4 mining and its impacts to environment
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- Mining involves extracting valuable minerals from the earth through various surface and underground methods. Surface methods include strip mining, open-pit mining, mountaintop removal, and dredging. Underground methods involve excavating tunnels and shafts. - The extraction process produces both ore and waste rock. Ore undergoes crushing, grinding, and separation processes like flotation and cyanidation to extract minerals. - Mining has environmental impacts like flooding, erosion, water and air pollution, and wildlife habitat damage. Preventive measures include replanting vegetation and stabilizing slopes. The government regulates mining through agencies like MGB and EMB and laws like the Mining Act.
4 mining and its impacts to environment
- 1. Mining and its Impacts to Environment
- 2. Learning Objectives • Describe how ore minerals are mined and processed for human use • Cite ways to prevent or lessen the environmental impact that result from the exploitation, extraction, and use of mineral resources
- 3. • Answer this question Would you allow large scale mining operation to operate in your locality? Explain your answer.
- 4. Group Activity • “Role Playing – MININANG BAYAN” • Imagine yourself living in impacted mining areas and conceptualize realistic scenario for role playing. - Class will be grouped into two. - Each group is given 10 minutes to dramatize the scenario(s).
- 6. What is Mining? • Is the extraction of valuable minerals or other geologic materials from the earth from an ore body, lode, vein, seam, reef or placer deposits which form the mineralized package of economic interest to the miner.
- 7. Mining Methods 1.Surface Mining – broad category of mining in which soil and rock overlying the mineral deposit are removed
- 8. Types of surface mining 1. Strip Mining – removing a long strip of overlying soil and rock practical when ore body is relatively near the surface coal and lignite two forms: area stripping and contour stripping
- 11. Types of surface mining 2. Open-pit mining – extracting rock or minerals from the earth through their removal from an open pit or burrow
- 13. Types of surface mining 3. Mountaintop removal – is a form of coal mining that mines coal seams beneath mountaintops by first removing the mountaintop overlying the coal seam. explosive are used to break up rock layers critics: disastrous practice
- 15. Types of surface mining 4. Dredging – method for placer mining below the water table mostly associated with gold mining large scale : used floating dredge (barge like vessel )
- 17. Underground 2. Underground mining – extracting minerals and ores that are buried too far underground to be mined using surface mining methods. Mining Methods
- 19. • Adits - is an entrance to an underground mine which is horizontal or nearly horizontal, by which the mine can be entered, drained of water, ventilated, and minerals extracted at the lowest convenient level
- 20. • Shaft mining or shaft - refers to the method of excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom.
- 21. • Drift mining – involves cutting an opening horizontally into the side of a mountain or hillside to access a mineral seam - creation of a drift, a tunnel dug and driven directly along a horizontal path
- 22. • Tunnel
- 24. Milling Process • Materials extracted or “mined” are rocks composed of both ore and waste material • Extracted rocks undergo process of mineral (e.g metal) separation and recovery • Crushing and screening are the first stages of controlled size reduction followed by grinding where rocks are pulverized.
- 25. Milling or Recovery Processes 1. Heavy media separation – crushed rock are submerged in liquid where the heavier/denser minerals sink (separate from lighter minerals)
- 27. 3. Floatation – powdered ore is placed into an agitated frothy slurry where some minerals and metals based on physical and chemical properties may either sink to the bottom or may stick to the bubbles and rise to the top thus separating the minerals and metals from waste
- 29. 4. Cyanide heap leaching – used for low-grade ore where the crushed rock is placed on a “leach file” where cyanide solution is sprayed or dipped on top of the file. as the leach solution percolates down through the rocks, the gold is dissolve into the solution The solution is processed further to extract the gold
- 31. Environmental Impacts • Flooding • Erosion • Subsidence • Water and air pollution • Damage to wildlife and habitat
- 41. Impact Preventive Measures • Topsoil replacement using uncontaminated soil • Reintroduction of flora and fauna • Neutralizing acidic waters • Backfilling and sealing of abandoned underground mines • Stabilizing the slope to reduce erosion
- 44. Laws • RA 7942 – The Philippine Mining Act • EO 79 – People’s Small Scale Mining Areas
- 45. Role of Government • Mines and Geoscience Bureau (MGB) – Undertake final evaluation of all mining application, conduct audit of the disposition of mineral lands and resources, and manage the Mineral Rights Management System • Environmental Management Bureau (EMB) - Issued ECC and monitor its commitments and compliances
Editor's Notes
- #12: -sometimes mistakenly referred to as "strip mining"
- #14: - Explosives are used to break up the rock layers above the seam, which are them removed
- #24: winze is a minor connection between different levels in an underground mine
- #26: - Also called sink-and float separation
- #29: -METAL BUBBLES
- #30: a series of chemical reactions that absorb specific minerals and then re-separates them after their division from other earth materials
- #33: -carascal