METHOD TO OUTLINE INCREASED STRESS ZONE IN ROCK MASSIF AND DEVICE FOR ELECTROMAGNETIC ROCK RADIATION SIGNAL MEASUREMENT IN WELL Russian patent published in 2008 - IPC E21C39/00 

FIELD: mining geophysics, particularly devices for testing in situ the hardness or other properties of minerals, for example, for giving information as to the selection of suitable mining tools.

SUBSTANCE: method involves drilling measuring well; arranging recording device included in electromagnetic radiation signal measurement system along with converter in front of the well; forming digital signal with the use of analog-digital converter and liquid-crystal display of recording device; measuring electromagnetic radiation intensity N_i in several intervals with the use of said device; comparing N_i value with critical value N_k typical for particular mining and geological conditions to determine maximal electromagnetic radiation intensity value. Converter is made as independent unit. The converter is placed in well with the use of dielectric rod so that the first rod end is connected to converter, another rod end is secured to recording device. Recording device is linked to converter through screened cable. Electromagnetic radiation intensity N_i is measured in several intervals by converter moving from one interval to another one with the use of dielectric rod. Electromagnetic radiation intensity values N_2...n are compared with each other beginning from the second interval so that current N_i value is compared with maximal value of previously detected ones to determined maximal value N_max taken as critical value N^' _k for a given massif. Zone boundaries are calculated from N_min=0.8N^' _k. Device comprises converter and electromagnetic radiation signal recording device conductively connected with each other. The electromagnetic radiation signal recording device comprises power source with earthed central point, operational amplifier and serially connected detector, analog-digital converted and liquid-crystal display. Converter comprises receiving magnetic differential antenna made as two coils wound onto ferrite core. Coil outputs are linked to data inputs of measuring amplifier. Converter has power source with earthed neutral bus linked to total coil connection point and central amplifier point. Converter members are placed in dielectric case and connected to one end of dielectric rod. Recording device is connected to opposite end thereof. Amplifier and recording device are connected with each other through screened cable. Electromagnetic radiation signal pass band expander is installed between operational amplifier and recording device detector.

EFFECT: increased reliability and decreased labor inputs due to electromagnetic radiation pulse pick-up directly in measuring well drilled on rock massif from underground mine working.

4 cl, 2 dwg