Mining - Environmental Impact and Resources

Mining  Ore: these are commercially valuable deposits of minerals that are harvested and collected for use as raw materials Let’s talk about Metals: elements that conduct electricity, heat, and have properties that are goo...

Mining  Ore: these are commercially valuable deposits of minerals that are harvested and collected for use as raw materials Let’s talk about Metals: elements that conduct electricity, heat, and have properties that are good for building mining… things. Reserves: the amount that we have left that can be mined. Usually measured in years left of extraction.  How long will our supplies of minerals last?  Good – we have abundant deposits of iron and aluminum  Bad – Deposits of chromium, manganese, cobalt, and platinum  Ehhh – deposits are not found equally around the world and often need trade agreements  US, Canada, Russia, South Africa, and Australia supply most of the modern world with nonrenewable minerals  Sharp rise in per capita use of minerals since the 1950s  US depends on imports of more than 50% of the 24 most important nonrenewable mineral resources  Strategic resources – manganese, cobalt, chromium, platinum  Future Supply  Actual/potential supply of minerals  Rate at which we use them  We won’t run out of them completely, but like some of our food they will become economically depleted because we will spend more than we will get out of it.  Market prices Rare earth elements are a group of metals that are critical ingredients for a greener economy, and the location of the reserves for mining are increasingly important and valuable. Most rare earth elements find their uses as catalysts and magnets in traditional and low-carbon technologies. Other important uses of rare earth elements are in the production of special metal alloys, glass, and high-performance electronics. REEs, also called rare earth metals or rare earth oxides, or lanthanides, are a set of 17 silvery-white soft heavy metals.  Grading Low grade ore - deposit mixture thtt has a small amount of the desired ore High Grade – deposit that has a large amount of desired mineral In order for us to make it worth it when we dig, we have to be able to make a profit. Gangue – worthless material that surrounds the ore  Smelting This is a process that uses heat and chemicals to turn ore into usable material.  So why do we mine? Advantages Disadvantages  Income and profit for materials  Uses tons of energy  Revenues for cities, states, and  Soil erosion countries  Habitat destruction  Jobs  Produces a lot of waste, air , water, and soil pollution Surface Mining This is when we remove the overburden to get to the ore underneath TYPES: Open pit, strip, mountaintop removal, and placer Mountaintop removal = very damaging to landscape, habitats, and streams Used in upwards of 90% of nonfuel/rock resources Used in up to 60% of coal removal  Mountain Top Removal Removal of vegetation & soil  Topsoil erosion  Habitat loss  Increased stream turbidity  Increased PM in air When ore on the surface become harder to find, we move to underground mining Subsurface mining  Often used for deep coal deposits and metal ores  More expensive due to higher costs for workers (insurance and healthcare)  Risks: poor ventilation leading to toxic gas exposure, mine shaft collapses, lung cancer (Black lung), asbestos, fires, explosions  Increasingly used as surface coal deposits are depleted   Rainwater carries sulfuric acid into nearby streams or ground water  Lowers pH of water, toxic metals like Hg and Al more soluble Environmental  Methane release: coal mining releases methane gas (CH4) from rock around coal Impact  Vented out of mines so explosions can’t happen and continues after mine closes  PM release - soot and other particulates that irritate lungs for both humans and animals Acid mine drainage: rainwater leaks into abandoned mine tunnels & mixes with pyrite to form sulfuric acid Mining Leftovers Overburden: Soil, vegetation, & rock that are removed to get to the ore deposit underneath. Tailings and slag: leftover waste material separated from the valuable metal or mineral within ore (stored in ponds and water holds at site) Mine Reclamation Restoring the land back to the original state after mining Fill empty mine shafts and holes Restore original contours Return topsoil, with acids, metals, and tailing removed Replanting native plants to restore community to as close to original state as possible  Surface Mining Control and Reclamation Act of 1977  Establish a program for regulating surface coal mining and reclamation activities  Establishes mandatory uniform standards for these activities on state and federal lands, including a requirement that impacts fish, wildlife, and related environmental concerns to be minimized  Creates an abandoned mine reclamation fund for use in reclaiming and restoring land and water resources adversely affected b y coal mining