Opinion ID: 381301
Heading Depth: 1
Heading Rank: 1

Heading: the manufacture of cement

Text: 4 Taxpayer is an integrated mining and manufacturing company producing cement. In the production of cement, taxpayer generally extracts limestone (source of calcium carbonate), shale, and/or clay (source of silica, alumina and iron). These minerals are conveyed to a primary crusher which crushes the minerals. The crushed mineral is stockpiled near the cement plant along with other necessary minerals, which are either purchased or extracted from taxpayer's quarries. These materials then undergo a raw grinding process in which water is added to make a mixture having the appearance of mud. The product of this raw grinding process is called slurry. The slurry is then pumped to large blending and storage tanks where it is continually agitated to keep the solids from settling and to keep the mixture homogeneous. The slurry is then moved from the blending and storage tank as kiln feed into a large rotary kiln where it is burned. Complex chemical reactions occur in the kiln, and a cement clinker results from this burning process. The cement clinker is cooled, and later the clinker, along with gypsum, is ground into finished cement. The finished cement is then conveyed to storage silos at the plant where it is stored until it is shipped by rail, barge, or truck, either directly to taxpayer's customers or to distribution terminals operated by taxpayer in cities other than those where taxpayer maintains plants. When cement has been transported to a distribution terminal, customers may take delivery there or it may be shipped to them from there. Taxpayer loads the bulk cement from the storage silo, located either at the plant or at a distribution terminal, directly into rail cars, barges, or trucks for shipment. 5 Approximately 10% to 20% of taxpayer's sales are in bags, rather than in bulk. Upon receiving an order for bagged cement, the finished bulk cement is conveyed from the storage silo to a bagging machine. After the bag is filled according to weight, the bagged cement is hand loaded onto a truck or rail car for shipment to the customer. 6