Category Nuances for coal_ash:

• solid,
• residual,
• hot,
• inert,
• harmful,
• inorganic,
• glassy,
• dark,
• industrial,
• insoluble,
• undesirable,
• artificial,
• colored,
• natural,
• environmental,
• powdery,
• beneficial,
• raw,

Simple Categories for coal_ash:

• particle,
• material,
• carrier,
• waste,
• matter,
• residue,
• substance,