ENVS 1000 Mining Issues PDF

ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES ENVS 1000 - Environmental Science Environmental Problem: Land Resources – Mining What Land Resources are Mined? What Fossil Fuels are Mined? How is Coal Formed? How are Coal and Metals Mined? What are the Impacts of Coal...

ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES ENVS 1000 - Environmental Science Environmental Problem: Land Resources – Mining What Land Resources are Mined? What Fossil Fuels are Mined? How is Coal Formed? How are Coal and Metals Mined? What are the Impacts of Coal 1  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Rocks in the Earth’s crust provide metals, minerals and fuel resources Gradual and catastrophic geological processes influence distribution of rocks and minerals in the Earth’s crust (lithosphere) and their availability Rock = solid aggregation of minerals Mineral = a naturally occurring solid chemical element or inorganic compound with a crystal structure, a specific chemical composition, and distinct physical properties 2  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Mining = the systematic removal of rock, minerals, soil, or other materials from the Earth’s crust for the purpose of extracting resources of economic interest Earth’s crust is composed of: 1. chemical elements - silicon, iron, aluminum, calcium, potassium, sodium, Sedimentar magnesium, oxygen, y copper, zinc, nickel, cobalt, uranium, phosphorus, etc. 2. rock types (ores, minerals) - Igneous rocks (metals) Igneous Metamorphic - Metamorphic rocks (marble) - Sedimentary rocks 3 From: https://www.geeksforgeeks.org/rock-cycle/  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Metal and Mineral Resources are Distributed unevenly Some resources (e.g. tantalum and diamonds from DRC - Democratic Republic of the Congo) are considered conflict minerals Figure 23.6 from Withgott et al. (2018) 4  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Many resources buried in in the Earth’s crust are extracted to support our needs for metals, rare earth elements (REE) and non-metals CATEGORY EXAMPLES USES Metals cadmium, nickel variety of products - batteries copper, iron, lead, zinc, bauxite metal products, cosmetics gold, silver, platinum currency, jewelry, tools, uranium energy Rare Earth neodymium, europium, terbium, electronics, clean energy, Elements dysprosium, yttrium, tantalum aerospace, automotive, defense Precious Stones diamonds, sapphires, rubies, jewelry, tools emeralds, jade Non-metals asbestos, phosphorus, insulation, fertilizer, industrial potassium, sulfur, gravel, sand processes, building materials Fossil Fuels coal / oil sands energy oil / natural gas energy / various materials 5  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Use of Earth’s Mined Resources Many items we use everyday are made from elements mined from the Earth Figure 23.1 from Withgott et al. (2018)  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Use of Earth’s Mined Resources At current rates of use, a child born in 2015 will use more than 1.4 million kg of minerals and fuel during their lifetime Most of this is for fossil fuels and construction materials Figure 23.2 from Withgott et al. (2018)  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Metals and Rare Earth Elements are Extracted from Ores Metal = a type of chemical element, that typically is lustrous, opaque, and malleable, and can conduct heat and electricity Most metals are not found in a pure state in nature Found in an ore = a mineral or grouping of minerals from which metals are extracted - coltan is the ore from which tantalum is extracted - pyrite is an iron-sulfide ore from which gold, silver, nickel, copper, zinc and uranium are Figure 23.3 from Withgott et al. (2018) extracted 8  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Metals and Rare Earth Elements are processed after Mining Ores must be pulverized and washed before desired metals/ minerals can be physically or chemically extracted Smelting = process of heating an ore beyond its melting point and combining it with other chemicals to extract a metal Copper / nickel smelter at Copper Cliff, Ontario Figure 23.4 from Withgott et al. (2018) 9  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Land Resources are Mined? Other Resources are Extracted and Processed Examples of non-metallic minerals - gemstones, limestone (calcium carbonate), salt (sodium chloride), and potash (source of potassium) Mining of Beach Sand Sand and gravel aggregates are the most commonly mined mineral resources - these are non-metallic, but are useful for making products such as concrete and building materials Similar mining technologies are used for all resources with similar environmental problems resulting Will now focus on the mining of fossil fuel resources 10  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What Fossil Fuels are Mined? Fossil fuels used today were formed under anaerobic environments (in absence of oxygen) from organisms that lived 100 to 500 million years ago Organic matter is converted into fossil fuels (under pressure and heat) Types: 1. coal 2. oil 3. natural gas 4. others 11  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Formed? World’s most abundant fossil fuel – long history of use From: https://socratic.org/questions/how-does-the-formation-of-coal-differ-from-that-of-natural-gas-and-oil 12  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Formed? Major Types of Fossil Fuels - Coal Figure 16.5 from Withgott et al. (2013) 13  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Formed? Major Types of Fossil Fuels - Coal Infographic 19.3 from Branfireun et al. (2014) 14  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How are Coal and Metals Mined? Coal mining is similar to most other mining activities (e.g. for metals and minerals) – extractive process Coal is found concentrated in coal “seams” found in an ore, (= the rock in which valuable materials have been concentrated over time by geological processes – typically in minerals like quartz, clays, feldspars, sulfides, and carbonates) Coal Seam 15  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Mined? Mining Activity Systemic removal of surface rock, soil, or other material to extract buried coal deposits Mining focuses on highest concentrations of coal in surface or underground “coal seams” 16  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Mined? Types of Mining Methods for Coal 1. Strip Mining = heavy machinery removes huge amounts of earth to expose and extract resource Infographic 19.4 from Branfireun et al. (2014) 17  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? 