To reserves estimation of Khulj hot spring

The first prospect evaluation hydrogeological survey of underground mineral thermal waters formed by Khulj hot spring in Bulgan aimag, Mongolia was conducted in 1973. And since then no research has been conducted. However, in 2020–2021, the Governor of Bulgan aimag initiated a hydrogeological exploration study of Khulj spring in order to determine its mineral thermal water resources. The works were funded by the state budget. It was the first time that the mineral thermal water resources of Khulj spring were estimated and classified to the category B in accordance with the degree of geological and hydrogeological study. Conducted exploration works allowed to investigate and specify geological-structural, hydrogeochemical and hydrogeothermal features that determined the formation of the mineral thermal water deposit.