Introduction to Civil Mining Engineering by nikeborome


									Introduction to Civil & Mining

  Materials Handling - Earthmoving
Open Bowl Scraper Model 631G

                        336 Kw
                        23.7 m^3
                        34 tonne
                        rated load
The Scraper
• The scraper is a self-loading, transporting
  and spreading machine.
• Used on projects such as road and airport
  runway construction, for distances < 3km
• Essentially the earth is cut & loaded directly
  into the scraper box or bowl, transported to
  the discharge area and finally spread in
  layers. The process is a continuous cycle
• Towed & motorised scrapers available
  dependent on the project size
   Excavating Action
                                  • Cutting the bowl is
                                    lowered and apron
                                  • Forward movement, soil
                                    cut boils upwards into the
     Key to diagram:-
                                  • Approx 50-100m of travel
     1 Apron
                                    is reqd. to fill the bowl
     2 Bowl cutting edge
     3 Ejector plate              • Excavate in layers 150 -
                                    300mm in depth
                                  • Discharge occurs on the
Tractor pulled scrapers 8-30m^3     run, height of bowl set
Motorised scrapers 15-5-m^3       • Ejector plate pushes the
heaped capacities.                  soil out
Motorised Scraper
Cat 613C Elevating Scraper
                        131 kW
                        27t loaded
                        12t tare
                        Max speed
                        35 kph in
                        6th. gear
Motorised Scraper
•The scraper frequently requires pushing assistance
during the loading phase, because of loss of traction

•Haul speeds of up to 60km/hr are possible on well graded roads

•Capability example, 20m^3 heaped bowl capacity over
1km haul distance outputs of 150m^3/hr is possible

•The larger scrapers up to 50m^3 capacity may be equipped
with 1 or 2 large diesel engines up to 380kW each
Motorised Scrapers
•   Standard single engine scraper
•   Double engine scraper
•   Four wheeled tractor scraper
•   Self-loading scraper
Output of Motorised Scrapers

                      Ideal output of the
                      motorised scraper

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