The Biggest Mine
IN THE EARLY 1930S, DEEP WITHIN THE STEEP, ROCKY SLOPES OF Utah’s Oquirrh Mountains, the Utah Copper Company reached a strange milestone. For almost 30 years the company’s giant power shovels had been eating away at a massive mountain of low-grade copper ore that lay at the head of narrow Bingham Canyon. Workers had detonated the first charges of dynamite on the flanks of the mountain in 1904, and as miners girdled the mountain with a corkscrew of broad steps that cut steadily inward, the residents of the nearby town of Bingham referred to the mine site simply as “The Hill.” By 1932 the managers of Utah Copper could boast that they had dug out more than half a billion tons of ore and waste rock from the mountain. But sometime during that decade the residents of Bingham gradually stopped calling the mine The Hill and began calling it “The Pit,” for there was no longer any hill left to speak of. As Utah Copper’s public relations department would often boast in later years, the company had succeeded in making a molehill out of a mountain.
Today, nearly a century after Utah Copper began digging, the Bingham Canyon open-pit mine continues to grow larger and deeper. The Kennecott Corporation is the current owner of what some have called the largest technological artifact on the planet, spanning about two and a half miles from rim to rim and dropping precipitously downward for more than half a mile. The hill that became a pit has made billions of dollars for its owners through the years, yet when operations began, many mining experts thought the giant mountain of copper was worthless.
Those experts failed to see that the profitable development of the Bingham mine would be made possible by a new idea, an idea that was put into action by a metallurgist named Daniel Cowan Jackling. Simply put, Jackling believed he could adopt the powerful principles of industrial mass production to create a parallel system of mineral mass extraction . It wouldn’t matter that the ore was low in copper, since Jackling proposed to mine and process it in vast quantities. The idea was simple, but its realization would present enormous challenges.
Jackling’s early life had prepared him to face such challenges. He was born in 1869 near rural Appleton, Missouri, and his father died when he was four months old. His mother followed when he was not yet two. The orphaned boy spent the first 18 years of his life living with relatives in Missouri, Illinois, and Arkansas, earning his keep by working farm jobs. As he entered adulthood, he planned to become a teacher, hoping eventually to save enough money to buy his own farm. But a chance encounter with a friendly surveyor sparked a fascination with science and technology. After a year at the state normal college, he enrolled in 1889 at the Missouri School of Mines at Rolla, where in 1892 he earned a bachelor’s degree in metallurgy. After a year as a professor of chemistry and metallurgy at Rolla, he decided to head for the rapidly industrializing mining districts of the West, where a smart young man of modest means might still make his fortune.
In January 1894, following another summer of farm work and a brief stint as a miner in Kansas, the tall and lanky Jackling arrived in the booming Colorado mining district of Cripple Creek. He knew nobody there and walked into town with just three dollars and his boundless self-confidence. He found work in an assay office, and after a few other jobs, he was hired in 1896 to build and run a gold mill operated by a mining entrepreneur named Joseph Rafaël De Lamar. Lamar quickly recognized Jackling’s keen technical skills, and in 1899 he chose the 29-year-old metallurgist, along with a mining engineer named Robert C. Gemmell, to investigate an immense deposit of copper in Bingham Canyon, southwest of Salt Lake City. Was there enough gold mixed in with the extensive but low-grade copper deposit to make a gold-mining operation pay?
After taking many samples and testing ore from exploratory drill holes, Jackling and Gemmell reported that the property would not make much of a gold mine. But, they continued, it could be profitably developed as a giant openpit copper mine if Lamar was willing to invest in the steam shovels and locomotives needed to move immense amounts of ore at high speeds through a massive milling system.
Jackling and Gemmell’s report envisioned a copper mine unlike any that had ever before been attempted. For decades it had been thought that a successful mine required ore that assayed at least 5 percent copper, and preferably closer to 10. Mine operators thought of copper as a mineral that was concentrated in rich veins. Skillful miners would follow these veins down into the earth, carefully avoiding the wasted time and expense of mining any barren rock or lower-grade ore.
No one doubted that the Bingham Canyon deposit, taken as a whole, held millions of tons of copper. It was present mostly in the form of chalcopyrite, a mixed sulfide of copper and iron. Unfortunately, that chalcopyrite was not concentrated in veins. Rather, tiny specks of it (sometimes referred to as porphyry ore) were scattered throughout huge expanses of rock. A typical chunk of ore contained only 2 percent copper or less. Most copper-mining men of the day were confident that such a low-grade deposit would never repay the cost of mining it. As the Engineering and Mining Journal stated in 1899, “There appears to be no doubt as to the worthlessness of the proposition.”
