This article discusses developing methods for assessing environmental and socio-economic sustainability, using examples of mineral and raw materials sector companies in Northern Asia (Russia). We identified a sustainability criteria system and proposed an indicator system. These indicators represent a mechanism that orders the complex of existing indicators following the goals and strategy of sustainable development at the micro level. The proposed methodology for constructing a generalized index is based on aggregating three indicator blocks that characterize the environmental and socio-economic aspects of company development. The Sustainable Development Generalized Index (SDGI) allowed us to integrate the complex environmental and socio-economic development processes of mineral and raw materials sector companies and assess their sustainability. Its main feature is the reflection of the environmental specificity of companies. The indicator system adapted to the peculiarities of the mineral and raw materials sector development is a tool for identifying the main trends in the extractive industry development and determining the factors that positively or negatively affect the sustainable development of production companies. The obtained results have information significance for state structures in ensuring the regulation, planning, and control of the consequences of decisions made in the greening production activities at the micro level.