As plant and machinery gets older, it is more prone to emit higher than the designed amounts of harmful gasses. While you can’t usually see evidence of this, it becomes very dangerous working in confined spaces and especially dangerous with underground equipment.

Most Exhaust Gas Emission testing is performed on heavy machinery and plant headed for an underground mine. There is legislation in place regarding the concentration of these gasses in machinery exhaust at normal and high revs. These concentrations also change site to site as some mine operators have even stricter rules for underground ventilation or general environmental reasons.

Your company should be aware of the health effects and understand the legislation that is in place around diesel Plant and Machinery to ensure safety and compliance.

Legal Requirements

To comply with the Mines Safety and Inspection Regulations 1995, Underground diesel Plant and Machinery must have an exhaust analysis performed;

  • every 250 hours of operation or every month if machine has no hour meter;
  • after maintenance work or;
  • at the request of an inspector.

The maximum allowable levels found during the exhaust analysis are 2000 ppm of Carbon Monoxide (CO) or 1800 ppm of Oxides of Nitrogen (NOx). The machinery or plant must not be returned to service until the exhaust emissions are below these levels and have been reduced as much as reasonably practicable.

If the plant or machine exhaust emissions have not been reduced below acceptable levels for a period of 24 months then CO and NOx emissions must be reduced below 1500 and 1000ppm, respectively, under any engine conditions or load until the equipment can be returned to duty.

What are Exhaust Emissions

Diesel engine exhaust contains a number of different gasses and other matter including;

  • Diesel Particulate Matter (DPM)

    DPM Representation

    Schematic representation of DPM (after Twigg and Phillips, 2009)

  • Carbon Dioxide (CO2)
  • Carbon Monoxide (CO)
  • Water vapor (H2O)
  • Oxides of Nitrogen (NOx)
  • Unreacted gasses from air such as Nitrogen

The DPMs include organic carbon compounds, solid carbon cores and some metallic compounds. More than 90% of these carbon particulates are small enough to enter the deepest part of the lungs.

When carrying out Exhaust Gas emission testing you may have noticed that the vehicle is warmed up before readings are taken. This is to get the engine to its normal operating temperature to get readings that accurately reflect the emissions you would usually have. At low operating temperatures, diesel engines will emit a larger amount of CO. This is because there has been a much lower rate of Carbon oxidation in the fuel.

High readings of CO can also be caused by bad fuel / air mixtures.

Health Impacts

Exposure to exhaust gas and particulates from diesel engines can have a wide range of short and long term effects. In the past DPM was regulated on a weight basis. This was effective in reducing overall DPM but let the fine DPM slip through the gaps. The fine particles are the most harmful, as they are able to penetrate the deep parts of the lungs.

The short term health effects of diesel exhaust exposure include but are not limited to;

DPM size

Originally published United States Environmental Protection Agency –

  • Headaches
  • Eye and Nose irritation
  • Nausea
  • Asthma

Long term exposure shows increased risk of;

  • Respiratory disease
  • Cardiopulmonary disease
  • Cardiovascular disease
  • Lung inflammation
  • Cancer

There is also the risk of chemical asphyxiation from CO. CO reduces the capacity of blood to carry Oxygen around the body. This can cause loss of consciousness and even death.

In June, 2012, the International Agency for Cancer Research (IARC) classified diesel exhaust (including DPM) as a known human carcinogen (Group 1). The World Health Organisation (WHO) also classes diesel exhaust as carcinogenic.

What does the Exhaust Analysis involve?

An exhaust analysis is a quick and simple task to carry out. One of our Inspectors or Engineers will come to your site / yard / offices with the testing machine and be out of your hair in around 45 minutes. For large machinery and Plant one of your experienced operators is sometimes required to assist with getting the revs right, as samples are taken after the vehicle is warmed up at idle and at high idle. High idle is basically the revs the Machine would be when operating underground using ancillary equipment like moving booms around or blades up and down.


About Rapallo’s Inspection Services

Rapallo has a dedicated cloud based inspection program tailored to keeping inspection, maintenance and other equipment documentation in the same place whilst conforming to all legislative requirements. Click here for more information.

If you haven’t had your Plant and Machinery Inspected in a while or need some advice, call Rapallo’s Stephen Niederberger in our Perth office on (08) 6279 0900 or Thomas Mvula in our Kalgoorlie office (08) 9021 8399 for a chat.

We use our Inspection program to effectively track the Inspection and maintenance of our client’s plant and machinery. Our clients are using this program to provide critical information to insurance companies, WorkCover, WorkSafe and the Department of Mines and Petroleum. If queried by the DMP or WorkSafe or to provide information for risk assessment our program provides this information much easier than a spreadsheet or SAP.

Companies that benefit from regular inspection include:

  • Exploration and Drilling Companies
  • Plant and Machinery Hire Companies
  • Mining Contractors
  • Compressor Hire Companies
  • Mining Companies
  • Port Authorities
  • Hospitals
  • Haulage and Trucking Companies
  • Construction Companies
  • Shires and Councils
  • Crane Hire
  • EWP Hire
  • Service stations
  • Breweries
  • Power Stations
  • Steam Engines
  • LNG Plant
  • Oil and Gas platforms
  • Fuel Storage and Distribution

Rapallo inspects:

  • Drill Rigs
  • Pressure Vessels
  • Tanks
  • Boilers
  • Cranes
  • Lifting Equipment
  • Elevated Work Platforms
  • Trailer Drawbars
  • Compressors
  • Fuel Farms
  • Classified Plant
  • Plant and Machinery
  • Trucks
  • Rail Wagons
  • Ball Studs

Rapallo perform:

Click here for more information on Rapallo’s Inspection capabilities or call Rapallo’s Stephen Niederberger in our Perth office on (08) 6279 0900 or Haitao Han in our Kalgoorlie office (08) 9021 8399 for a chat.


Sign up for more Rapallo news and articles



Scroll to Top