The easy pickings are long gone. The remaining gold is buried in slender seams at least three kilometers down, tiny but precious particles flecked within the subterranean reefs of unyielding rock.

Each day, the miners crowd into the open-cage elevators, descending into the earth at a depth greater than the Grand Canyon, then boarding the small trains that carry them through the lattice of tunnels. It can take 90 minutes just to reach the high-powered drills at the next pocket of unclaimed ore.

That far down, heat floats off the rock at about 43 degrees Celsius (110 Fahrenheit), a temperature made tolerable only by refrigerated air blown through the passageways. The drilling is done in narrow, low-roofed clefts that have been gouged out of the gold- bearing reef. Explosives are then wedged into each hole. Entombment under the suffocating weight of falling rock is the biggest danger.

The value of the extracted gold is measured in currency, but of course there is a human toll as well - fatalities that, while declining, continue to be appalling enough that Parliament has been considering a measure that threatens company executives with prison time for deaths within their mines.

A 1995 national commission estimated that 69,000 mineworkers were killed in South Africa between 1900 and 1993, with 25 times that many seriously injured, the vast majority digging for gold. That does not count the untold numbers felled by lung diseases owing to the contaminated air - or those rendered deaf by the bone-jolting noise.

The rate of mining fatalities compared "unfavorably with most other countries in the world," the commission concluded. Since then, safety measures have reduced the annual number of deaths from an average of 742 to about 220. (By comparison, the mining industry in China reported 3,770 deaths in 2007, nearly all in coal mines, about 80 percent of all mining deaths worldwide. China's population is 1.3 billion, compared with about 50 million for South Africa.)

But this is post-apartheid South Africa, and the welfare of miners - nearly all of them black - is a matter of more scrupulous concern than in 1993.

"We've had pockets of amazing improvements, but people continue to work in conditions that are patently unsafe," said Mavis Hermanus, the director of a center on mining at the University of the Witwatersrand.

The new legislation would subject company executives to prison for up to five years or fines of up to $300,000 - making administrators sitting in offices criminally culpable for mishaps in the dank underground.