. Mining and Scientific Press . ey IS inches RP M 1800Horsepower 30. AFTER numerous belting troubles, the Tacony Steel Com-pany of Philadelphia finally selected Test Special RubberBelting for this belt-devouring drive—a hot saw cutting nickelchrome steel of great density and toughness. —other belts lasted one month—Test Special Rubber Belting showedan average life of three months I be BODditioill s]M-nk for thePMBiTM ? belt-traveling over email paUejl at feet per iiiinui.—a sudden belt-racking strain when the saw bites into ,|„. >t«-l —a shower i I - parks and uteel particle*— IT K
. Mining and Scientific Press . ey IS inches RP M 1800Horsepower 30. AFTER numerous belting troubles, the Tacony Steel Com-pany of Philadelphia finally selected Test Special RubberBelting for this belt-devouring drive—a hot saw cutting nickelchrome steel of great density and toughness. —other belts lasted one month—Test Special Rubber Belting showedan average life of three months I be BODditioill s]M-nk for thePMBiTM ? belt-traveling over email paUejl at feet per iiiinui.—a sudden belt-racking strain when the saw bites into ,|„. >t«-l —a shower i I - parks and uteel particle*— IT K Mi Tift S|Kt-ial proved it- worth. And—consider thin—it cost lew than the. ither kind. A sample of Tett Special Belting with copy of Belt Engineering tent on requett NOV Ytf RK BOJINS & PfltKINS TO MEC HA N1CAL RUBBER GOODSSALT LAKE CITY - 313 Felt Bldi. - EL PASO - YORK BOSTON CH1CAC0 ST. LOUIS PHlLAOaPHIA PITTSBURGH SAN FRANCISCO MINING AND SCIENTIFIC PRESS December :!1, 1921. Fifty Years ^of Progress ina Great Industry ALLIS-CHALMERS MANUFACTURING COMPANY and its predecessorshave been identified with the development of mechanical equipment used 111connection with mining and metallurgical operations during the past fifty years. This period covers the development of the precious metal mining industryin the United States, as well as the metallurgical processes connected therewithfrom its infancy. Prior to the discovery of gold in California, in 1849, very littlegold, silver, copper, zinc or lead was produced in the United States. There was some gold mining—both placer and quartz—in Georgia and theCarolinas and lead was mined in Illinois, but the methods employed in themining and reduction of ore were based on European practice and compared withpresent day methods were crude and costly. The discovery of gold in California stimulated prospecting for this metalthroughout the mountain regions of the west and incidentally led to the d
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