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MINISTRY OF SCIENCE AND TECHNOLOGY
DEPARTMENT OF
TECHNICAL AND VOCATIONAL EDUCATION
Sample Questions & Worked Out Examples
For
Min 05094
EXCAVATION ENGINEERING
B.E.
Mining Engineering
Min. 05094 Excavation Engineering I
B.E. (Mining)
Question
Chapter 1
1.*
Explain briefly the three principal states in which earthmoving material may exist.
2.*
Write short notes on the followings:
3.*
(a)
Soil in natural state
(b)
Soil after excavation or loading
(c)
Soil after compaction
Explain the followings:
(a)
Swell percent
(b)
Shrinkage percent
(c)
Load factor
(d)
Angle of repose
4.* A soil weighs 2,000 lb/ cu. yd. Loose and 2,500 lb/ cu. yd. in – place. Find the swell and
load factor for the soil.
5.** A scraper has a payload capacity of 100,000 lb and a heaped volume capacity of 35 cu. yd.
How many bank cubic yards of the soil in problem 4 can the scraper carry. How much
pounds of soil will be carried by this scraper?
6.** What will be the heaped volume capacity and bank volume capacity of the scraper if the
scraper, in problem 5, will carry its full pay load capacity of 100,000 lb?
7.** A project requires that 100,000 cu. yd. in – place of the soil be excavated, and hauled. The
soil weighs 1,920 lb/cu.yd loose and 2,400 lb/cu. yd. in – place. Find the swell of this soil
and determine how many loose cu. yd. must be hauled?
8.*** A project requires that 100,000 cu. yd. in – place of the soil be excavated and hauled. The
soil weighs 2,400 lb/cu. yd. in – place and has the swell of 25 percent. The project’s
engineer proposed to use a fleet of dump trucks having 4 dump trucks and it is estimated that
each dump truck will produce on output of 175 loose cubic yards/hr. The project will be
working on one 8 hour shift per day. Calculate the no. 17 working days to be taken to
complete the project.
9.*** How many dump trucks would be needed, in problem 8, if the project is to be completed
in 12 days? Rounded to nearest integer number.
10.*** A mining company requires to move 120,000 tons of overburden material. The
overburden material weighs 2,500 lb/cu. yd in – place and has the swell percent of 25
percent. The company’s mining engineer proposed to use a fleet of dump trucks having 4
dump trucks each of which has 30 yd3 heaped volume payload capacity. Calculate the
number of trips required to complete the job.
Chapter 2
1.*
Explain briefly the components of a crane-shovel
2.*
Write short notes on the followings:
3.*
4.**
5.**
(a)
Cranes
(b)
Lifting capacity of a crane
(c)
Clamshells
Write short notes on the followings:
(a)
Shovels
(b)
Draglines
Write brief notes on the followings:
(a)
Bucket selection for clamshell
(b)
Shovel employment
(c)
Dragline employment
(d)
Hoes (or) Back hoes.
Write brief notes on the followings:
(a)
Job planning and management for crane operations
(b)
Job planning and management for clamshell operations
(c)
Job planning and management for shovel operations.
6.**
Given the following information on a shovel excavation job, determine the hourly
production in bank cubic yards that can be expected.
Shovel dipper size = 3 cu. yd
Material
= Tough clay
Swing depth factor = 1.03
Theoretical output = 360 CBY
Efficiency factor
7.**
8.**
= 0.75
Determine the estimated hourly production in LCY for the following dragline operation:
Bucket size
-
¾ cu.yd
Theoretical output
-
105 BCY/hr
Swing – depth factor -
1.09
Efficiency
-
50 min/hr
Material
-
common earth
Swell percent
-
25%
A 3 yd3 power shovel is being used to load well- blasted rock into trucks. The ideal
output/hr of the shovel is 410 BCY/hr for the material being loaded. The swing depth factor
100% of optimum depth of cut is 0.88. The efficiency factor is 0.78 and the swell percent of the
material is 15%. How many bank cubic yards and loose cubic yards of rock should be loaded per
hour.
