Cement manufacturing industry is identified by North American Industry Classification System (NAICS) code 32731 (formerly identified as SIC code 3241). The procedure of cement making follows:
1. The cement manufacturing process begins when limestone, the basic raw material used to make cement, is transported by rail to the Edmonton plant from the Cadomin limestone quarry 220 kilometers west of Edmonton.
2. The limestone is combined with clay, ground in a crusher and fed into the additive silos. Sand, iron and bottom ash are then combined with the limestone and clay in a carefully controlled mixture which is ground into a fine powder in a 2000 hp roller mill.
3. Next, the fine powder is heated as it passes through the Pre-Heater Tower into a large