Mineral and Mineral Resources Section 1
What Is a Mineral? • A mineralis a naturally occurring, usually inorganic solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical properties.
Mineral Resources • We depend on the use of mineral resources in almost every aspect of our daily life. • The current challenge is to obtain the minerals that an ever-increasing world population demands at minimal cost to the environment.
What Is a Mineral? • Native elements, these include the elements gold, silver, and copper. • Most minerals are compounds. • The mineral quartz is made up of silica, which consists of one silicon atom and two oxygen atoms.
Ore Minerals • An ore mineralis a mineral that contains one or more elements of economic value. • Ore minerals, are refined using various methods to extract the valuable elements they contain. • For mining to be profitable, the price of the final product must be greater than the costs of extraction and refining.
Metallic Minerals • Ore minerals are either metallic or nonmetallic. • Metals have the following characteristics: • can conduct electricity • have shiny surfaces • are opaque • Examples: gold, silver, and copper.
Nonmetallic Minerals • Nonmetals have the following characteristics: • tend to be good insulators • may have shiny or dull surfaces • may allow light to pass through
Mineral Resources and Their Uses • Certain metals are of major economic and industrial importance. • Alloys: 2 or more metals combine. Example: zinc, brass
Mineral Resources and Their Uses • Nonmetals are among the most widely used minerals in the world. • Gypsum, is used to make building materials such as wallboard and concrete. • Gemstones:include diamond, ruby, sapphire, emerald, topaz.
Subsurface mining • Subsurface mining is a mining method in which soil and rocks are removed to reach underlying coal or minerals. • Room-and-pillar mining is a common method of subsurface mining. This method is used to extract salt and coal.
Longwall mining is a more efficient method of removing coal from a subsurface seam. • A machine called a shearer moves back and forth along the face of a coal seam.
Solution mining is an economical method to mine for deposits of soluble mineral ores, such as potash, salt, and sulfur.
Surface Mining • Surface miningis a mining method in which soil and rocks are removed to reach underlying coal or minerals. • In open-pit mining, ores are mined downward, layer by layer. • coal, gold, and copper are minedwithopen-pit mining.
Quarrying • Quarriesare open pit used to mine near-surface materials such as building stone, crushed rock, sand, and gravel. • Aggregates, which are sand, gravel, and crushed rock, are produced by quarrying.
Solar Evaporation • The solar evaporation process consists of placing sea water into enormous shallow ponds. • The sun evaporates the sea water, which causes the sodium chloride concentration to increase. • About 30% of the world’s salt comes from the solar evaporation process.
Placer Mining • Placer deposits are deposits that contain valuable minerals that have been concentrated by weathered rocks. • Stream placers are the most important placers. Streams transport mineral grains to a point where they fall to the streambed and are concentrated.
Smelting • Smeltingis the melting or fusing of ore in order to separate impurities from pure metal. • Flux – materials that bond with impurities and separates from the molten metal.
Undersea Mining • The ocean floor contains significant mineral resources, • Since the late 1950s, several attempts have been made to mine the ocean,. • 2 Reasons why unsuccessful: • Competitionwith land-based companies that can mine minerals more cheaply and the great water depths at which some mineral deposits.
The Environmental Impacts of Mining • Mining has a large impact on the environment. • Mining industries are heavily regulatedin the U.S. • There are high coststo preserve the environment. • Reclaiming the land, is now a part of every surface mining coal operation.
Air and Noise Pollution • Noiseis created by equipment and by blasting. Blasting can cause physical damage to nearby structures. • Large amounts of dust are produced by all aspects of mining.
Water Contamination • Water that seeps through mine sites can pick up or dissolve toxic substances. • These contaminants can wash into streams, where they can harm or kill aquatic life. • The sulfur in coal reacts with oxygen and water to produce sulfuric acid.
Displacement of Wildlife • Removing soil removes all plant life. • A good development plan to reclaim a mine site can ensure that the displacement of wildlife is temporary. • Dredging a river disturbs river bottoms and destroys aquatic life.
Erosion and Sedimentation • Excess rock from mines is sometimes dumped into large piles called dumps. • Running water erodes unprotected dumps and transports sediments into nearby streams.
Soil Degradation • Soil at a mine site is removed from the uppermost layer downward.
Subsidence • Subsidence is the sinking of regions of the ground with little or no horizontal movement.
Underground Mine Fires • Firesare a serious environmental consequences of coal mining. • Lightning, forest fires, and burning trash can all cause coal-seam fires. • Underground fires that burn their way to the surface release smoke and gases that can cause respiratory problems
Mining Regulation and Reclamation • Mines are regulated by federal and state laws. • Mining companies must comply with the Clean Water Act and the Safe Drinking Water Act, Endangered Species Act.
Reclamation • Reclamation is the process of returning land to its original condition after mining is completed. • The Surface Mining Control and Reclamation Act of 1977 created a program for the regulation of surface coal mining on public and private land.