MINN1001

Surface Mining Methods

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Surface Mining

Quarrying

Granite, marble, limestone – valuable for mechanical or chemical properties

Massive or bedded orebody

Usually on hillsides

Usually small, cheap operation

Example of a quarry

Surface Mining

Open Pit

Copper, uranium, gold, tin, etc.

Can be kilometres long by 100’s of metres deep

Size of excavation exceeds volume of ore

Large, capital intensive operations

Original ground surface

Ore bodies

Benches

Bench height+/- 15 m

Bench width6 – 20 m

Bench slope

Pit slope

Example of Open Pit: Palabora

El Chino Mine, New Mexico (USA)

Open Pit Blasting

Open Pit Blasting

Open Pit Blasting

Open Pit Blasting

Open Pit Blasting

Open Pit Blasting

Open Pit Blasting

Surface

Volcanic pipe containing diamonds

Shaft

Open Pit to Underground Mining

700 m

Kimberley, today

Surface Mining

Strip Mining

Mostly relatively shallow coal

Flat dipping

+/1 1 000 m long by 50 – 80 m wide

Large, capital intensive operations

Ongoing rehabilitation part of process

Basics of Strip Mining

Step 1: Remove topsoil, store elsewhere Topsoil

Rock

Coal

Basics of Strip Mining

Step 2: Create boxcut, place spoil next to cut

Basics of Strip Mining

Step 3: Remove coal

Basics of Strip Mining

Step 4: Repeat, place spoil in pit

Basics of Strip Mining

Step 6: Repeat, replace topsoil when space available

Basics of Strip Mining

Step 7: Repeat, replace topsoil when space available

Basics of Strip Mining

Step 8 etc: Continue cycle

Basics of Strip Mining

Step 8 etc: Continue cycle

Basics of Strip Mining

Final phase: Place first spoil in final void

Basics of Strip Mining

Final phase: Complete final rehabilitation

Basics of Strip Mining

Basics of Strip Mining

Rehabilitation Complete

Basics of Strip Mining

Highwall

+/- 20o

450 - 600

Low-wall

6 - 10 m20 – 50 m

Strip Mining

Rough dimensions

10 – 80 m

Satellite view of Strip Mine

Mining direction

PitSpoils

Levelled Spoils

Rehabilitated

Spoil pile prior to grading

Rehabilitated

Spoil Piles

Some examples of equipment

Truck and Shovel

Truck

Dragline

Interesting facts….

Boom length 100 m

Bucket capacity 50 – 100 m3

Loading rate 3 000 – 5 000 m3 / hr

Bucket travelling rate 40 – 50 km/hr

Dragline in Operation

Inside Dragline

Bucket Wheel Excavator, Germany

Some Examples of Rehabilitation

Spoils water drainage and re-vegetation, Korea

Passive water purification, Korea

Active water purification, Korea

Kang-Won Land, Korea

Butte Chaumont Park, Paris

Butte Chaumont Park, Paris