BO4 Practical Exercise Road Crater Charges
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School
Concorde Career Colleges, Memphis *
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Course
12BALC
Subject
Geology
Date
Feb 20, 2024
Type
docx
Pages
7
Uploaded by andrew_lamance
Course
052-12B30-C45 (DL) - Phase 1 - COMBAT ENGINEER ALC - FY24
Test
PE - B04: Calculate Road Crater Charge Practical Exercise
Started
12/3/23 3:29 PM
Submitted
12/3/23 3:33 PM
Status
Completed
Attempt Score
130 out of 150 points Time Elapsed
3 minutes
Instruction
s
Overall Scenario:
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number of calculations to determine the explosive requirements for the road crater obstacles. As a leader in an engineer unit, it is your responsibility to supervise a demolition mission to create a number of road craters to block the enemy.
Calculate Road Crater Charge Overview:
It is important to know how to create road craters because, as a leader in an engineer unit, you may be called upon to plan, organize,
and supervise any type of demolition mission. A complete understanding of how to calculate charges is imperative for successful completion of your mission. The purpose of this lesson is to learn how to calculate the explosive requirements for the three types of road craters including hasty, deliberate, and relived-face.
Road Crater Charge Calculation Activities:
Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Use the appropriate formula to calculate the amount of explosives and number of boreholes required for deliberate road craters.
Use the appropriate formula to calculate the explosive requirements for relieved-
face road craters.
References:
TM 3-34.82, Explosives and Demolitions, 07 March 2016
GTA 05-10-033, Demolitions Card, 03 Jan 1994
Results Displayed
Submitted Answers, Feedback, Incorrectly Answered Questions
Question 1
0 out of 10 points
Activity 1 (Questions 1-5):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a hasty road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Task
: To form a crater that is effective against tanks, boreholes must be at least
[a]
feet deep with at least
[b]
pounds of explosive in each hole.
Specified Answer for: a
5
Specified Answer for: b
1
0
Response Feedback:
Incorrect. To form a crater that is effective against tanks, boreholes must be loaded with 10 pounds of explosive per one foot of borehole depth. It is recommended that you review the information about hasty road craters to reinforce your knowledge in this area.
Question 2
10 out of 10 points
Activity 1 (Questions 1-5):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a hasty road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Task
: Your mission is to calculate the amount of explosives required to create a hasty road crater in a road that is 25-feet wide. The first step is to determine the length of the crater.
Crater length = _____ feet
Selected Answer:
35.3
5
Response Feedback:
CORRECT.
Nice work, SSG. Craters should be cut across the desired gap at a 45° angle from the direction of approach. To obtain a 45° angle, the following formula should be used: width x 1.414 = length of crater. The length of a hasty crater for a road that is 25-feet wide is 35.35 feet.
W x 1.414 = L
25 x 1.414 = L
L = 35.35 feet
Reference: TM 3-34.82 chapter 3-57.
Question 3
10 out of 10 points
Activity 1 (Questions 1-5):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a hasty road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Task
: The next step is to calculate the number of boreholes required for the same 35.35-foot crater.
Number of boreholes = _____
Selected Answer:
5
Response Feedback:
CORRECT
. Nice work, SSG.
A 35.35-foot crater requires 5 boreholes.
N = L - 16
+ 1 5
N =
35.35
- 16
+ 1 5
N = 4.87
N = 5 boreholes
Reference
: TM 3-34.82, para 3-
63
Question 4
10 out of 10 points
Activity 1 (Questions 1-5):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a hasty road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Task
: What is the amount of explosives required for each borehole if they are dug at a depth of 5 feet?
Explosives per borehole = _____ lb(s).
Selected Answer:
5
0
Response Feedback:
Correct. Nice work, SSG. Boreholes for hasty road craters are loaded
with 10 pounds of explosive per one foot of borehole depth. So, 5 foot holes require 50 pounds of explosives for each borehole.
