Occupational accidents in mining workers: scoping review of studies published in the last 13 years

Abstract

Objective

Mining activity represents one of the most hazardous occupations related to health, with 8% of fatal injuries concentrated in this sector worldwide. Thus, it is crucial to timely identify the factors involved in such injuries. We aimed to explore the sociodemographic and occupational/organisational factors associated with injuries, causative agents and subsequent disabilities and fatality of workers exposed to occupational injuries in the mining sector.

Design

A secondary scoping review was conducted following the Joanna Briggs Institute guidelines.

Data sources

Scopus, Embase, Virtual Health Library, SciELO and PubMed databases were searched in February 2022 and updated in October 2023. The protocol was developed in April 2022.

Eligibility criteria for selecting studies

We included observational studies published within the last 13 years (2010–2022) which provided information on injuries of the mining workers and reported associated factors as well as health consequences.

Data extraction and synthesis

Two independent reviewers examined the eligibility criteria, screened and coded the extracted information using prevalidated data extraction tools, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses—Extension for Scoping Reviews reporting guidelines.

Results

A total of 123 studies were found, of which nine were selected for inclusion in this review. Participants were between 15 and 80 years old, and the rate of injuries ranged from 4.4% to 10.6% of reported cases. Among the total selected studies, mechanical agents were identified as the leading cause of injuries in six studies. The factors associated with injuries included age, gender (female) and biochemical characteristics. On the other hand, occupational and organisational factors encompassed work shift, outsourcing (contractors) and less than 2 years of experience in the sector.

Conclusion

This review emphasises that both work-related and individual characteristics are significantly related factors of injuries. Moreover, commonly reported health consequences of injuries encompass mortality, average days lost and permanent, partial or total disability.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• This scoping review uses data available in different databases of mining populations around the world.

• We used a rigorous assessment methodology manual by the Joanna Briggs Institute.

• A systematic search strategy was used for transparency and reproducibility.

• This study was limited to publications in the selected languages and research articles only, which may bias some studies published in languages not included or local reports for this scoping review.

Introduction

In the mining industry, workers are exposed to various risks and hazards resulting in occupational injuries, some of which are severe and even fatal.¹ Despite representing only 1% of the total workforce, mining-related injuries account for 8% of the fatal injuries in the world.² The International Labor Organization (ILO) has reported that even in industrialised nations, small-scale mines have six to seven times greater injury rates than larger mines.^{2 3} A recent study conducted on Chinese coal mine workers identified factors related to the environment, organisation and safety which contribute to these injuries.⁴ Among these factors, inadequate resource management, deficient organisational processes and failure to address noncompliance with safety regulations are common contributors to unsafe acts.⁴

The 2014 tragedy in Manisa, a province in Turkey, serves as a poignant illustration of the dire circumstances in which many coal mines operate, leading to the tragic loss of 301 lives due to carbon monoxide poisoning in a single event.⁵ This incident not only exposed the precarious conditions in Turkish mines but also unveiled a stark lack of compliance with workplace safety regulations.^{6 7} The aftermath of this disaster reverberated on an international scale, prompting the ILO to take decisive action in 2015. Recognising the urgent need for change, the ILO committed to implementing a series of measures aimed at enhancing the safety and well-being of mining workers. These measures included the mandatory enforcement of the Occupational Safety and Health Act by employers, the establishment of improved systems for recording occupational diseases and a substantial increase in the number of labour inspectors, among other critical reforms.⁸

