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 THE MINERAL INDUSTRY OF ARIZONA 
grams per cubic meter by 1974. The status of operating and partially constructed
sulfur removal facilities at Arizona smelters at yearend 1972 was as follows:
At the Douglas facility, new emission collecting equipment being installed
would allow the smelter to operate at 58% capacity. Only short-term pollution
control expenditures are economically justifiable at this 65-yearold plant.
Morenci facilities installed or under construction should recover 70% of
the sulfur. Ajo facilities under construction should recover 90% of the sulfur.
Hayden (Kennecott Copper Corp.) facilities installed or under construction
should recover 90% of the sulfur. Hayden (American Smelting and Refining
Company) facilities now operating recover 55% of the sulfur, and a higher
stack was being built and a new sulfur dioxide monitoring network was being
installed. Inspiration facilities under construction should recover over
90% of the sulfur. San Manuel facilities under construction should recover
70% of the sulfur. Sulfur removal equipment at the coal burning Mohave, Nev.,
powerplant removed 90% of contained sulfur during test runs; however, excessive
deposition of sulfates in the scrubbers remains a problem. 
 Enabling legislation was passed by the State allowing local governmental
agencies to financially assist private pollution abatement programs, thus
allowing pollution control to be financed by tax-exempt loans. However, pollution
facilities installed will be taxed by local and State - jurisdictions on
exactly the same basis as existing production facilities. The first loan
granted under this act was for $30 million from the Industrial Authority
of Pinal County to Newmont Mining Corp. for pollution control to 
be installed at the San Manuel smelter. The constitutionality of the enabling
law was questioned but was upheld in a May 1973 ruling of the Arizona Supreme
Court. 
 Bureau of Mines engineers are studying ground breakage and movement during
undercut stoping to obtain information for developing more efficient mining
methods. Data are being collected in a test blockcaving stope, being mined
by Phelps Dodge Corp., to determine mining characteristics of the Safford
ore deposit. Advanced measuring instruments are used to record ground movement
resulting from the stoping. Bureau engineers also studied blasting techniques
to break ore bodies for in situ leaching. Test blasts were made using various
drill hole spacings in an Arizona porphyry copper deposit. Core drilling
was used to obtain samples of rock before and after blasting for fragmentation
evaluations. 
 Bureau metallurgists are studying methods for recovering copper from screened
Arizona mine waste. The higher grade fine fraction is considered a promising
- source of concentration or vat leaching feed. The coarse material yields
a higher copper recovery by dump leaching than unscreened waste, because
circulation impeding fines have been removed. Metallurgical research was
also done on agitation leaching of copper silicate ores. Studies continued
on tailings dam stabilization and On prevention of surface water pollution
from drainage of tailings impoundments and waste dumps. 
 The U.S. Geological Survey and the Bureau of Mines studied the:mineral potential
of the proposed Chiricahua Wilderness Area in Cochise County and the Galiuro
Wilderness Area in Graham County. 
REVIEW BY MINERAL COMMODITIES 
METALS 
 Copper production continued to dominate Arizona metal mining activity. Thirty-three
mines produced copper ore or siicious fluxing material containing low values
in gold, silver, and copper. Copper-zinc ore was produced at one mine, lead-zinc
ore at one mine, iron at one mine, and tungsten ore at one mine. 
 Copper.—Arizona mines produced 908,612 tons of copper, 11% more than
in 1971 (when strikes idled most plants for 1 to 2 months) and only 1% below
the record 
1970 production. Thirty-three mines reported copper production. Of these,
16 mined principally concentrating ore, 5 leaching ore, 3 both concentrating
and leaching ore, 5 direct smelting ore, and 4 low-grade silicious fluxing
ore. Tailings containing copper were shipped from one property for flux.
Cleanup material was shipped to smeltera from five mines or plants. Of the
total copper production 783,918 tons was recovered from 153.09 million tons
of ore treated by concentration, 57,482 tons from 12.45 million tons of ore
treated by vat or