The hidden risk factors that impacts on the health and safety of operators.
The real issue is respirable dust (particulate) inside the breathing zone and the emphasis must be to prevent disease for the entire working life of operators. It is invisible to the human eye but it is found whenever extracted and processed minerals have been crushed, milled, screened, blasted, drilled, shovelled and conveyed.
Definition: "Dust of less than 10 microns which is capable of penetrating deep into the alveoli" (Source BSEN 481)
Mining machines operate 24/7 in hot, dirty, dust-laden environments. Keeping the operator’s environment safe and healthy is an extreme task for equipment designers and maintenance crews.
In effect, the installed air quality (filtration) system is an essential component of a well-designed operator cabin. Environmentally controlled cabins reduce exponentially operator exposure to harmful particulates such as respirable crystalline silica, aerosols, particulate matter and other airborne contaminants or toxic gases.
Though it must also be noted that the very same respiratory hazards of fine airborne dust are the causes that shorten the life of air conditioning systems and other electrical equipment.
Picture of HVAC evaporator contaminated with dust
Dust exposure causes irritation and inflammation of the eyes and worsens pre-existing conditions. It has a drying effect with skin contact that can result in dermatitis. Prolonged exposure to fine dust results in increased nasal and respiratory conditions such as coughing. The result of high and prolonged exposure leads to inflammation of the lining tissue of the respiratory system with further complications such as bronchitis and pneumonia. Respirable dust (diameter <5 micron) is suspended in air that can travel to the deep tissue of the lung and pass through to blood stream associated with higher risks to health.
The mitigation process is a multi-level approach with dust separation techniques with well-designed engineering controls.
There is evidence available to recommend Breathe-Safe technology which can protect workers in situations where they are exposed to several respirable hazards from low to high exposure concentrations at their working environment in mineral processing sites, construction sites, waste and landfills and agricultural settings.
The methods to isolate and protect a worker are:
The ecosystem BEGINS with a sealed (environmental) cabin with fresh air pressuriser in a climate controlled environment (HVAC). With the following features: HEPA filtration, auto pressure control, digital display with alerts and warning, remote monitoring, brushless long life pressuriser motor.
The system to control respirable dust / particulate matter with a two-stage high efficiency filter media (Fresh air & return air filtration)
3.Remote monitoring / on board display
Management of data to analyse and review internal environmental conditions and operator awareness/alerts that the system is working.
Management can review data over time which demonstrates that system is working and providing a safe work environment for the service life of the machine.
Reduce repairs and maintenance costs.
Do you have fine dust inside the cabin?
Is the heating, ventilation and air conditioning (HVAC) system underperforming or not cooling as before?
Has the machine been stood down often due to HVAC service or repairs? (Dust contamination)
If you answered yes to any of these questions, the main issue may be fine (respirable) dusts and the fact that for the most part these are invisible and can potentially remain airborne for days or weeks. Fugitive fine dust which become airborne is produced at mineral processing sites by blasting, shovelling, drilling, screening, crushing, conveying and handling.
Airborne particulate that has a diameter of less than 10 microns in size will pass through installed cabin filters easily that were never intended to mitigate against fine respirable dust in the first place.
Settling dust may deposit inside the cabin surfaces, foot well and inside HVAC components (Evaporator). Hazardous conditions occur for the operator when internal deposited dusts are lifted by air conditioning-HVAC, machine vibration and operator body movements and consequently, internal dust contamination, become airborne inside the cabin without any means of particilate capture.
The installed cabin pressuriser / filtration system must be configured for respirable dust (Particulate) mitigation.
The best practice that applies and keeps an operator safe is the same practice and procedure that can be used to keep the HVAC system and the inside of the cabin clean.
The same applies to reduce unexpected costs of unscheduled service cycles due of component failure and/or HVAC system underperformance caused by fine dust contamination.
The following key points have proven effective in reducing service and maintenance costs:
- Keep the cabin environment clean (Always keep doors and windows closed & use a HEPA vacuum in the cabin at least twice a week)
- The cabin needs to be sealed tight against external particulate contamination
- Pre-cleaner should be used to expel coarse particles and extend filter service life
- Ensure fresh air pressurisation with a HEPA filter (High efficiency filter to control respirable particulate)
- Use computer control pressurisation (Precisely control cabin environment and extend filter service life)
- Employ computer cabin pressure controller with display and warning/alert for operator (Site management warning/alert by remote monitoring)
- Have a brushless motor, with an operating design range between 10000 to 15000 hours of operation (Maintenance free)
- Provide a HEPA return air filter to capture contamination from clothes and shoes (Keeps evaporator free from dust contamination)
- Use remote monitoring for analytics 24/7 (May be used to develop filter maintenance intervals)
- Maintain cabin integrity by replacing worn out seals (Audits as part of implemented dust management plan)
At site operations, a cabin is exposed to different concentration levels of dust and other toxic substances. The operating environment may be subject to extreme levels of dust coupled with high ambient heat. When fine dust contamination begins to accumulate in the evaporator, the performance level decreases over time and eventually causes airflow restrictions. This process of contamination increases heat load and it is the ultimate factor that causes HVAC failures. To learn more click here
To view available data and to understand the performance parameters of an installed system contact Breathe-Safe.
Click below to view Breathe-Safe white paper in regards to respirable dust: