MNO2608
ASSIGNMENT 5
(PORTFOLIO)
SEMESTER 1
MEMO | DUE
MAY 2025
NO PLAGIARISM
[School]
[Course title]
, Exam (elaborations)
MNO2608 Assignment 5 (Portfolio)
Semester 1 Memo | Due May 2025
Course
Fundamentals of Industrial Hygiene (MNO2608)
Institution
University Of South Africa (Unisa)
MNO2608 Assignment 5 (Portfolio) Semester 1 Memo | Due May 2025. All
questions fully answered.
QUESTION 1 [20] CASE STUDY ONE (1): Respirable Silica Dust Exposure and
Heat Stress in an Underground Gold Mine. In 2022, twenty-five (25) mine
workers at an underground gold mine in South Africa were exposed to
dangerously high levels of respirable crystalline silica dust during routine
drilling operations. The dust suppression systems, including water sprays
and misting, were not functioning properly, and the underground ventilation
system was underperforming due to delayed servicing. Exposure monitoring
later revealed silica dust levels exceeding 0.25 mg/m³, which is more than
double the legal limit of 0.1 mg/m³. Additionally, the underground working
environment was extremely hot. Workers faced heat stress due to
inadequate cooling systems and limited access to water in the work area.
Prolonged exposure to heat stress, combined with poor air quality, put
workers at risk for both heat-related illnesses and respiratory problems.
Note: This case study is fictional and intended solely for portfolio assessment
purposes. Any resemblance to actual persons or real events is purely
coincidental. Make use of Case Study 1 and conduct additional research to
answer the question. Remember to reference the sources of your
information. 1.1. Identify the key failures that led to workers being exposed
to respirable silica dust and heat stress. (5) 1.2. Discuss the health risks
associated with prolonged exposure to respirable crystalline silica dust and
heat stress in an underground mining environment. (5)
QUESTION 1 [20] – CASE STUDY: RESPIRABLE SILICA DUST EXPOSURE
AND HEAT STRESS IN AN UNDERGROUND GOLD MINE
1.1 Key Failures That Led to Worker Exposure (5 marks)
, 1. Malfunctioning Dust Suppression Systems:
o Water sprays and misting systems, which are essential to control airborne dust,
were not operating effectively, allowing silica dust to become airborne during
drilling.
2. Poor Ventilation Performance:
o The underground ventilation system was underperforming due to delayed
maintenance, leading to inadequate airflow to dilute and remove airborne
contaminants and heat.
3. Lack of Exposure Monitoring and Immediate Action:
o The mine failed to proactively monitor dust levels in real-time or to take
corrective action when the threshold was exceeded (0.25 mg/m³ vs. legal limit of
0.1 mg/m³).
4. Inadequate Heat Management Systems:
o Cooling systems in the mine were either insufficient or not functioning,
exacerbating heat buildup underground.
5. Limited Access to Potable Water:
o Workers had limited access to drinking water, increasing the risk of dehydration
and heat stress.
1.2 Health Risks Associated with Prolonged Exposure (5 marks)
A. Respiratory Risks from Crystalline Silica Dust:
1. Silicosis:
o A progressive, irreversible lung disease caused by inhalation of silica dust,
leading to inflammation and scarring in the lungs (fibrosis).
2. Lung Cancer:
o Classified by the IARC as a Group 1 carcinogen; prolonged silica exposure
increases the risk of lung cancer (IARC, 2012).
3. Chronic Obstructive Pulmonary Disease (COPD):
o Long-term silica exposure can lead to COPD, including chronic bronchitis and
emphysema.
B. Risks from Heat Stress:
4. Heat Exhaustion and Heat Stroke:
o Can cause symptoms ranging from fatigue and nausea to life-threatening
conditions like heat stroke if core body temperature exceeds safe limits.
5. Dehydration and Fatigue:
o Inadequate hydration and prolonged heat exposure lead to decreased
concentration, increased risk of errors, and physical collapse.
Combined Effect:
When both risks are present, they compound each other: heat increases breathing rates,
, potentially increasing silica inhalation, while dehydration can impair the body's natural ability to
regulate dust exposure through mucous membranes.
References:
International Agency for Research on Cancer (IARC), Monograph on the Evaluation of
Carcinogenic Risks to Humans – Silica Dust, 2012.
National Institute for Occupational Safety and Health (NIOSH), “Workplace Safety and
Health Topics: Silica Dust,” CDC.
Mine Health and Safety Council (MHSC), South African Mine Occupational Health and
Safety Statistics Report, 2021.
World Health Organization (WHO), Protecting Workers from Heat Stress, 2023.
1.1 Key Failures Leading to Worker Exposure (5 marks)
The main failures that contributed to the exposure of workers to respirable crystalline silica dust
and heat stress include:
1. Malfunctioning Dust Suppression Systems: The water sprays and misting systems—
critical for controlling dust levels—were not operational, allowing dust to accumulate and
be inhaled by workers.
2. Inadequate Ventilation: The underground ventilation system was not functioning
optimally due to delayed maintenance, resulting in poor air circulation and accumulation
of harmful dust and heat.
3. Lack of Environmental Monitoring and Timely Response: There was a delay in
detecting and responding to the excessive dust levels and rising temperatures
underground, indicating poor environmental hazard monitoring.
4. Insufficient Cooling Systems: The working area lacked adequate cooling infrastructure,
intensifying heat exposure for workers in already high-temperature environments.
5. Limited Access to Drinking Water: Workers did not have proper access to hydration in
the extreme heat, increasing the likelihood of heat-related illnesses.
