Learning from investigations: Worker injured after being trapped underneath a loader cab

Summary

On November 30, 2020, at a limestone mine, a contract worker suffered injuries after being trapped beneath the cab of a Volvo L220H wheel loader during maintenance. The incident occurred due to the failure to secure the cab with a lock pin, relying instead on the hydraulic ram for support. As the worker reached under the raised cab to adjust harnesses, the cab unexpectedly descended due to an inbuilt float function. Investigations revealed flaws in the cab's design and the reliance on inadequate risk controls, with recommendations emphasizing improved safety measures such as engineering controls and comprehensive training.

Highlights

• A worker at a limestone mine was injured after the loader cab he was under descended unexpectedly due to an inbuilt float function. 😮
• The investigation found the incident was caused by reliance on inadequate safety measures and a lack of proper training and information. 🛠️
• New safety measures, including guarding to prevent body access, are now available for Volvo L220H loaders. 🚜
• Recommendations emphasize using higher-order engineering controls and providing detailed safety training. 📋
• The incident underlines the importance of assessing and updating safety management plans regularly. 📅

Key Takeaways

• Always secure a load with a secondary support – never rely solely on hydraulics! ⚠️
• Understand and heed service manuals' warnings and instructions. 📚
• Employ high-order engineering controls rather than lower-order administrative ones. 🛡️
• Regularly review and update safety protocols and guidelines. 🔄
• Ensure thorough training and competency verification for workers. 💪

Overview

It started as a routine maintenance task at the Atanga limestone mine, but things took a turn for the worse when a contract worker found himself pinned under the loader cab he was working on. Despite following what seemed like a straightforward procedure, relying on a hydraulic ram without a secondary lock pin proved dangerous. The incident highlighted crucial safety gaps, from equipment design to worker training, urging for immediate attention and action.

Following the accident, investigations revealed a series of oversights and shortcomings in how safety was managed. The hydraulic ram’s float function, which caused the cab to lower unpredictably, was a significant contribution to the disaster. Additionally, tension from aftermarket installations and insufficient worker training further compounded the risks, leading to the harrowing incident.

In response, stricter safety measures are now recommended. Higher-order engineering controls such as guarding are advised over administrative measures, and clarity in worker training is emphasized. Everyone involved in maintenance and safety management is urged to rethink and reinforce their strategies. The incident stands as a sobering reminder of the ever-present need for vigilant and comprehensive safety practices in high-risk industrial environments.

Chapters

• 00:00 - 00:30: Introduction and Incident Description On November 30th, 2020, at the Atanga Limestone Mine, a contract worker engaged in maintenance under the tilted cab of a Volvo L220H wheel loader. The task involved replacing failed cab mounts on the loader, performed in the mine's service bay without any other workers present. The service manual instructed securing the raised cab with a lock pin during such repairs. The worker initiated the cab raising using the built-in manual pump.
• 00:30 - 01:00: Raising and Securing the Loader Cab In this chapter, the process of raising and securing a loader cab is described. The worker uses a hydraulic ram to tilt the cab upwards, observing that various harnesses and hose straps were becoming tight. To address this, the worker loosens the items under the raised cab. However, the worker neglects to secure the cab with a lock pin when changing the cab mounts. After replacing the mounts, he begins to lower the cab, halting at about 310 mm above the chassis to enter underneath the tilted cab.
• 01:00 - 01:30: Incident Occurrence The chapter titled 'Incident Occurrence' details a hazardous incident involving a malfunctioning hydraulic ram. A worker was caught between the cab and chassis of a vehicle after a cab, held in place by a hydraulic ram, self-lowered unexpectedly due to an inbuilt float function. This descent trapped the worker's upper chest, head, and shoulders for 3 to 5 minutes until he was freed and taken to the hospital for treatment.
• 01:30 - 02:00: Investigation Findings The investigation findings reveal a critical safety risk, identifying both an unsafe design and hazardous procedure. Firstly, testing confirmed the presence of a dangerous condition that could potentially lead to fatal or serious injuries. The issue was traced back to the cab tilt function's design flaw, which created a crushing hazard by allowing workers to position their upper body in a dangerous gap. Secondly, evidence showed that the incident likely occurred when the worker accidentally bumped the cab that was raised slightly over 300 mm, triggering the float function. The investigation established these as the two primary causes of the incident.
• 02:00 - 02:30: Risk Controls and Causal Factors The chapter 'Risk Controls and Causal Factors' discusses an incident involving a loader's cab that could self-lower unexpectedly, creating a hazardous situation. A worker entered beneath the raised cab relying only on a hydraulic ram for support, which is identified as an unsafe act. The investigation highlighted ineffective risk controls and causal factors, such as tension in aftermarket cables and harnessing installed under the cab, which contributed to the risky situation.
• 02:30 - 03:00: Worker's Actions and Post-Incident Changes This chapter details the actions of a worker involved in an incident and the changes made post-incident. It highlights the shortcomings in safety measures as the access by a worker's upper body to the crush hazard between the Lotus cab and Chassis was poorly controlled with lower order administrative controls instead of higher order engineering controls like guarding. The worker was not adequately informed, instructed, or trained, nor did he possess the experience regarding the float function before the incident occurred.
• 03:00 - 03:30: Recommendations for Safety Improvements The chapter discusses the various safety lapses that occurred, contributing to a worker's exposure to risk. The worker failed to use available support devices during a task change, disregarding established safety procedures and warnings outlined in the Volvo service manual. Additionally, the worker imposed unnecessary time constraints on himself, with no external pressure, leading to further safety oversights. The chapter likely explores recommendations for preventing such oversights in the future.
• 03:30 - 04:00: Duty Holders' Responsibilities The chapter discusses the responsibilities of duty holders following an incident at a mine. It details the actions taken by the mine operator, who implemented new safety measures on the Volvo l220h machinery. The safety upgrade includes a guarding system designed to reduce the risk of a worker's upper body entering under the cab, by reducing the gap between the cab and chassis by about 50%. Further recommendations can be found in the investigation report on the resources regulator website.
• 04:00 - 04:30: Workers' Responsibilities and Compliance The chapter discusses the responsibilities of designers, manufacturers, importers, and suppliers in ensuring the health and safety of workers handling mobile plant equipment. It emphasizes the importance of considering foreseeable worker behavior in risk assessments. Additionally, it advocates for the implementation of higher-order engineering controls, such as guarding, over lower-order administrative controls whenever feasible, to better manage and mitigate safety risks.

