SU174380A1 - - Google Patents

Description

The known devices containing an elastic wave source with seismic signal sensors do not allow direct exploration of mineral deposits with a piezoelectric effect.

The proposed device can be used in exploration during geophysical work for the purpose of direct prospecting and exploration of a wide range of mineral deposits associated with quartz and pygmatite formations (piezoquartz, gold, nonferrous and rare metals, etc.), as well as sphalerite deposits. and nepheline. To do this, it uses electromagnetic oscillation receivers, which are metal pins, amplifiers made according to a circuit with differential symmetrical inputs, and a recorder synchronized with a seismic sensor.

FIG. 1 shows a block diagram of the device; in fig. 2 - schematic diagram of the amplifier of oscillations; in fig. 3 - oscillogram obtained at one of the fields; in fig. 4 is a plot of amplitudes of piezo pulses.

When the device is operated, the unit 2 with a control panel, which includes eight identical measuring amplifiers, a calibration generator and a control volt-ohmmeter, are used to control the operation of the device and amplify the piezoelectric and seismic signals. Calibration generator is designed to calibrate the sensitivity of the channels of the device,

and a volt-ohmmeter to monitor the voltage of the power source, the correct connection of the electrodes and the geophone, and the evaluation of the resistance values between the receiving electrodes. As a registrant

Device 3 uses an H-700 loop oscilloscope. The power supply unit 4 includes anode batteries and a battery. Sources 5 elastic vibrations are explosions or impacts of a mechanical pile driver.

The measuring amplifier (Fig. 2) consists of an input cascade on the lamp and the amplifier itself on the lamps L and L. The amplifier is characterized by a differential high-impedance state; (R-i R-2 MOM), performed on a double triode. The use of a differential input stage circuit ensures the symmetry of the input, which reduces the influence of interference, and eliminates the galvanic coupling between the amplifiers, which allows co-amplifiers. By using high impedance inputs, variations in grounding resistances between the receiving electrodes do not affect the registration of the received signal. In the amplifier, two LC 7 and 8 filters are applied. A filter 7 is connected between the anodes. Of a la.mpa 6 according to iCxeAie of a series resonance and tuned to a frequency of 50 Hz. Filter 8 is connected to the L-2 negative feedback circuit and tuned to 475 Hz. The use of two resonant filters in the amplifier circuit provides a damping value at a frequency of 50 Hz, equal to 70 dB, and allows recording the bad effect under conditions of industrial noise. The amplifier has a smooth adjustment of the gain s and a stepped adjustment of D.

As a result of a mechanical action by explosion or impact on rocks with piezoelectric properties, an electromagnetic wave is generated, which excites the pendulum electrodes / variables e. d. The electrical signal from the receiving electrodes through the wires fed to the inputs of the measuring amplifiers. The amplified piezoelectric signals are recorded by a recording device 3.

On the oscillogram (Fig. 3), obtained at one of the deposits, the channels / -3 recorded e. D. s., which arose on the receiving electrodes located above the pegmatite vein, covered with sediment,

and channels 4 --- 7 - ed. c., arisen on the electrodes located above the host rocks (gabbro-noritamn); channel 8-control geophone and 9-channel mark of the moment of the explosion.

As a result of processing the oscillograms, a graph is plotted (Fig. 4), in which the amplitudes of piezoelectric pulses in µV are plotted along the Y axis, and the profile distance in m is shown along the X axis. It is shown. that the magnitudes of the amplitudes of the piezo-imulses over the pegmatite vein significantly (25 times) exceed the magnitudes of the amplitudes of the violent pulses above host rocks, which indicates

About the possibility of using the proposed device minerals having a piezoelectric effect.

Subject invention

A device for prospecting for minerals, containing sources of elastic vibrations with seismic signal sensors, characterized in that, in order to improve the accuracy of measurements at the mineral prospecting with a piezoelectric effect, it uses electromagnetic wave receivers made in the form of metal pins, amplifiers made according to circuit with differential balanced inputs, and the recorder, synchronized with the sensor seismic signals.

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