Heeding the prevalent opinion, and unwilling to make the great initial investment that would be required, Lamar rejected the advice of his two investigators and chose not to invest in the Bingham Canyon property. Jackling went on to other projects in Washington and Colorado, but his memory of the massive mountain of copper stayed fresh. For years he championed the Bingham project to every financier he encountered and was repeatedly rebuffed. The preliminary investments were too great, most said, and Jackling’s plan was too unorthodox and unproven. Finally, after four years of fruitless pitching, he managed to persuade three Colorado businessmen to provide him with enough capital to buy an interest in the property and begin a small-scale experimental operation, the Utah Copper Company.
He could hardly have started mining copper at a better moment. In 1880 American mines had produced about 1.2 pounds of copper for every person in the country; by 1910 the per capita production would expand fivefold to 6.0 pounds. The explanation for this sharp rise in demand was simple: electricity. Between 1880 and 1914 the use of electricity in manufacturing went from practically nil to almost 14 billion kilowatt-hours, with a roughly equal amount consumed in residential, commercial, and other uses. Nearly all this electricity was carried over copper wires.
As the demand for copper skyrocketed, some experts warned of impending shortages. The high-grade copper veins in the Upper Peninsula of Michigan and in “The Richest Hill on Earth,” in Butte, Montana, were far from exhausted, but they could not promise the huge increases in production needed to realize national electrification. Where would all that new copper come from?
Jackling thought he had the answer: It would come from deposits that were far leaner than those that had traditionally been mined, but also far larger. The Bingham mine would in a sense substitute quantity for quality, abandoning the painfully slow methods of selective underground mining in favor of a fast-paced open-pit operation that did not waste time discriminating between rich and lean ore.
Open pits had a number of obvious benefits. Much of the expensive and cumbersome equipment required for underground mining—timbers to prevent cave-ins, ventilation systems, steam hoists, and more—would be unnecessary. But these potential cost savings were not the real keys to the success of the open-pit mine. Jackling’s ambitious plan included a railroad, steam shovels, a giant 3,000-ton-perday mill (which would be increased to 6,000 tons per day by the time it opened) to process the ore, and a smelter and refinery—several million dollars, all told, in start-up costs.
Even his Colorado investors balked at such a price tag. All they offered was enough capital to barely get the mine started. As a result, Jackling spent his first year at Bingham using traditional underground mining methods to extract the richest ore in the canyon, a practice miners called “picking the eyes out of a mine.” He knew that the mass of lowgrade copper could never be profitably mined this way, but by showing a profit after only a year of operations, he hoped to attract the big capital he desperately needed. His gamble paid off, as reports of the young metallurgist’s early profits and his bold plans for a new type of copper mine reached the wealthy Guggenheim family. With more than seven million dollars of Guggenheim cash backing his Utah Copper Company, Jackling finally had the wherewithal to proceed.
In creating the Bingham system of mining, Jackling himself made few technical innovations. Instead, he skillfully brought together the innovations of others in new ways and on a previously unheard-of scale. He envisioned a system of mass extraction based on three closely linked elements: ore breaking, ore moving, and ore processing. All three had to be precisely integrated into a smoothly operating machine that could handle thousands of tons of rock with great speed and very little wasted effort.
The first step of the system, the ore-breaking process, would rely on precisely controlling the destructive force of explosives. A power shovel could move finely fragmented ore at three or four times the rate it could move uneven, bouldery rock. A stone that was too big to fit into a shovel’s dipper would have to be either blasted again or pounded into smaller pieces. To avoid this wasted effort, Jackling sought out the explosive that would produce the greatest fragmentation when used on the Bingham rock. He eventually settled on a 60 percent ammonium nitrate dynamite, which was custom-made for Bingham by the nearby Hercules Powder Company.
He also made extensive use of deep-drilling technology, which had originally been invented for water wells, to sample the Bingham deposit and provide a guide for where and how to blast. If not for deep drilling (which began to be adopted by petroleum and mining engineers in the late nineteenth century), exploring anything more than the exposed surface rock would have required driving a mansized shaft into the ore. But with a rock drill, Jackling could sample ore hundreds of feet beneath the surface through holes that were only a few inches wide and far cheaper than any shaft. In the period up to World War II, Utah Copper sank 159 churndrill holes into the Bingham Canyon deposit, drilling a total of almost 24 miles. Never before had such a large copper deposit been so thoroughly explored and mapped.
Having succeeded brilliantly in streamlining the ore-breaking process, Jackling needed a way to move thousands of tons of broken rock from the mine to the mill every day. The task was far beyond the strength and speed of human- or animal-powered loading. In their original report to Lamar, in 1899, Jackling and Gemmell had insisted that only steam shovels paired with railroads would be able to load and move the rock quickly enough to make the mine profitable.