According to reports from the ILO, globally almost 3 million people die every year because of work-related injuries and diseases, and 395 million workers have sustained nonfatal injuries annually.⁹ In the mining sector, it is worth mentioning that despite its intrinsic importance, medical literature does not always represent the most authoritative source of information. However, it is important to use national reports as indicators of the cases of a country or region. For instance, the Mining Technical Directorate of the Ministry of Energy and Mines of Peru showed that there were 23 fatal injuries in the mining sector in 2021, resulting in 63 victims, a significantly greater number than the number of reported incidents in 2020 (dataset).¹⁰ Furthermore, in 2022, 34 fatal injuries occurred, for a total of 39 victims, accounting for 13.58% of all injuries (dataset).¹¹ The causes of these injuries may vary from collapses to falling objects on mining sites¹⁰ to preventable factors such as having inadequate personnel protective equipment, working shift goals and working more than 8 hours.¹² Due to these factors, an accident at the Yanaquihua, Arequipa mine occurred in May 2023, where the fire caused the deaths of 27 workers due to carbon monoxide inhalation. In accordance with these reports, until June 2023, there were eight fatal injuries, 34 of which were victims.¹³

These injuries have a direct impact on the health of workers. In 2022, out of the total injuries in Peru, 61.19% resulted in disabilities, 38.08% were considered mild and 0.73% were fatal.¹⁴ Such incidents also result in expenses and exert economic and social influence on both workers and companies.^{15 16}

However, comprehensively assessing the impact of injuries across diverse sectors, particularly in mining, presents challenges due to the methodologies employed for the valuation and quantification of effects on individuals,¹⁷ which results in deficient estimates due to the absence of related outcomes, such as lost days, severity of injury and disability. In addition, there is a lack of systematic review studies that identify occupational/organisational factors, such as outsourcing, experience and demographic variables related to injuries in the mining sector, and the impact of injuries on health and fatality. Consequently, while being aware of these indicators remains crucial and beneficial, obtaining fundamental information characterising injury occurrence is equally essential.

Materials and methods

Protocol and registration

This review was conducted following the guidelines of the Joanna Briggs Institute (JBI) reviewer’s manual and the criteria suggested by Levac et al.¹⁸ A study protocol was developed and registered on the Open Science Framework, and it is available at https://osf.io/3pnqu/.

Safety authorities and public health officials advise against using ‘accidents’ for injuries, as this approach implies unpredictability. We opted to use the term ‘injury’ rather than ‘accident’ in workplace contexts. This choice reflects the understanding that most injuries and their causes in these settings are predictable and preventable, unlike accidents. Therefore, in this review, the term ‘injury’ was used.¹⁹

Eligibility criteria

The eligibility criteria were defined at the beginning of this review. We considered peer-reviewed observational studies that reported injuries and incidents related to the activities of mining workers and presented outcomes related to health consequences from injuries such as mortality, the severity of the injury, lost days and disability. The language was limited to studies published in Spanish, Portuguese or English. Preprint articles, review articles, editorials and letters to the editor were considered exclusion criteria.

Sources and search strategies

We determined the search strategy using the P (population), E (exposure) and O (outcome) formats. A systematic exploration was conducted in four databases and a search engine—Scopus, Embase, Virtual Health Library, SciELO and PubMed. The search used both free and controlled terms (MeSH and Emtree). The strategy consisted of a combination of three blocks: (1) mine worker and coal mining worker; (2) “labour accident”, “occupational accidents” and “occupational injury” and (3) “mortality,” “absenteeism,” “disability” and “injury”. The search was limited to studies published in the last 13 years (2010–2022) since the most relevant and related information was reported by Nowrouzi-Kia et al,²⁰ who provided insights into associated factors, agents and time lost during previous years. In addition, there have been significant advancements in occupational safety and health, particularly in the USA, where comprehensive information systems are available.²¹ In 2010, 1% of workplace injuries were attributed to the mining sector, with an average of 24 days lost, despite safety implementations.²² This indicates the global improvement in safety systems but still has a significant impact on health. Therefore, we used this information as a reference. The search was conducted on 24 February 2022 and updated in October 2023. Further details are available at https://osf.io/3pnqu/.

Article selection and data extraction

The search results were exported to the bibliographic manager Zotero (https://www.zotero.org/), and duplicate records were eliminated. The remaining articles were subsequently transferred to the web application Rayyan (Qatar Computing Research Institute, Qatar Foundation, https://rayyan.qcri.org) for assessment.

