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Calc and Place > Dirt Cratering (Chapter 12) > Flashcards

Dirt Cratering (Chapter 12) Flashcards

1
Q
  1. What is explosive requirement for Dead stumps?
A

1lb of explosive is used per 1’ of diameter

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2
Q
  1. What is the spacing between deliberate crater boreholes?
A

5 feet between boreholes, center to center

Same as hasty crater

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3
Q
  1. An expedient cratering charge should be primed with what?
A

Prime with 1lb of TNT (dual priming is recommended)

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4
Q
  1. What is formula to calculate number of boreholes for a relieved face crater?
A

N_fr = ((L-10) / 7) + 1

Calculates number of charges for friendly row of boreholes.

Round any fractional numbers to next higher number

N_er = N_fr - 1

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5
Q
  1. What is characteristics of deliberate crater?
A

V shaped
7-8 feet deep
25-30 wide
37 degree slope

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6
Q
  1. What is measurement requirement for boreholes at the end of a deliberate crater?
A

End boreholes are 7’ deep

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7
Q
  1. What is explosive requirement for live stumps?
A

2bls of explosive is used per 1’ of diameter

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8
Q
  1. What is measurement and explosive requirement for an enemy row in a relieved face crater?
A

4’ deep

30 lbs explosive

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9
Q
  1. How do you measure for stump removal?
A

Stumps are measured 12-18” above ground level then diameter is rounded to next higher ½ foot

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10
Q
  1. What is the spacing between hasty crater boreholes?
A

From center to center 5’ between boreholes

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11
Q
  1. An effective craters takes _______ allowing time to employ anti-tank weapons
A

4 or more passes

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12
Q
  1. How do you improve craters?
A

Digging face vertically on friendly side
Mining
Filling with water
Any other means to further delay the enemy

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13
Q
  1. What are the geometric characteristics of hasty crater?
A

V shaped
6-7 feet deep
20-25 wide
25-35 degree side slope

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14
Q
  1. What is the fuel oil requirement to mix with fertilizer?
A

1 quart per 25lbs of fertilizer

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15
Q
  1. What is minimum weight of explosive per borehole used in hasty craters?
A

At minimum 50 lbs of explosive per borehole

DOES NOT MATTER WHICH EXPLOSIVE
Do not convert using RE factor, only divide by pounds per unit

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16
Q
  1. To construct relieved face crater, which row will be fired first?
A

Enemy row

1/2 to 1 1/2 second delay

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17
Q
  1. For breaching hard surface pavement, how many pounds of explosives should be used?
A

1 pound for every 2 inches of pavement

Tamp charge twice the breaching radius (thickness of the pavement) (2 x Br)

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18
Q
  1. What is depth of deliberate crater boreholes?
A

A combination of 5’ and 7’ deep

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19
Q
  1. What is the placement/spacing between friendly and enemy rows when constructing a relieved face crater?
A

On Dirt or Gravel roads: 8 feet apart

On Hard surface road: 12 feet apart

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20
Q
  1. What is explosive requirement for complete tree?
A

3lbs of explosive is used per 1’ of diameter

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21
Q
  1. How much nitrogen must be contained in Ammonium nitrate fertilizer?
A

33 1/3% of nitrogen

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22
Q
  1. What is hasty crater blowout distance?
A

Approximately 8 feet beyond the end boreholes

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23
Q
  1. What are the three methods of boulder removal?
A

