Labor Standards Act Article 31

The working hours of a worker operating in a pit or tunnel shall begin from the time of entrance to the pit or tunnel and shall end at the time of departure therefrom.
中文原文 勞動基準法第31條
在坑道或隧道內工作之勞工,以入坑口時起至出坑口時止為工作時間。

English translation for reference only; the Chinese text prevails. Not legal advice.