Introduction to Civil

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Introduction to Civil Mining Engineering
Materials Handling - Bull Dozers
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Bulldozers

• Are very versatile machines frequently used for
• Stripping top soil clearing vegetation
• Shallow excavations
• Pushing Scrapers
• Maintaining haul roads
• Opening up pilot roads
• Spreading grading
• Ripping

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Bulldozers dozers
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Bulldozers dozers
Liebherr Bulldozer
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Bulldozers dozers
Caterpillar Bulldozer
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Bulldozer

• The dozer normally operates with a straight
  blade, fixed perpendicular to the line of
  movement, to push material forward, or angled to
  move the soil to the side.
• Tractors may be fitted with a rear mounted
  ripper.
• Output falls off in direct proportion to the
  pushing distance.
• Shovels trucks should be considered for pushes
  over 30 meters.

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Bulldozers dozers
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Dozer Blades

• Properly matching tractor dozer blade is a
  basic requirement for maximizing production
• First consider the kind of work the tractor will
  be doing most of its life. Then evaluate
• Material to be moved
• Tractor limitations
• Blade capacities

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Landfill Dozer Blade
24m3 capacity, 2.2m width
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Cushion Dozer Blade Pusher Blocks
8.75m3 capacity, 1.6m width, D9N
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Dozer w/- Reclamation U- Blade
30m3 capacity 2.4m wide Cat D10N
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Dozer Blades

• Blade ability to penetrate obtain a blade load
  is kW/m of cutting edge
• The higher kW/m the more aggressive the blade
• kW/Lm3 indicates the blades ability to push
  material
• The gt kW/Lm3 the gt the blades potential for
  pushing at gt speed

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Tractor Limitations

• The weight and power of the machine determines
  its ability to push. No tractor can exert more
  push than the machine itself weighs and its
  power train can develop

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Caterpillar Blade Specifications for D10R
tractor/dozer
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Bulldozer Production Estimate

• Production Lm3 Maximum production
  Correction Factors
• Bulldozer production curves give max uncorrected
  figures are based on the following conditions
• 100 efficiency60 min.hr. - level cycle
• Machine cuts for 15m then drifts blade to dump
  over a high wall dump time 0 secs.
• Soil density 1370 Lm3
• Coefficient of Traction 0.5 track, 0.4 wheel
  m/cs

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Estimated Dozing Production
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Dozing Correction Factors
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Estimated Dozing Production
Example problem Determine average hourly
production of a D10R/10SU, moving hard packed
clay an average distance of 45m down a 15 grade
using a slot dozing technique. Esimated material
weight is 1600Lm3 Operator is average, Job
efficiency is estimated at 50min./hr
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Estimated Dozing Production
Solution Uncorrected Maximum Production - 900
Lm3/hr Applicable correction factors Hard-packed
clay hard to cut material 0.8 Grade
correction factor from graph 1.3 Slot
dozing 1.2 Average operator
0.75 Job efficiency 50min.hr
0.83 Weight correction 1370/1600
0.86 Production Max. Prod. Corrctn Factors
9000.81.31.20.750.830.86 601 Lm3/hr
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Ripping Rock
The principle of ripping hard soil and rock has
become practical only with the development of
powerfull dozers robust tracks

• The ripping effect requires
• penetration of the soil by a strong steel ripping
  tool
• tractor with sufficient power to advance the tool
  point through the material
• heavy tractor to generate sufficient traction
• strong robust tractor to take the strain

• The ripping tool is normally
• Radial arc type- simple needs little
  servicing. Tends to lift the rear of the tractor
  and reduce traction.
• Parallel linkage type- tool enters ground
  vertically, point digs in immediately, pulls
  tractor down increases traction

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Ripping Techniques

• For tough work min. tractor power 300kW required
• Travel speed 1-2 km/hr
• Subject to matl. conditions use 3 teeth
• Rip as deep as possible, modern teeth OK to 1m
• Distance between passes hard matl. 1-1.5 m, light
  fractured mat. 2-2.5 m.
• Ripping may offer 80 saving cf. explosive use

• Rocks favourable to ripping
• Stratified rocks soil
• Rocks with fractures, faults planes of weakness
• Large grained rock of brittle texturs
• Most shales, slates mudstones
• Soft rock

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Theoretical output for rippable rock
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Estimate of Ripping Production

• A D10R with No. 10 shank
• 900 mm between passes
• 1.5 km/hr average speed
• Length of rip 95m
• Depth of rip 0.75m
• 50 min/hr
• Turn time 0.3 min.

• Time per pass - 95/1500/60 3.8min
• hence 3.8 0.3 4.1min/p
• passes /hr 50/4.1
• 12.2passes/h
• volume ripped -
• 95m0.90.75
• 64.13 BCM/cycle
• Production -
• 64.1312.2 780 BCM/hr
• This method often predicts output 10-20 above
  practice