Possible Clues:

• No longer a manual worker, he's qualified to conduct tests
• That's a testy sort of person
• Frisco paper
• Marker a former pit employee positioned outside
• Formerly a worker underground, he demands answers
• One looks for information from a tunneller
• Old underground worker without answer for inspector
• Hearst's San Francisco newspaper
• Formerly one worked underground, now one is just trying
• Formerly working for the underground, now one's work is more testing