Statements of Fact Quiz VI
From the 2012 Revised Coal Mine Rescue Statements of Fact
Progress Indicator:
 
Question 2 of 25
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
|
|
|
| 