P = 10 lbs. * borehole depth
P = 10 lbs. * 5 ft.
P = 50 lbs. per borehole
Question 5
10 out of 10 points
Activity 1 (Questions 1-5):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a hasty road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for hasty road craters.
Task
: The final step is to calculate the total explosives required for this 35.35-foot hasty road crater using 5-foot deep boreholes.
Total explosives = _____ lb(s).
Selected Answer:
25
0
Response Feedback:
Correct. Nice work, SSG. Total explosives is determined by multiplying the number of boreholes (step 2) by the explosives per borehole (step 3).
P = Explosives per borehole * number of boreholes
P 50 lbs. per borehole * 5 boreholes
P = 250 lbs.
Question 6
10 out of 10 points
Activity 2 (Questions 6-10):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number of calculations to determine the explosive requirements for a deliberate road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for deliberate road craters.
Task
: Using the field notes below, calculate the desired length of a deliberate crater at a 45 degree angle. Round your response to the next whole number.
Field Notes:
Road Crater Mission
Highway 452
Coordinates:
41°24'12.2"N 2°10'26.5"E
Width = 60 feet
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_____ feet
Selected Answer:
8
5
Response Feedback:
Correct. Great work, Soldier. For a 60-ft wide road, the desired length of the deliberate crater at
a 45 degree angle is 85 feet.
L = w * 1.414
L = 60*1.4.14
L = 84.84
L = 85 feet
Question 7
10 out of 10 points
Activity 2 (Questions 6-10):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a deliberate road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for deliberate road craters.
Task
: The next step is to calculate the number of boreholes required for this 85-ft deliberate road crater. Submit your response in numerals.
_____ boreholes
Selected Answer:
1
5
Response Feedback:
Correct. Nice work, SSG. To cut a deliberate crater into a road that is 60-feet wide, you will require 15 boreholes.
N = [(L–16)/5] + 1
N = [(85 –16)/5] + 1
N = 14.8
N = 15 boreholes
Question 8
10 out of 10 points
Activity 2 (Questions 6-10):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a deliberate road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for deliberate road craters.
Task
: For the 15 boreholes required to complete this mission, at alternating depths of 7ft and 5ft, what is the amount of explosives required for each hole?
Explosives for 5ft boreholes = _____ lb(s).
Explosives for 7ft boreholes = _____ lb(s).
Selected Answer:
8
0
Response Feedback:
Correct. Nice work, SSG. The explosive requirement for a 5-foot deliberate crater borehole is 40 lbs and for a 7-foot deliberate crater borehole is 80 lbs.
Question 9
10 out of 10 points
Activity 2 (Questions 6-10):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a deliberate road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for
deliberate road craters.
Task
: What is the total explosives required for this 85ft hasty road crater using 15 alternative 7ft
and 5ft boreholes?
Total explosives = _____ lb(s).
Selected Answer:
92
0
Response Feedback:
Correct. Nice work, SSG. Total explosives is determined by multiplying the number of boreholes (step 2) by the explosives per borehole (step 3).
P = Explosives per borehole * number of boreholes
P = 80 lbs. per 7ft borehole * 8 boreholes = 640 lbs
+ 40 lbs. per 5ft borehole * 7 boreholes = 280 lbs
P = 920 lbs.
Question 10
10 out of 10 points
Activity 2 (Questions 6-10):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a deliberate road crater. Use the appropriate formula to identify the amount of explosives and number of boreholes required for deliberate road craters.
Task
: How many packages of C4 will be required to prime the charges for this 85-ft crater with 15 boreholes?
Selected Answer:
d.
30
Response Feedback:
Correct. Nice work, SSG. You must dual prime all boreholes with two packages of C4, regardless of the number of cratering charges. So 15 boreholes will require 30 packages of C4 for dual priming charges.
Question 11
10 out of 10 points
Activity 3 (Questions 11-15):
Your unit has received a mission directive to create obstacles in an
effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a relieved-face road crater. Use the appropriate formula to calculate the explosive requirements for relieved-face road craters.