Later, based on the titles and abstracts, two pairs of authors, NAC-T+PFS and LC-A+VJV-P, independently conducted the selection process. Any discrepancies were resolved through consensus or with a third diriment AC-L. The subsequent stage involved reading the entire text and applying the eligibility criteria to determine the inclusion of studies in the review.

Synthesis of results

The synthesis process involved data extraction using a standardised form designed in an Excel spreadsheet. The form included information regarding the author, year of publication, country, study design, population characteristics, type of mining, risk agent causing the injury and outcomes. This process was independently performed in duplicate, after which the authors compared the records and resolved the discrepancies. In addition, we performed a quality assessment of the reports through the Strengthening the Reporting of Observational Studies in Epidemiology statement for each type of study and reported the results according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses—Extension for Scoping Reviews.²³

Patient and public involvement

No patient was involved.

Results

After examining the full-text studies, nine studies were selected for inclusion in the review and data extraction. The selection process details are shown in figure 1.

Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow chart of selected studies.

Characteristics of the included studies

On examining the full-text studies, four out of nine studies originated from the USA, two from Latin America, one from Turkey, one from China and one from Australia. Additionally, six out of nine studies used a cross-sectional design, one employed a case‒control approach and the other followed a retrospective cohort study methodology. Regarding the period covered in the studies, two studies included data from the 1980s, two provided information spanning more than 25 years^{24 25} and only one study²⁶ focused on data from a single year. The median duration of information in the studies was 5 years, with an IQR of 4–17 years.

Participants in the included studies were between 15 and 80 years old and were mostly males, and five of the studies focused on coal extraction as a mining activity2427,30 followed by metal and nonmetal mining.²⁴

The health outcome measures reported in the studies included mortality; standardised mortality ratio; days lost (absenteeism); percentage of days lost per injury; frequency index; and permanent, partial or total disability. The total days lost ranged from 1 to 938.4 days,^{27 31} and one study reported the fingers as the most commonly affected region of the body, followed by the registered injuries in mining, which reached up to 10.6% in 2014.³² According to Ozer et al, in a case series, the majority of deaths occurred in the private sector (76.2%), with the remaining percentage originating from the public sector.³⁰

The factors associated with injuries in mining workers include sociodemographic and occupational factors, such as age, years of experience, sex (female), working for a mining contractor,²⁴ working night shifts²⁴ and irregular shift timings.²⁴ Biochemical factors, such as glucose, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels, were also found to be associated with injuries (table 1).³²

Table 1. Characteristics of the studies and findings.

