-"slake durability"
This area comprises weak Mudstones with a high slake durability which require a higher level of
support than Sandston.

- "strata lip"
Once the arches have been set up to the end of the open cut it is then
planned to pour concrete to encase them. This concrete should be poured
to a height so that it goes under the strata lip

- "square to roof and floor position."
On a decline, it is common practice to set supports half way between the
vertical and square to roof and floor position.

Спасибо.