Task
: For relieved-face road craters, the borehole depth on the enemy side is __ feet and on the
friendly side is __ feet.
Selected Answer:
a.
4; 5
Response Feedback:
Correct. Nice work, SSG. The amount of explosive required for 4-
foot boreholes on the enemy-side and 5-foot boreholes on the friendly-side.
Question 12
0 out of 10 points
Activity 3 (Questions 11-15):
Your unit has received a mission directive to create obstacles in an
effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a relieved-face road crater. Use the appropriate formula to calculate the explosive requirements for relieved-face road craters.
Task
: How far apart should the borehole rows be spaced to cut a relieved-face crater in the road
shown here?
Selected Answer:
d.
12 feet
Response Feedback:
Incorrect. The spacing of rows on a gravel road as shown here is 8 feet apart. For a paved or hard-capped road, the spacing is 12 feet.
Question 13
10 out of 10 points
Activity 3 (Questions 11-15):
Your unit has received a mission directive to create obstacles in an effort to deny the enemy forward movement. To create the obstacles, you must perform a number of calculations to determine the explosive requirements for a relieved-face road crater. Use the appropriate formula to calculate the explosive requirements for relieved-face road craters.
Task
: Review your field notes, then determine the total number of boreholes required to cut a relieved face crater in this road.
Field Notes:
Road width = 25 feet
L = w * 1.414
L = 35.35
Friendly side:
[a]
boreholes
Enemy side:
[b]
boreholes
Specified Answer for: a
5
Specified Answer for: b
4
Response Feedback:
Correct. Nice work, SSG. This 25-foot wide road will require 5 boreholes on the friendly side and 4 on the enemy side.
Friendly side
N = [(L–10)/7] + 1
N = [(35.35–10)/7] + 1
N = 4.62
N = 5 boreholes
Enemy side
Friendly boreholes – 1
4 boreholes
Question 14
10 out of 10 points
Activity 3 (Questions 11-15):
Your unit has received a mission directive to create obstacles in an
effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a relieved-face road crater. Use the appropriate formula to calculate the explosive requirements for relieved-face road craters.
Task
: What is the explosive composition needed for the 5 friendly side and 4 enemy side boreholes for this same crater?
Friendly side:
[a]
lb(s).
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Enemy side:
[b]
lb(s).
Specified Answer for: a
20
0
Specified Answer for: b
12
0
Response Feedback:
Correct. Nice work, SSG. This relieved-face crater will require 200 lbs. in the friendly-side boreholes and 120 lbs. in the enemy-side boreholes.
Friendly side
40 lbs. of explosives for each 5 ft. hole in the friendly row
40 * 5 boreholes
200 lbs. of explosives
Enemy side
30 lbs. of explosives for each 4 ft. hole in the enemy row
30 * 4 boreholes
120 lbs. of explosives
Question 15
10 out of 10 points
Activity 3 (Questions 11-15):
Your unit has received a mission directive to create obstacles in an
effort to deny the enemy forward movement. To create the obstacles, you must perform a number
of calculations to determine the explosive requirements for a relieved-face road crater. Use the appropriate formula to calculate the explosive requirements for relieved-face road craters.
Task
: The final step is to calculate the total explosives required for this relieved-face road crater. Calculate the total cratering charges and packages of C4 for this crater.
40 lb. Cratering charges:
[a]
C4 packages:
[b]
Specified Answer for: a
5
Specified Answer for: b
10
6
Response Feedback:
Correct. Nice work, SSG. This relieved-face crater will five 40 lb. cratering charges and 106 packages of C4.
Friendly
5 holes x 1 CC = 5 CC
5 holes x 2 pkgs of C4 = 10 pkgs of C4
Enemy
4 holes x 24 pkgs of C4 = 96 pkgs of C4
Total
5 CC and 106 pkgs of C4