Landfills' remote locations make resource recovery a challenge.

The rising price of metals could jumpstart another way to use what we’ve already thrown out: landfill mining.

First tried in Israel in the 1950s, landfill mining is exactly what it sounds like: digging up landfills and extracting resources (mainly metal) from the mounds of trash.

While there are no verifiable instances of landfill mining going on in the United States currently, the sheer amount of metal in landfills around the world gets a new group of people interested in the concept every few years.

Patrick Atkins used to be the director of energy innovations for Alcoa (NYSE: AA) where he first explored landfill mining as a less-intensive resource for aluminum. Now he runs a consulting firm in Pittsburgh and is an advisor for Pegasus Capital Advisors, a private equity firm. He says about 1 percent of U.S. landfill content is aluminum. Rising metals prices, in his view, have made landfill mining an attractive idea once again.

Reid Lifset, associate director of the Industrial and Environmental Management Program at Yale University and editor of The Journal of Industrial Ecology, conducted a study of seven metals in 90 countries through the Stocks and Flows Project at Yale, a nearly decade long study of how metals flow through economies and the environment.

Although there’s a lot of metal in landfills in aggregate, the amount in individual landfills “is pretty small,” he says On top of that, Lifset says, recovered metals are need to be cleaned before a recycler will take them, adding expense to the process.

Lifset says landfill mining could be a secondary benefit for operators that already dig into landfills to extract soil that was spread as daily cover and buried as more trash was put on top of it. Sifting trash to reuse dirt, rather than trucking in new soil, could become profitable as oil prices rise, and it could also maximize current landfill capacity, Lifset says.

Atkins, for his part, suggests that land value plays the largest role in determining profitability. “There will be a time when the land, which was remote from communities, will have so much value that it will allow people to make the investments to mine the landfill so the land can be used for other purposes,” he says.