Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market
Issue link: https://rock.epubxp.com/i/566624
www.rockproducts.com ROCK products • September 2015 • 31 stores can move furs in August," wrote one producer, "we stone men ought to be able to find a way of moving stone in January." At a meeting of the PCA in 1924, the 100 th anniversary of the first patent on portland cement was celebrated. The same goals for research seen throughout the crushed stone industry and directed at gypsum and lime also effected the cement industry. In 1928, a number of studies covering cement issues were published. Papers mostly covered the specifics of cement and clinker composition, hydration and hardening, improvements to cement kilns, and admixtures. National Standards The need for national standards for building materials in a variety of uses became more widely recognized in this peri- od. Representatives of the concrete masonry manufacturing firms established, in 1925, standard sizes for products. The American Engineering Standards Committee revised its procedure for determining standards in 1928, making it easier for producers to have input into the process regarding their own materials. Rock Products reported that the revised procedure was, "founded on the principles that the basic test to be applied in all cases is the fact of the assent, affirmative- ly expressed, of the groups having substantial interest in the standard." A number of significant equipment evolutions and plant design changes were made in the mid and late 1920s. • In 1928, the first portland cement mill in the world designed to include slurry filters was built at Federal Portland Cement Co. in Buffalo, N.Y. • The cement kiln gun was invented in 1924. • A Polysius four-compartment tube mill, the first of its kind in the U.S., was installed at Coplay Cement Manufacturing Co. • At a Cleveland quarry, a dredge with an 18-in. pump was used, the largest ever reported by Rock Products at the time. • In 1929, a new type of dredge, built by Dravo Contracting Co., and introduced at the Ohio Sand Co.'s plant, was the first in the world to use vibrating screens mounted on deck. Diesel engines were heralded in the late 1920s as the most reliable of any type of engine. By 1925, neither electric nor diesel shovels were new, but their range had been greatly extended. Diesel power by that time was applied to smaller units as well as large ones. Electric motors had been developed to reach adequate pow- er output, but the speed was too high. Speed reducers were developed for wide use in these years. By 1925, 40 percent of all shovels were electric, and crawl- er treads were used on almost all of them. Bucyrus Co. (now Bucyrus-Erie) offered a 4-cu. yd. full revolving shovel with the speed and power of the railroad type with the advantages of the crawler tread. The machine weighed 140 tons and was built for either steam or electricity. Conveyors were being installed in longer units, and self-lu- bricating idlers with ball or roller bearings had become almost universal installations. Dust conveyors and collectors in 1925 were recognized as indis- pensable. A self-cleaning cloth type of dust collector was intro- duced by the J.W. Paxon Co. It was designed to eliminate moving parts that would be cut by abrasive dust. In 1928, a 400-mesh wire cloth was introduced to the market. Depression After almost nine years of steady progress and production growth, a world-wide depression set in after the Wall Street crash of October 1929, and the rock products industry cer- tainly felt the hit. Crushed stone production fell from 141 million tons in 1929 to 127 million tons in 1930, and would continue to drop to 70 million tons in 1933. Production of portland cement also dropped after the crash, from 32 mil- lion tons in 1929 to 12 million tons in 1933. The 1920s had seen constantly climbing production rates, which peaked in 1929; those same levels of production would not really be seen for another 10 years. Next Month: Focus on Recovery. Natomas Rock Plant #1 was located on the American River in Fair Oaks, Calif. In the 1960s it became Pacifc Cement and Aggregates, and later it was acquired by Lone Star Industries. Photo, part of the Stumpf family collection, was likely taken in the late 1910s.