104 
MINERALS YEARBOOK, 1967 
 
serves. Consideration was given to the development of new mining methods,
new entries to the mine, and additional production and treatment capacities.
If carried out, the program would increase daily production capacity of ore
from 1,500 tons to a minimum of 2,200 tons at an estimated cost of $20 million.

 Twenty-two miles southwest of Tucson at the Mission mine, operated by Asarco,
the $9 million expansion program was completed during the first quarter~
increasing daily capacity about 50 percent to 25,000 tons. The company mined
4.6 million tons of ore and 14.3 million tons of waste material from the
pit during the year. Concentrates containing 36,746 tons of copper were produced.
Also recovered at the concentrator was 194 tons of molybdenum concentrate
and a small tonnage of zinc concentrate. The mine was shut down on July 17
because of the strike at the smelter to which it ships its output. At the
Silver Bell mine, 40 miles northwest of Tucson, Asarco mined 3.8 million
tons of ore and 9.2 million tons of waste material. The mine was operated
at full capacity throughout the year, producing concentrates containing 22,960
tons of copper. 
 About 1.5 miles north of the Mission mine on the San Xavier Indian Reservation,
4.6 million tons of waste material was stripped from a mineralized area.
The mine will provide siliceous oxidized copper ores for use as a converter
flux at the company Hayden smelter. 
 Plant construction and premining stripping of overburden was begun at the
Duval Sierrita Corp. copper-molybdenum ore body adjacent to the Esperanza
property. Funds required to finance the project, estimated at $151 million
including working capital, were to be obtained from the following sources:
$83 million from GSA, $48.75 million from commercial bank loans, and the
remainder from Duval as equity or loans. Duval agreed to provide management
and technical guidance to Duval Sierrita Corp. at cost. 
 The contract provided that the repayment of the Government advances was
to be made by deliveries of refined ç~opper to the Government by June
30, 1975; advances to be credited at the rate of 38 cents per pound of copper
delivered. The contract also provided that from the begin- 
fling of production to the final repayment date certain minimum deliveries
were to be made at stated intervals. 
 Development of the mine for production was to require removal of 105 million
tons of overburden. The plant was designed for a minimum daily capacity of
60,000 tons of ore. Production from known reserves was expected to total
1.3 million tons of copper and 119,500 tons of molybdenum, together with
9 million ounces of silver. 
 Reaching an agreement with its unions on September 1, Pima Mining Co. operated
throughout the copper strike. The new 3-year contract was expected to increase
labor costs about 6 percent over the term of the contract. Authorized in
September 1966, the third major expansion in 3 years was completed in July,
a $16.6 million project which increased capacity of the mine and mill from
18,000 tons to 30,000 tons per day. The molybdenum recovery plant, completed
late in the year as a part of the expansion program, was expected to recover
approximately 450 tons annually. 
 Sales of copper in concentrates totaled 36,500 tons in 1967, compared with
34,500 tons in 1966. Copper concentrate produced from ores mined and milled
at Pima were normally smelted and refined by Asarco and Phelps Dodge ' Corp.
Because of the strike these smelters were closed; thus, the company negotiated
sales to smelters in Japan and ' Canada, shipping concentrates to these countries
between August and October. 
 Under terms of an agreement dated November 23, 1959, Pima mined and milled
ores from the Banner Mining Co. property, a part of the Pima pit. Banner
reimbursed Pima for mining, milling, smelting, and refining costs. 
 Cement copper recovered from the leaching of ore and waste dumps, in tanks
and in place, at 23 operations contained 69,473 short tons of recoverable
copper. The copper content of the precipitates ranged from a low of 46.3
percent copper to a high of 80.8 percent, averaging 73.8 percent. Copper
produced by precipitation from mine-water and leach solutions with iron represented
10.5 percent of the mine production. 
 Eight primary smelters were operated in the State, primarily on ores produced
by the operating company. Four of the smelters—Phelps Dodge Corp. smelter
at