Welder (Shop)

FMC employees were attempting to seal the hoist shaft at the Bremen Portal at Ken American Paradise Mine No. 9. Steel beams were welded in place metal decking was secured covering the shaft. Methane accumulated in the shaft and caused a series of two explosions 4-5 seconds apart. The second explosion killed FMC employee. No other fatalities or injuries occurred.

Texto original en inglés de la MSHA

On Wednesday, July 31, 2019, at 4:31 p.m., Richard Knapp, a 62-year-old contract welder/iron worker, died when multiple methane gas explosions occurred in the intake air shaft. When the explosions occurred, Knapp was working on metal sheeting above the shaft, in preparation for a concrete pour, to seal the shaft. This placed Knapp in the direct line of the explosion forces. The accident occurred because the mine operator did not: (A) instruct the contractor, hired to seal the shaft, in the provisions of the ventilation plan and ensure the plan was followed, (B) properly measure methane concentrations, and (C) prevent smoking, oxygen-acetylene torches from being used, and grinding from being performed after measuring excessive methane concentrations. Furthermore, the contractor: (1) did not properly measure methane concentrations, (2) used oxygen-acetylene torches in the presence of excessive methane concentrations, (3) smoked in the presence of excessive methane concentrations, and (4) did not stop using oxygen-acetylene torches, grinding, and smoking when a gas detector alarmed because of excessive methane concentrations. Also, the mine operator and contractor should have properly eliminated or safely mitigated the risks involved with the method used to seal the shaft. The installation of metal sheeting over the open shaft involved trimming the metal sheeting, with tools that create ignition sources, over an atmosphere that had the potential to contain explosive gas.

1. The mine operator did not ensure that the ventilation plan was followed – specifically, methane was not monitored and responded to as required. The mine operator did not train workers on the dangers of oxygen-acetylene torches, grinding, and smoking where fire or explosion hazards exist around open mine shafts. Also, the mine operator did not instruct the contractor, who was hired to seal the shaft, on the provisions of the ventilation plan, nor did it adequately oversee the work practices of the contractor.

   Acción correctiva: FMC was removed from the mine site and replaced with Miller Contracting Services, Inc. (Miller) (MSHA I.D. S956). Miller employees received training on the dangers of smoking, welding, and cutting where fire or explosion hazards exist around open mine shafts. The mine operator submitted another shaft sealing plan, and MSHA approved it on August 16, 2019. Mine management issued Miller a copy of the new sealing plan, trained all workers on the provisions in the plan, the hazards of methane, and how to properly test for methane. The new shaft sealing plan contained detailed seal and construction sequence details and detailed steps to maintain adequate ventilation to dilute and remove explosive gases. In addition, it contained the following safety provisions:

2. The contractor: (1) did not properly measure methane concentrations, (2) used oxygen-acetylene torches in the presence of excessive methane concentrations, (3) smoked in the presence of excessive methane concentrations, and (4) did not stop using oxygen-acetylene torches, grinding, and smoking when a gas detector alarmed because of excessive methane concentrations.

   Acción correctiva: Methane was continuously monitored in the shaft during the construction of the intake shaft seal by Miller. Sampling tubing that was lowered into the shaft was used to sample the atmosphere in the shaft. No welding or cutting was performed during the intake shaft sealing operation and there was no smoking near the shaft.

Hallazgos del informe final de investigación de la MSHA, que sustituye la narrativa preliminar anterior.

Actividad al momento del incidente

Welding Or Cutting

Subunidad / ubicación

SURFACE AT UNDERGROUND

Tipo de accidente

Golpeado por onda de choque

Fuente de la lesión

METHANE GAS-IN MNE & PROC

Naturaleza de la lesión

MULTIPLE INJURIES

Parte del cuerpo afectada

MULTIPLE PARTS (MORE THAN ONE MAJOR)

Experiencia minera total

40 years

Experiencia en esta mina

0 years

Experiencia en este puesto

19 years

Grado de la lesión

FATALITY