Driller's feet crushed in drill foot clamps

Mine type

Exploration site

Incident

A driller had his feet crushed when drill rig foot clamps unexpectedly closed.

The operator was standing at the bottom of the mast attaching the cyclone pipe. Both of his feet were under the open foot clamps.

The driller's offsider accidentally knocked a set of Allen keys off the control console. The keys hit the control lever operating the foot clamps closing both on to the operator's feet.

The foot clamps operate under hydraulic pressure. At the time of accident the engine for the hydraulic pump was running. As the foot clamps are required to hold the drill string in place, they will operate through the accumulator even when the hydraulic pump is not operating.

Equipment

Warman 1000 drill rig

Hazard

Uncontrolled potential energy source

Cause

• Unsafe operating practice due to absence of risk assessment and lack of a suitable formal procedure.
• Loose object falling from top of control panel on to control lever when operator was in drill string area and foot clamps in the open position.

Comments

• The operator was in the drill string area where mechanical movement occurs.
• It was noted that drillers also place their hands or other items behind the guard on the non-rotating drill string, while feeling for the core tube to seat on the bit. A similar situation could occur if the rotation control was activated while the driller was in contact with rods.

Recommendations

• Conduct a risk assessment on all operations of the drill rig, and review/create procedures/standard work instructions to ensure the hazard controls are implemented giving consideration to the hierarchy of controls.
• A lockout/isolation process is required for the drill control console when the driller is in the drill string area.
• Where possible, controls are to return to a neutral position when pressure to a lever is released.
• Ensure items cannot fall from top of drill control console on to control levers. Due to the control console being flat, it is a natural place to put items. Using procedures alone to prevent personnel placing items here will be difficult to enforce and therefore ineffective.
• The mine's site senior executive must ensure equipment is to original equipment manufacturer's (OEM) standards or better.

Authorised by Roger Billingham - Chief Inspector of Mines

Contact: minesafetyandhealth@dnrm.qld.gov.au

Issued by Queensland Department of Mines and Energy