The Lafarge Exshaw Cement Plant is moving forward with the long-discussed design for extending the life of the quarry. While plans have been in the works for years, we want to make sure community members know what to expect from the project. We hosted an information session on Tuesday, November 26 at 6 p.m. at the Exshaw Cement Plant. Quarry Manager Dylan Treadwell, a mining engineer with extensive experience managing quarries for Lafarge and back home in Australia, oversees all quarry operations, onsite and in the office. He will lead the Back Mountain project; we spoke with him to learn more.
Why is Lafarge extending the quarry?
The existing quarry has has approximately seven years of limestone reserves remaining at current production rates. The Back Mountain Project will help us continue operations for the next 50 years. It has always been part of the long-term plan of the quarry and has been shared with the community over the years. We now have the green light within Lafarge Canada to get started.
Why did you host an information session?
We want to make sure our neighbors know what to expect. This is a multi-phase, multi-year project that will extend the quarry north along the ridge line. Our first focus will be on building the access ramp for production. All this work is within the Lafarge lease land and operating permits, but it will be more visible from Canmore, from the viewpoint off Highway 1, and Exshaw residents might notice the changes. We want to make sure everyone is up to speed on the work and why it’s happening.
What will the project involve?
It is going to mean more blasting, but smaller blasts in size. A normal production blast will contain upwards of 50 holes. These additional blasts will be generally less than 10 holes and won’t be as deep, meaning less impact. These blasts will be happening more often; we expect daily, with exception to Sundays. The design of the access ramp has been carefully selected in order to minimize impact for Exshaw residents, with the main portion of being on the Southern and Western Ridge, with work on the Eastern side being minimal.
Will residents feel any vibrations from this?
We don’t expect there to be any vibrations felt by the community from blasting. We have our seismograph at the water treatment plant that records all ground vibration and air overpressure. It’s a super sensitive monitor that gives us results within two hours of each blast. Our goal is to not go above 5 millimetres per second of ground movement. Even superficial damage, as a result of blast vibrations, has not been observed at less than 50 millimetres per second. We are giving ourselves a ten times safety factor to ensure we protect everything around us. Blasting technology has improved a lot in recent years—we are now using a chip in each detonator that is programmed to detonate to the millisecond. This effectively eliminates the risk of vibration waves compounding.
Will this mean an increase in production?
We are estimating removing on average 300,000 tonnes of rock each year for the first three years of the access ramp. The overall production rate from the quarry will stay the same, we will just be taking some of that rock from the new works.
Will this mean more fugitive dust?
With the area of work being on top of the ridge, there will be an increased chance that you will notice some visible dust. We’ve come a long way with dust management and we’ll suppress as
much as possible. If it’s windy and blowing towards Exshaw, we’ll hold blasting. We’ll keep operating our water truck on the haul roads and continue to explore paving and hydroseeding options each year. We are currently trialing a new dust suppressant on the roads with positive initial results that we hope to continue using in the warmer months. We will do all that we can to prevent as much dust as possible, especially in the direction of Exshaw.
Is safety a concern for employees?
Safety is going to be a big priority. I’ve been working closely on the design for the future with Eric Fontaine, Lafarge’s raw materials expert for North America and a former Exshaw Quarry Manager, so he knows the plant well. The initial access ramps are steep and exposed but will be carefully controlled to ensure the safety of all operators. There’s been lots of discussion about the best approach, we’ve been working with five potential designs and we’re moving forward with the one that removes as much risk as possible; including less exposure for the community.
Where is the project at right now?
Lafarge is starting work on the Back Mountain Project in October of 2020. At this time, community members can expect to see the increase in blasting during the day from then through to winter 2021. Exact timing will depend on weather. Updates on blasts and other details will be made on our website and through email updates.