QUESTION $3$ Open Pit Design $[11]$

$3\mathrm{.}1$ Define the terms below:

a$.$

Face angle $(\backslash$alpha $)(1)$

b$.$

Bench height $($H$)(1)$

c$.$

Toe $(1)$

d$.$

Crest $(1)$

e$.$

Bench width. $(1)$

f$.$

Bank width. $(1)$

$3\mathrm{.}2$ What is a safety bench? $(2)$

$3\mathrm{.}3$ Recommend the guidelines used to determine the width of safety benches? $(3)$