e freeport-mcmoran copper & gold sulfuric acid …

Freeport-McMoRan Copper & Gold and Jacobs Engineering deliver an energy-efficient acid plant in Arizona.

Efficient Power

[ B y B R I A N S A l G A D o ]There are plenty of aspects to con-

sider when building a $150 millionsulfuric acid plant. However, forowner Freeport-McMoRan Copper &

Gold, the No. 1 priority during con-struction of the 50,000-square-footproduction facility adjacent to itsopen-pit copper mine in Safford, Ariz.,is the safety of the more than 800workers who will man this job at theheight of the construction schedule.

“It is a challenge trying to manage alarge group like that safely and effi-ciently,” says David Simmons, projectmanager for Freeport-McMoRan.

Add a fast-track schedule and a job

site with limited space to the mix andyou get a project that would have mostcontractors scratching their headsabout how to pull it off. However, withan experienced company like JacobsEngineering on the job as the engi-neering, procurement and construc-tion manager, the project wasdelivered within budget and on timein April 2011.

The sulfur-burning plant is a keycomponent of the Dos Pobres copper

The Freeport-McMoRan Copper & Gold sulfuric acid plant requires more.

than 800 workers on site during peak construction..

“It is a challenge trying tomanage a large group likethat safely and efficiently.”// DAVID SIMMONS, project manager

www.fcx.com | Location:

Safford, Ariz. | Scope: Sulfur-burning plant for

copper production | Employees: 800

Freeport-McMoRan Copper & Gold. sulfuric acid plant.

P R O F I L E

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everyone’s minds during construc-tion of the sulfur plant. Simmonssays the leadership team hammeredthis point home throughout the year-long schedule. This included hostingtailgate meetings to address poten-tially dangerous situations as well asdetailed, site-specific proceduresposted throughout the job site.

The job site also implemented a“Stop the Drop” program that keptworkers out of harm’s way duringthe various crane lifting processes.This created a systematic way toalert all employees on the job sitethat cranes were in use by soundinghorns, flagging areas and setting upbarricades around the area.

mine in Safford. The high-efficiencyfacility supports the copper leach-and-recovery process; sulfuric acid is re-quired to recover copper from raw ore.

To keep up with the 1,550 tons ofcopper ore per day produced by themine, the sulfur plant has the capac-ity to produce approximately 500,000tons of acid annually. The plant sitson a 10-acre site with an enclosedbuilding that houses the control roomdirectly behind it. The main facilitycontains 5,000-horsepower maincompressors, a catalytic converter,gas-to-gas heat exchangers, absorbercolumns and associated process con-trols, according to Simmons.

SAFETY FIRST

With so many trades involved for thisproject, safety was at the forefront of

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Open for Business_____

The Safford, Ariz., open-pit copper mine

consists of two copper deposits that have

oxide mineralization overlaying primary

copper sulfide mineralization, according

to Freeport-McMoRan Copper & Gold Inc.

The predominant oxide copper minerals

are chrysocolla and copper-bearing iron

oxides, with the predominant copper sul-

fide material being chalcopyrite.

The property is a mine-for-leach proj-

ect and produces copper cathodes, the

company says. The operation consists of

two open pits feeding a crushing facility.

The crushed ore is delivered to a single

leach pad by a series of overland and

portable conveyors. Leach solutions feed

a solvent-extraction electrowinning facil-

ity with a capacity of 240 million pounds

of copper annually. Currently, the Safford

mine is producing at approximately 75

percent of capacity.

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each other in tight conditions. With asmany as eight cranes on site at anygiven time, the trades shared cranes asmuch as possible.

“The crane sharing was successful,”Simmons explains. “If you let every

subcontractor have its own crane, itwould have been an impossible task.We strategically located multiplecranes to be used by all the differentsubs instead.”

MAJOR CHANGES

Though the capacity to produce 1,500tons of copper makes this facility oneof the most efficient in existence, ittook some cajoling by Jacobs Engi-neering to bring the plant to this state.The original capacity for the plant wasdesigned to top off at 1,350. However, aweek before groundbreaking was setto commence, Freeport-McMoRan de-cided to increase capacity to 1,500.

Although this was only a 15 percenthike, the Simmons says this essen-tially changed the entire scope of theproject. For instance, sulfur plants likethis typically require cast iron pipesfabricated with silica lining for protec-tion against erosion. These pipes –known as Mondi pipes – are cast inspecific sizes and typically take four tosix weeks to deliver.

With the increased capacity, thepipes originally delivered to the sitedid not meet the new requirements forthe project. Instead of ordering newpipes and delaying work for a monthor so, the construction team reachedout to a job shop located in Phoenixthat could retrofit the Mondi pipes inless than two days.

While the incremental cost of theincreased capacity was $3 million,Simmons says the project would nothave continued without a hitch with-out the talented EPCM team Jacobshad in place. “The fact that we hadsuch a good engineering and procure-ment and construction team was key,”Simmons says. “our mantra was, ‘Justmove forward,’ so we kept moving for-ward while understanding we might

“There was a high level of aware-ness for this one,” Simmons says.

Along with paying close attention tothe location and operation of craneson the job site, trades working on thesulfur plant had to make room for

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Freeport-McMoRan made sure its operators knew how to run the facility well-before starting operations..

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The Production Process_____

Leaching – also known as solution extraction and electrowinning – is a process that uses

weak sulfuric acid solutions to remove copper from rock, according to Freeport-McMoRan

Copper & Gold. In the first step, low-grade ore from the mine is either stockpiled for treat-

ment or is crushed before stockpiling. This ore is then placed in these stockpiles, or “pads,”

in 15- to 30-foot-high “lifts.”

