Where should tests for explosive gases and oxygen deficiency be conducted when drilling near abandoned underground areas?

Where should tests for explosive gases and oxygen deficiency be conducted when drilling near abandoned underground areas?

• A. At the collar of the hole
• B. Far from the hole
• C. On the surface
• D. In the drill rig cab

Answer: (A)

The tests should be conducted at the collar of the hole. This location is where air enters the borehole and is the most representative point of the atmosphere the drill crew will encounter when starting work or entering the hole. Gases from abandoned underground workings can migrate into the borehole and accumulate near the opening, so measuring at the collar provides an accurate check for explosive gases and oxygen deficiency before exposure. Testing far from the hole, on the surface, or inside the drill rig cab could miss dangerous pockets of gas that exist right at the entry point, leading to a false sense of safety.

The tests should be conducted at the collar of the hole. This location is where air enters the borehole and is the most representative point of the atmosphere the drill crew will encounter when starting work or entering the hole. Gases from abandoned underground workings can migrate into the borehole and accumulate near the opening, so measuring at the collar provides an accurate check for explosive gases and oxygen deficiency before exposure. Testing far from the hole, on the surface, or inside the drill rig cab could miss dangerous pockets of gas that exist right at the entry point, leading to a false sense of safety.