Author et al year	Country	Type of study and time frame	Population characteristics/ cases	Type of mining and agent involved	Ratio of injuries and associated factors	Outcome
Margolis 201019	USA	Cross-sectional2003–2007	n=10 345, age:17–69 years, Me=43 years (SD±11.22)	Not reported /Coal mining underground	Prevalence not reported. Factors associated were increased age, years of experience in mining and as a coal miner	Total lost days: 1–376, Me=32 days (SD±77.23)
Vásquez Trespalacios 201318	Colombia	Cross-sectional2011	n=186, 39.23% were 18–21 years old 94.61% male	Extractive mining / Mechanic, chemical	23.12% of workers had an injury	315 days of absence, IF (frequency index): 25.47; IS (severity index): 195.65 lost days and PTP (percentage of time lost): 0.65
Ozer et al 2014 (21)21	Turkey	Case series2005–2008	n=42, age: 17–52 years, Me=32.9 years	Coal mining /Mechanic, chemical, physical	76.2% of fatal injuries are from private mining and 23.8% in public mining	Not reported
Zhang et al 201625	China	Cross-sectional2005–2010	n=320 miners	Coal mining/ Mechanic, chemical	27.19% of injuries happened in 2005, 25% in 2006, 12.18% in 2007, 12.81% in 2008, 12.19% in 2009 and 10.63% in 2010	320 cases of fatal injuries
Gomero-Cuadra et al 201823	Peru	Case‒control retrospective2009–2014	n=3638 (control group: 3360, case group: 278); age: control group: 35 years (IQR: 31–41), case group: 38 years (IQR: 34–45)	Not reported/ Not reported	2009: 25 (4.6%),a 2010: 24 (4.4%),a 2011: 47 (8.0%),a 2012: 51 (7.6%),a 2013: 66 (9.8%),a 2014: 65 (10.6%).aFactors associated with accidents: low levels of glucose, high LDL and low HDL	Not reported
De et al 2020 24	USA	Cross-sectional1983–2015	n=547 537, 97.94% males. Group ‘1 hour in the shift’: 505 (3.1%) females, age: 40.5±11 years. Group: ‘>2 hours in a shift’: 10 714 (2%) females, age: 39±10.7 years	Coal mining, mining for the extraction of metals and nonmetals /Mechanic	In the group 1-hour shift, 16 446 (3%) injuries occurred. In the group >2 hours in the shift: 529 091 (97%)Predictors of injuries occurring in the first hour of the shift: age (per 10 years), being female, working for a mining contractor <2 years of mining experience, irregular shift start, night shift 11 p.m. to 6:59 a.m., surface mining	2662 fatal injuries: 77 (1-hour shift); 2585 (>2-hour shift); 7505 cases of permanent, partial or total disability: 193 (1-hour shift), 7312 (>2-hour shift); 213 239 cases lost 11 or more days: 7002 (1-hour shift), 206 237 (>2-hour shift)
Arif et al 202017	USA	Cross-sectional1986–2014	n=5111, age: 39.7 years (CI 39.1–40.7), 85.8% males	Mining (oil and gas miners were excluded since 2004)/ Not reported	6.7% were unintentional injuries/accidents	Standardised mortality ratio adjusted for residual causes of death: SMRa*: 1.41 (95% CI 1.03–1.85) compared with the general population
Alessa et al 202022	USA	Cross-sectional2000–2017	n=47 903 body injuries (upper limb)	Not reported/ Mechanic	31 163 (69%) finger injuries, 9850 (22%) hand injuries and 4166 (9%) wrist injuries.	Total days lost: 938.4. Percentage of days lost due to finger injury: 616.7 (66%), hands: 187.4 (20%) and wrist: 134.3 (14%). Median number of days lost in the group of finger injuries 19, hands 12 and wrist 24.
Chong & Collie 202120	Australia	Cohort retrospective2003–2017	n=30 309, age: 15–80 years, 83% males	Coal mining/ Mechanic	60% of the workers suffered from musculoskeletal injuries and fractures	The mean time lost across the whole sample was 4.2 weeks (IQR: 1.2–14.0)

a, Ratio of accidents in miners in that year. IF, Proportion of absence episodes in the period/Total scheduled man-hours×240 000. IS, Total number of days lost in the period/Total scheduled man-hours×240 000. PTP, Total number of days lost in the period/Total scheduled man-hours in the period×100, as a percentage of the total cases per year×Ratio of observed specific death counts and adjusted expected death counts.

HDLHigh-density lipoprotein cholesterolLDLLow-density lipoprotein cholesterolMe, Median;

Factors involved in injuries

Figure 2 illustrates the distribution of the risk agents involved in occupational injuries. Of the nine reviewed studies, six involved the use of mechanical agents through various mechanisms, including falls,^{26 29} trauma,^{26 28 31} compressions,³⁰ transportation^{29 30} and slides.^{24 29} In three studies, chemical factors were reported as the cause, involving poisoning²⁶ and methane gas inhalation.^{29 30} Additionally, in one study, the physical agent was mentioned as the cause, involving electrocution.

Figure 2. Risk agents involved in occupational injuries.