Snake-hole, mudcapping, and block-hole method

24
Q
  1. What is the shape/characteristics of a relieved face crater?
A

Trapezoidal shape
7-8 deep
25-30 feet wide
Unequal side slopes

25
Q
  1. For hasty crater, what is average traverse attempts of modern tanks?
A

Average of 4 attempts

26
Q
  1. What is taproot hole depth equivalent to?
A

Equal to stump diameter

27
Q
  1. What is measurement and explosive requirement are a friendly row in a relieved face crater?
A

5’ deep

40 lbs explosive

28
Q
  1. For relieved face crater, where would you place first borehole?
A

5 feet in from the desired edge of the crater

29
Q
  1. What is the spacing between relieved face crater boreholes?
A

7 feet between boreholes, center to center

30
Q
  1. What is lateral hole depth equivalent to?
A

Equal to stump radius

31
Q
  1. What is minimum explosive requirement of deliberate crater boreholes?
A

5’ holes will have 40 lbs of explosive

7’ holes will have 80 lbs of explosive

32
Q
  1. What is formula of deliberate crater?
A

N = ((L-16) / 5) +1

L = length of crater in feet
Round up any fractional hole to next higher number

33
Q
  1. For hasty craters, what is minimum depth of boreholes?
A

At least 5 feet deep

34
Q
  1. What is the requirement of effective craters?
A

Must be too wide for track vehicles to span and too steep-sided for vehicles to pass

35
Q
  1. For deliberate crater, what is the average number of traverse attempts of modern tanks?
A

Average of 8 attempts

36
Q
  1. What is the formula for hasty crater?
A

N= ((L-16) / 5) + 1

Round up any fractional number of holes to next higher number

L is length in feet

37
Q
  1. What are the two types of rows required to construct relieved face craters?
A

Friendly row and Enemy row

38
Q
  1. What is deliberate crater blowout distance?
A

Approximately 8’

39
Q

What do repeated attempts to traverse do to a crater?

A

Pull loose soil into the crater, reducing both depth and angle of the crater.

40
Q

What should you do for hasty boreholes?

A

Stem all boreholes with a suitable material

41
Q

Can you have two 5 foot boreholes next to each other on a deliberate crater?

A

No

No two 5 foot holes side by side

42
Q

What is the resulting number of 5’ and 7’ boreholes for an EVEN number of boreholes in a deliberate crater?

A

Difference of 2, 7 foot holes being the higher number

43
Q

What is the resulting number of 5’ and 7’ boreholes for an ODD number of boreholes in a deliberate crater?

A

Difference of 1, 7 foot holes being the higher number

44
Q

What is the blowout for a relieved face crater?

A

Approximately 5 feet

45
Q

How should you prime the rows for a relieved face crater?

A

Prime separately

Allow for a 0.5 to 1.5 second delay between firing each row

46
Q

For a relieved face crater, will the friendly and enemy sides have an equal number of boreholes?

A

No

N_er = N_fr - 1

47
Q

How much should you tamp a charge to breach hard surface pavement?

A

2 times the breaching radius

2 x thickness of the pavement

48
Q

What is an expedient cratering charge?

A

Mixture of ammonium nitrate fertilizer and fuel oil (Motor oil, diesel, gas)

49
Q

How long should you soak an expedient cratering charge for?

A

1 hour

50
Q

What is important when working with an expedient cratering charge?

A

Protect from moisture
Never leave the charge in the borehole for long periods of time, charge will accumulate moisture, reducing its effectiveness

51
Q

Procedure for expedient cratering charge

A

Measure and mix fertilizer and fuel for desired charge
Mix thoroughly
Allow to sit for 1 hour
Place half of mixture in borehole or container
Place two primed 1 lb blocks of explosive in borehole or container
Add remaining mixture
Tamp remaining space with dirt

52
Q

What is the snake hole boulder removal method?

A

Dig a hole under the boulder large enough to hold the charge, then stem the charge

53
Q

What is the mudcapping boulder removal method?

A

Place the charge on a crack in the boulder and cover with 10 to 12 inches of mud or clay

54
Q

What is the block-hole boulder removal method?

A

Drill a hole in the top of the boulder deep and wide enough to hold the amount of explosives required

Prime the charge with det cord and tamp firmly

55
Q

Do you ever use RE when calculating for dirt cratering?

A

No, pounds of explosives is the same, no matter what type.

Calc and Place (20 decks)

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