Nigeria is very much endowed with vast and varied solid mineral resources which have remained largely untapped. Solid minerals processing is a very important aspect of industrial raw materials sourcing. Most non-metallic minerals occur naturally in impure form and need to be processed before they can be used as direct input in manufacturing. The solid non-metallic minerals such barites, feldspar, limestone/marble/dolomite, diatomite and bentonite are of great economic importance in industries. These non-metallic minerals are very useful as industrial raw materials in many industries such as oil (for oil drilling), plastics, chemicals, glass, ceramics, paint, adhesive, animal feeds, rubber, matches etc. The need for local content development in the manufacturing industries and the high demand for ground non-metallic minerals prompted the Federal Institute of Industrial Research, Oshodi (FIIRO) to develop technology for milling of non-metallic solid minerals with overall objectives of stimulating industrial development, creating employment, reducing poverty and adding value to the nation’s non-metallic solid minerals.