Premium coal (cleaned coal) refers to coal that has undergone mechanical processing at a coal washing plant, which reduces its ash and sulfur content and removes some impurities, making it high-quality coal suitable for specific purposes. Premium coal can be divided into coking coal for smelting and other uses. The premium coking coal for smelting has particle sizes of less than 50 millimeters, 80 millimeters, and 100 millimeters; with ash content less than or equal to 12.5%, briefly called smelting premium coal. The other use coking coal has particle sizes also less than 50, 80, 100 millimeters, with ash content between 12.5%-16%, briefly called other premium coal.