9.*** Select the most economical shovel from the three listed below to load well – blasted rock
into trucks. All three shovels are operating at optimum depth of cut swing angle is 75˚ and the
swing depth factor at 100% of optimum depth of cut is 1.07. The efficiency factor is 0.83.
Followings are the shovel data:
Shovel size
Ideal output
Cost/hr
(cu.yd)
(BCY/hr)
($/hr)
1.00
125
26.25
1.75
205
31.50
2.00
230
36.75
What is the estimated cost per bank cubic yard for the shovel chosen.
10.
Estimate the cost per ton of material for problem 9, if the density in – place of the
material is 2500 lb/cu.yd.
Chapter 3
1.*
2.*
3.*
4.*
5.*
Write short notes on the followings:
(a)
Wheel Loaders
(b)
Track – type Loaders
(c)
Bucket Wheel Excavators
Explain briefly the followings:
(a)
Loader Buckets
(b)
Operating Load
(c)
Dredges
Write brief notes on the followings:
(a)
Employment of Loaders
(b)
Cycle time of a wheel Loader
Would you recommend a wheel loader or track loader in the following situations? Why?
(a)
Operating on a side slope of 20%
(b)
Operating up a grade of 40%
(c)
On a level haul of 400 ft
How many bucket loads would be required for a 5 cu. yd loader to fill a dump truck
holding 16 LCY with well – blasted rock. Take bucket efficiency factor of 0.85.
6.**
Calculate the expected production in LCY per hour of an articulated loader under the
following conditions:
Application
= Load – haul – dump
Bucket size
= 6 cu.yd
Basic cycle time = 0.40 min
Travelling and return time = 1.00 min
Material to be load and haul = ½” gravel in 15′ high stock pile
Correction factors:
Material
= -0.01min
Loading conditions
= 0.00 min
Operating conditions
= +0.03 min
Bucket efficiency factor = 0.90
Job efficiency
7.**
= 50 min/hr
How many hours should it take a 5 cu. yd wheel loader to load a 2,000 cu. yd are
stockpile into dump trucks. Apply the following information.
Basic cycle time
Travelling and return time
Material
8.**
= 0.45 mi
= 1.50 min
= 0.00 min
Loading conditions
= +0.01 min
Operating conditions
= +0.03 min
Bucket efficiency factor
= 0.85
Job efficiency
= 50 min/hr
What is the bucket payload of the wheel loader in tons for problem 7, if the density in –
place of the stockpiled material is 2500 lb/cu. yd and the swell percent is 25% ? Also calculate
the production.
9.*** A mining project requires that 350 ton/hr of over burden soil be moved from the pit. The
soil weighs 2,400 lbs/cu. yd in – place and has the swell of 25%. The project engineer proposed
to use a wheel loader together with a fleet of dump truck. The project engineer wants to know the
size of the bucket of the wheel loader to be selected in order to fulfill the target production rate.
The assumptions he made were as follows.
Basic loader cycle time
= 0.40 min
Bucket efficiency factor
= 0.85
Job efficiency factor
= 50 min/hr
Determine the size of the bucket of the wheel loader to be selected for this project.
10.*** Describe in detail the following two loading machines.
(a)
Front – end loader
(b)
Track – type loader
Chapter 4
1.*
Write short notes on the following
(a)
Dump trucks
(b)
Wagons
(c)
Pay load
2.*
Explain briefly the components of the haul cycle.
3.**
In planning an excavation operation you have available a 3 cu. yd. shovel and 20 BCY
dump trucks. Given the following information, determine how many trucks would be needed to
service the shovel if travel time is 0.5 hr. How many bank cubic yards per hour will be produced
by this combination?
Type of material
= Tough clay
Swing depth factor
= 1.03
Ideal output of shovel = 360 BCY/hr
Efficiency factor
4.**
= 0.75
In planning on excavation operation you have available a 3 cu. yd wheel loader and 12
cu. yd. (heaped) dump trucks. The soil is dry sand and gravel (bucket efficiency = 100%). Job
conditions are good and management is excellent (efficiency factor = 0.78). Loader cycle time is
estimated at 0.40 min and truck travel time is estimated at 18 min.
