Coal Mine Dust Lung Diseases - What you need to know

In recent years a number of cases of coal mine dust lung diseases have been confirmed here in New South Wales. Coal mine dust lung diseases were thought to have been eradicated in the New South Wales mining industry and the cases reported in 2017 were the first reported since the 1970s. The specific number of confirmed cases in New South Wales has not yet been reported.

Cases have also been reported in Queensland, in 2015 the first coal miner in decades was diagnosed with Black Lung disease and in February this year it was reported that there were 133 confirmed cases of coal mine dust lung diseases in Queensland with with 36 new cases reported during the 2019 financial year. *

The number of cases of coal mine dust lung diseases reported in recent years is a sobering reminder that continued vigilance must be a key factor in ensuring the eradication of these diseases in New South Wales.

It is crucial that workers are educated on the diseases to ensure early detection.

What are ‘coal mine dust lung diseases’

There are several respiratory diseases caused by long-term occupational exposure to high concentrations of respirable coal and other mineral dust. As a group these diseases are called ‘coal mine dust lung diseases’ or CMDLD and include:

• Coal workers’ pneumoconiosis (CWP) is caused by prolonged exposure to respirable coal dust and the general build up of coal dust particles within the terminal airways. CWP is commonly known as ‘black lung disease’ as the effected lungs appear to be black in colour rather than pink.

• Mixed dust pneumoconiosis (MDP) is a disease of the lungs resulting from chronic exposure to more than one type of mineral dust, for coal miners this is generally coal and silica dust. There is evidence to suggest the toxicity of mixed dust is greater than coal dust alone.

A workers body reacts to these dust particles by forming layers of scar tissue over the affected areas. Fibrotic nodules may also form on the lungs. The dust collections and scarring may appear as small round shadows on a workers regular chest x-ray.

Other related dust lung diseases also include silicosis and chronic obstructive pulmonary disease.

What is respirable dust?

The dust particles created by mining coal generally fall into two size categories  - inhalable dust and respirable dust.

Inhalable dust is about 0.1mm in diameter and is visible to the naked eye. This type of dust gets caught in the mouth, nose and upper respiratory tract and can cause short-term effects such as eyes and nose irritation, asthma and bronchitis.

Respirable dust on the other hand is invisible. It is around 0.005mm in diameter and passes through defences and directly into lung tissue. This form of dust causes irritation to the lungs, which the body attempts to heal, causing scar tissue to form (fibrosis). This replaces health lung tissue and causes an increase in mucous production, shortness of breath and wheezing.

The different categories of dust have different effects on the human body. It is a workers exposure to high levels of ultra-fine respirable dust over an extended period of time that can lead to the development of a coal mine lung dust disease.

Who is at risk of developing coal miners’ pneumoconiosis?

Any worker exposed to harmful levels of dust is at risk of developing a dust-related lung disease. The risk is linked directly to your total level of exposure to dust – the longer a person is exposed to high concentrations of respirable dust, the more serious and life-altering the disease becomes.

What are the symptoms of pneumoconiosis?

There are two types of pneumoconiosis: simple and complex. The diagnosis is dependent upon the level of progression of the disease and simple pneumoconiosis can progress to become complex pneumoconiosis if exposure to dust continues.

Complex pneumoconiosis (also known as progressive massive fibrosis, or PMF) is the end stage of pneumoconiosis where irreversible lung damage from mineral dust causes an inflammatory response within the lung tissue.  

Pneumoconiosis can cause symptoms such as shortness of breath on exertion and eventually at rest, chronic cough, chronic chest infection, noticeable wheeze, black sputum, lung dysfunction, pulmonary hypertension, emphysema and can lead to heart problems.

Pneumoconiosis typically has a very long latency period (usually 10- 20 years or more), which means that workers exposed to chronic levels of coal and other dust may not show symptoms of the disease for a very long time. This means that workers should not rely on waiting until symptoms develop before they seek medical assistance.

What is the likely prognosis for a worker who is diagnosed with pneumoconiosis?

For workers with simple pneumoconiosis, prognosis is for a normal quality of life with small modifications depending on the severity of diagnosis. It is also possible that avoiding exposure to harmful dust may stabilise the disease.

If a worker is diagnosed with complex pneumoconiosis, prognosis is poor and there is no cure. The treatment regime from this point is to maintain and protect remaining lung function.

What do workers in the coal industry of NSW need to do?

There are a number of controls implemented by Coal Services including periodic health surveillance, chest x-rays and independent airborne dust monitoring at mine sites that work towards preventing dust disease – however workers also need to be diligent with regards to their own health.

We cannot emphasise enough the importance of coal mine workers having regular chest x-rays and where appropriate chest CT scans. A chest x-ray is required every six years if you have a high risk of dust exposure. In addition, it is important that workers ensure they are undergoing their Periodic Health Assessment with Coal Services every three years. As part of this assessment, lung health is examined along with a number of other occupational health issues such as noise, fatigue, mental health and musculoskeletal issues.

Prevention is key and early detection can be life saving.

If you have any queries regarding this article or coal mine lung dust diseases, get in touch with our team today.

 * “Cases of mine-dust lung disease and silicosis increasingly found in Queensland coal mine workers”, Jemima Burt and Rachel McGee for ABC Capricornia (26 February 2020) https://www.abc.net.au/news/2020-02-25/silicosis-and-black-lung-cases-rise-queensland-workers/11998404