Discussion

Our findings revealed that most of the information originates from countries such as the USA and involves male populations engaged in coal mining. The observed injury ratio is less than 11%,³² and a noteworthy detail is the higher fatality ratio, particularly in the private sector, reaching 76.2%.³⁰ This observation revealed a decreasing trend in the annual incidence of injuries compared with that in previous years. For instance, higher injury rates were observed in countries such as Ghana from 2008 to 2017 (70%).³³ Similarly, Argentina (73.0%)³⁴ experienced a substantial surge, with a 73.0% increase in 2005. It is essential to consider that this study did not differentiate between fatal and nonfatal injuries or job types, potentially leading to overestimation.^{35 36}

The literature generally identifies individual and organisational factors in occupational injuries. However, the Human Factors Analysis and Classification System proposes four levels of human errors: (a) unsafe acts by operators, (b) preconditions for unsafe acts, (c) unsafe supervision and (d) organisational influences.³⁶ Therefore, irregular shift starting times, working for a mining contractor and working night shifts²⁴ are organisational and supervisory factors determining injuries. Regarding night shifts, the evidence yields contrasting findings. On the one hand, night-shift workers appear to face a lower risk than day-shift workers, regardless of the start time of the work shift.^{35 37} On the other hand, data from the years 1992–1994 show that although mining contractors accounted for approximately 10% of working hours, they reported 29% of fatal injuries and 6% of disabling injuries in coal mining.³⁸ Although labour legislation and occupational safety and health laws have improved over the last decade,² sectoral policies have undergone delayed development, especially in developing countries,³³ resulting in slow regulation, adaptation and implementation of proper policies and better working conditions for mining workers.

Similarly, it has been observed that the most common age range for injuries is between the third and fourth decades of life.^{20 24 25 30 32} The mining workforce predominantly consists of workers aged more than 40 years, as their jobs require significant experience²⁷ and competence in various roles.³⁹ Interestingly, a study by Vasquez et al revealed that the age ranging between 18 and 21 years was the most prevalent.²⁶ Additionally, reports indicate that workers aged between 21 and 30 years may be more likely to suffer injuries.⁴⁰ In contrast, Nowrouzi et al reported that there was a lower incidence of accidents in miners older than 45 years.⁴¹ These differences may be attributed to specific job characteristics in emerging mining companies, which require young personnel, such as operators or labourers, who have less experience³³ and expertise^{20 24 27}; who are more susceptible to distractions (inattention)¹² and who work long hours,³⁷ predisposing them to unsafe acts and work-related injuries.

Previous studies have shown that material handling⁴¹; lack of adequate protective equipment; and repair, maintenance, cleaning, drilling, lifting and lowering activities are the main activities leading to incidents and injuries.^{33 42} Our findings identified mechanical agents, such as falls, improper handling of containers and entrapment, as the primary factors associated with injury,2426 29,32 followed by chemical agents, such as inhalation poisoning,^{26 29 30} and physical agents like electrocutions.³⁰ Additionally, upper limb fractures were the main injuries resulting from this agent^{28 31} similar to studies that reported fractures, lacerations and amputations in specific body parts, such as fingers, hands and wrists,⁴³ as the most common injuries in small-scale miners.⁴⁴ However, a study of Colombian miners reported that the lower limbs were the most affected anatomical regions, followed by the upper limbs, head and back.³⁹ These differences may be related to job subactivity or roles, such as exploitation, maintenance and machinery repair,⁴² as well as the size of the mine.⁴⁴

