Classification as lignite under heading 2702 versus sub-bituminous coal under heading 2701 turns on calorific value thresholds and rank criteria set out in the chapter notes. Lignite generally has a higher moisture content and lower gross calorific value on a dry, ash-free basis. A laboratory analysis confirming calorific value is typically required to support the classification.

Agglomerated and non-agglomerated lignite fall under separate subheadings (270220 and 270210 respectively), and duty rates may differ between them. Importers should confirm the applicable rate for the specific form being shipped, as briquetting or pelletizing the material changes its tariff classification even though both forms remain within heading 2702.