1 / 57

Mining

Mining. And its environmental impact. Outline. 1. Types of Mining (and why we use them) 2. Beneficiation 3. Smelting 4. Environmental Concerns of 1 through 3. What determines the type of mining?. Underground v.s. Surface Mining v.s. Solution Depth of below surface

kaiser
Télécharger la présentation

Mining

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mining And its environmental impact

  2. Outline • 1. Types of Mining (and why we use them) • 2. Beneficiation • 3. Smelting • 4. Environmental Concerns of 1 through 3

  3. What determines the type of mining? • Underground v.s. Surface Mining v.s. Solution • Depth of below surface • Size of the ore body • Shape of the ore body • Grade • Type of Ore

  4. Depth and Size

  5. Shape of Ore Body

  6. versus

  7. Type of Ore • Is the ore mineral soluble in water? • Can the ore be melted?

  8. What are the types of mining? • Surface • Strip • Open Pit • Placers--Dredging • Underground • Solution

  9. When do you use Surface Mining? • Large tonnage • High rates of production • Overburden (including rock) is thin

  10. Strip Mining of Coal Kansas Geological Survey

  11. Open Pit Mining

  12. Some photos and machinery used in open-pit mining

  13. ?Dinky Toy?

  14. Drilling in pit

  15. Crushing in pit

  16. Loading ore in pit

  17. Underground Mining

  18. When do we mine underground? • The ore deposit is deep • Ore body is steep • Grade is high enough to cover costs

  19. Some types of underground mining • Room and Pillar • Cut and Fill • Long wall (coal) • Shrinkage Stoping • Block Caving

  20. Room and Pillar

  21. Cut and Fill

  22. Long Wall

  23. Shrinkage Stoping

  24. Block Caving www.ivanhoe-mines.com/s/Mongolia_ImageGallery

  25. Solution Mining

  26. Beneficiation Means of separation of ore mineral from waste material (or gangue minerals) Also known as Liberation

  27. What does it entail? • Crushing and Grinding • Ball mill or rod mill • Separation • Density (e.g. diamonds with a jig) • Magnetic properties • Electric properties • Surface properties

  28. Refining the Ore Smelting removes the metal from the ore mineral by a variety of ways Heap Leaching removes metal from the ore by solution

  29. Iron in review • Blast Furnace • 3CO + Fe2O3 2 Fe + 3CO2 (gas) • 4CO+Fe3O4 3Fe + 4CO2 (gas)

  30. Sulphide Minerals • Are sometimes roasted • Heated in air without melting to transform sulphides to oxides • Gives off H2S and SO2 • Then oxides processed like Fe

  31. Sulphides cont’d • Process of roasting and smelting together creates a matte • Sulfides are melted into a matte and air is blown through. S is converted to sulfur dioxide and Fe to iron oxide, and Cu and Ni stay in melt

  32. Smelting

  33. Result at Kidd Creek

  34. Sulphides cont’d • Solvent extraction/electroplating • Used where rock contains Cu but in too little amounts to be recovered by classical methods

  35. Heap Leaching • In this process, typically done for Au, the ore is not ground, but rather, crushed and piled on the surface. • Weak solutions of NaCN (0.05%) percolate through the material leaching out the desired metals. • The solutions are collected and the metals are precipitated

  36. Potential Environmental Problems • A. Mining operation itself • Disposal of a large amount of rock and waste • Noise • Dust • Beneficiation • Smelting and refining

  37. From Underground Mining • Subsidence • Block/caving • Room and pillar • Salt mining (Droitwich)

  38. Subsidence in rancher’s field

  39. Subsidence from Pb-Zn mining

  40. From Underground • Acid Mine Drainage • FeS minerals in coal • Sulphide deposits • Acidic streams can pick up heavy elements and transport them

  41. Rock that has acid forming material

More Related