The Encyclopedia Americana: The International Reference Work, Volume 7Americana Corporation, 1960 - Encyclopedias and dictionaries |
From inside the book
Results 1-3 of 81
Page 152
... coal is obtained from underground mines . The two principal systems employed in mining underground coal are the room - and - pillar method and the longwall method . In the first method pillars of coal are left to support the roof and ...
... coal is obtained from underground mines . The two principal systems employed in mining underground coal are the room - and - pillar method and the longwall method . In the first method pillars of coal are left to support the roof and ...
Page 157
... coal for railroad fuel declined sharply . The Class 1 railroads , which required 132 million tons of coal in 1944 , pur- chased only 12,308,000 tons in 1956 . A similar trend is seen in retail dealer de- liveries , which means ...
... coal for railroad fuel declined sharply . The Class 1 railroads , which required 132 million tons of coal in 1944 , pur- chased only 12,308,000 tons in 1956 . A similar trend is seen in retail dealer de- liveries , which means ...
Page 158
... Coal Resources of the United States , U.S. Geological Survey Circular 293 ( Washington 1953 ) ; National Coal Association , Bituminous Coal Trends , 1956 ( Washington ) ; American Mining Congress , Year Book on Coal Mine Modernization ...
... Coal Resources of the United States , U.S. Geological Survey Circular 293 ( Washington 1953 ) ; National Coal Association , Bituminous Coal Trends , 1956 ( Washington ) ; American Mining Congress , Year Book on Coal Mine Modernization ...
Other editions - View all
Common terms and phrases
19th century agricultural altitude American anthocyanins anthracite army Battle became Bituminous bituminous coal blue Bogotá British called cent century Church Clark clay Cleveland climate coal coast cobalt coeducational coelacanths coffee coins coke College colloidal Colombia colonies color Colorado Columbia Columbus comet comic books command commerce Confederate Congress County seat Department East elected England English established federal feet forces France French Germany Henry History important Indian industry Island John June known land later latitudes Lignite London manufacturing ment miles mines North Ocean operation organized Paris period plants polar easterlies president railroad region River Roman served ship South Southern species square miles temperature theater tion tons town trade transportation Union United University Valle del Cauca vessels William World War II yellow York