Documentary is the social conscience of cinema, and in the hands of masterful, largely uncelebrated filmmakers, it remains the most stirring articulation of life on earth. But don't expect cathartic moments. Fine documentaries like The Devil's Miner aren't crafted to deliver an "ah hah!" Instead, they resemble an emotional freefall, in this case down a Stygian tunnel to a nearly depleted silver mine.

When Kief Davidson and Richard Ladkani climbed into that Bolivian mine with two adolescent boys, brothers Basilio and Bernardino Vargas, to film by the light of their open-flame headlamps and acetylene torches, documentary once again fulfilled its promise. Plunging along with them into the mineral dust that will despoil the lives of the boys, we also sink into despair, as deep and inveterate as the mountain's silver veins. Fueling that despair are the 800 other children who toil in the mines, and whose faces we can only imagine: Cerro Rico ("rich pinnacle"), known to the locals as "the mountain that eats men alive," has 20,000 other tunnels the filmmakers didn't explore.

The documentary's grainy, tenebrous images are an eloquent expression of the brothers' desperate existence, but that wasn't intentional: Because of the closeness of the tunnels, The Devil's Miner could not have been made except with the use of a very small-format video camera. Fitted to the large screen of a theatre, the image is naturally degraded, but the nail-biting suspense of the documentary eventually erases any consciousness of this flaw. At any moment, the child miners-not to mention the filmmakers-could be shut in by an explosion in a neighboring tunnel, suffocate from dust, or die from the release of poisonous gas. At one point, the screen goes dark as the filmmakers and the boys run headlong down a narrow tunnel to escape a collapse.

We experience firsthand all the deleterious effects of child labor, too, of children assuming the burdens, financial and emotional, that properly belong to their parents. When asked what he wishes for the future, Basilio says "a father," and rightly so; when his was killed, he became father to his two younger siblings. It was then that Basilio felt compelled to work in the mines and, later, to take his younger brother there. Davidson and Ladkani don't blame the children's mother, which is to their credit: That would be facile and dishonest. Mrs. Vargas, who makes $25 a month guarding the miners' equipment, either lacks the imagination to move elsewhere, or is overcome by the melancholia which permeates the thin air of Potosi, the neighboring town, and Cerro Rico itself. The miners accept that they will die by the time they're 40, and Mrs. Vargas accepts without question the necessity of Basilio filling his father's shoes.

In the portentous lives of the Vargas boys, and the adult miners, all indigenous Quechua-speakers, we see the vestiges of centuries of colonialism. In the 16th century, Cerro Rico enriched the Spanish empire. Los Indios worked the mines then, and they work them now. The few dollars a day that Basilio and Bernardino earn enable them to attend school, but there they are subject to European standards of dress and behavior, and they must hide the fact that they work in the mines or risk the ridicule of the other students. If that is not proof enough that colonialism has left its mark, consider the Manichean beliefs of the miners: A Roman Catholic God may rule in Potosi, but the mine is the realm of the devil. The devil's bargain is protection in exchange for llama blood and, worse, half of the cocoa leaves that would relieve the hunger of the boys' 24-hour shifts in the mine.

The flawless progress of this documentary lies in the filmmakers' unwavering fealty to their subjects. Davidson and Ladkani did not set out to put faces to the dry statistics of poverty or child labor. There is no narration in The Devil's Miner, no talking heads enumerating the failures of the Bolivian government. In fact, the only adults in the film, the men to whom the boys are apprenticed, are remorseful. Basilio and Bernardino are never for us anything but flesh and blood. We want to write a check for their schoolbooks. We want to scream so loudly that our voices will reach Bolivia: Yes, President Evo Morales, make the sale of cocoa legal, anything to keep Basilio and Bernardino from the devil mountain!

The Devil's Miner puts Bolivia on the map, but more importantly it maps an evil without ever sacrificing the humanity of its subjects.

-Maria Garcia