Bloomberg Businessweek (North America) - - Focus On / Mba -

he en­trance to Amer­ica’s deep­est mine shaft sits on a plateau high above the Ari­zona desert, about an hour east of Phoenix. Tucked against the base of a ridge of steep cliffs, it looks south­east over miles of ragged boul­der fields. What looks like a large cap­i­tal A rises above its en­trance. It’s the steel head­frame used to hoist equip­ment in and out of the shaft, a con­crete tube 30 feet wide that goes 6,943 feet straight down.

The No. 10 mine shaft, as it’s called, is on the south­ern edge of an old un­der­ground mine. For 86 years, the Magma Su­pe­rior mine pulled cop­per and sil­ver out of the sur­round­ing moun­tains be­fore clos­ing in 1996 when the min­er­als ran out. Over its life­time, Magma grew to in­clude nine sep­a­rate shafts, some of them miles apart. The fi­nal shaft, No. 9, was fin­ished in the 1970s. Af­ter Magma closed, No. 9 sat aban­doned for nearly 20 years be­fore be­com­ing part of the new Res­o­lu­tion Cop­per mine. It’s now the ven­ti­la­tion shaft for its younger, deeper cousin, No. 10, just a few hun­dred feet away.

Vis­ited on a chilly day in De­cem­ber, the area around the top of the mine, the “col­lar” in min­ing terms, doesn’t look invit­ing. Steam clouds pour from the mouth of No. 9. It’s the hot air be­ing drawn from the cave dug at the bot­tom of No. 10. That far down, rocks formed bil­lions of years ago still carry heat from the molten core of the earth. With­out the elab­o­rate re­frig­er­a­tion sys­tem that pumps chilled air down No. 10, the bot­tom of the mine would be 180F, far too hot for a hu­man to with­stand. “You’d cook,” says Randy Sep­pala, 60, pro­ject man­ager for shaft de­vel­op­ment. Min­ers have long called this heat the “hand of the devil,” reach­ing up from the depths. Sep­pala works for Res­o­lu­tion Cop­per Min­ing, a ven­ture be­tween the two largest min­ing com­pa­nies in the world, Rio Tinto and BHP Bil­li­ton. To­gether they’ve spent more than $1 bil­lion, in­clud­ing $350 mil­lion sink­ing the No. 10 mine shaft, in hopes of tap­ping nearly 2 bil­lion met­ric tons of ore. Less than 2 per­cent of it is be­lieved to be cop­per. It might not sound like much, but that’s con­sid­ered dense, mak­ing it the fourth-largest un­de­vel­oped cop­per de­posit in the world.

Res­o­lu­tion Cop­per plans to dig four more shafts over the next 15 years. At peak pro­duc­tion, this will be the big­gest cop­per mine in the U. S., pro­duc­ing 100,000 tons of rock a day, and enough cop­per to meet a quar­ter of the coun­try’s de­mand. It could also end up be­ing a fi­nan­cial prob­lem for its own­ers. The price of cop­per, along with lots of other com­modi­ties, has crashed as China’s econ­omy has slowed. The Res­o­lu­tion mine is es­sen­tially an enor­mous bet that the third­most-used metal in the world is over­sold and that prices will re­bound by the time the mine opens in sev­eral years. “This is a pretty big gam­ble,” says Dane Davis, a com­mod­ity an­a­lyst at Bar­clays. “We’re in a new era for cop­per, and no one truly knows what de­mand is go­ing to be like. So I would say this is quite risky.”

Be­fore go­ing down the No. 10 shaft, vis­i­tors learn how to put on an emer­gency breath­ing kit con­sist­ing of a nose clip, breath­ing tube, and small oxy­gen bag you at­tach to your belt. As the safety video points out, a fire or ex­plo­sion can oc­cur at any time in an un­der­ground mine. Your abil­ity to sur­vive de­pends on be­ing pre­pared.

There are lots of ways to die in a mine. Roughly in or­der of like­li­hood, the most com­mon in­clude get­ting struck by ob­jects fall­ing down the shaft, fall­ing down the shaft your­self, and be­ing killed by an ex­plo­sion. In the last case, it’s prob­a­bly not the fire that kills you, or even the force of the blast. It’s the toxic gases that get re­leased, par­tic­u­larly the high con­cen­tra­tions of car­bon monox­ide. Ac­cord­ing to Andy Bravence, Res­o­lu­tion’s mine su­per­in­ten­dent and Sep­pala’s No. 2, the breath­ing kit can get used up in a few breaths if you’re hy­per­ven­ti­lat­ing. Dan­ger­ous lev­els of car­bon monox­ide are in the range of 3,500 parts per mil­lion. “One breath of that, and pretty much she’s gonna col­lect your in­sur­ance,” Bravence says. “It sucks all the oxy­gen out of the blood and knocks you out. Your next breath you won’t re­mem­ber tak­ing, and you’re pretty much done af­ter that. But you know: Don’t worry.”

