Canadian Occupational Safety

JUNE/JULY 2017 25 for the selection of clean engines. Approved engines have been tested for emissions and to determine required ventilation volumes. Certifi cation is specifi ed in some provincial regulation. "Not all engines are Canmet- certifi ed. If you have one that is Canmet-certified, you'll have no issues," Demers says. Contaminates can be eliminated altogether by replacing traditional diesel-powered equipment with electric, battery-powered machinery. In addition to providing a healthier atmosphere due to reduced fuel con- sumption, electric-powered vehicles have lower maintenance and venti- lation costs. Charging stations are installed based on the range the vehicle is expected to travel in a shift. Battery size depends on the require- ments of the specifi c mine: how far the vehicle has to travel and how much of the distance is upgrade. "A mining vehicle is much heavier than a surface car, and you're running on ramps, on 20 per cent grades. You do regenerate as you go down, but you use more energy climbing ramps," Demers says, adding some vehicles also have on-board charging, which allows an operator to re-charge a bat- tery during breaks. Implementing a program of regu- lar inspection and maintenance is very important, too. Routine maintenance can reduce diesel particulate matter exhaust concentration by fi ve per cent, according to research cited by Work- place Safety North. In underground mines, equipment maintenance — of intake fi lters, leaks, exhaust, engine and cooling — should be performed every 250 hours. Having a policy of not idling equip- ment unnecessarily — and impressing on staff the importance of the policy — will also help reduce diesel par- ticulate matter emissions directly at the source, as will the installation of devices such as catalytic converters and diesel particulate fi lters on diesel engine exhaust systems. "But if your engine is not tuned properly and it's emitting a lot of black soot, you will plug up your fi lter in no time. And that's not going to help your cause. Maintenance is the key to everything. You have to have very good maintenance," Demers says. Many vehicles, especially larger ones such as haulage trucks, which have higher horsepower, also have pressurized operator cabs to provide the operator with fi ltered, clean air within an enclosed cab. After limiting diesel particulate matter at the source, it's important to install and maintain an energy-effi - cient ventilation system, Grenier says. "It costs a lot to ventilate a mine properly, especially a deep under- ground mine; it will cost you millions of dollars a year. You want to make sure you are putting that money to good use and using it in those areas where dilution of the contaminants that you couldn't trap at the source takes place and protects the worker." Air-purifying respirators, which cover the nose and mouth, can also be used to reduce worker inhalation of diesel particulate matter but should, of course, be seen as a last line of defence. They must be used to supple- ment engineering and administrative controls where these controls are insuffi cient to reduce worker exposure to the required level or where those controls cannot be implemented. Miners required to wear a respirator must be evalu- ated to ensure they are medically able to wear it. Safety managers should also review CSA Z94.4- 11 (R2016) on the selection, use and care of respirators. It includes information on fi t-testing proto- cols and training requirements. SAMPLING AND MONITORING Provincial and territorial regulations require mining companies to measure workers' exposure to diesel particulate matter by calculating the airborne concentration of diesel particulate. Personal sampling is performed to measure the exposure of individual workers. Monitoring exposure is also a good way for a company to assess the effectiveness of its equipment maintenance and of the benefi t of its engineering controls. Sampling is done through the duration of a worker's shift. The worker wears a pump and a fi lter and the pump sucks in air within the worker's breathing zone, a half-metre radius distance from the person's nose and mouth. "The pump sucks air at a known fl ow rate for a known period of time. So then we know exactly the volume — how many cubic metres were sampled throughout the shift. That allows us to end up with a fi gure of milligrams per cubic metre that we can compare with the provincial limit of exposure," Grenier says. The traditional method of analyz- ing diesel particulate matter samples is called the Respirable Combus- tible Dust method. This test, still used in some provinces, is simple and inexpensive. However, it has the disadvantage that it is non-selective. Some mineral dusts can lead it to underestimate the amount of diesel particulate in the sample of air, while sources of carbon, such as drill oil mists and cigarette smoke, can cause it to overestimate exposure to diesel particulate matter. Alternatively, the NIOSH 5040 method uses an analytical instru- ment to measure elemental carbon and organic carbon independently. Because it measures the elemental carbon portion of the total carbon produced, this method is regarded as a more accurate method of mea- suring diesel particulate matter than the Respirable Combustible Dust method. It is specifi cally required in Saskatchewan, Ontario, Quebec and Newfoundland and Labrador. Industrial hygiene guidelines will suggest how often monitoring should be done, based on factors including the likelihood of exposure for the occupa- tional group, number of employees and what they do, Grenier says. "There are industrial hygiene rules that would prompt you to set up an appropriate occupational hygiene sampling plan for your operation as it pertains to diesel. And the mining inspectors would be looking for such a plan for every mining operation that they oversee," he says. Over the last 20 years, concentra- tions of diesel particulate matter underground mines have been reduced signifi cantly, Grenier says. But there is still progress to be made. "This substance is a known human carcinogen, and there is no safe expo- sure levels for a carcinogen," he says. "So we need to continue down that road and keep lowering permissible exposure limits on an ongoing basis." Linda Johnson is a freelance journalist based in Toronto. She can be reached at lindajohnson@sympatico.ca. Available Risk-Free for 30 Days Order online: www.carswell.com Call Toll-Free: 1-800-387-5164 In Toronto: 416-609-3800 Has your workplace met all requirements under the new Bill 132? New Edition Pocket Ontario OH&S Act & Regulations 2017 – Consolidated Edition © 2017 Thomson Reuters Canada Limited 00243CP-A86353-CM Your peers rely on this best-selling pocket resource for invaluable guidance on workplace safety law. From preparing job hazard analyses and creating safety training programs to developing anti-harassment policies and performing violence risk assessments – the new 2017 edition of this best-selling resource will help your organization meet all your OHSA obligations, including the new requirements under Bill 132. To see what's new, go to www.carswell.com/pocket-ohs Order # 987844-65201 $23.95 Softcover approx. 1080 pages March 2017 978-0-7798-7844-4 Also available in French. Call for details. Also available Large format edition with tabs Order # 987846-65201 $23.95 Softcover approx. 780 pages March 2017 978-0-7798-7846-8 eBook available for web browser or download to your desktop, laptop, iPad or Android tablet.* Learn more at carswell.com/proview *eBook not available to trade bookstores, third-party distributors, academic institutions, and students. Order # 987844-65201 Also available Shipping and handling are extra. Price(s) subject to change without notice and subject to applicable taxes

• Cover