salt mine
noun
Definitions
Any mine used for the extraction of salt.
(by extension) Any laborious work situation, especially in a confined space.
An abundance of indignation felt by one person or a group of people due to over-sensitivity, humourlessness, disappointment, or defeat; a gold mine (sense 3) of salt (noun sense 11).
Example: The fan forum was an absolute salt mine after the football team's loss to the last-place team in its division.