Chapter 15 Minerals: A Non-renewable Resource

1. Chapter 15Minerals: A Non-renewable Resource

2. Overview of Chapter 15 • Introduction to Minerals • Mineral Distribution and Formation • How Minerals are Found and Extracted • Environmental Impact of Minerals • An International Perspective • Increasing the Supply of Minerals • Substitution and Conservation

3. http://www.youtube.com/watch?v=RPixjCneseE&feature=related • http://www.youtube.com/watch?v=GZoQ5Gw0r7Q&feature=channel

4. Introduction to Minerals • Minerals • Elements or compounds of elements that occur naturally in Earth’s crust • Rocks • Naturally formed mixtures of minerals • Ore – rock with large amount of mineral

5. Introduction to Minerals • Examples of Minerals • Nonmetal: salt, sand, stone • Metal: copper, aluminum, iron

6. Mineral Distribution • Abundant minerals in crust • Aluminum and iron • Distributed unevenly across globe • If found in low abundance, mining is not profitable

7. Mineral Distribution • US imports over 50% of its most needed • Depleted reserves leads to mining of lower grades which needs more processing and produces more pollution • Examples of distribution of global reserves • Oil: Middle East • Natural Gas: Middle East • Coal (largest source of fuel for electricity): China • Diamonds - Africa • Gold – S. Africa • Six tons of waste to make 2 gold rings

8. Formation of Mineral Deposits • Result of natural processes • Magmatic concentration (igneous) • As magma cools heavier elements (Fe and Mg) settle • Responsible for deposits of Fe, Cu, Ni, Cr • Hydrothermal processes • Minerals are carried and deposited by water heated deep in earth’s crust • Sedimentation • Weathered particles are transported by water and deposited as sediment on sea floor or shore • Evaporation • Salts are left behind after water body dries up

9. Extracting Minerals • Surface Mining • Remove overlying soil/rock (overburden) and then scoop out minerals • More common because less expensive • Two kinds: open pit and strip mining (ex: mountain top removal for coal) • Subsurface Mining • Mineral and energy resources are extracted from deep underground deposits • Two kinds: shaft mine and slope mine • Disturbs land less, more expensive, more dangerous

10. Extracting Minerals-Open Pit Surface Mining

11. Relevant laws • Surface Mining Control and Reclamation Act (1977) – requires reclamation of land mined for coal

12. Reclaiming of Mining lands • Reclaim to semi-natural state • Prevent further erosion • Control source of toxic pollutants • Giving purpose to land other than mining

13. Reclaiming of Mining Land • Creative Approaches • - Wetlands • Trap sediment and pollutants before they get into streams, improving water quality • Expensive to create and maintain, but cost effective compared to using lime to decrease acidity • - Phytoremediation • Use of specific plants to absorb and accumulate toxic materials in soil • Great potential

14. Environmental issues • Toxic heavy metals: tailings - wastes after processing, toxic (cyanide, mercury, sulfuric acid) – pollute air, soil, water • Acid mine drainage • Smelting – air pollution, mainly sulfur emitted, reacts with oxygen to form sulfur dioxide which reacts with water form to sulfuric acid. Also, cadmium (cancer), lead (neurotoxin) into air • Massive energy usage – mostly fossil fuels (depletes reserves and produces CO2) • Massive water usage • Destroys vegetation • habitat loss, erosion

15. Processing Minerals • Smelting- process in which ore is melted at high temps to separate impurities from the molten metal

16. Environmental Impacts of Refining Minerals

17. Will We Run Out of Important Metals? • Mineral Reserves • Mineral deposits that have been identified and are currently profitable to extract

18. Mineral Conservation • Includes reuse and recycling of existing mineral supplies • Reuse- using items over and over again • Reduces both mineral consumption and pollution • Benefits greater than recycling – less energy inputted • Recycling- converting item into new product • Common practice throughout industrialized world • Reduces land destruction from mining • Reduces solid waste • Decreases energy consumption and pollution

19. North American Consumption of Selected Metals

20. Changing Our Mineral Requirements • Must change out “throw away” mentality • Damaged or unneeded articles are thrown away

21. Minerals: An International Perspective • Highly developed countries rely on mineral deposits in developing countries • They have exhausted their own supplies • Governments in developing countries lack financial resources to handle pollution • Acid mine drainage • Air and water pollution

22. Increasing Supply of Minerals –Locating and Mining New Deposits • Many known mineral deposits have not yet been exploited • Difficult to access • Ex: Malaria ridden forests of Indonesia • Insufficient technology • Ex: polar regions • Located too deep • Ex: 10km or deeper

23. Increasing Supply of Minerals –Minerals in Antarctica • No substantial mineral deposits identified to date • Geologists feel they will be discovered in near future • No one owns Antarctica • Antarctica Treaty (1961) • Limits activity to peaceful uses (i.e. scientific studies) • Madrid Protocol (1990) • Moratorium on mineral exploration and development for minimum of 50 years

24. Increasing Supply of Minerals- Minerals from the Ocean • May provide us with future supplies • Extracting minerals from seawater • Mining seafloor- Manganese nodules (below)

25. Advance Mining and Processing Technologies • Special techniques to make use of large, low-grade mineral deposits world-wide • Currently requires a lot of energy • Biomining • Using microorganisms to extract minerals from low-grade ores

26. Finding Mineral Substitutes • Important goal in manufacturing • Driven by economics- cut costs! • Substitute expensive/scarce mineral resources for inexpensive/abundant ones • Examples: • Using plastic, glass or aluminum in place of tin • Using plastic instead of lead and steel in telecommunications cables • Using glass fibers instead of copper wiring in telephone cables

27. Mineral Flow in an Industrial Society