Figure 20.0.1 The Climax Molybdenum Mine outside of Leadville, CO. Note the “benches” in the background where mining takes place, and the ore processing facilities in the foreground.

It has been said that “if you can’t grow it, you have to mine it,” meaning that anything we can’t grow we have to extract from Earth in one way or another. This includes water, of course, our most important resource, but it also includes all the other materials that we need to construct things like roads, dams, and bridges, or manufacture things like plates, toasters, and telephones. Even most of our energy resources come from Earth, including uranium and fossil fuels, and much of the infrastructure of this electrical age depends on copper (Figure 20.0.1).

Figure 20.0.2 The main components of a tablet computer.

Virtually everything we use every day is made from resources from Earth. For example, let’s look at a tablet computer (Figure 20.0.2). Most of the case is made of a plastic known as ABS, which is made from either gas or petroleum. Some tablets have a case made from aluminum. The glass of a touch screen is made mostly from quartz combined with smaller amounts of sodium oxide (Na₂O), sodium carbonate (Na₂CO₃), and calcium oxide (CaO). To make it work as a touch screen, the upper surface is coated with indium tin oxide. When you touch the screen you’re actually pushing a thin layer of polycarbonate plastic (made from petroleum) against the coated glass—completing an electrical circuit. The computer is then able to figure out exactly where you touched the screen. Computer processors are made from silica wafers (more quartz) and also include a significant amount of copper and gold. Gold is used because it is a better conductor than copper and doesn’t tarnish the way silver or copper does. Most computers have nickel-metal-hydride (NiMH) batteries, which contain nickel, of course, along with cadmium, cobalt, manganese, aluminum, and the rare-earth elements lanthanum, cerium, neodymium, and praseodymium. The processor and other electronic components are secured to a circuit board, which is a thin layer of fiberglass sandwiched between copper sheets coated with small amounts of tin and lead. Various parts are put together with steel screws that are made of iron and molybdenum.

That’s not everything that goes into a tablet computer, but to make just those components we need a pure-silica sand deposit, a salt mine for sodium, a rock quarry for calcium, an oil well, a gas well, an aluminum mine, an iron mine, a manganese mine, a copper-molybdenum-gold mine, a cobalt-nickel mine, a rare-earth element and indium mine, and a source of energy to transport all of the materials, process them, put them together, and finally transport the computer to your house or the store where you bought it.

Media Attributions

• Figure 20.0.1: Wikimedia Commons
• Figure 20.0.2: “Ipad Air” © Zach Vega. Adapted by Steven Earle. CC BY-SA.
• Figure 20.0.3: “Ballpoint pen parts” by unknown. CC BY-SA.