5.**
(a)
How many dump trucks should be used?
(b)
What is the estimated production in bank cubic yards per hour?
What is the estimated production in tons/hr for problem 11, if the material weighs 2,600
lb/cu. yd. in – place and has the swell percent of 30%.
6.**
Using queueing theory for a fleet of 7 trucks having a loading time of 0.1 hr and travel
time of 0.4 hr, find the probability of the following.
(a)
A haul unit being available at the loader at any instant.
(b)
No haul unit being available at the loader
7.*** An open – put mine requires to move the overburden top soil. The mine wants to use the
wheel loader and trucks combination. The size of available wheel loader is 5 cu. yd and two sizes
trucks are available as shown in the following information. Loader cycle time is estimated at
0.45 min and the bucket efficiency is 0.85. Job conditions are good and management is excellent
providing the efficiency factor of 0.78. The material’s swell percent is 15%.
(a)
Which size truck and how many of them should be used to provide the
lowest loading and hauling cost?
(b)
What will be the production of this system?
Wheel loader cost as $ 36 per hour and truck data are as follows:
Size Truck
Cost
Travel Time
(BCY)
($/hr)
(min)
14
13.00
27.60
18
15.00
28.80
8.*** Repeat problem 6 if the material’s loose density is 1800 lb/cu. yd. Show your answer in
$/ton for part (a) and tons/hr for part (b).
9.*** Repeat problem 6 if truck data are changed as follows:
Size Truck
Cost
Travel Time
(tons)
($/hr)
(min)
20
22.00
29.00
24
25.00
32.00
Show your answer in $/ton for part (a) and tons/hr for part (b). Material’s density in –
place is 2070 lb/cu. yd.
Chapter 5
1.*
2.*
Write short notes on the followings:
(a)
Rolling Resistance
(b)
Grade Resistance
(c)
Effective grade
Write short notes on the followings:
(a)
The universal blade
(b)
The cushion blade
(c)
The angle dozer
3.*
4.*
Write brief notes on the followigs:
(a)
The straight blade
(b)
The Angle blade
(c)
Resistance to movement
Write short notes on the followings:
(a)
Rim pull
(b)
Drawbar pull
(c)
Maximum usable pull
5.**
Explain briefly with sketches the various types of dozer blades
6.**
What is bulldozer? Explain in detail.
7.**
A power shift crawler tractor has a rated blade capacity of 5 LCY. It is being used to push
loose common earth an average distance of 80 ft. Maximum dozing speed in second gear range is
2 m. p .h and maximum reverse speed in second gear range is 4.6 mph. Fixed cycle time for this
dozer is 0.05 min. What is the estimated production of this dozer per 50 min. how?
8.**
A wheel tractor is being operated on a soft roadway with a tire penetration of 5 in. The
tractor weighs 20 tons. What is the total resistance and effective grade when.
(a)
the tractor is ascending a slope of 4%?
(b)
the tractor is descending a slope of 6%?
9.*** A contractor is planning to put the following spread on a dam job. What is the estimated
production and cost/BCY?
Equipment
11 – 631 E Series II Wheel Tractor – Scrapers
2 – D 9 N Tractors with C – dozers
2 – 12 G Motor graders
$ 75/hr
@ $ 15/hr
1 – 825 C Tamping Foot compactor @ $ 40/hr
Material
Description
- Sandy clay; amp, natural bed.
Density
- 300 lb/BCY
Load Factor
- 0.8
Traction Factor- 0.50
Job Layout - Haul and Return
C
4 % grade
length 1000 ft
0 % grade
length 1500 ft
A
B
RR = 200 lb/ton
Cycle time Elements
(i) Travel Time
Section A – B = 1.00 min
Section B – C = 1.20 min
220
(ii) Return Time
Section C – B = 0.55 min
Section B – A = 0.80 min
1.35
(iii) Load Time = 0.7 min
Maneuver Time = o.7 min
Weigh of Machine
Empty wt
- 88,000lb or 44 tons
Weight Distribution
Loaded = 54% on driving wheels
Empty
= 69% on driving wheel
RR = 80 lb/ton