This was not a new idea either. William Otis had built the first practical steam shovel back in 1835, and 30 years later, miners put an improved version of the Otis shovel to work strip-mining Illinois coal. More significantly, a Minnesota mining company had begun a rapid switch to steam shovels in the Mesabi iron range’s open-pit mines in 1893. By the early twentieth century, the major steam-shovel manufacturers were making specialized shovels for specific industries, including mining.
In 1906 Jackling and Gemmell went to Minnesota to study the use of steam shovels at the Mesabi mines and to persuade an experienced open-pit manager named J. D. Shilling to become the Bingham mine’s superintendent. Under Shilling’s skilled guidance, rail-mounted steam shovels soon commenced the huge task of removing Bingham’s covering of earth, gravel, and solid rock that overlay the copper ore. Stripping at a monthly rate of about 100,000 tons—roughly an acre-sized chunk of 70-foot-thick overburden—the shovels had exposed nearly six acres of ore by June of the following year.
As one mining engineer observed, “The digging unit is the ‘heart’ of an open-pit operation; other phases are carried on to keep the shovels busy.” To use the expensive and fuel-hungry power shovels at Bingham profitably, Jack- ling’s drill and dynamite crews had to ensure a constant supply of properly broken ore. Speed was essential, so Jackling and his successors steadily adopted bigger and faster power shovels at Bingham, and the size of the ore-breaking explosions had to keep pace.
The first major innovation that Jackling adopted to increase loading speeds was the fully revolving shovel. With the old Otis railcar-mounted model, the dipper and boom had only about 180 degrees of side-to-side swing. But with the fully revolving shovel, the entire shovel platform rotated —housing, engine, operator, and all—allowing the boom to move full circle. This not only made the shovel a more flexible and efficient digger and loader; it also allowed the operator to pick up his own heavy railroad tracks from behind and swing them around to the front as he traveled forward, eliminating much of the labor of the track-laying crew.
After World War I, Jackling further improved his loading speeds by doing away with rails for shovels altogether and adopting the new caterpillar drives, which allowed a vehicle to continuously lay down and pick up its own tread as it moved along. Besides eliminating the need for track laying, caterpillar mounts helped prevent shovels and operators from being buried by falling ore. With the old railroad mounts, pit crews had to block the wheels of the shovel into position to keep it from sliding back on the rails while digging. It took at least 10 minutes to prepare a railroad shovel to back up. By contrast, caterpillar shovels could immediately back away from a rock slide.
In years to come, the size and lifting power of the Bingham shovels grew steadily, and starting in the 1920s they ran on electricity rather than steam. Jackling’s earliest shovels could lift 2l/2 to 3 cubic yards of rock, and by 1914 a typical shovel could pick up 4 or 5 cubic yards in a single bite, and larger, specialized machines could easily lift a small automobile. Today the largest shovels used in the Bingham pit have dippers capable of lifting 56 cubic yards of material, but even these giants are dwarfed by the building-sized custom-built shovels used in other open-pit operations. This steady growth in the size—and hence the speed—of shovels, combined with improvements in flexibility, power, and traction, resulted in machines that could do the work of thousands of men or animals at an astounding pace.
Jackling’s final contribution to the Bingham system lay in finding ways to pick those tiny specks of chalcopyrite out of tons of worthless rock. Indeed, the whole operation depended on the success of this concentrating process. He opened his Magna concentrator in 1907 at Garfield, on the south shore of the Great Salt Lake (15 miles north of Bingham), because of its plentiful supply of water. In the begin- ning, the company relied on the Denver and Rio Grande Western Railroad to carry its ore from the mine to the concentrator. But the D&RGW’s freight operations were not always reliable, and the Bingham mine’s high-volume system could not easily absorb any disruptions in service. So the company built its own railroad, the Bingham and Garfield.
At first Jackling’s mill had relied on traditional concentrating devices known as jigs, vanners, and tables, which were essentially mechanized improvements on the simple technology of a miner’s gold pan. Just like the gold pan, in which the swirling action of water carried away the lighter sand and dirt and left behind the heavier particles of metal, these machines depended on differences in density between the ore and waste rock to achieve separation.
Jigs, the oldest technology, used a pulsating column of water to push the waste up and away from the metal, while vanners used a continuouslv shakine rubber belt to move finely ground ore up a slight incline while a current of water flowed downward and washed away the waste. Most successful of all the gravity methods, though, were the table concentrators—broad, flat horizontal platforms lined with shallow series of long, parallel riffles, or grooves. An electric motor vibrated the table at a precisely controlled rate that carried the lighter waste rock away but captured the heavier metallic ore in the low riffles.
