Category Nuances for coal_ash:

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

Simple Categories for coal_ash:

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