In 2010, when 33 men were trapped thousands of feet underground by a massive rock fall in a mine in Chile, the news went global — and stayed that way for 69 days, until their astonishing rescue.

One of the countless remarkable things about their story was a pact the miners made while still trapped: “They will not reveal, individually, what they suffered as a group. That story is their most precious possession, and it belongs to all of them.”

Until now, the world has not known that full story. Journalist Hector Tobar tells it, and tells it extraordinarily well, in “Deep Down Dark: The Untold Stories of 33 Men Buried in a Chilean Mine, and the Miracle That Set Them Free.”

Based on hundreds of hours of interviews with the miners and others, the book is a gripping thriller as well as a deeply human story. Tobar, a novelist (The Barbarian Nurseries) and a Pulitzer Prize-winning journalist, fleshes out fully the men we glimpsed in news coverage, in flawed moments as well as heroic ones.

He begins before the disaster, as the men on the A shift gather at the remote San Jose copper mine, set in a surreal desert landscape and marked by a long history of “cutting corners” and shoddy conditions. Some of them live in nearby Copiapo, others travel as much as a thousand miles for a difficult, perilous seven-day shift.

Their jobs pay well in a shaky economy, enough for many of them to own homes and send their kids to college, and they are proud, skilled workers. Most of them are middle-aged family men and regulars on the crew. Dario Segovia is there for an extra overtime shift, and for Carlos Mamani, a Bolivian immigrant, it’s his first day on the job.

Tobar’s description of the mine’s collapse and the men’s discovery of their situation is breathtakingly, horrifyingly vivid. “A single block of diorite, as tall as a forty-five story building, has broken off from the rest of the mountain and is falling through the layers of the mine, knocking out entire sections of the Ramp and causing a chain reaction as the mountain above it collapses, too.”

What follows underground is 17 days when the men have no contact with the outside world and no idea whether they will ever be freed. When a drill bit crunches through the ceiling of the room called the Refuge where many of them are gathered, they bang madly on it with wrenches to signal their presence to the searchers on the surface. It’s an exhilarating scene — but there are 52 days to go before they will see daylight.

Tobar skillfully tells the stories above ground as well, of the camp of families and other supporters at the mine, the corporate dodging and political wrangling, the intense efforts of the rescue team, which included advisers from NASA.

And he follows the men after their rescue, as they go to Disney World and the Holy Land, quarrel with and support one another. Some take money they receive and start their own businesses; others struggle with post-traumatic stress disorder. And some are back underground — not in the San Jose, which is shut down, but at other mines.

Ariel Ticona tells Tobar, “The first day, I felt a little strange.” But, he says, “The fourth day, I was starting to like it.”