When building his Magna mill, Jackling used the newest and most efficient jigs, vanners, and tables available, and he linked them together in a complex recirculating system designed to maximize his ore recovery. Yet even with the best of that technology, he still lost significant amounts of ore in the form of a material aptly called “slime.” To liberate the tiny particles of chalcopyrite from the waste rock, he had to crush the Bingham ore very finely. Inevitably, this close grinding process meant that some of the ore became so finely pulverized that when mixed with water, it turned into a viscous, slimy paste that was almost impossible to process with gravity methods. As a result, he found that as much as 30 to 40 percent of his profitable copper and other metals were being carried off to the waste dumps.
Fortunately, Tackline’s mass-extraction mining system proved so efficient and profitable that he was able to make a good profit despite the losses. Still, he continually sought out new methods in hopes of solving his slime problem. In 1912 he finally found an answer in a concentrating technology called flotation.
A basic principle behind flotation had been patented in 1886 by Carrie Everson of Chicago, possibly with help from her husband. When a finely ground mixture of rock and ore is agitated in a vat of oily water, the oil tends to cling to certain types of minerals, notably sulfides, allowing them to be separated from the rest of the mixture. By itself, the natural buoyancy of oil is not sufficient to separate the desired minerals from the waste. Rather, the secret to successful flotation (which is not mentioned in Everson’s patent) lies in the tendency of small air bubbles to cling to the oil-coated particles, causing them to float while the waste sinks. In this way, flotation turns traditional ore separation on its head by making the metal-bearing mineral lighter than the waste, rather than heavier. Some of the necessary bubbles arise naturally in the course of agitation, but not enough. It took years of frustrating experimentation before a group of inventors in the early 1900s came up with a system that added air to the oily mixture with frothing paddles.
Jackling first witnessed the potential of froth flotation at a Butte copper mine in 1912. By 1917 he had redesigned one of his company’s two mills to treat the slime by flotation. The results proved well worth the investment. Between 1905 and 1917 he had been able to recover only 61 percent of the copper in the Bingham ore. With flotation, the recovery rate rose to 81 percent by 1923 and would eventually exceed 90 percent. Jackling’s concentration system soon became the most efficient in the world, and in subsequent years even ores with less than one percent copper could be profitably processed, leading the Utah Copper Company to boast in 1930, “We have no waste, but [only] low and lower grade ore.”
Thanks to his powerful mining system, by the mid-1920s the once-impoverished orphan had become one of the richest men in the world and was attracting the attention of an American public fascinated by great wealth. Despite Jackling’s great desire for privacy, his lavish spending habits kept him in the public eye. In the 1920s all San Francisco was abuzz when he gutted the entire penthouse floor of the city’s finest luxury hotel and had it ostentatiously remodeled as one of his homes.
He never had children, and in the years following his 1942 retirement from Kennecott, he traveled the world with his wife in their half-million-dollar yacht, the Cyprus (named for the island that in ancient times was responsible for giving copper its name). According to one historian, Jackling’s 300-foot yacht “carried a crew of 50, had accommodations for 30 guests, contained a movie theater and miniature golf course, and could defend itself with two brass guns against pirates.”
During World War II, when copper was so much in demand for military uses that pennies were made of steel one year, Bingham Canyon provided one-third of all the copper used by the Allies. Jackling’s system of massextraction mining proved so successful that mines of all types adopted its basic principles. By the time of Jackling’s death, in 1956, almost 90 percent of all metal mining in America was done in open pits—a complete reversal from the situation at the turn of the century. Modern open-pit gold-mining operations in Nevada that process almost three tons of ore to produce enough gold for a wedding band are Jackling’s direct descendants.
But as the use of mass-production mining technology has increased, so has the environmental price, for wastes are mass-produced as well. The disappearance of an entire mountain symbolizes the visual damage and destruction of habitat that open-pit mining can cause. In 1994 the U.S. Environmental Protection Agency identified Kennecott’s Bingham mining complex as one of the worst sources of toxic waste in the nation. Chemicals leaching from the massive mountain of tailings produced by Jackling’s concentrating system have contaminated ground water over an area of more than 77 square miles, and lead and arsenic levels in soil and ground water far exceed safe levels. Kennecott has spent more than $200 million to clean up and control the pollution at Bingham, yet much remains to be done. A complete environmental remediation of the huge Bingham site may be impossible.
The legacy of Jackling’s large-scale, mass-production mining system remains mixed. His brilliant skills in engineering and business have provided a century’s worth of the cheap, abundant copper that was essential to industrial expansion, but only at the cost of a devastated and polluted landscape that may not fully recover for centuries to come. It remains to be seen whether a modern-day Daniel Jackling can create a new, more environmentally responsible system for supplying the raw materials of our industrial civilization.