1. Mining & Mineral Resources
Chapter 16, Section 2: Mineral Exploration &
Mining
Standards: SEV4a, b, e

2. What are the steps in harvesting
minerals?
 Prospecting- finding places
where ores occur
 Mine exploration &
development- learn whether
ore can be extracted
economically
 Mining- extract ore from
ground
 Extraction- separate ore
minerals from other mined rock
 Smelting & refining- extract
pure mineral from ore mineral
(get the good stuff out of waste
rock)
 Transportation- carry
mineral to market
 Marketing & sales- find
buyers & sell the mineral

3. How do we know where mineral
deposits are located?
 Airplanes can carry instruments that
detect
 Patterns of gravity
Images of the Saline Valley in California.
 Magnetism
Left picture- red indicates trees, white
 Radioactivity indicates snow
 Data is collected, satellite images are Middle picture- short wavelengths used
taken, and a geologic map is created. to identify types of rocks
Right picture- thermal infrared used to
 Rock samples are taken & analyzed for
identify types of rocks that contain
their content & grade valuable minerals. Red indicates quartz
 Test holes are drilled to create a 3D
estimate of the extent of the ore
 This will tell the driller if the amount
and grade of ore is high enough to
warrant the cost of opening a mine.
How Much Does a Mine Cost?

4. 3 Types of Mining
A. Subsurface mining
B. Surface mining
C. Placer mining

5. A. What is subsurface mining?
 Mining of ore deposits 50m
or more below Earth’s
surface. (This is as long as
an Olympic size pool)
 3 types of subsurface
mining:
1. Room & Pillar mining
2. Longwall mining
3. Solution mining

6. 1. Room & Pillar Mining
 Coal & Salt can be mined this
way
 “Rooms” are cut into a coal
seam. Coal seam is a long,
wide, layer of coal.
 The “walls” of the room act as
pillars to prevent collapse.
 After all rooms of coal
removed, the pillars are taken
down starting with farthest
away.

7. 2. Longwall mining
 A shearer machine moves
back and forth along the
coal seam.
 Sheared coal drops onto a
conveyor belt and exits the
mine
 Hydraulic roof supports
are used to prevent
collapse

8. 3. Solution Mining
 Potash, salt, sulfur are soluble
in water
 Hot water is injected into ore
 Ore is dissolved
 Removal of ore from water:
 Compressed air pumped into
dissolved ore and ore trapped
in air bubbles that rise to
surface… or…
 Water evaporates from
dissolved ore leaving ore
behind.

9. B. What is surface mining?
 Used when ore deposits are
located close to Earth’s
surface
 3 types
1. Open Pit Mining
2. Quarrying
3. Solar Evaporation

10. 1. Open Pit Mining
 Soil & rock (overburden) are
removed from top of ore deposit
 Use explosives or heavy machinery
 AKA- mountain top removal
 Loaders remove the exposed coal
 Pit is then refilled with overburden &
covered with soil.
 Some types of ore are taken to heap
leaching ponds where mineral is
removed from the ore rock.
 Gold miners used to use mercury to
extract gold but proved very
poisonous to animals & plants
 Now gold is extracted from ore rock
using cyanide. Cyanide is also very
poisonous.
Bottom picture: Open pit gold mine with
heap leaching cyanide ponds down below.

11. Machine used in open pit mining
Bucket Wheel Excavator- cost $184,400,000
Takes 5 people to operate it, moves 10 meters per minute, power lines have to be removed when
moving it.

12. 2. Quarrying
 Open pit mine that is used
to harvest
 Granite
 Marble Granite quarry in Elberton, GA
 Sand
 Gravel
 Crushed rock (aggregates) LaFarge
Granite
 Clay
Quarry in
 Gypsum Douglasville,
GA
 Talc

13. 3. Solar Evaporation
 Place sea water into
shallow ponds
 Water evaporates and
leaves crystallized salt
behind
 30% of world’s salt
produced this way
 Used largely in developing
countries
Salt evaporation ponds in San Francisco
Bay. The beautiful colors are a result of
harmless bacteria and brine shrimp
that live among the salt. The colors
vary depending on the “age” of the
pond.

14. C. What is placer mining?
 Rock with minerals weathers &
disintegrates
 Minerals carried by water in
streams
 As streams bend, the water slows,
minerals fall out of slower water
and accumulate as placer deposits
 Can also occur along coastline
where waves keep minerals from
moving out to sea.
 Use dredging to remove minerals
 Bucket system that scoops
sediment with minerals from
bottom of body of water.
 Minerals are separated from
sediment
Scoop placer deposits in bucket,
deposit on barge, barge takes to
refinery for separation.

15. How is mineral removed from ore?
 Smelting
 Crushed ore heated to high temps.
 Impurities are trapped by a
material called flux & create slag
that forms a layer on top of the
melted metal which is easily
removed (but toxic)
 Purified molten metal falls to the
bottom of the furnace and is
harvested.
 Heap Leaching
 Using chemicals to dissolve
mineral from ore
 Ex: cyanide used to remove gold
 Ex: sulfuric acid used to remove
copper
Copper can be extracted thru smelting (top)
OR thru heap leaching (bottom).