.png){kind=logo}
MSHA Underground Miner Competency Certification Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf
- What is the primary purpose of the Mine Safety and Health
- To provide insurance for mining companies
- To enforce safety and health standards in mining
- To design mining equipment
- To train miners
Administration (MSHA)?
Answer: B
Rationale: MSHA exists to enforce federal health and safety standards and
reduce mining accidents and hazards.
- / 4
- When must a miner receive hazard training?
- Only after an accident
- Before performing new work tasks
- Once every five years
- Only after MSHA requests it
Answer: B
Rationale: New tasks require hazard training before the miner begins that
work to ensure awareness of risks.
- What is the required minimum oxygen level for safe underground
mining entry?
A. 15%
B. 17%
C. 19.5%
D. 22%
Answer: C
Rationale: Air with less than 19.5% oxygen is considered oxygen-deficient
and unsafe for miners.
- What gas is known as the “silent killer” underground due to being
odorless and toxic? 2 / 4
- Methane
- Nitrogen
- Carbon monoxide
- Carbon dioxide
Answer: C
Rationale: Carbon monoxide is odorless and highly toxic, causing rapid
oxygen displacement in the blood.
- What instrument is used to measure methane concentration?
- Noise dosimeter
- Radiation meter
- Gas detector (methanometer)
- CO badge
Answer: C
Rationale: Methanometers detect and measure methane levels to prevent
explosion hazards.
- At what methane level must equipment be shut down immediately?
A. 0.5%
B. 1.0%
- 1.0% or greater
D. 3.0% 3 / 4
Answer: C
Rationale: At 1.0% methane, MSHA rules require immediate shutdown of
electrical equipment to eliminate ignition sources.
- What is the explosive range of methane in air?
A. 2–4%
B. 5–15%
C. 15–25%
D. 30–40%
Answer: B
Rationale: Methane becomes explosive when the concentration is between
5% and 15% in air.
- What should a miner do first if unusual roof movement is detected?
- Continue working
- Ignore it
- Report it and withdraw to safety
- Attempt repairs alone
Answer: C
Rationale: Roof instability is an immediate hazard; miners must report and
withdraw until the area is secured.
- / 4
.png)