test 1 Flashcards
(88 cards)
view from above
plan/top view
view from side
side view
view from under
bottom view
angled view
isometric view
what is the bottom point of a bench called?
the toe
what is the angle between the pit floor and line drawn to the surface?
overall slope angle
what is the point of the bench closest to the middle of the bench called?
crest
what is the angle between horizontal and a line between two toes called?
interramp angle
purpose of a bench?
safety: improve stability and stop/catch material
operational: easier to mine and grade control
face angle and overall slope angle factors
geomechanics and economics. steeper is more economical but less safe.
normal face angle
55 to 80 degree
which angle changes with mine life?
overall slope angle and interramp angle
what is the final bench width?
approx 1/3 of the bench height
how can benches in the final pit be different?
may have double benches followed by single bench catches of double width
where are berms necessary?
where drop offs exist of sufficient grade or depth to cause a vehicle to overturn
how tall must berms be?
mid axle height of largest self propelled vehicle which usually travels the roadway
when can you not have berms?
infrequently traveled roads
when can you not have berms?
infrequently traveled roads
what must you have to not have berms?
locked gates and warning signs
typically impact zone width to catch material on a bench?
3 to 5 m
what is the strip ratio?
amount of waste rock which must be removed per unit ore. or inverse. may be any combination of weight or volume
what is highest typical strip ratio seen?
1:10 weight to weight
typical density of unbroken rock
2.7 tonne per cubic meter
specific gravity?
ratio of density of material to density of water
