Савко, А.Д., Дмитриев, Д.А., Крайнов, А.В. and Милаш, А.В. 2018. Mineral-raw material base of non-metallic mineral resources of central black earth region and its rational use. Article 1. situation of the mineral-raw material base of non-metal mineral. Proceedings of Voronezh State University. Series: Geology. 3 (Aug. 2018), 50-65. DOI:https://doi.org/10.17308/geology.2018.3/1592.