FIELD: geophysical examination of boreholes, specifically, nuclear physical methods of investigation of mineral resources. SUBSTANCE: process includes sequential irradiation of rocks by fluxes of gamma- quanta and fast neutrons, registration of flux of scattered gamma radiation at fixed distance from gamma source whose intensity is used to evaluate presence of magnesite strata in section of boreholes. Soft N1 and hard N2 components of scattered gamma radiation are recorded, flux of thermal neutrons N3 is measured, effective atomic number Zeff is calculated and lifetime N3 of thermal neutrons in strata is computed by intensity of flux τ and known diameter of borehole. Contents of MgO and CaO in strata are found correspondingly by nomograms P(Mg0)=f(Zeff,τ) and P(CaO)=f(Zeff,τ). Zeff=a-b lg N1/N2, where a and b are constant coefficients. τi in i-th interval of boreholes is found as τi, where τrefN3i(r,d)/N3ref(r,d) where τref is lifetime of thermal neutrons in reference interval; N3i(r,d) and N3ref(r,d) are counting rate of thermal neutrons in i-th and reference intervals of boreholes with fixed dimension r of sonde and diameter d of borehole. Nomograms (Zeff,τ) and (Zeff,τ) are constructed with known computed values Zeff, τ and with known contents of MgO and CaO in core samples by plotting of isocurves of equal contents of MgO and CaO by interpolation method in coordinates Zeff, τ. EFFECT: enhanced accuracy of evaluation of quality of magnesite ores. 3 cl, 4 dwg, 1 tbl
Title | Year | Author | Number |
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TECHNIQUE DETERMINING CONTENT OF MAGNESIUM AND CALCIUM OXIDES IN MAGNESITE ORE | 1997 |
|
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PROCEDURE DETERMINING CHARACTER OF SATURATION OF COLLECTORS | 1997 |
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GAMMA-SPECTROMETRY TECHNIQUE | 1997 |
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METHOD OF DETERMINATION OF CONTENT OF IRON IN ORES | 1992 |
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METHOD FOR NEUTRON ACTIVATION CHLORINE LOGGING | 1992 |
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METHOD FOR DETECTION OF CONSEALED ORE BODIES | 0 |
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SU1800425A1 |
Authors
Dates
2000-09-10—Published
1997-03-26—Filed