Zambia, Zimbabwe and Botswana: The wealth beneath FROM BEHIND THE wheel of an air-conditioned car on the Great North Road bisecting northern Zambia it is easy to argue that Africa can be wealthy and well-governed. The country's road system is so good that many visitors hire a car and drive themselves. The police are benign and rest stops are plentiful. The same goes for much of southern Africa. Lines of tarmac unspool in all directions across fertile savannahs and open deserts. Most roads have been financed with what is found below them: a wealth of minerals and metals. Ever since the arrival of Cecil Rhodes more than a century ago, local miners have generated immense wealth and inspired successive eras of Afro-optimism. From colonial railways to modern airports, public infrastructure would not exist without this wealth of resources. In the central province of Copperbelt, a day's drive south-west of the Tanzanian border, copper has been mined since 1895. Puffing smelters and hill ranges of slag loom over towns. High-voltage power lines and dual carriageways cut up the countryside. "My firstborn wants to be a lawyer," says a father of three who guards a mine. I think it's possible. National copper production recently broke a four-decade-old record, generating enough revenue for the government to announce the building of two new power plants and three new universities. Government income from mining levies increased by 25% in 2012. Across the continent, official budgets are being buoyed by resource revenues. Commodities are estimated to generate one-third of Africa's GDP growth, not counting indirect benefits. Many expatriate miners, especially Chinese, eventually move into other occupations, spreading skills, contacts and capital more widely. Chinese vendors, for example, have come to dominate Zambian chicken markets. The Chinese have rushed to Zambia before. During an earlier commodities boom in the early 1970s Mao Zedong financed a railway line from Tanzania. But the gains petered out, mismanaged by officials on both sides of the border. This time may be different. No African resource boom in the past has ever coincided with democratisation. In the 1970s socialists and autocrats held sway. When elections became more widespread in the 1990s, commodity prices were depressed and there was no money to invest. Now for once everything is coming together. Democracy in Zambia and elsewhere is flourishing, prices are high and economic management is improving. Africa's economy is not all about commodities. That became clear during the 2007-08 financial crisis: African growth rates did not dip as much as those elsewhere because domestic demand held up. But the continent cannot insulate itself from the world economy altogether. In Zambia just now all eyes are on copper, which makes up 80% of the country's exports. One Canadian mining company, First Quantum, generates 15% of the country's tax take. Agriculture at best ticks over, and the government is committing itself to ever more expensive projects such as highways in remote areas. What happens when world demand for copper falls and prices drop from recent record levels? Ndola, the capital of the Copperbelt, knows the answer. Only ten years ago, in between booms, Ndola was a ghost town. The grand but run-down Savoy hotel, built in the 1970s, was closed for a while. Even now that it has reopened the owners refuse to renovate. Who knows how long the current boom will last? Many African countries have come to rely on incomes inflated by the commodities boom Commodities, famously, are a mixed blessing. Many African countries have come to rely on incomes inflated by the boom, raising unrealistic expectations. Their leaders nervously watch prices on international markets. Moreover, too much wealth in the ground makes elites greedy. Neighbouring Zimbabwe is a prime example. It telegraphs its misery ahead. Before taking his bus to the Zimbabwean capital, Harare, a driver buys cheap Chinese shoes in a Zambian shopping mall and hides them in bags to smuggle them across the border. On the other side they are a rare luxury item. Peanuts and diamonds Zimbabwe's economy has collapsed, along with its currency. Shops use dollar bills. In the absence of American coins, they give out bags of peanuts instead of change. The country's GDP is pretty much the same as it was three decades ago, despite extraordinary mineral wealth. The ground is full of bauxite, coal, diamonds, gold, platinum and nickel. Mining is still going on, but is of little benefit to ordinary people. Diamond mines are run by security forces to prop up the party of Robert Mugabe. Many foreign investors stay away, not least because they fear nationalisation. The government claims to be "empowering" the nation by taking stakes in foreign- and white-owned businesses. It started with farms more than a decade ago and now interferes with almost all sectors of the economy. Savior Kasukuwere, a cabinet minister, is happy to invite your correspondent to a meeting where he personally requisitions a stake in Mimosa, a subsidiary of a company listed on the London Stock Exchange. Even in benign hands commodities can be problematic. Zimbabwe's neighbour Botswana is Africa's oldest functioning post-colonial multi-party democracy, and income from diamond mining is spread widely enough to provide almost half the population with middle-class lives. But all mines eventually run out, and Botswana's may have less than two decades to go. The government has already taken action to deal with that, persuading De Beers, the world's biggest diamond firm, to move its global trading operation from London to Gaborone, Botswana's sleepy capital. Long after the last domestic mine shuts down, teams of Botswanans will still be sitting in a hermetically sealed room near the airport, sorting buckets of diamonds flown in from across the globe. Nonetheless, many African governments find it hard to diversify their economies. It is too tempting to make the most of commodities while the going is good.