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2010 Arizona Mining Review

Article Author(s): 

Nyal Niemuth

The value of Arizona's non-fuel mineral production totaled $6.7 billion in 2010 according to preliminary USGS figures.1 This was 10.5% of the United States' total, making Arizona the number two producer in the nation. Principal commodities mined were copper, molybdenum, sand and gravel, cement and crushed stone. In addition, Arizona coal production added another $273 million bringing the total mined value to nearly $7 billion.

Arizona Mineral Production1
(Value in millions)2


2009 Value

2010 Value










Sand & gravel



Stone, crushed



Other (includes cement, clay, lime, gold, gypsum, molybdenum, perlite, pumice, salt, silver, dimension stone, and zeolites, dimension stone, and zeolites)









1. Unpublished U.S. Geological Survey data, subject to change, final data will be published in the Arizona Chapter of the USGS Mineral Yearbook, Area Reports: Domestic 2009 and 2010, volume II
2. Data rounded and may not add to totals shown
3. Estimate of value provided by the Arizona Geological Survey

Copper and Molybdenum
Arizona accounted for 63% of primary copper production in the U.S. The price of cathode copper averaged a record high $3.42 per pound in 2010, an increase of $1.01 or 42%. The value of copper produced rose similarly up 47% to $5.33 billion. The economic impact from copper mining was $12.1 billion dollars and the industry directly employed over 10,000 workers according to Western Economic Analysis Center4. Two operators accounted for most of the copper production, Freeport McMoran at 65% and Asarco at 29%. Morenci led all mines, producing 514 million pounds, over a third of the newly recovered copper in the state.

Three mines, Freeport McMoran's Sierrita (18 million pounds) and Bagdad (7 million pounds), along with Mercator's Mineral Park (4.35 million pounds), accounted for all of the molybdenum concentrate, with Arizona ranking 2nd in production.

The recovery in copper prices had companies pursuing expansions and developing new mines. Freeport McMoran restarted the concentrator at Morenci in March and increased both the mining and milling rate during the rest of the year. These increases are expected to increase production by 125 million pounds in 2011. At the Miami mine, Freeport McMoran initiated mining in association with ongoing reclamation projects. During an approximate five-year mine life, production is expected to increase at Miami to approximately 100 million pounds of copper per year by late 2011. At Safford, Freeport's newest mine, construction resumed in the second quarter of the $150 million sulfur burner project. Completion of the plant in the 1st quarter of 2011 supplies the leach operation with 465,000 tons of sulfuric acid per year, and generates 11 MW of electrical power.

The Rosemont project of Augusta Resource, expected to be the state’s next major copper mine, remained in the planning stages as the Coronado Forest Service continued work on the Environmental Impact Statement. (On 1 June 2011, the draft environmental impact statement released by the US Forest Service proposed approval of Rosemont Mine.) The mine is projected to produce annually 221 million pounds of copper, 4.7 million pounds of molybdenum, 2.4 million ounces of silver, and 15,000 ounces of gold as a by-product over a 20 plus year mine life.

Resolution Copper hosts the world’s third largest undeveloped copper resource. According to a recent Joint Ores Reserve Committee (JORC) compliant report it contains 1.62 billion tons of 1.47% copper and 0.037% molybdenum. Joint venture partners Rio Tinto and BHP-Billiton continued the sinking of a new 7000' deep shaft, the No. 10, while awaiting Congressional approval of a land exchange. A pre-feasibility study underway suggests that the planned operation would be capable of producing 1.3 million pounds of copper per year, about 80% of Arizona’s current production! Initial production is expected in 2020.

Freeport McMoran reported that the recently acquired Twin Buttes deposit adjacent to its Sierrita mine may contain 700 million tons of copper and molybdenum mineralization. Review of historic exploration data along with new drilling is underway to confirm size and grades and allow mine planning.

In situ leach proposals have been announced for three deposits, Florence, (aka Poston Butte), I-10 and Van Dyke. By far the most advanced project is Florence where Curis Resources acquired a 100% interest and announced plans for production, possibly as early as 2012. The copper oxide portion of the deposit contains over 425 million tons that is expected to produce over 75 million pounds of copper for 19 years. Both major and junior companies were actively conducting copper exploration in nine Arizona counties.