Learning from investigations: Worker injured after being trapped underneath a loader cab Transcription

• 00:00 - 00:30 on the 30th of November 2020 at the atanga Limestone mine a contract worker was conducting maintenance under the Tilted cab of a Volvo l220h wheel loader the worker was replacing failed cab mounts on the loader he did the repairs in the Min service Bay with no other workers present instructions in the service manual advised workers to raise the cab to where it can be secured by a lock pin the worker began raising the cab using the built-in manual pump which
• 00:30 - 01:00 extended a hydraulic ram that tilted the cab upwards as the worker raised the cab he noticed various harnesses and hose straps were becoming tight he reached under the raised cab to loosen those items at that point the worker decided to stop raising the cab he changed the cab mounts without securing the cab with the lock pin after he replaced the cab mounts the worker started pumping the cab down pausing about 310 mm above the shazis he entered under the Tilted cab
• 01:00 - 01:30 to tighten a hose strap the suspended cab was held in place only by the hydraulic ram the cab then self-initiated a descent pinning his upper chest Head and Shoulders between the cab and the shazzy the hydraulic ram had an inbuilt float function that caused the cab to self lower without warning at about 300 mm above the Chazzy the worker was pinned for about 3 to 5 minutes before being freed and taken to hospital the worker received treatment
• 01:30 - 02:00 for soft tissue injury later testing established there was a risk of fatal or Serious injury to the worker that testing also established the worker likely bumped the cab when it was just above 300 mm causing the float function to initiate the investigation established two direct or primary causes of the incident one an unsafe condition the design of the cab tilt function gave rise to a crush Hazard allowing a worker to Place their upper body in the gap
• 02:00 - 02:30 between the loaders cab and Chazzy in circumstances where the cab could self lower without warning or control two an unsafe act the worker entered under the raised cab relying only on the hydraulic ram for support the investigation further established that the following four ineffective risk controls or causal factors permitted the two direct causes to exist tension in the aftermarket cables and harnessing installed under the cab led the worker to enter under
• 02:30 - 03:00 the cabin to loosen and tighten them access by a worker's upper body to the crush Hazard between the Lotus cab and Chazzy was controlled by lower order administrative controls that proved ineffective not higher order engineering controls like guarding the worker was not provided with information instruction or training nor did he have the experience to know about the float function prior to the date of the incident another number of Acts or
• 03:00 - 03:30 Emissions on the part of the worker contributed to his exposure to the risk he did not place a support device available nearby and in his vehicle under the suspended cab when the work task changed he did not as required by the contractor or mine operator's procedures either risk assess the change or contact a supervisor he did not account for warnings provided in the Volvo service manual he worked to self-impose time constraints with no time pressure from the contractor or
• 03:30 - 04:00 mine operator to complete the task following the incident guarding was designed tried and installed on new Volvo l220h Lotus and is available for retrofitting the guarding reduces the gap between the cab and Chazzy by around 50% and reduces the risk for a worker's upper body to enter under the cab for the full recommendations please refer to the investigation report on the resources regulator website resources
• 04:00 - 04:30 regulator. nw. auu key recommendations are summarized as follows designers manufacturers importers and suppliers of mobile plant must take account of reasonably foreseeable worker behavior when assessing health and safety risk arising from mobile plant where reasonably practicable implement or cause the implementation of higher order engineering controls like guarding over lower order administ ative controls to
• 04:30 - 05:00 manage foreseeable worker Behavior Duty holders involved in inspection servicing maintenance and repair of mobile plant review their health and safety management plan to ensure it provides Safe Systems of work directed toward eliminating or minimizing by the most effective means in accordance with the hierarchy of controls health and safety risks arising from the following work under suspended loads Crush hazards Lan work infrequent work tasks and reasonably foreseeable worker Behavior
• 05:00 - 05:30 providing information instruction and training programs that include analysis of a workers role and competency needs and verification of worker compliance with safe work procedures workers must take reasonable care for their own health and safety by not entering under a suspended load without a secondary support device in place and not working around uncontrolled Crush hazards and comply with any reasonable instruction and Cooper with any reasonable policy or
• 05:30 - 06:00 procedure including suspending work and contacting a supervisor due to changed circumstances