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Underground mining methods .pptx
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- 2. Introduction Undergroundmining When do we go for underground mining Mining terminologies Surface mining Differences between underground and surface mining OUTLINE OF MY PRESENTATION
- 3. ♦ The processof extracting precious resources from the earth is known as mining, such as fossil fuels, minerals, and even water. Miners usually determine the type of mining depending on the type and position of the ore body. Each mining method also has other safety and environmental impact levels, for legitimate mining operations. ♦ This presentation will focus on two main types of mining which are underground (sub-surface) and surface mining methods. Moreover, it will also clarify the differences between them. INTRODUCTION
- 4. Underground miningis a technique used to access ores and valuable minerals in the ground by digging into ground to extract them. Minerals ore deposits are exploited from beneath INTRODUCTION
- 5. Ore depositis deep. Where surface mining is not economical. Certain conditions which surface mining is not permissible. such as- If there is reserve forest. If there is river flowing beside or one the ore deposit. If there is habitation area. When do we go for underground mining?
- 6. Shaft: Primaryvertical or near-vertical opening, connecting the surface with underground workings; also vertical shaft. Slope: Primary inclined opening, usually a shaft, connecting the surface with underground workings; also vertical shaft. Drift: Primary or secondary horizontal or near-horizontal opening, oriented parallel to the strike of a pitching deposit. Entry:-secondary horizontal or near-horizontal opening, usually driven in multiples. Raise: underground opening driven upward from one level to a higher level or to the surface Mining Terminology
- 8. Room andpillar is a method employed in underground mining in which rooms are cut into the coal bed and pillars of ore are left to provide support. This method is usually employed when ore is positioned in flat and narrow deposits. The room and pillar method also helps control the flow of air within the mine. Most underground coal mining is completed by this method. It is a popular mining method for underground mining in tabular and lenticular deposits. Room and pillar mining is usually used while extracting coal, iron, and copper ores; it is best suited for deposits that are relatively flat. Rooms generally are 2,067 feet (630 m) wide and pillars are up to 328 feet (100 m) wide. Room and pillar mining:-
- 9. Figure of roomand pillar mining
- 10. Shrinkage stopingis a mining method used to extract ore from narrow, steeply dipping ore bodies with regular boundaries. Miners drill and blast holes in a slice of intact ore, then remove 30–40% of the broken ore to create space for the next slice. The miners then work off the newly blasted ore. Shrinkage stoping is best for ore bodies that are 70–90° steep, with strong ore and waste, and where the ore won't oxidize in the stope Shrinkage stoping
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- 12. Sublevel stopingis a mining method that involves blasting ore from different levels and removing it from the bottom of the mine. Sublevel stoping
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- 14. Cut-and-fill isthe most common of these methods and is used primarily in steeply dipping metal deposits. The cut-and-fill method is practiced both in the overhand (upward) and in the underhand (downward) directions. As each horizontal slice is taken, the voids are filled with a variety of fill types to support the walls. The fill can be rock waste, tailings, cemented tailings, or other suitable materials. Cut-and-fill mining is one of the more popular methods used for vein deposits and has recently grown in use. Cut-and-fill mining
- 16. Block cavingis a mining method that uses gravity and rock stresses to break large masses of rock into pieces that are easier for miners to handle. Block caving is achieved by undercutting the ore body and inducing gravity to drop the ore into collection points. First, a “grizzly” level and haulage tunnel are put in below the undercut level. Then, a large “undercutting” or series of flat lying tunnels are driven into the orebody. Block caving
- 18. It hasminimal surface disruption. High productivity and efficiency. It requires higher cost and energy. The inside tunnel can be dangerous for both radiation and toxic gases. Underground tunnel causes surfaces subsidence. This mining method needs more human resources. Advantages and Disadvantages of Underground mining
- 19. Surface miningis the process of removing the soil and rock that covers mineral deposits to extract ores near the Earth's surface Access to the ore body First, Miners use earthmovers to remove the overburden in all surface mining methods. The ore is then removed with bucket-wheel excavators and shovel loaders and loaded into haul trucks. Surface Mining
- 20. Strip Mining:Strip mining gets its name from the fact that the process involves stripping the surface away from the mineral that’s being excavated (usually coal). This type of mining makes sense when the mineral is near the surface. If the ore is too far under the surface, the process of strip mining becomes impractical and needlessly damaging to the terrain. Open-pit mining: Open-pit (Opencast)mining is a method of extracting rock or minerals from the ground by removing them from an open-air pit, also known as a borrower. Methods
- 21. Mountaintop Removal:is a type of surface mining at a mountain’s summit or summit ridge. The process involves blasting the overburden with explosives above the mineral seam to be mined. The broken mountaintop is then shifted into valleys and fills below. This type of mining is used when the ore to be retrieved is 400 feet or deeper. Dredging: Dredging is a term used to describe removing. Dredging is the process of using floating equipment to excavate a placer deposit underwater. Depending on the method of material transport, dredging systems are categorized as mechanical or hydraulic. Methods
- 22. Most ofthe surface mines recover quickly. About 95 – 100% of mines recover after the mining is done. Surface mining is less expensive It also doesn’t require more human resources than underground mining. Explosive and heavy machines cause sound pollution. Advantages and Disadvantage
- 23. Differences between undergroundand surface mining Content Underground Mining Surface Mining Type Underground mine needs tunnels through the earth under the earth’s surface. Surface mining is open under the sky. Complexity More hazardous and complex to access the ore body Much easier for miners to access materials Risks Risky and dangerous to reach the underground ore Less risk compared to underground mining Ore grade High-grade ores Low-grade ores Labors Require more laborers to operate the tunnels and mining Require less labor than underground mining. Cost Costly and efficient Cost-effective Productivity 500 to 800 tonnes per day 5000 to 100000 tonnes per day The Mine Life To > 100 years 10 to 25 years, rarely longer.
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