1) Strip Mining – leads to development of open pit mines Open pit mines are so massive because of the amount of waste rock that must be removed to extract small amounts of ore of economic interest Figure 23.10 from Withgott et al. (2018) 18  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES How is Coal Mined? Types of Mining Methods for Coal and Metals 2. Subsurface Mining = underground deposits reached by digging vertical shafts deep underground and excavating networks of horizontal tunnels that are dug or blasted out to follow the underground ore deposits containing minerals/metals 19 Infographic 19.5 from Branfireun et al. (2014)  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal and Metal Mining? Mining and Processing Coal have Environmental Costs and Human Health Costs Methods (for metals and coal) are water- and energy-intensive Coal mining in particular have serious human health impacts (e.g. mining accidents, black lung, lung cancer, etc.) Numerous environmental impacts from coal mining: (1) strip mining / open-pit mining (2) subsurface mining (3) waste rock (gangue) (4) tailings (5) acid mine drainage (AMD) (6) mountaintop mining (7) air pollution 20  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? ) Strip Mining or Open Pit Mining Layers of soil and rock are removed to expose the resource Overlying soil and rock is removed by heavy machinery Used for coal, oil sands, sand, gravel and some metals Destroys natural communities over large areas and triggers erosion and habitat loss, surface and groundwater pollution 21  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? (2) Subsurface Mining Commonly used with coal Deepest mines extend nearly 4 km underground Most dangerous form of mining - dynamite blasts, collapsed tunnels, toxic fumes, coal dust Subsurface mines can affect people years after they close - acid drainage, polluted groundwater - sinkholes - damage roads and homes, etc. 22  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? (3) Waste Rock (Gangue) Waste rock and non-valuable minerals removed before extraction (= overburden) Used for roads, railbeds, dams 23  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? 4) Tailings Ore left over after coal (or metal) has been extracted Pollutes soil and water May contain heavy metals or acids (e.g. sulfuric acid) Water evaporates from tailings ponds, which may leach pollutants into the environment (air, surface water, groundwater and land) 24  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? Oxidized Tailings 4) Tailings - Orange colour due to ferric sulfates formed by bacteria that use ferrous sulfides as an energy source resulting in the production of sulfuric acid Reduced Tailings - Black colour due to ferrous sulfides 25  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? ) Acid Mine Drainage (AMD) Sulfide minerals form sulfuric acid and flow into surface waterways and into groundwater As the sulfuric acid runs off, it leaches metals from the rocks, that are toxic Toxic liquid is called leachate 26  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? ) Acid Mine Drainage (AMD) 27  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? (6) Mountaintop Mining Entire mountaintops are blasted off and the waste is dumped into valleys (valley filling) For coal in the Appalachian Mountains of the eastern U.S. Economically efficient Environmentally costly ̶degrades and destroys vast areas ̶pollutes streams, deforests areas, erosion, mudslides, and flash floods 28  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? (6) Mountaintop Mining People living in communities near the sites experience social and health impacts - mine blasting cracks foundations and walls - floods and rock slides affect properties - overloaded coal trucks speed down rural roads - coal dust/contaminated water cause illness 29  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are the Impacts of Coal Mining? (7) Air Pollution from Impurities in Coal Sulfur, mercury, arsenic, lead and other trace metals released from coal-fired power plants Sulfur content depends on whether coal was formed in salt water or freshwater (e.g. coal in eastern U.S.) When high-sulfur coal is burned, it released sulfate air pollutants, which contribute to smog and acidic deposition – mercury can bioaccumulate / biomagnify through food chains/webs Ways to reduce pollution must be found (e.g. scrubbers) 30  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are Reclamation Methods? Restoring Mining Sites can be Very Challenging Governments in developed countries require companies to reclaim (restore) surface-mined sites In Canada, companies are required to post bonds to cover reclamation costs before mine development is approved - some countries have no regulations Reclamation aims to bring a site to a condition similar to its pre-mining condition - remove structures, replace 31  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are Reclamation Methods? Restoration of Mined Sites Even on restored sites, impacts may be severe/long-lasting Complex communities are simplified - forests, wetlands, etc. are replaced by grasses Essential symbioses are eliminated and often not restored Water can be reclaimed - remove heavy metals - pH is moderated 32  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES Summary of Mining Impacts Review this figure From: https://www.sciencedirect.com/science/article/pii/S0301479720315486 33  ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES Conclusion Mining of coal, metals (e.g. copper, gold, iron, nickel, silver, uranium, zinc, etc.), rare earth elements (e.g. lithium, tantalum, etc.) and minerals (e.g. aggregates, gravel, sand, etc.) all use similar extraction methods that have similar impacts on the environment Short-term - need to modify methods to reduce environmental impacts Long-term – need to find alternatives for the materials extracted through mining (all of which are limited resources) Higher consumption habits in the developed countries and increasing demands from higher populations in the developing countries have increased impact of mining worldwide Economically, there is a move towards incorporating external costs of mining into cost of products – will push towards more sustainable options (e.g. recycling, reprocessing, researching alternatives) 34 ENVS 1000 – PROBLEMS: LAND RESOURCES – MINING ISSUES What are your Questions? 35