David Lowell may not be the last word on the world’s largest copper deposits. But he’s certainly the first.

In 1970, David co-authored a scientific report outlining the Lowell-Guilbert model of porphyry ore deposits – massive bodies of once-molten rock that host staggering amounts of copper, gold, silver and other metals. This groundbreaking bit of geological detective work revolutionized the way that exploration geologists search for porphyries. Thirty years later, these ideas are still compulsory learning for geology students.

How did David become the leading expert on these ores, earning the title of “World’s Greatest Explorer” from the Australian Journal of Mining? In short, he looked at a lot of rocks. Right from the beginning of his geological career, after graduating from the University of Arizona in mining engineering in 1949, he was the type who preferred to be out scrambling over mountains to get an up-close look at deposits. In fact, he hung a sign above his seldom used desk, reading, “Ore bodies are found in the field, not in the office.”

Putting this motto into action, David went to work for copper producer Asarco in Mexico, returning to the U.S. after a few years to explore for uranium with the Atomic Energy Commission. Even after being accepted to Stanford for a Masters degree, he couldn’t tear himself away from the field. Instead, he toiled at his thesis on evenings and weekends while spending the week crawling over rocks as exploration manager for a subsidiary of Canadian firm Ventures Ltd.

It was during this time that David developed his lifelong fascination with porphyry deposits. After looking at many such ores in places like British Columbia, his employers recognized him as a copper expert, which led to a job as a specialist with Utah Construction Company. If this name doesn’t sound familiar, perhaps the company’s later moniker will: Utah Construction went on to become the copper arm of the world’s largest mining company, BHP.

Over much of the next decade, David relentlessly expanded his knowledge of porphyries, which, at that time, were poorly understood deposits. In between his numerous field visits, he gathered with friends in industry and academia to debate the nature of the world’s biggest copper deposits, gradually forming his own conception of how the Earth gave birth to these giants, and how to recognize massive ore bodies that lay undiscovered.

Then in 1965 came the acid test of his new theories. Namely, the San Manuel copper deposit in Arizona. Here, a large porphyry had been split by a massive fault, with half of the ore body being carried away. Work to that point had failed to locate the missing piece. David poured over the geologic data, and, based on his ideas about the dynamics of porphyries, picked a drill location. The drilling confirmed his theory, locating the elusive half of San Manuel, which was named Kalamazoo, and became a major mine for BHP.

After publishing his now proven ideas on porphyries, David was, as he describes, “The prettiest girl at the prom.” Majors fell over themselves to attract him to work on their projects. This led to a series of jobs in the world-class copper fields of the Philippines, and a series of major discoveries, including Dizon, FarSoutheast and Lepanto. The latter was truly David’s baby: he was one of the sole believers who cajoled skeptical management into drilling to the considerable depths at which the rich ore body was finally found.

It was then that a new chapter in David’s career began: South America. After touring Argentina looking at deposits for Kaiser Aluminum, David got a job offer from a much bigger employer: the government of Chile. The nation had just emerged from Communist rule, under which mining infrastructure had degraded badly. David and a team of other international experts were called in to revitalize the flagging industry.

From 1974 to 1979, he did just that. And then – not content to simply work on existing mines – he went looking for new finds in one of the world’s richest copper regions. His endeavor – dubbed the “Atacama Project” – involved scouring underexplored ground in the Chilean desert, looking for giant ore bodies.

After drilling a few prospects, David’s team came to an unassuming piece of ground where four drill holes revealed high-grade copper mineralization. Immediately, he suspected they were onto something big. In fact, big turned out to be an understatement – the deposit went on to become the Escondida mine, the world’s largest copper operation.

Following this and a number of other finds, David decided – following a talk with some friends at a cocktail party in Santiago – to pursue a few “side projects” exploring for gold. The move quickly paid off as he and his co-workers, operating under the umbrella of a newly-formed company, Minera del Inca, discovered the one-million-ounce San Cristobal deposit.

Encouraged by this success, and enjoying the freedom of running his own exploration companies, David moved to more virgin territory in Peru. The nation had recently come under the control of Alberto Fujimori, and the investment climate had improved significantly following 15 years of corrupt military governments that scared away nearly all mineral companies. Here, David operated for two years with funds supplied by himself and a friend, before finally forming a junior company, Arequipa Resources.

Getting into the country at this early stage meant braving rebels and their machine guns. But it also gave David and his crew wide-open territory to explore. They zeroed in on one particular area, later to become the Pierina mine, where the geology seemed to indicate significant mineralization. Toiling in the remote wilderness with nothing more than picks and shovels, they carved out a number of pits to take a look below the surface. That Christmas, as David held down the exploration camp by himself, the assay results came back – they had found gold, at a grade of six grams per tonne.

In fact, the high grades and the considerable extent of the mineralization turned out to be almost too attractive. After drilling only nine holes on the property, Arequipa became the subject of a hostile takeover bid from Barrick Gold. Recognizing that the work at Pierina was still too early stage to command full value in such a buyout, David and his team kicked their work up a notch. They drilled thirty-three holes in a month and proved up a resource of seven million ounces of gold. Faced with the new data, Barrick ended up paying over a billion dollars Canadian for the deposit.

So, what’s next for the world’s greatest explorer? Not surprisingly, he’s sticking with what he does best: looking for giant copper deposits. After doing some consulting work with silver explorers Bear Creek Mining (V.BCM) – a company that has recently grabbed market attention after jumping from a share price of C$0.75 to as high as C$3.80 in a month and a half – David’s thoughts once again turned back to the copper grounds of South America. Phoning one of his long-time business partners, he summed up his idea for a new project, saying, “I think there’s a sleeper out there.”

David’s belief that there might be another major copper ore body left to be found led to the formation of the Peru Copper Syndicate, a group dedicated to taking a hard look at passed-over Peruvian deposits. Evaluating more than a dozen such projects, David focused in on one: Toromocho. Located just 150 kilometers east of Lima, and in a proven mining district with good infrastructure, this deposit had what David was looking for. Namely, a solid resource of copper, silver, and molybdenum that looked to have been underestimated by past work, and that had significant potential for expansion by applying some new geological thinking.

The group has now gone public with the project as Peru Copper Inc. (T.PCR). As with many of David’s past endeavors, work is proceeding at a frenetic pace, with nearly 80,000 meters of drilling having been completed, in addition to 42,000 meters of historic work. With a resource that has increased by four times to more than 1.8 billion tonnes of ore, the project is now moving into feasibility studies. Preliminary indications are that David’s discerning eye may have found another winner – it appears that Toromocho could be the world’s fifth-largest undeveloped copper deposit.

We always like situations where a great explorer gets a chance to apply their particular expertise in an area they know well. In this case, you couldn’t ask for a more qualified expert than David, or a better place to work than his old stomping ground of South America. We’ll be watching to see if this promising-looking project comes up with the same success as his work to date.