Let's say that you have a super-sub sandwich with tons of meats, cheese, lettuce, tomatoes, and the works all layered together. Your challenge is to "mine" out one select layer of ham, sandwiched in the middle, by pinching out finger-sized bits from above and below. And after you've removed all the ham, you somehow have to put the sandwich all back together so it looks the same (minus the ham) as before you started. Impossible? With a sandwich, maybe it is. But how do industrial sand miners do something very similar on hundreds of acres of landscape? The answer is that they use a "geomorphic mine reclamation plan".
As you'll see in the video here, mining industrial sand isn't as easy as scooping up loads of the stuff off the ground. Mother Nature and the unique geology that created industrial sand layers make it challenging and a bit complicated. Take, for instance, the industrial quality sandstone zone in the open mine at Tunnel City, Wisconsin. It's like the ham in your sub sandwich as it's sandwiched in the middle and covered with tons of "overburden" that need to be dug and hauled off bit by bit using bulldozers, front end loaders, and huge trucks.
Mother Nature did smile on the miners here, however, as the prime sandstone layer is not cemented very much between the grains. Many ancient sandstone layers undergo the geologic process of "secondary cementation" where mineral-rich waters in the formation precipitate various forms of calcite or silica over time and cement all the individual grains together into a massive block of sandstone. Sure, it makes really solid material for building pyramids, but also makes it almost impossible to mine for the industrial sand that must consist of loose and clean individual grains.
Once they expose the quality zone of sandstone, they can extract it with big D-11 bulldozers and front end loaders. No blasting needed here. You can almost break the sandstone apart with your bare hands. However, moving tons of loose sand with all that machinery has the potential to create a health hazard. It's called silica dust that can, in some instances, cause a lung condition called silicosis. Click on the Learn More tab below to learn more about the kinds of potential silica dust and how miners control and monitor it.
To dig further into the more Serious Science of industrial sand mining, explore these videos and companion lesson activities:
The educational partner listed below supported the science video content you see here. Visit their page to learn more about their sand mining operations.