Wet Ground Mica Powder is produced in mills of the chaser types. It consists of a cylinderical steel tank with a diameter of 6 to 10 feet and height of 3 to 5 feet. The bottom is lined with wooden blocks laid with the end grain up. Four wooden rollers of 2 to 3 feet in diameter and 1 to 3 feet across the faces revolve round a central shaft, at 13 to 30 r.p.m. These rollers are so fitted that they can be raised or lowered according to the height of the charge in the wall. Cleaned and washed mica scrap is fed into the mills, water is added and the rollers revolve at low speed and churn tha mass until the grinding is complete. After about 36 hours the water is siphoned from the settling tanks, the sludge is dewatered and dried either in steam-jacketed kettles or in a steam-heated drier. The dried product is sieved on multiple-deck vibrating screens, usually in 160 and 325 mesh, and finally bagged for marketing. Wet ground mica have a high metallic lustre or silvery sheen and is free from grit. However, it is a slow and costly process, and therefore, the product is relatively expensive. It is especially used as a pigment extender in paints, pa