As each level is built, a network of plastic tubing and drip systems or sprinklers is spread

over the top of the pad to deliver the slightly acidic solution known as “raffinate.” The raffi-

nate percolates through the stockpile, dissolving copper minerals contained in the rock

surface, according to Freeport-McMoRan, and the copper-laden water called “pregnant

leach solution” exits the bottom of the stockpile and flows into collection ponds. From

there, the company says, it is pumped to tanks at a solution-extraction plant on the site.

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ventional analog systems. Some ofthe technology was new to a numberof the contractors on site, so Founda-tion Fieldbus set up onsite trainingprograms for the Freeport-Mc-MoRan employees who would serveas instrument hands.

Along with the Foundation Field-bus field team, Freeport-McMoRan

also commissioned the constructionof a training simulator for the facil-ity. The company tapped SNC-lavalin for this portion of the job.

The simulator not only helped getoperators up to speed on how to runthe facility, but also taught them howto handle potentially critical situa-tions. These operators can now han-

run into issues along the way.”For the controls of the structure,

Simmons says approximately 1,200integrated operations systems had tobe coordinated with the main facility,including a Foundation Fieldbus two-way communications system and con-

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Worldwide Leader_____

Based in Phoenix, Freeport-McMoRan

Copper & Gold Inc. is a leading interna-

tional mining company that operates

large, long-lived and geographically di-

verse assets with significant proven and

probable reserves of copper, gold and

molybdenum. The company says it is the

world’s largest publicly traded copper pro-

ducer, boasting a portfolio of operating,

expansion and growth projects through-

out the copper industry. It is also among

the world’s largest producer of molybde-

num and a significant gold producer.

This portfolio includes the Grasberg

mining complex in Indonesia, which is one

of the largest copper and gold mines in

terms of recoverable reserves. Freeport-

McMoRan also has significant mining op-

erations in the Americas, including the

large-scale Morenci and Safford minerals

districts in North America and the Cerro

Verde and El Abra operations in South

America. The Tenke Fungurume minerals

district in the Democratic Republic of

Congo is another area of work.

“Our global work force includes over

29,700 employees,” Freeport-McMoRan

states. “The company has a strong com-

mitment to safety performance, environ-

mental management and to the local

communities where it operates. FCX is a

founding member of the International

Council on Mining and Metals and com-

mitted to implementation of the ICMM

Sustainable Development Framework.”

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“our operators knew how to runthis thing by startup,” Simmons says.“It provided a way to train operatorswith mitigated risk. It was especiallyuseful for new processes and inexperi-enced operators.

dle high-pressure steam in a 750-psisystem, which could lead to dangerousconditions if not operated properly.operators knew exactly how to runthe highly technical facility long be-fore it was operational.

“Among lessons learned, this one ofthe best things we’ll recommend goingforward,” Simmons adds.

SELF-SUSTAINING PLANT

The 750-psi system is part of a self-sustaining power-generating plantcreated for the sulfur-burning facility.The superheated steam from the 17-megawatt steam generator powersplant. Gas scrubbers decrease the So2emissions by more than 20 percentbelow regulated mandates.

“Part of our recent performance testcame in considerably below the recentPPo,” Simmons says. “That is a realfeather in our cap. The acid plant ex-ports power to the mine site.

“It is an island – the acid plant is

This project required meticulous planning and detailed, site-specific directions to ensure safety..

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Because of the remoteness of thesite, the project required a 3-mile-longpumping system to transfer its prod-uct. This system, designed by HDREngineering of Phoenix, involvesthree in-line vertical pumps and stain-less steel pipe fully contained in a heatdeflection temperature liner.

“This pump is capable of transfer-ring all product 3 miles with elevationchanges that drop lower than 500feet,” Simmons says.

STRONG TEAM

Freeport-McMoRan benefits fromhaving a corporate engineering divi-sion that designs facilities like thissulfur-burning plant throughout theworld. This, combined with the sub-

part of a startup that can go into islandmode,” he adds.

“Everything else around us can shutdown and we can continue to operate.It provides acid to the site, but it alsoexports power.”

contractors hired by Jacobs Engineer-ing, created a formidable team thatcould adapt to any situation createdduring the course of construction.

“This team was incredibly flexibleand supported all aspects of the proj-ect,” Simmons says.

“our mantra was to move forwardand resolve problems,” he continues.“We understood there would be obsta-cles and conflicts, so we had dailymeetings to inform each other of whatwas pertinent and hot.” EMI

+ QUADNA, A DXP Company, was pleased to supportFreeport McMoRon’s on its recent Safford Arizona acidplant project. Our involvement included the supply andstart-up of the plant’s main cooling tower circulationwater and boiler feedwater pumps, partnering withITT/Goulds Pumps in Seneca Falls, N.Y., and Lubbock,Texas. Quadna engineered, packaged and successfullyperformed commissioning services for the pumpingsystems supplied for this effort.

Mid-Project Acquisition_____

Freeport-McMoRan initially partnered

with Aker Solutions’ Tucson, Ariz., office

for engineering, procurement and con-

struction of its sulfur-burning plant. How-

ever, in February 2011, Jacobs

Engineering acquired Aker Solutions’

process and construction division, and

consequently took over the project.

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e freeport-mcmoran copper & gold sulfuric acid …

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