COAL FORMATION AND TYPES Coal is a sedimentary rock formed primarily from the remains of plants that accumulated in swampy environments millions of years ago. Through the processes of burial, compaction, and metamorphism, plant material undergoes chemical and physical changes, resulting in different types of coal. Coal is classified based on its carbon content, hardness, and energy value. STAGES OF COAL FORMATION (Coalification): 1. Peat (Partially altered plant material): The initial stage of c