5.5 Mineral resources: formation, mining, environmental impact

Learning objectives

After reading this module, students should be able to

• know the importance of minerals to society
• know factors that control availability of mineral resources
• know why future world mineral supply and demand is an important issue
• understand the environmental impact of mining and processing of minerals
• understand how we can work toward solving the crisis involving mineral supply

Importance of minerals

Mineral resources are essential to our modern industrial society and they are used everywhere. For example, at breakfast you drink some juice in a glass (made from melted quartz sand), eat from a ceramic plate (created from clay minerals heated at high temperatures), sprinkle salt (halite) on your eggs, use steel utensils (from iron ore and other minerals), read a magazine (coated with up to 50% kaolinite clay to give the glossy look), and answer your cellphone (containing over 40 different minerals including copper, silver, gold, and platinum). We need minerals to make cars, computers, appliances, concrete roads, houses, tractors, fertilizer, electrical transmission lines, and jewelry. Without mineral resources, industry would collapse and living standards would plummet. In 2010, the average person in the U.S. consumed more than16,000 pounds of mineral resources Americans also consumed more than 21,000 pounds of energy resources from the Earth including coal, oil, natural gas, and uranium. (see Table Per Capita Consumption of Minerals ). With an average life expectancy of 78 years, that translates to about1.3 million pounds of mineral resources over such a person’s lifetime. Here are a few statistics that help to explain these large values of mineral use: an average American house contains about 250,000 pounds of minerals (see Figure Mineral Use in the Kitchen for examples of mineral use in the kitchen), one mile of Interstate highway uses 170 million pounds of earth materials, and the U.S. has nearly 4 million miles of roads. All of these mineral resources are nonrenewable, because nature usually takes hundreds of thousands to millions of years to produce mineral deposits. Early hominids used rocks as simple tools as early as 2.6 million years ago. At least 500,000 years ago prehistoric people used flint (fine-grained quartz) for knives and arrowheads. Other important early uses of minerals include mineral pigments such as manganese oxides and iron oxides for art, salt for food preservation, stone for pyramids, and metals such as bronze (typically tin and copper), which is stronger than pure copper and iron for steel, which is stronger than bronze.