The document discusses methods for evaluating the quality and resources of oil shale. It finds that determining the calorific value of oil shale is time-consuming, and using indicators like ash content alone is not adequate. However, the content of burning matter can sometimes accurately evaluate quality when mining technology and material structure are constant. Additionally, current methods for calculating oil shale resources based on calorific value do not account for relationships between clay and lime minerals, leading to deviations from actual resources. The authors evaluate errors in this method and provide recommendations for recalculating oil shale resources.