations and turning off the current, curve 3 (the third measurement cycle) is started with the potential responsible for registration. on pyrite. Then, the transition from the pyrite reaction to the chalcopyrite, then with the Sayay reaction on the chalcopyrite, the transition section to the next reaction on galenite ({f -0.84B) and the beginning of this reaction was recorded. Similarly, curves 4 and 5 are removed with registration on curve 4 reactions on galena and sphalerite (y - 1.28) and on curve 5 reactions on the sphalerite and hydrogen process on the sum of all minerals at potential N - 1.48 V.

According to the results of observations for individual cycles, a total sex of

one curve, by adding its segments, written in the form of curves 1--5. When combined, the known properties of polarization curves are used, namely. that the potentials and the limiting current intensity of electrochemical reactions do not depend on the angle of the aclon of straight line segments, reflecting the corresponding electrochemical processes. This makes it possible, by combining the portions of the curves in the transition region from the preceding reaction to the subsequent and

10 slope of the straight line segments so that the potential of the reaction remains unchanged, add curve 1, curve 3, then curve 3 to the curve 1, etc. The result of the addition of curves 1–5 is the total 15 polarization curve 6. Found from curves 1– 5 and the cumulative curve b, the potentials and the specific reaction Current Strength, are used for op; determine the composition, size and reserves of the ore body. 20

 The application of the proposed method of geoelectrical exploration makes it possible to study the composition, size, reserves and other characteristics of the ore bodies without limiting their size depending on the thickness

25 used electrical sources

i current. Decrease of power. current source causes a reduction in the cost of technical means. Removing the restriction on the size of the ore bodies being surveyed allows Zy to study the body of a mole with a groom of several km.

Claims (2)

. Invention Formula A geoelectroprospecting method in which direct current is passed through the surface of the ore body, the potential of the ore body relative to the host rocks is measured linearly over time, the measurement results are presented in the form of polarization curves: the measured potential depends on the current, and is judged mineral composition and size of the ore body by comparing the measured values of the potential with the reference values of the potentials of the reactions of known minerals, different in that, in order to reduce the power | current sources, the current is passed in cycles, in each nanosecond of which the current is changed from zero to the limit value, after which it is turned off and the potential intends to turn off (the specific body, and the next cycle starts at the potential value, corresponding to the last electrochemical reaction excited in the previous cycle, according to the results of measurements of potentials for individual cycles, the total polarization curve of the ore body is constructed. Sources of information taken into account during the examination I. south. The use of the contact method of polarization curves for ore grade ores in the exploration of ore deposits. Sat “Exploration geophysics of the USSR at the turn of the 70s. M. "Nedra. 1974, p. 375-380. 2. Copyright certificate of the USSR № 360630, cl. G 01 V 3/00, 1972 (prototype). to f, -B