Section 300: Electrical Test No. 3 Practice test questions for the PA Mine Officials' Exam Progress Indicator: Question 1 of 15 1.  If methane gas is found at _______ or greater, the individual in charge shall immediately stop the machine, cut off the current at the nearest switch and report the matter to a mine official. Choices: 1.0% 1.5% 2.0% none of the above