Sources:
ASSIGNMENT 5
(PORTFOLIO)
SEMESTER 1
MEMO | DUE
MAY 2025
NO PLAGIARISM
[School]
[Course title]
, Exam (elaborations)
MNO2608 Assignment 5 (Portfolio)
Semester 1 Memo | Due May 2025
Course
Fundamentals of Industrial Hygiene (MNO2608)
Institution
University Of South Africa (Unisa)
MNO2608 Assignment 5 (Portfolio) Semester 1 Memo | Due May 2025. All
questions fully answered.
QUESTION 1 [20] CASE STUDY ONE (1): Respirable Silica Dust Exposure and
Heat Stress in an Underground Gold Mine. In 2022, twenty-five (25) mine
workers at an underground gold mine in South Africa were exposed to
dangerously high levels of respirable crystalline silica dust during routine
drilling operations. The dust suppression systems, including water sprays
and misting, were not functioning properly, and the underground ventilation
system was underperforming due to delayed servicing. Exposure monitoring
later revealed silica dust levels exceeding 0.25 mg/m³, which is more than
double the legal limit of 0.1 mg/m³. Additionally, the underground working
environment was extremely hot. Workers faced heat stress due to
inadequate cooling systems and limited access to water in the work area.
Prolonged exposure to heat stress, combined with poor air quality, put
workers at risk for both heat-related illnesses and respiratory problems.
Note: This case study is fictional and intended solely for portfolio assessment
purposes. Any resemblance to actual persons or real events is purely
coincidental. Make use of Case Study 1 and conduct additional research to
answer the question. Remember to reference the sources of your
information. 1.1. Identify the key failures that led to workers being exposed
to respirable silica dust and heat stress. (5) 1.2. Discuss the health risks
associated with prolonged exposure to respirable crystalline silica dust and
heat stress in an underground mining environment. (5)
QUESTION 1 [20] – CASE STUDY: RESPIRABLE SILICA DUST EXPOSURE
AND HEAT STRESS IN AN UNDERGROUND GOLD MINE
1.1 Key Failures That Led to Worker Exposure (5 marks)
, 1. Malfunctioning Dust Suppression Systems:
o Water sprays and misting systems, which are essential to control airborne dust,
were not operating effectively, allowing silica dust to become airborne during
drilling.
2. Poor Ventilation Performance:
o The underground ventilation system was underperforming due to delayed
maintenance, leading to inadequate airflow to dilute and remove airborne
contaminants and heat.
3. Lack of Exposure Monitoring and Immediate Action:
o The mine failed to proactively monitor dust levels in real-time or to take
corrective action when the threshold was exceeded (0.25 mg/m³ vs. legal limit of
0.1 mg/m³).
4. Inadequate Heat Management Systems:
o Cooling systems in the mine were either insufficient or not functioning,
exacerbating heat buildup underground.
5. Limited Access to Potable Water:
o Workers had limited access to drinking water, increasing the risk of dehydration
and heat stress.
1.2 Health Risks Associated with Prolonged Exposure (5 marks)
A. Respiratory Risks from Crystalline Silica Dust:
1. Silicosis:
o A progressive, irreversible lung disease caused by inhalation of silica dust,
leading to inflammation and scarring in the lungs (fibrosis).
2. Lung Cancer:
o Classified by the IARC as a Group 1 carcinogen; prolonged silica exposure
increases the risk of lung cancer (IARC, 2012).
3. Chronic Obstructive Pulmonary Disease (COPD):
o Long-term silica exposure can lead to COPD, including chronic bronchitis and
emphysema.
B. Risks from Heat Stress:
4. Heat Exhaustion and Heat Stroke:
o Can cause symptoms ranging from fatigue and nausea to life-threatening
conditions like heat stroke if core body temperature exceeds safe limits.
5. Dehydration and Fatigue:
o Inadequate hydration and prolonged heat exposure lead to decreased
concentration, increased risk of errors, and physical collapse.
Combined Effect:
When both risks are present, they compound each other: heat increases breathing rates,
, potentially increasing silica inhalation, while dehydration can impair the body's natural ability to
regulate dust exposure through mucous membranes.
References:
International Agency for Research on Cancer (IARC), Monograph on the Evaluation of
Carcinogenic Risks to Humans – Silica Dust, 2012.
National Institute for Occupational Safety and Health (NIOSH), “Workplace Safety and
Health Topics: Silica Dust,” CDC.
Mine Health and Safety Council (MHSC), South African Mine Occupational Health and
Safety Statistics Report, 2021.
World Health Organization (WHO), Protecting Workers from Heat Stress, 2023.
1.1 Key Failures Leading to Worker Exposure (5 marks)
The main failures that contributed to the exposure of workers to respirable crystalline silica dust
and heat stress include:
1. Malfunctioning Dust Suppression Systems: The water sprays and misting systems—
critical for controlling dust levels—were not operational, allowing dust to accumulate and
be inhaled by workers.
2. Inadequate Ventilation: The underground ventilation system was not functioning
optimally due to delayed maintenance, resulting in poor air circulation and accumulation
of harmful dust and heat.
3. Lack of Environmental Monitoring and Timely Response: There was a delay in
detecting and responding to the excessive dust levels and rising temperatures
underground, indicating poor environmental hazard monitoring.
4. Insufficient Cooling Systems: The working area lacked adequate cooling infrastructure,
intensifying heat exposure for workers in already high-temperature environments.
5. Limited Access to Drinking Water: Workers did not have proper access to hydration in
the extreme heat, increasing the likelihood of heat-related illnesses.
Sources:
