Watch This Massive Steam Explosion at a Kazakhstan Mine

Water can explode, too.

Jan 28 2015, 4:45pm

Earlier this week, this Michael Bay-esque video appeared online. The footage was purportedly shot outside the the Aksu Ferroalloy Plant in Pavlodar, Kazakhstan, which would make sense because vapor explosions like this are a real danger at mining facilities.

The vehicle in the video is supposedly carrying slag, a by-product created when a desired metal—like iron, copper, or lead—is separated from the ore through smelting. Ferroalloys, like the ones processed in Pavlodar, are types of iron that have high amounts of another element, like aluminum, that are used to make steel, so the plant would produce slag.

But whether it's slag or another type of molten metal, the process causing the explosion is the same: a vapor, or steam, explosion. When the molten metal hits the ground, it heats up the water—possibly from a puddle or just normal ground moisture—so fast that it instantly turns to steam. The sudden change in state releases a burst of energy, causing the explosion.

Even small amounts of hot metal mixing with water can cause an explosion, and vapor explosions are a serious concern for industries from mining to paper manufacturing, in part because a lot of people don't realize that water itself can create a risk for explosion. As we can see from this video, you don't need fire to make one hell of an explosion.

Hendrick van Oss, a mineral commodity specialist with the United States Geological Survey, told me it's difficult to see exactly what happens in the video. He said it's likely there was a steam explosion, but also noted it appears as though a gas explosion is taking place as well. But he had a possible explanation for what happened:

"Although I have not witnessed this personally, if you dumped molten iron into water, there could beapart from the flash conversion into steamsome thermochemical dissociation of the water, thus releasing hydrogen gas, which then could explode," van Oss said.

He also had another possible theory. van Oss pointed out that it looks as though a solid chunk of slag, not molten metal, falls to the ground. van Oss said there's a chance some carbon monoxide or other flammable gas got trapped inside the slag during the separation process, which would lead to more than just a vapor explosion when it hits the water.

"You might have a still very hot mass that still contains some furnace gas which, falling into cold water (and maybe rupturing at the same time) could lead to the catastrophic result you saw," he said, but noted: "I am just speculating."

This story was updated with quotes from van Oss.