+ Mining and Extraction Lecture

Lecture Purpose: Learn how we mine and extract the ores and minerals we use every day. Think about the sustainability of this resource use for your family’s EcoFootprint. You will need your Note-Taking Tool for Audit Proposals.

+ What Do We Mine? Our civilization depends on the mining of many different minerals: Iron = steel Copper = pipes, electrical wires… Aluminum (via bauxite ore) = packaging, products… Lead = batteries, medical x-ray protection… Tungsten = incandescent light bulbs, alloy in metals… Uranium = nuclear power industry Gold, silver, and many, many more…

+ Types of mining In order to extract the minerals and metals in the earth’s crust, various techniques have been developed to mine ores and to separate residual rock and materials from the valuable resources. Ores consist of concentrated accumulation of economically valuable minerals and metals. Two kinds of mining take place on land: SURFACE MINING SUBSURFACE MINING

+ Surface mining STRIP MINING Removes strips of soil and rock to expose ore. Strip mining is used when ore is relatively close to the Earth’s surface Ex: sedimentary materials such as coal and sand are located close to the surface Once the resource is extracted, the waste material (called mining spoils or tailings) is returned to the hole created by mining. A variety of strategies can be used to restore the affected area to something close to original conditions.

+ Surface mining OPEN-PIT MINING Creates a large pit or hole in the ground. Used when resource is close to the surface but extends beneath the surface horizontally and vertically (ex. copper mines) Kennecott Bingham Canyon Mine near Salt Lake City, UT, is one of the largest open-pit mines in the world

+ Surface mining MOUNTAINTOP REMOVAL Miners remove the entire top of a mountain with explosives. Large earth-moving equipment removes the resource (for example, coal). Tailings are deposited in nearby lower-elevation regions, often in or near rivers and streams

+ Surface mining PLACER MINING The process of looking for metals and precious stones in river sediments. River water is used to separate heavier items like diamonds, tantalum, and gold, from lighter items like sand and mud. (ex. California gold rush)

+ Subsurface mining Subsurface mining is used when resources are more than 100 meters (328 feet) below Earth’s surface. Begins with a horizontal tunnel dug into the side of a mountain or feature. Vertical shafts are drilled from the horizontal tunnel. Elevators are used to bring miners down to the resource and back to the surface. Resources that often require subsurface mining include coal, diamonds, and gold.

+ Stop & Think… What were the most important ideas from this section of the lecture? Tell a partner. Which types of mining do you think cause the most and least harm to the environment? Explain why with evidence from the lecture. Why does knowing about mining practices matter to our investigation of our EcoFootprint? Note-Taking Tool for Audit Proposals: Record your answers For citation purposes, you can put down this lecture title, or refer to Chapters 12 and 19 for more detail.

+ Mining safety and the environment The extraction of minerals has various environmental impacts and human health consequences Deposits of spoils and tailings can cause contamination; they can also block or change the flow of rivers. Mining companies may not restore mining sites back to their original states. Subsurface mining can cause acid mine drainage, where lower pH water from the mine is pumped and drained above ground, lowering the pH of nearby soils and streams. Risks to miners: Subsurface mining accidents are extremely dangerous long term exposure to gases and particles can cause respiratory diseases

+ Mining legislation Governments have sought to regulate the mining process for many years: The Mining Law of 1872 (General Mining Act) – regulates the mining of silver, copper, and gold ore as well as fuels, including natural gas and oil, on federal lands. Written to encourage development and settlement in the western United States, it contains very few environmental protection provisions. The Surface Mining Control and Reclamation Act of 1997 – regulates surface mining of coal and the surface effects of subsurface coal mining. The act mandates that land be minimally disturbed during the mining process and reclaimed after mining is complete Mining legislation does not control all of the practices that can have harmful effects on air, water, and land.

+ Working toward sustainability In the U.S. the Surface Mining Control and Reclamation Act of 1997 requires coal mining companies to restore the lands they have mined. Regulations also require other types of mining operations to do some level of restoration. 1. Fill in the hole or depression in the landscape. 2. Fill material must be relatively free of metals, acids, and other compounds and shaped to follow the preexisting contours. 3. The land must be replanted to re-create the communities of organisms that inhabited the area before mining. Properly completed reclamation makes the soil physically stable so that erosion does not occur and water infiltration and retention can proceed.

+ Uneven distribution of minerals Oxygen, silicon, aluminum, and iron are unevenly distributed over 88 percent of the crust Because of uneven distribution, the global supply of mineral sources are difficult to quantify Countries must trade with one another to obtain important and valuable minerals and metals that are not found within its territories

+ Stop & Think… What were the most important ideas from this section of the lecture? Tell a partner – use your notes if needed. Increasing human populations and industrialization also increase the demand for mined resources: How do you think this will impact… the environment? human health and safety? social and political relationships between different countries? Think like an environmental scientist about your lifestyle: What modern object could you not live without? What components in that object are created from mined minerals (and how would you know)? How would you know about the sustainability of their source? Note-Taking Tool for Audit Proposals: Record your answers For citation purposes, you can put down this lecture title, or refer to Chapters 3 and 19 for more detail.