Arizona Copper Mine Production (million pounds)

Mine, Company




Morenci, Freeport McMoran and Sumitomo




Ray, Asarco




Bagdad, Freeport McMoran




Mission, Asarco




Sierrita, Freeport McMoran  




Safford, Freeport McMoran




Silver Bell, Asarco and Mitsui




Mineral Park, Mercator




Carlota, Quadra




Pinto Valley, BHP




Miami, Freeport McMoran




Johnson Camp – Nord5




Tohono, Freeport McMoran












5. Nord reported copper sold, not production for 2009 and 2010
6. Other is Bisbee, Coprecco LLC and/or Tohono

Strong gold prices supported production decisions and encouraged widespread exploration.
Mohave Desert Minerals reopened the Gold Road underground mine at Oatman in Mohave County. A significant change to the 500 ton-per-day mill operation was conversion to dry stack the tailings. This is believed to be the first application of the method in the state. It is noteworthy that this method is also being proposed for the tailings of the Rosemont copper flotation operations.

Copperstone, located north of Quartzsite, is another past gold producer expected to reopen in late 2011. American Bonanza has been installing a gravity and flotation mill along with advancing underground development on the 330,000 ounce deposit.

Early in the year Patriot Gold announced a 590,000 ounce gold equivalent (silver credit) resource for the Moss mine, also in the Oatman district. This is believed to be the largest gold resource in Arizona. In March 2011, Northern Vertex acquired a 70% interest in the property and is conducting additional drilling prior to making a production decision.

Following a drill campaign at the Burro Creek mine south of Wikieup, Northern Freegold released a report identifying a resource of 60,000 ounces of gold and 2 million ounces of silver. The company has expressed interest in selling the property.

Kayenta mine, Arizona’s sole coal mine, produced 7.8 million tons of coal with an estimated value of $273 million3,7. Production increased slightly, up 2.7%, reversing a 4-year declining trend. The Kayenta mine, operated by Peabody, ranks among the 25 largest coal mines in the nation. It supplies the Navajo generating station located near Page via automated unit trains.

Industrial minerals
Driven by a tenfold increase in the price of potash, a property acquisition and exploration boom was underway in the Holbrook Evaporite Basin. The concealed basin underlies an area of hundreds of square miles. An Arizona Geological Survey assessment reports a content of between 682 million and 2.27 billion tons of potash8. In 2009 Passport Metals drilled the first exploration holes for potash in over 40 years. During 2010 the Arizona Oil and Gas Commission issued twenty well permits and two holes were drilled.

In contrast to potash, the producers of aggregate materials and cement are coping with the huge drop in demand due to the slump in construction activity accompanying the banking crisis and weak economy of the great recession. Production of sand and gravel has fallen 54% percent since the peak building period in 2006. Drake Cement completed a $300 million cement plant north of Prescott, the third in Arizona. It began production at about one third of its 600,000 ton per year capacity.

Exploration was reported for a number of other commodities including manganese, silver, iron, rare earths and uranium. A general indicator of exploration activity is the number of Federal mining claims. The total number of claims in Arizona at year’s end was over 44,0009, a high level of activity. This was despite the large number of claims staked for uranium that were dropped by claimants in response to the Secretary of Interior’s moratorium and proposed withdrawal for large areas of the Colorado Plateau.


4. Leaming, G., 2010, The Economic Impact of the Arizona Copper Industry 2010, Western Economic Analysis Center, May, 2010, 53p.
7. Watson, W., Paduano, N. Raghuveer, T. and Thapa, S., 2011, U.S. Coal Supply and Demand: 2010 Year in Review, Department of Energy, U.S. Energy Information Administration.
8. Rauzi, S., 2008, Potash and Related Resources in the Holbrook Basin, Arizona, Arizona Geological Survey OFR 08-07. (AZGS online Potash Map Service for isopach map and up-to-date drilling permit information)
9. Mass Action Code query

Nyal Niemuth

Phoenix Branch Manager
Arizona Geological Survey

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