Hydrate Plant Operator fatality at Sierra Ready Mix Quarry (Sierra Ready Mix), NV, February 25, 2021

The employee was last seen on top of the tower and determined to be missing. The employee was found in a pipe traveling from the cyclone discharge box to the thickener tank. Investigation has revealed that the employee traveled outside the provided safe access to the cyclone discharge box. It is not yet determined how the employee entered the pipe.

On February 25, 2021, at 8:48 a.m., Angel Mariscal-Robles, a 26-year-old plant operator with three years of mining experience, died when he entered a cyclone discharge box. Emergency personnel later found his body in a pipe connected to the bottom of the cyclone discharge box. The accident occurred because the mine operator: (1) did not have adequate policies and procedures in place for confined space or safe access, and (2) did not assure that miners were trained in confined space and safe access policies and procedures.

1. The mine operator did not have adequate policies and procedures in place for confined space entry or safe access.

   Corrective action: The mine operator revised their written policies and procedures for safe access and confined space entry for this site. The mine operator updated their training plan for this site to include the revised policies and procedures. The mine operator provided training to all employees and managers in the revised policies/procedures. The mine operator will also include the training in annual refresher, newly hired experienced miner, and new miner training.

2. Miners were not task trained on safe access or confined space entry policies and procedures.

   Corrective action: The mine operator provided training to all miners and managers in the revised written policies and procedures. The mine operator will include the training in annual refresher, newly hired experienced miner and new miner training.

Read the full report (PDF)

Findings from MSHA's final investigation report, which supersedes the preliminary narrative above.

Activity at time of incident

Machine Maintenance

Subunit / location

STRIP, QUARY, OPEN PIT

Accident type

Fall from headframe, derrick or tower

Source of injury

METAL,(Not Elsewhere Classified)(PIPE,WIRE,NAIL)

Nature of injury

MULTIPLE INJURIES

Body part affected

MULTIPLE PARTS (MORE THAN ONE MAJOR)

Total mining experience

3 years

Experience at this mine

0 years

Experience in this job

0 years

Degree of injury

FATALITY

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