Two opposing places
Rectangular
1-2” Thick and twice as wide as they are high
On circular timber, charge should cover at least ½ the circumference
Remove the bark or notch tree to match dimensions of charge
Used for external formula P=D^2/40
Trees up to 18” diameter = 1 hole
Larger than 18” diameter = 2 hole
a) Dimensional
Holes are side by side and should face direction of fall
b) Circular
Holes are at right angles and the direction of fall is in between holes
Dynamite, plastic and sheet explosives
Wind and Lean
Most critical factors for determining direction of fall
Always attack the least dimension
For unknown types make a test shot to determine optimal size of the charge
Fallen trees partially attached to their stumps, used as an obstacle
P (lbs of TNT) = D^2 (Diameter) /250
Plastic and sheet explosives
The explosive band should be as wide as possible
At least ½” thick for trees up to AND INCLUDING 15”
1” thick for medium and large trees up to 30”
Add 15% to circumference when constructing the charge
Add 1 lb kicker charge, optimally 2/3 up tree opposite of the main charge. Fire simultaneously with main charge.
Ensure obstacle is at least 75 meters in depth
Fall trees 45 degrees towards ENY
Detonate one side of road, allow delay then other side of road IOT avoid deflecting
2” diameter, and 2/3 deep in timber
P=D^2/50
Internal
(Dynamite, plastic and sheet)
External
(Circular: Plastic and sheet; Dimensional: TNT, plastic, and sheet)
Ring
(Plastic and Sheet)
P=D^2/40
Circular, plastic and sheet explosives
Dimensional: TNT, plastic, and sheet explosives
How should you attack timber with a charge?
Attack the least dimension
What are the most critical facts for determining direction of fall?
Wind and Lean
What should you do after placing explosive in hole for internal charges?
Cap bore holes with mud or clay using a non sparking tool
What should you do to the circumference when constructing a ring charge?
Add 15%
Two types of ring charges
Dimensional
Circular