POSSIBLE GAS GEOCHEMICAL AND GAS DYNAMIC TESTS FOR EVALUATING THE TECTONOPHYSICAL STATE (STRESS AND BURST PRONENESS) OF LOCAL ZONES OF EXTRUSIVE ROCK

Abstract

In recent decades, underground miners of ore minerals and solid nonore minerals both in this country and abroad have increasingly encountered natural gas pockets and dynamic manifestations of rock pressure such as gas and rock bursts. Field measurements on the gas phase in shafts of the Lovozero deposit have provided new data indicating that the gas properties and tectonophysical characteristics of localized rock zones are correlated. The investigations were performed in two seams near the top of the productive complex, consisting of numerous fairly thin, gently dipping, rhythmically alternating layers of luyavrite, foyaite and urtite. All of the rock varieties exhibit high strength and elasticity and are prone to rock bursts. Our field measurements indicate that there exists a correlation between the gas-geochemical, gasdynamic and tectonophysical properties of extrusive rocks and that the locations and times of gas liberation and of manifestations of rock pressure coincide or are related. There is thus a possibility that the gas components (such as He, H2, CH4 and C2H6) of rocks in alkalic agpaite bodies can be used as indicators of the magnitude and nature of the stress on the rocks and that variations in the concentrations, composition (including isotope composition), liberation rate, and rate of fall or rise in the pressure of the gas phase can be used to predict the time, place, and intensity of dynamic manifestations of rock pressure such as bursts.