Overhead Line and Pit Entry During Rig Move
A truck-mounted rotary rig must be moved into a backyard through a 13-ft-wide gate. Overhead 7.2-kV distribution lines cross the driveway at about 18 ft above grade; the rig mast is 32 ft tall when raised. The job is to abandon an old dug well and drill a replacement. At the old well, a 6-ft-deep sump pit contains standing water and gives off a hydrogen sulfide odor. A helper climbs into the pit without a harness, gas meter, or attendant to retrieve a dropped wrench. The driller is operating the rig and does not see the helper enter the pit. The property owner is watching from the deck and offers to help by holding a flashlight. No utility locate has been called, and the crew plans to set the stabilizers on a paved patio.
1. Identify the safety hazards and the controls that should have been in place before work started.
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Hazards include overhead energized lines, underground utilities, an unventilated sump pit with possible H2S and low oxygen, unstable patio or stabilizer support, and lack of a spotter. Controls: call 811 and have utilities located and marked; maintain the required minimum approach distance from the 7.2-kV lines or have the utility de-energize or cover them; use a spotter when raising the mast and moving under lines. Treat the pit as a permit-required confined space unless evaluated otherwise: test oxygen, flammables, H2S, and CO before entry, ventilate, use a harness/tripod and attendant, and have rescue arrangements. Set stabilizers on cribbing or mats and verify stable ground. Keep the owner and nonessential people out of the work zone.
2. What should the crew do now that the helper is in the pit?
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Do not enter after the helper. Stop rig operations, call 911, and initiate the site emergency plan. The attendant should try non-entry retrieval with the wristlet or rope if the helper is conscious and the system is rigged; if not, wait for trained rescuers with SCBA. Move the owner away from the deck and keep vehicles clear for emergency access. Shut down the rig and lower or secure the mast if it is safe. Do not use a flashlight or phone in a potentially flammable atmosphere. After rescue, the pit must be evaluated and ventilated before anyone else enters, and the incident documented. The helper should not have entered without atmospheric testing, a permit, and an attendant.