Link between prospected quality and actual quality.
{| border="1" cellpadding="3" cellspacing="0"
! Outside !! Inside !! Samples
|-
| Poor <Unknown rock> || - Pretty bad || -25.00, 28.00, 33.00, 39.00
|-
| Acceptable Poor || Pretty bad || 28.00, 32.00, 33.00, 3920.00
|-
| Acceptable || Pretty bad || 32.00|-| Normal || Normal || -> 42.00
|-
| - || Good || -
| - || Utmost || -
|}
Uh-oh, both acceptable and poor show as the same inside caves. Therefore separating out the values observed on "pretty bad" rock, which could be either poor or acceptable.
== Entrance hypothesis ==
When mining a cave entrance, the chance of getting rock shards is 25%.