THE MINERAL INDUSTRY OF COLORADO 193 
 
less than 1,000 pounds. The four largest operators, in order of output, were
Union Carbide Corp., Climax Uranium Co., Cotter Corp., and Foote Mineral
Co. 
 Vanadium Corporation of America, a substantial producer of uranium and vanadium
in the State, was merged into Foote Mineral Co. on August 31. 
 Exploration drilling continued at a high pace, with 803,076 feet reported
drilled during the year; rotary drilling accounted for almost half of the
footage. 
 
 Vanadium.—~Although vanadium production declined 380 tons, 10 percent
below the 1966 output, Colorado provided two-thirds of the Nation's output.
The vanadium, obtained from 571,866 tons of uranium-vanadium ores averaging
1.34 percent V205, was recovered at the uranium mills of Union Carbide Corp.
in Rifle and Uravan; Climax Uranium Co. in Grand Junction; Foote Mineral
Co. in Shiprock, N. Mex., and Atlas Corp. in Moab, Utah. In order of output
counties with mine production were Montrose, San Miguel, Mesa, Garfield,
and Rio Blanco. 
 
 Zinc.—Output of zinc was 4 percent in quantity and 9 percent in value
below the figures of 1966. An 0.7-cent drop in the price of zinc, from 14.5
to 13.8 cents per pound, was the reasOn for the different percentage changes
in quantity and value. 
 The seven mines that were the principal producers of lead were also the
leading zinc sources. However, based upon zinc output the Eagle mine was
the leading source, then came Idarado, Sunnyside, Brenneman, Keystone, Emperius,
and Rico Argentine. These mines, the only ones with outputs exceeding 1,000
tons of zinc, yielded 97 percent of the State's zinc output. There were 25
producing mines, including the seven leading ones, compared with 36 in 1966.

 Fourteen counties, the same as in 1966, had production. Leading counties
in order of output were Eagle, San Miguel, and San Juan; the total output
of these three counties was 42,888 tons, 82 percent of the State total. 
 
MINERAL FUELS 
 
 Asphalt and Related Bitumens (Gilsonite).—American Gilsonite Co. produced
gasoline, diesel fuel, high-grade metallurgical coke, and other products
at its gil- 
sonite refinery near Fruita. Gilsonite was transported by pipeline to the
refinery from the company mining operations at Bonanza, Utah. To remove the
last remaining mineral impurities in melted gilsonite and recycle oil, a
final vacuum filtering system was installed before the delayed coker section
so that high-grade coke could be produced. 
 
 Carbon Dioxide.—Because of expanding markets by Colorado Carbonics,
Inc., output of carbon dioxide from the McElmo field, Montezuma County, increased
24 percent. Production was from the Mississippian formation in the field.

 Ten billion ciThic feet of carbon dioxide produced with oil from the McCallum
field, Jackson County, was unmarketable owing to entrained hydrocarbons.
After separation from the oil, the gas was vented to the atmosphere. 
 
 Coal (Bituminous).—Coal production, 4 percent or 217,000 tons greater
than that of 1966, surpassed the 5-million-ton mark for the second consecutive
year. The value of the output was the third highest of all mineral commodities
produced in the State. Of the 5.4 million tons produced, electric utility
companies consumed 60 percent for power generation. Thirty-eight percent
of the output was sent to steel companies for producing coke, and the balance
was shipped to sugar beet plants and small individual consumers. About 1.4
million tons was shipped out of State, mostly for steelmaking. 
 Coal output was reported from the same 14 counties as in 1966. Nine of the
counties had production exceeding 100,000 tons. Routt County had the largest
production; with one-third of the State output, 1.8 million tons, the county
was the only one with output greater than 1 million tons. The county also
had the greatest increase (274,000 tons) in output. Four other counties had
increases over their 1966 output. Pitkin County had the largest decrease
(88,000 tons), followed closely by Las Animas County (87,000 tons). 
 Coal production was reported by eight fewer mines than in 1966. Of the 63
mines with production, seven strip mines including one operation that used
both stripping and augering methods, accounted for 34.2 percent of the State
output; 55 underground mines, 65.7 percent; and one auger operation, 0.1
percent. Twenty-eight un