Mine Rescue Field Exam
From the 2013 Ohio Valley Mine Rescue Contest, Cadiz, OH
Progress Indicator:
 
Question 2 of 10
2. Methane monitors shall be maintained in permissible and proper operating conditions and shall be calibrated with a known airmethane mixture at least __________.
Choices:
- once each operating shift
- once each week
- once every 31 days
- once each month
|
|
|
|
