Advanced Method & Optimizing

1. Advanced Methods in Estimating
& Optimizing
Equipment System Productivity
SHAIFUL AMRI FKA UTM

2. 1.PEURIFOY’S METHOD
Rimpull
• Traction or tractive force between tyre and
surface travelled.
• Max rimpull, RP 375 hp e
V
e engine efficiency, V velocity in mph
SHAIFUL AMRI FKA UTM

3. SHAIFUL AMRI FKA UTM

4. 1.1 RP vs Grade & Rolling Resistance
• The RP required to overcome GR & RR
RPR W (RR 20( S ))
RPR is rimpull required in lbs
W is vehicle weight in tons
RR in lbs/ton
S is slope %
SHAIFUL AMRI FKA UTM

5. 1.2 Cycle Time & Optimum Units
• CT for trucks
CT = Load + Travel + Dump
• Optimum no. of trucks N = CT
L
Productivity rate P = 60N ( SH)
CT
P in ton/hr or yd3/hr
SH is truck size in tons or yd3
SHAIFUL AMRI FKA UTM

6. 2.Phelps Method
• Breaks into Fixed Time, Variable Time and
Loading Time
Total acceleration time = 0.3x + 0.2y
Total deceleration time = 0.02(x + y)
x = no. of accelerations loaded
y = no. of accelerations empty
• Less waste actually happens in longer task,
therefore multiply by 45 min-hr is inaccurate
SHAIFUL AMRI FKA UTM

7. 2.1 Variable time
HAUL TYPE DISTANCE feet FIXED TIME minutes
SHORT 200 – 1200 F = 4.5 + L
MEDIUM 1200 – 5000 F = 4.0 + L
LONG 5000 – 9600 F = 3.5 + L
These contain one acceleration and deceleration per haul and return trip.
If intermediate stops occur, increase the value appropriately.
** L = Loading time
SHAIFUL AMRI FKA UTM

8. 2.1 Variable time
375(hp)(e) 375(hp)(e)
VH VR
WF( RR 20( S )) WE(RR 20( S ))
60d 60d
V
VH VR
VH haul velocity loaded mph VR return velocity empty mph
WF weight fully loaded tons WE weight empty tons
V variable time minutes d haul distance miles
SHAIFUL AMRI FKA UTM

9. 2.2 Instantaneous & Sustained CT
• Instantaneous cycle time Cti
Cti = Fi + V + L
Fi instantaneous fixed time (minutes), sum of
all fixed time except waste time W.
Fi = F - W
SHAIFUL AMRI FKA UTM

10. 2.2 Instantaneous & Sustained CT
• Sustained cycle time Cs
Cs = C + W
60( N )(SH)(h)
Ps
Cs
N no of haulers, SH capacity of hauler (yd3)
h shift length (hours)
SHAIFUL AMRI FKA UTM

11. SHAIFUL AMRI FKA UTM

12. SHAIFUL AMRI FKA UTM

13. 3. OPTIMIZING HAULING SYSTEM
• Based on loading facility characteristics
(normally loader controls)
Load size
bank yd3
PRODUCTIVE
NON-PRODUCTIVE
3.1 LOAD GROWTH CURVESHAIFUL AMRI FKA UTM
CONSTRUCTION Load time minutes

14. SHAIFUL AMRI FKA UTM

15. Move to stockpile 0.05 min
Fill bucket 0.10
Move & maneuvre 0.15
Dump 0.10
Total 0.40 min
SHAIFUL AMRI FKA UTM

16. SHAIFUL AMRI FKA UTM

17. 3. OPTIMIZING HAULING SYSTEM
Load size
tons
Actually starts with a
parabolic shape until top
operating speed where it
becomes a straight line.
3.2 SIMPLIFIED BELT CONVEYOR LOAD GROWTH
SHAIFUL AMRI FKA UTM
Load time minutes
CURVE

18. SHAIFUL AMRI FKA UTM

19. SHAIFUL AMRI FKA UTM

20. SHAIFUL AMRI FKA UTM

21. SHAIFUL AMRI FKA UTM

22. 3.3 Optimum No. of Haul Units
375(hp)(e) 375(hp)(e)
VH VR
WF( RR 20( S )) WE(RR 20( S ))
d 1 1
T
88 VH VR
• The above info were obtained like in previous
(2.1). The loading time L is taken from the load
growth curve. Delay time D is estimated.
CT = L + T + D N = CT
L
SHAIFUL AMRI FKA UTM

23. ROUNDING OF NO. OF UNITS
Based on Productivity
• Rounding up maximizes loader productivity.
• Rounding down maximizes hauler
productivity.
• Compare which productivity is higher.
SHAIFUL AMRI FKA UTM

24. SHAIFUL AMRI FKA UTM

25. SHAIFUL AMRI FKA UTM

26. SHAIFUL AMRI FKA UTM

27. ROUNDING OF NO. OF UNITS
Based on Profit Differential
• Rounding up or down and compare which
would yield the greatest amount of profit.
• The aim is to find the best trade-off between
the added cost of using extra unit vs the
benefit of having or not having the unit.
SHAIFUL AMRI FKA UTM

28. SHAIFUL AMRI FKA UTM

29. SHAIFUL AMRI FKA UTM

30. SHAIFUL AMRI FKA UTM

31. Next Topic
SHAIFUL AMRI FKA UTM