Bravence, 56, is wider and taller than Sep­pala, who’s lithe and lean. Both men have im­pres­sive mus­taches and walk around most days in ei­ther jeans and steel-toed boots or navy blue can­vas over­alls called dig­gers, which have built-in boots. As we prep to go un­der­ground, they’re both in their dig­gers, Sep­pala with a cam­ou­flage base­ball cap pulled low over his eyes, Bravence in his min­ing hel­met. Sep­pala spends most of his time th­ese days above ground, but Bravence goes down al­most daily to check on the work.

One de­scends No. 10 in a gi­ant bucket or in a metal cage. Both travel at 500 feet per minute, or a lit­tle faster than 5 miles an hour. Yel­low de­cals in the cage warn of haz­ards us­ing pic­tures of stick peo­ple in var­i­ous states of dan­ger: One has an arm caught be­tween gears; an­other is get­ting hit by fall­ing rocks. The con­crete shaft runs by, al­most close enough to touch through a few half-dol­lar-size holes.

“What hap­pens if we turn off our hel­met lights?” I ask.

“You find the true def­i­ni­tion of dark,” Sep­pala says. We turn them off. Black­ness, and the rum­bling cage.

Af­ter eight min­utes a low roar from below picks up. By now, about 4,600 feet from the sur­face, and 400 feet below sea level, the air pumped down by the re­frig­er­a­tion sys­tem has lost its chill. At this depth, Res­o­lu­tion has built a se­cond cool­ing sta­tion, dug lat­er­ally off the mine shaft. Here, the air gets cir­cu­lated through a se­cond set of gi­ant cool­ing coils, built into the rock and en­cased in metal. Two fans, 5 feet wide, blow the freshly chilled air back to the bot­tom of the mine. A gi­ant duct car­ries it the re­main­ing 2,300 feet down.

Back in the cage, it takes an ad­di­tional seven min­utes to get all the way to the bot­tom of the mine. Sep­pala steps out and im­me­di­ately wipes fog off his cus­tom-made safety glasses. Steam­ing hot wa­ter pours off the rocks; dur­ing con­struc­tion, work­ers bored into an an­cient lake trapped thou­sands of feet un­der­ground by im­per­me­able rock, and it’s leak­ing into the mine. It’s like stand­ing in a trop­i­cal rain­storm. A dig­i­tal hy­drom­e­ter on the wall reg­is­ters 100 per­cent hu­mid­ity. Over­head, cooled

air gushes out of a metal duct, blow­ing the rain side­ways and keep­ing the tem­per­a­ture in the mid-70s.

In a few years, this tun­nel will have of­fices and high- speed In­ter­net where en­gi­neers and ge­ol­o­gists can work with­out hav­ing to go back up to the sur­face. Right now it’s a hot, wet cave: Steam billows past flood­lights hung from the ceil­ing; pipes and cables, some of them jig­gling, run along wet, rocky walls; a fron­tend loader stays dry un­der a party tent bought at Wal­mart.

Sep­pala walks war­ily around in the rain, a spot­light on his yel­low hard hat point­ing the way. At the bot­tom of the mine, a 170-foot lat­eral tun­nel is laid out like a cross. On the left is the pump­ing sta­tion. A 6-foot­tall sub­mersible pump in 20 feet of wa­ter be­neath the shaft fills a dump­ster-size tank. From the tank, two large pumps each shoot 700 gal­lons a minute up to the sur­face, where it’s treated and used by lo­cal farm­ers. If the whole thing stopped work­ing, the tun­nel would flood in 15 hours. Two life pre­servers hang nearby, just in case.

Across from the pump sta­tion, a thick vein of cables de­liv­ers 4,100 volts of power into a metal shed. Per­fectly dry, bright, and clean in­side, it’s filled with racks of hum­ming elec­tri­cal gear, trans­form­ers, and switches. The shed runs ev­ery­thing from the lights to the pumps to the drills to the im­mac­u­late, in­dus­trial-use por­ta­ble toi­let. A two-man drill crew works at the head of the tun­nel, bor­ing test holes into the rock. They look like Spi­der-men: Wire mesh cov­ers the lenses of their safety glasses in a pro­tec­tive black screen. Sep­pala mo­tions off to the side of the tun­nel, his arm cocked at a 45-de­gree an­gle. “It’s up that way,” he says, mean­ing the cop­per de­posit, still be­hind sev­eral hun­dred feet of rock. “That’s the whole rea­son we’re down here.”

South­east­ern Ari­zona has been mined for more than a cen­tury, but it wasn’t un­til the 1990s that ge­ol­o­gists found the mas­sive de­posit next to No. 10. For decades they spec­u­lated about some­thing big­ger lurk­ing be­neath the shal­lower veins of cop­per run­ning un­der the desert. What­ever was down there was deep though, more than a mile down, and far out­side the reach of cost-ef­fec­tive min­ing tech­niques. Then, in 1994, as the Magma mine was run­ning out of cop­per, a team of ge­ol­o­gists bored a test hole un­der the Tonto Na­tional For­est and hit pay dirt. De­posits this big are usu­ally strip-mined, but this one is too deep, so Rio Tinto will mine it from the bot­tom up. As it’s drilled and blasted from below, the ore will crum­ble and drop into a se­ries of chutes and con­vey­ors. This type of min­ing, called block cav­ing, has been around since the 1950s, but it’s never been done at any­where close to this depth or on this large a de­posit.

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