Just below the dusty topsoil here in the scrubby African bush lie some of the richest copper deposits in the world.

Many of the world's largest mining companies, including Phelps Dodge Corp. of Phoenix and Anglo American PLC of London, have done business here. They eventually went home, stymied by central Africa's corruption, crumbling infrastructure and often violent political unrest.

Now, copper prices are close to records, and the world's mining giants are looking for new mother lodes. But in this part of Africa's interior, the dominant players these days are companies like First Quantum Minerals Ltd., a relatively unknown Vancouver, British Columbia, outfit that managed to hang on here even when copper prices plunged a few years ago.

First Quantum, whose Toronto-listed stock has been rallying (it also trades in London), is one of a number of smaller mining concerns rushing to develop more copper, nickel, and other commodities at a time when their big-name counterparts, including Phelps Dodge, BHP Billiton and Rio Tinto, are struggling to meet demand.

The production of these "junior" miners is hard to quantify but has implications for prices. For now, their output is small: First Quantum expects to produce about 220,000 tons of copper this year. In Chile, the world's biggest producer, that much is mined every 15 days.

Still, over time, analysts predict, junior miners likely will play a bigger role, and possibly help bring commodity prices back to earth. That is because they are willing to operate in higher-risk areas, as many big players focus more on mergers and acquisitions than on developing new mines.

The juniors also are increasing spending more quickly to hunt new deposits. According to Metals Economics Group, a Nova Scotia research firm, juniors have accounted for 57 percent of the $3.2 billion increase in exploration spending world-wide since 2002. Last year, they accounted for 63 percent of the increase, a figure many analysts believe will keep climbing.

Some investors worry the sudden emergence of more juniors, at a time when the rest of the mining industry is consolidating, suggests a commodity bubble could be developing. Some smaller companies, which include United Kingdom-listed Vedanta Resources PLC, Ivanhoe Mines Ltd. of Canada and Equinox Minerals Ltd. of Australia, didn't exist a few years ago, and many are flush with cash invested by speculators.

For now, the risk of a glut seems slim. Demand continues to outpace supply for many minerals, and analysts say, more junior exploration successes are needed just to prevent prices from going higher.

Events in central Africa's "Copper Belt" spotlight the juniors' bigger role.

The region – which includes Zambia and the Congo, formerly known as Zaire – once was one of the world's biggest copper suppliers. In the 1970s, those two countries produced more than a million tons a year, more than 10 percent of global output.

Corruption, political unrest and mismanagement of state-owned mines drove foreign investors away. In the Congo, upheavals that killed as many as four million people in recent decades intensified in the 1990s. By 2000, Zambia was producing less than 286,000 tons a year; Congo's output fell to almost nothing.

First Quantum smelled opportunity amid the gloom. "It's like the old story: If you want to shoot elephants, you have to go where the elephants are," says Matt Pascall, a U.K. citizen born in Zimbabwe who now serves as First Quantum's director of operations near the Zambia-Congo border.

First Quantum has a market capitalization of 4.1 billion Canadian dollars (US$3.65 billion). The shares have risen 67 percent in Toronto this year and 57 percent in London.

Philip Pascall, Matt Pascall's brother, founded the company in the mid-1990s after a hunting trip in the region. With cash raised in part through a South African bank, his first target was Bwana Mkubwa, a decrepit mining operation near the Congo border that Zambian officials had closed in the 1980s. The area lacked reliable electricity and paved roads.

In 2001, copper prices fell to multiyear lows. Anglo American, the big miner that also had invested in Zambian mines in the late 1990s, decided to bail out after more than $500 million in losses.

First Quantum had no other major assets, so it stayed. Now, copper prices are about five times higher, at just under $3.50 a pound on the New York Mercantile Exchange, up from less than 70 cents a pound in 2001. First Quantum is riding high, with two mines in operation and others in development. The company reported net profit of $205 million in the first half of this year, up 265 percent.

First Quantum is particularly bullish on a mine called Kansanshi, near the town of Solwezi. The site was mined in the early 1900s and includes a graveyard filled with the bodies of early European prospectors who died of malaria. The mine has been largely abandoned in recent years. First Quantum is spending $70 million to upgrade processing facilities there, with plans to crank out as much as 165,000 tons next year, up from 77,000 last year and none in 2004.

A few years ago, "this place was dormant," says Probby Chama, 35-year-old manager of Janki Enterprises, a dry-goods store that supplies the Kansanshi mine. Since 2000, his sales have more than doubled.

Environmental activists and labor advocates fear that companies in places like Africa are able to sidestep basic environmental and safety standards. They also contend that it is almost impossible to operate in the Copper Belt without paying bribes. Indeed, some areas along the Zambia-Congo border are a wasteland of clear-cut forests, belching smokestacks and assorted industrial activity. Several mining projects, including one First Quantum holds a small stake in, have suffered work-related fatalities.

First Quantum officials say they follow international environmental and financial standards established by the World Bank and say they haven't had any fatalities at facilities they operate. The company also says it doesn't pay bribes and has established its own international border crossings, which help it bypass bribe-taking government agents at official border stations. Mr. Pascall says executives take Canadian diplomats with them when they meet government officials to discourage extortion.

Thanks in part to First Quantum's investments, Zambia is inching back to its 1970s copper-output levels, and a host of other companies, as well as some Chinese investors, are making their way into the region. Analysts believe output from Zambia and Congo combined could exceed a million tons of copper in a few years.

Meanwhile, high prices could begin to lure some of the mining giants back as well. Phelps Dodge, for example, has started work on one of the world's largest undeveloped copper mines, called Tenke Fungurume, in the Congo, though it isn't clear when production will begin.