relief hole

relief hole

[ri′lēf ‚hōl]
(engineering)
Any of the holes fired after the cut holes and before the lifter holes in breaking ground for tunneling or shaft sinking.
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References in periodicals archive ?
The additional pressure relief hole in the ball enables pressure compensation, preventing a potential failure due to an internal build-up of pressure.
A relief hole was set in the middle bottom of the wall with a hole diameter of 80~100 mm.
Should this happen there are three relief holes venting gases to the right, and one larger relief hole down into the magazine well.
relief hole at each corner of the cutting line and again 1/4 in.
The frame has cracked, and it has a relief hole in place in the frame.
GOOD CAUSE: Sam Nixon and Mark Rhodes visiting Sharmans Cross Junior School in Solihul for Sport Relief HOLE LOT OF FUN: Mark on TV's Hole in the Wall contest
This method resulted in a new term in the trenchless industry: sight relief hole. This tight-fitting hole allows sewer lines to be installed without pipe floatation occurring once the pipe is installed.
Using a single relief hole in the burn cut, the length of round that can be pulled in a lateral heading is 0.9 m (3 ft) for each inch diameter of the relief hole.
A sleeve ejector pin from a new die was damaged by blast media trapped in the relief hole from the back of the die.
Burn Cut Pull optimization through varying Relief Hole Depths.
Caption: Figure 5--Multiple relief holes to simulate a larger relief hole.
Four single-boom jumbos drill 4.9 m long 50 mm diameter holes and a larger cut machine drills a 178 mm diameter relief hole. Redpath designed the drilling rigs and blasting pattern, a typical burn cut.