TIlE MINERAL INDUSTRY OF IOWA 317 
 
REVIEW BY MINERAL COMMODITIES 
NONMETALS 
 
 Cemcnt.—Shipments of portland cement decreased over 2 percent in quantity
and nearly 3 percent in value from 1966 levels. Overall unit value, f.o.b.
mill, dropped slightly from $3.32 to $3.31 per barrel. The five cement plants
in the State operated a total of 19 kiins and produced types I, II, and III
cement. The 13.7 million barrels of portland cement produced represented
nearly 89 percent of their combined capacity. 
 Types I and II (general use and moderate heat) cements accounted for 95
percent of the total portland cement production, of which about 11 percent
was air-entrained and 89 percent non-airentrained. Type III (high-early-strength)
cement accounted for 5 percent of total production; 40 percent was air-entrained
and 60 percent non-air-entrained. The wet process was used in manufacturing
cement at three plants and the dry process at the other two. Electrical energy
consumed in all plants totaled 320.1 million kilowatthours, a decrease of
nearly 5 percent from that of 1966; 83 percent was purchased and 17 percent
home generated. Nearly 86 percent of the total portland cement shipped from
Iowa plants was to consumers in Iowa and Minnesota. Other States, listed
in order of destination of shipments, were Wisconsin, Illinois, North Dakota,
South Dakota, Nebraska, Missouri, Kansas, and Colorado. Approximately 54
percent of the portland cement shipments were by truck and 46 percent by
rail. Of the total shipments, 93 percent were in bulk form and the remaining
7 percent in packaged containers. Approximately 62 percent of the State shipments
were to ready-mixed concrete companies, 16 percent to concrete product manufacturers,
12 percent to highway contractors, 6 percent to building material dealers,
and 4 percent to other users. Nearly 2.8 million barrels of portland cement
were shipped into Iowa from plants located in other States, principally Missouri,
Nebraska, Kansas, Illinois, and Indiana. 
 Raw materials consumed in manufacturing portland cement included over 3.7
million tons of cement rock and limestone, 
584,000 tons of clay and shale, 127,000 tons of gypsum, and small quantities
of iron ore, mill scale, sand, blast-furnace slag, airentraining compounds,
and grinding aids. 
 Masonry cement was produced at all of the State cement plants except the
PennDixie Cement Corp. plant in Polk County. Shipments decreased over 3 percent
in quantity and nearly 2 percent in value. The average value per 280-pound
barrel, f.o.b. mill, rose to $3.03 from $2.99 in 1966. About 76 percent of
the masonry cement marketed went to Iowa and Minnesota. Other States, in
order of receipts, were Illinois, Wisconsin, North Dakota, South Dakota,
Nebraska, and Missouri. Approximately 40,000 barrels of masonry cement was
shipped into Iowa from plants in other States. 
 
 Clays.—Production of clay and shale increased 7 percent in quantity
and 14 percent in value over 1966 levels. The gain in output was attributed
chiefly to the 2-percent increase in production for manufacturing cement
and a 14-percent increase for use in manufacturing heavy clay products. Total
output for lightweight aggregate, mortar mix, and floor and wall tile recorded
a 12-percent decrease. 
 Twenty-seven deposits of clay or shale were operated by 25 companies in
17 counties. Approximately 47 percent of the production was used for the
manufacture of cement, 45 percent for making heavy clay products (including
building brick, vitrified sewer pipe, and other miscellaneous heavy clay
products), and the remainder for lightweight aggregate, mortar mix, and floor
and wall tile. 
 All producing companies used their entire output in their own plants. 
 Sheffield Brick & Tile Co. began construction on a new drainage tile
and manufacturing facility at its Sheffield plant, which was expected to
be completed early in 1968. Anticipated capacity of the new facility, which
will include a top-fired tunnel kiln and tunnel dryer, is 100 tons of tile
per day. 
 
 Gypsum.—Production of crude gypsum in Iowa decreased 5 percent in
quantity and 7 percent in value from 1966 levels.