While the findings focus on factors related to work characteristics and human factors, it was evident that individual factors or biochemical markers, such as increased glucose and cholesterol levels, would result in poor health of the worker and consequently inadequate performance.³² Previous studies have emphasised the importance of monitoring worker health, including body mass index, blood pressure, glucose and cholesterol levels, especially in miners working at high altitudes (3800–4500 m above sea level) and exposed to intermittent hypoxia.^{45 46} In this sense, intermittent hypoxia can trigger physiological responses in the body, including an increase in the production of glucose and cholesterol. These responses represent natural adaptations aimed at ensuring an adequate supply of energy and oxygen under challenging conditions. Consequently, when these markers remain elevated, they can contribute to long-term health problems. This not only impacts cardiovascular health but also has consequences for workers’ cognitive abilities and decision-making processes. Issues such as fatigue, lack of concentration and diminished motor response are potential outcomes of metabolic imbalance, posing an increased risk of injury. Finally, regarding the impact on health indicators, the most frequent were estimates based on disability,²⁴ time lost in days^{24 26 27 31} followed by the standardised mortality ratio,²⁸ percentage of time lost and severity index.²⁶ The reported number of lost days ranged from at least 11 to 938.4 days.^{27 31} This finding contrasts with the lost days reported in the USA in 2010, in which a median of 24 lost days related to injuries in mining activities were identified.²²

It is essential to consider that mining information is underreported compared with information from other activities, which affects the accuracy of injury indicators.³⁴ Additionally, the heterogeneity in reporting systems diversifies the information according to the country and the subsequent estimation of direct compensation costs, suggesting the need for standardisation.

Practical and policy implications

The findings of this study have significant implications for both practical applications and policy considerations within the mining industry. To ensure the safety of mining workers, it is crucial to implement preventive measures, enhance training initiatives and enforce stricter regulations. Moreover, a comprehensive approach is essential for promoting the safety and overall well-being of mining workers. This holistic strategy should encompass improvements in working conditions, proper utilisation of personal protective equipment and the reduction of human errors.

In addition to organisational and managerial systems, achieving occupational safety in the mining sector requires multisystemic reforms. This inclusive strategy should consider factors such as the production environment, human behaviour, motivation and qualifications.⁴⁷ Enhanced safety measures and enhanced occupational surveillance for mitigating the risks associated with injuries, contributing to both individual worker safety and public concerns,⁴⁸ to introduce multisystemic reforms aimed at ensuring occupational and industrial safety at mines.

Strengths and limitations of the study

This study provides an updated assessment of injury rates through several studies in the mining sector over the past 13 years, reflecting the ongoing precarious conditions in which these workers continue to operate. Methodologically, the use of the JBI guidelines for data extraction ensured the quality of the presentation of the synthesis of findings in this review.

However, certain limitations should be considered in this study. First, a reporting bias may have arisen due to the variability inherent in injury reporting systems/records, potentially leading to underestimating frequencies. Furthermore, the lack of access to or exclusion of certain languages during the literature search introduces an information bias. However, the inclusion of at least three languages, with one being the primary language of scientific publication, ensured the incorporation of the most pertinent information available.

Moreover, this research did not distinguish between lethal and nonlethal incidents, employment categories or even industries, potentially causing an overestimation of the findings because of inherent factors such as risk, duration of activity and errors related to worker skills. Likewise, high variability in the quality of the reviewed studies, as well as appropriate characterisation of the population, risk factors and health outcomes, is crucial in understanding the impact of occupational injuries.

Finally, in this scoping review, a key limitation was the inadequate documentation of health outcomes in the included studies. Addressing this gap is essential for informing evidence-based practices and policies to prioritise worker well-being in the mining industry. Therefore, additional studies addressing specific aspects of risk factors and preventive measures in this context are needed, with particular attention given to reporting indicators such as the average duration of absence due to injuries.

Conclusion

This review presents a thorough analysis of the risk factors associated with injuries in the mining sector. In particular, factors such as advanced age, cumulative work experience, night shifts and mechanical agents have emerged as significant predisposing factors for injuries among miners. Considering the identified risk factors, these findings underscore the need for concrete measures to prevent and control injuries in the mining sector. Furthermore, improving the notification and recording of the injuries are crucial for obtaining more accurate indicators.

Data availability statement

Data are available in a public, open access repository (https://osf.io/29g5a).