1. Topic 1: Types of ore Bodies and Mine Processes
Extraction
Open Pit
Strip Mining
Underground
Crushing
Initial
Autogenous Circuit
Beneficiation
Physical
Chemical
Electrochemical
Smelting

2. Types of Ore Massive: base metal Cu, Ni, Zn Disseminated: gold,
INCO Thompson Ni ore
Massive: base metal Cu, Ni, Zn
Disseminated: gold,
Diamonds
Snow Lake
0.16 oz Au / tonne
Ekati, NWT, Diamonds
Bissett Au

3. Bedded Ore bodies Potash, Saskatchewan Syncrude, Oil sands,
Fort McMurray
Black Thunder Coal Mine Wyoming, USA

4. Extraction process depend on shape, position and value of ore body
Open Pit
Strip Mining
Underground Mine
Dissolution: potash, uranium,
In situ mobilization: oil shale
Heap Leach
What are the major environmental issues related to each form of extraction?

5. Open Pit Bingham Canyon Cu Mine Ekati Diamond Mine
Note: The amount of waste rock to be removed to provide reasonable gradient for trucks.
Only efficient for large ore bodies close to the surface
Can be useful for dumping mine waste at closure

6. Strip Mining Very efficient for high level flat lying ore bodies.
Overburden and top soil can be replaced minimizing environmental damage

7. Underground

8. Dissolution: potash, uranium In situ mobilization: sulfur, oil shale
NaCl or KCl dissolved in water
Acid in situ leach of metallic ore
Hot water or steam used to mobilize sulfur or oil

9. Heap Leach
Landusky, Montana, CN Heap Leach Gold Mine

10. Crushing
Ore bearing and non ore-bearing rock will be separated as soon as possible
What happens to non-ore-bearing rock?
Ore-bearing rock will be crushed to the size necessary to liberate the required mineral
Heap leach requires only very coarse crushing
Much finer crushing for gold and PGE as they
are enclosed within other mineral grains
Initial crushing underground
In mill, crushing in autogenous circuit with
feedback of large particles
Final crushing in rod or ball mills

11. Beneficiation (Extraction of metal from rock/mineral)
Physical techniques
Gravity
Gold from quartz
Diamonds
Tantalum
Flotation
Sulphides from silicates
Cu and Ni sulphides
NaCl from KCl
Chemical Techniques
CN leaching
Roaster oxidizes sulphide to SO2
Smelting
Electrochemical Refining of pure metal
Consider the waste generated at each stage

12. Gravity Separation
Whiffle table
Separator
Fine grained waste goes to tailings pond. What does it contain?

13. Flotation Cells
Ore becomes attached to air bubbles, float, and are collected.
Gangue sinks to the bottom of the flotation cells and piped to tailings pond
Chemicals added include:
Frothers: pine oils & alcohols promote the formation and stability of bubbles.
Collectors promote adherence of air bubbles to the mineral.
Conditioners: make the surface of the mineral particle either more or less susceptible to concentration.
Activators e.g. copper sulfate, lead nitrate, lead acetate
Depressants e.g. sodium cyanide, zinc sulfate

14. Chemical Separation Cyanide leaching for gold
at pH 11
gold retrieved by Merrill Crowe (precipitation on zinc dust) or Carbon in Pulp (CIP) process
Roaster oxidizes sulphide to SO2
Releases metal for refining and SO2 to the atmosphere unless scrubbers are in place

15. Smelting Separates remaining silicates from metals
Slag (molten silicates) pored off
Metal pores into bars or sent for final electochemical refining