HYDROGEOLOGY OF THE ERUNAKOVO REGION OF THE KUZNETSK BASIN IN THE CONTEXT OF COAL METHANE FORMATION AND MINING

Detailed study was given to the hydrogeology of the coal methane-promising Erunakovo region. We have established that all aquifers there are mutually related and form a single aquifer complex consisting of a series of microbeds of different water transmissivities and permeabilities. Two zones have been recognized in the Erunakovo region — of intense and slow water exchange (fresh- and brackish-water, respectively). Fresh waters with mineralization of up to 1 g/l and pH = 7–8 occur at depths down to ∼300 m or, seldom, 500 m. Brackish waters have mineralization of 1–13 g/l and pH reaching 10.1. The higher mineralization is due to the higher contents of $HCO3−$ and Na and, sometimes, $SO42−$⁠, produced through sulfide oxidation, and Cl⁻, concentrated as a result of evaporation. In the study region, CO₂ is not of mantle genesis but is the product of coal metamorphism.