Guidance About Underground Air Quality & Ventilation

The sheer number of metals and minerals we rely on in our everyday lives is staggering. From the cement we walk on to the screen you are using to read this article; our world and our very way of life depend on the products of modern mining production.Valuable minerals can be found all over the world, and more often than not, the only way to retrieve them is by mining them into the earth's ground. An important yet often unappreciated task that comes with many dangers.

Cave-ins, explosions, and extreme temperatures are some of the most perilous hazards observed to take place in underground mining. Ventilation, however, is the most critical safety aspect in an underground mine.

The Aim of Air Ventilation

Air pollution remains the most significant problem for miners, with many at risk of developing a lung disease called pneumoconiosis, which occurs when exposed to airborne respirable dust for long periods. Pneumoconioses can cause impairment, disability, and premature death. Confined spaces, minimal ventilation and underground vehicle emissions can all compromise air quality underground. The main objective of an underground ventilation system is clear: provide air flows in sufficient quantity and quality to dilute contaminant to safe amount.

When deep underground, another significant hazard besides not getting enough oxygen, is the build-up of methane and other gases. Too much, without proper ventilation, could result in explosions and multiple fatalities. Gas build-up must be monitored closely at all times with evacuation and shut down of the mine until the levels subside. Air ventilation can dilute and remove toxic and potentially explosive gases.

Air ventilation is also necessary for regulating the temperature inside the mine. Temperature levels in underground mines range from extremity-numbing cold to such heat that dehydration can be caused in a matter of minutes by profuse sweating. It's not just humans that are negatively affected by becoming sluggish in extreme heat or cold. Machines can overheat, freeze, or stop working in harsh environments. Even the support structure of the mine can become compromised in these conditions, leading to warping and collapse, every miner's worst nightmare.

Primary vs Secondary Ventilation

What is primary ventilation?

The basis of any adequate underground ventilation is the adequacy of the primary ventilation system. This is the total mine air volume flow through the significant underground workings, typically splitting into parallel circuits.Efficient ventilation is critical for production and energy efficiency, with ventilation alone contributing between 42% and 49% of a typical mine's energy cost. MINETEK'S innovative engineering has resulted in groundbreaking features that can deliver economic savings, durability and flexibility simply not possible with traditional fans.

The flexible airflow using the Performance On Demand (POD) system can ramp up or down, accommodating changes in activity throughout the life of the mine. Coupled with the Mine Air Control (MAC) system, MINETEK's fans automatically track vehicles moving into the heading and adjust the airflow accordingly. The system is controllable from the surface above and allows synchronisation of the entire ventilation system.

MINETEK's primary ventilation ensures power saving, durability, and flexibility while guaranteeing a Return on Investment (ROI). Conventional fans cannot guarantee this.

What is secondary ventilation?

Secondary ventilation refers to the provision of ventilation to development ends, stopes and services facilities that constitute secondary circuits tapped off the primary circuit or main through the flow of air. These headings are typically 'dead-end' configurations and may have multiple parallel headings where airflow is unavailable.

MINETEK's Secondary Axial fans are compact, 40% shorter, and 10% lighter than standard fans with low-profile ducting, which makes installation easy. The high-pressure capability of MINETEK's High Output (HO) axial fan is more than double of traditional fans of comparable size. This results in fewer fans needed overall.

MINETEK's Secondary Fans are available as both impulse-bladed and vane axial versions. The concentrated power of MINETEK's High Output (HO) Axial Fans makes them the ideal solution for long duct runs. Complimented by the need for only single duct run, PLC screen surface control and the bonus of being able to surge the fan past the critical duty point to clear gases and dust for fast re-entry make MINETEK the ideal choice.

What are underground mining ventilation requirements?

Ventilation plans for underground mines

It is the responsibility of the mine manager to ensure that a plan of the ventilation system of the mind is kept at the mine. This helps to communicate the direction, course, and volume of air currents, as well as the position of all air doors, stoppings, fans, regulators, and ventilating devices, in the mine. Managers must understand the impact the following factors have in determining the effectiveness of the ventilation planning process:

● the mine plan and schedule

● mine design and method

● modelling of airflow

● development of ventilation plans and schedules

● diesel equipment

● contaminants – both naturally occurring and man-made

Air Sources

The manager of the mine must also ensure that the following requirements are met:

The supply of air for any ventilating equipment used underground is obtained from the purest source available.

The recirculation of air within any secondary ventilation circuit is maintained at the minimum level that is practicable.

Where practicable, contaminated return air from any secondary ventilation circuit is exhausted directly to the primary return air exhaust system.

The Importance of Air Ventilation

Creating better air quality in underground mining environments is one of the most pressing issues facing mining companies today.

From 2007 through 2016, coal workers’ pneumoconiosis (CWP) was the underlying or contributing cause of death for 4,118 miners, highlighting how prominent the problem is.

Modern and well-maintained ventilation systems are crucial to eliminating or minimizing airborne contaminants and ensuring that fresh air is consistently supplied to miners.

To learn more about our underground mining ventilation fans visit our website