Rotary Bucket Excavator Operator fatality at Onyx Sterling Pit (Onyx Corporation), MA, August 22, 2024

A miner died when a highwall collapsed on the excavator the miner was operating.

On August 22, 2024, at 7:59 a.m., Brian Derby, a 67 year-old excavator operator with three years of mining experience, died after the excavator he was operating became engulfed in large rocks from a highwall failure. The accident occurred because the mine operator did not: 1) take down or support hazardous ground conditions, 2) use mining methods to maintain highwall stability, 3) designate persons experienced in examining and testing for loose ground to conduct ground condition examinations, 4) conduct a workplace examination, and 5) develop and implement a written safety program for surface mobile equipment.

1. The mine operator did not take down or support hazardous ground conditions.

   Corrective action: The mine operator developed and implemented a new written procedure to ensure hazardous ground conditions are taken down or supported. This plan includes training miners on recognizing, testing, and correcting adverse ground conditions. The mine operator trained all miners on this procedure.

2. The mine operator did not use mining methods to maintain highwall stability.

   Corrective action: The mine operator developed and implemented a new mining plan that establishes benches of a safe height and width. This plan requires continuous maintenance of benching for all future mining development and preparation. The stripping of overburden and implementation of berms along each bench must be designed to allow inspections of the top of each bench. Additionally, the mine operator will evaluate and implement mining methods in future site developments to ensure highwall stability.

3. The mine operator did not designate persons experienced in examining and testing for loose ground to conduct ground condition examinations.

   Corrective action: The mine operator developed and implemented new written procedures for ground condition examinations. The examination records must clearly and completely indicate that the hazards observed have been corrected and no longer pose a danger to miners working around the highwall. Examinations must be conducted and recorded by a competent person. Additionally, the mine operator developed and implemented a new written procedure requiring mine management review examination records to ensure examinations are conducted at the required intervals. The mine operator trained mine management and miners designated to conduct ground condition examinations on these procedures.

4. The mine operator did not conduct a workplace examination.

   Corrective action: The mine operator developed and implemented a new written procedure for conducting adequate workplace examinations. This includes training miners on recognizing hazardous conditions associated with highwalls during their examinations. The mine operator trained all miners on this procedure.

5. The mine operator did not develop and implement a written safety program for surface mobile equipment.

   Corrective action: The mine operator developed and implemented a written safety program for surface mobile equipment that sets clear expectations for work practices including hazards related to highwalls and dedicated training on best practices and hazard recognition.

Read the full report (PDF)

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

Activity at time of incident

Power Shovel, Dragline

Subunit / location

STRIP, QUARY, OPEN PIT

Accident type

Caught in, under or between collapsing material or buildings

Source of injury

CAVING ROCK,COAL,ORE,WSTE

Nature of injury

UNCLASSIFIED,NOT DETERMED

Body part affected

MULTIPLE PARTS (MORE THAN ONE MAJOR)

Total mining experience

3 years

Experience at this mine

1 year

Experience in this job

15 years

Degree of injury

FATALITY

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