Data Dump: Tailings Dump

New database quantifies enormous mine-waste problem

Each circle represents a major tailings storage facility. Numbers correspond to photos below. An interactive version of the map can be found here. Data source: Franks, D.M., Stringer, M., Torres-Cruz, L.A. et al. Tailings facility disclosures reveal stability risks. Sci Rep11, 5353 (2021).

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Mine tailings: They’re big, bad, ubiquitous, and piled up in such massive quantities that they become literal landforms—sandy, geometrically correct mesas, mountains, and plateaus, rising up from the Arizona desert, on the shores of the Great Salt Lake, or filling in valleys in Colorado. If the world’s tailings supply were piled evenly across an area the size of Manhattan Island, according to the results of the most comprehensive survey of tailings facilities to date, published last week in Nature, the pile would be twice as tall as the Empire State Building. And the biggest facilities aren’t in Russia or Kazakhstan or China, but in the Western United States. 

Tailings are the leftovers from mining. After the ore is gouged from the earth, the target metals—which make up a tiny percentage of the ore—are extracted via milling, smelting, cyanide-leaching, or a combination of these methods. Then everything that’s left, which usually consists of a slimy sludge and makes up one of the biggest industrial waste streams on the planet, is stacked up in storage facilities that are hundreds of feet tall and cover several square miles.

Tailings can be hazardous in a number of ways. Most contain metals that can be toxic to wildlife and humans and they are made up of fine dust that can get caught up in the wind and end up in people’s lungs. Uranium tailings are all of that, plus they contain radioactive material. And while they may look like mountains, few tailings piles are as stable as actual landforms. Dams can be breached or entire sections washed away in big rains, to deleterious effect, as was the case in Brazil in 2015 and 2019.

And yet, these mountains of nastiness and the havoc they wreak get very little attention compared to other mining-related impacts.

For example, the Gold King Mine blowout—which didn’t involve tailings—got as much attention as the Brazil disaster that same year. Opponents of the proposed mine at Oak Flat focus on the giant crater that will result when the earth above the mine sinks, and rightfully so. But the footprint of the tailings pile, placed somewhere nearby, will be far larger and is rarely mentioned. Both pro- and anti-nuclear activists typically zero in on spent reactor fuel (either emphasizing how small the volume is or how dangerous and difficult it is to dispose of), while virtually ignoring the massive amounts of tailings—also harmful nuclear waste—produced during extraction and processing. The Church Rock disaster of 1979 occurred when a tailings dam broke, sending millions of gallons of radioactive waste down the Puerco River, contaminating drinking water wells on the Navajo Nation miles downstream, but it garnered little notice compared to the Three Mile Island accident that same year. 

As humanity’s hunger for gadgets and the metals—especially copper—that go into them grows, and as miners go after lower and lower grades of ore (because they’ve already gone through the high-grade stuff), the planetary stockpile of tailings will increase at a rapid rate. 

The Land Desk created the map above, which shows major tailings storage facilities in the U.S., using the new database. An interactive version can be found here (unfortunately Tableau can’t be embedded in Substack, yet). By no means is the database, or the map, complete. The researchers surveyed publicly owned companies, and excluded abandoned, state-owned, and privately owned facilities. Left out were the Sunnyside Gold facilities outside Silverton, Colorado, and the Atlas uranium mill tailings near Moab, Utah. Also not on the map: The tailings facilities at the White Mesa Mill, the only active uranium mill in the nation, near Blanding, Utah, which threaten groundwater and springs in the area. 

The numbers on the map correspond with the Google Earth images of some of the biggest tailings piles in America—and the world. 

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1. The largest tailings facility in the world—650 times the size of the Great Pyramid of Giza—is the now inactive Kennecott Garfield Smelter pile on the banks of the Great Salt Lake. Also in the top ten is the active Magma pile. The image shows both: the inactive pile on the bottom and the active one on top. Google Earth image.
3. Freeport-McMoran’s Sierrita Mine tailings facility is the third largest, by volume, in the world. It is located south of Tucson and looms over Green Valley. The database puts it in the “extreme” hazard category.
5. The enormous tailings piles for the ASARCO smelter in Hayden, Arizona, bookend the Gila River and are contaminating groundwater that will eventually reach the stream. These facilities are not in the database, however.