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Update from Alberta Transportation on Gravel Pit Health Concerns

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Ward 6 official website
Last update: March 10, 2017
March 6, 2017
Please find below an update from Rizwan Hussain, Alberta Transportation Urban Construction Manager for the Calgary Ring Road, regarding the health concerns raised by the public, and the plans to address them:
Alberta Transportation
I understand you are concerned about the impact this gravel operation will have on your home life and your health. I recognize your concern about gravel operations and their potential to produce fine particulate silica dust.
Public health is absolutely our first concern and we will be taking every precaution at this site to ensure the health of onsite construction workers and nearby residents.
As with other Calgary gravel operations, a rigorous dust suppression program will be put in place and air quality will be routinely monitored to ensure that dust and fine particulates remain within the levels required by health and safety regulations.
Mining and crushing operations at this site will produce the different sizes of gravel needed for road construction—road base, gravel fill and asphalt.
  • Less than 15 per cent of the gravel we will mine and crush will be smaller than 80 microns.
  • An even smaller percentage will be 10 microns or less—the size that can be inhaled into human lungs and has the capacity to contribute to health issues.
  • Only a fraction of this fraction will be silica dust.
Because of this, with a consistent dust suppression program in place, the amount of fine particulates created by a gravel crushing operation stay well within legislated limits.
As mentioned, Alberta Transportation and KGL are committed to protecting the health of the site’s workers and adjacent residents, as well as minimizing the impact of the operations to your community.
We’ve modified the location and size of the dust berm, in response to residents, moving it west and raising its height to four metres from three. Back-up alarms on contractor’s trucks will be modified to reduce the amount of noise they make and site lighting will only be used during work hours and oriented away from homes. We are also looking into planting trees near the berm to further screen dust and improve sightlines.
More Details:
  • As the main source of any fine particulate dust, the crusher will be located between 100 and 250 metres from the nearest home, depending on where work is happening. It will be located in the gravel pit, starting at a depth of at least two metres below ground level, as the layers of top soil and clay will have been removed to uncover the gravel. The four-metre high berm will also be constructed prior to the start of crushing operations. This will help contain operational noise and dust.
  • As the pit becomes deeper with excavation, the crusher will be housed lower and lower in the pit, away from wind conditions at the surface. Because of this, the majority of the fine dust created by the crusher will be confined to the pit.
  • In addition, the crusher is equipped with a water system that sprays water during crushing and at transfer points to keep the gravel wet and further suppress the dust created by crushing operations.
  • As for the dust generated by excavation and haul trucks—which will not be a significant source of fine particulate—there will be ample water on site for water trucks to suppress dust from these sources. KGL is planning to draw water from a City of Calgary water line in the area.
  • Stockpiles will be watered and seeded to reduce erosion. Hydroseeding (a mixture of seed and mulch) will be used to reduce erosion until vegetation is established.
  • Finally, should wind pick up enough that dust suppression becomes unmanageable; operations will be shut down until the wind subsides and adequate dust suppression measures can be implemented.
Air Quality Monitoring
  • Because of the high concentration and duration of exposure required to experience negative effects from fine particulate silica, it is typically considered an occupational hazard.
  • Because of this, there is no guideline in Alberta or through Health Canada for non-occupational exposure. Outside of the workplace exposure via ambient air sufficient to pose a health risk is extremely uncommon.
  • According to the Alberta Occupational Health and Safety Code, the occupational exposure limit for workers is 25 micrograms per cubic metre of air over an eight-hour period.
  • For the purposes of this site, Alberta will be adopting Ontario’s guideline—a non-occupational exposure limit of five micrograms per cubic metre of air over a 24 hour period. (The non-occupational limit is lower than occupational because it errs on the side of protecting more vulnerable segments of society—i.e. children—and assumes 24 hour exposure.)
Alberta Transportation will release the Health Assessment Report and Air Quality Monitoring Plan after the review has been completed, and I will help distribute this on the Ward 6 website.
If you have additional questions or require further information, please see the reference guide below to assist in deciding who is best to contact.


Go back to the March 2017 W6 Report.

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This content represents the personal views and opinions of the Ward Councillor and should not be taken as a statement of policy of The City of Calgary. The inclusion of any external content does not imply endorsement by The City of Calgary.

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