VIBRATION AND STRUCTURAL INTEGRITY

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1 FACT SHEET VIBRATION AND STRUCTURAL INTEGRITY Objective The Canadian Malartic Mine (CMM) Team wants to harness the creativity of stakeholders to find solutions to eliminate, mitigate or, if necessary, compensate for vibration-related impacts that its operations may have. We believe that all ideas, from the simplest to the most complex, deserve to be heard. It is also important to note that solutions put forward during the workshop will be examined with regard to current and anticipated impacts. Defining the Problem Vibrations that may be caused by mine blasting operations have an impact on some citizens. Residents living in sectors near the pit report more adverse vibration-related impacts. Citizens are concerned about the potential impact of vibrations on the structural integrity of buildings. Citizens are concerned about a failure to meet standards and have asked that CMM systematically disclose its results. The Monitoring Program put in place for reported damage to homes does not seem to address the concerns of all citizens. Some believe that an independent committee of experts should be established to deal with blasting-related complaints. Challenges Faced: The standards that CMM must meet are significant technical challenges given the mine s urban location. Impacts may be felt across the community because the human vibration perception threshold is very low, at about 0.5 mm/s. Evaluating potential blasting impacts on homes is very complex. Several buildings in the town are old and some do not comply with the current building code. Sources: Blasting to extract ore generates vibrations. A nearby railroad track and heavy vehicles travelling on road 7 also cause noticeable vibrations in Malartic. Table: Complaints Received Over the Past Three Years Vibration-related Complaints Number per year This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants. The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.

2 BLASTING BLAST SEQUENCE mm/s SEISMOGRAPH FISSUROMETER Glossary The breaking of rock by boring in it a hole, which is filled with a blasting charge and detonated. Successive detonation of a series of blasting charges, without a time delay between detonations. Millimetres per second. A unit of measurement used to measure ground vibration. The velocity at which the oscillatory movement of the ground moves away from the blasting point. The greater the speed, the greater the perceived vibration may be. Referred to as particle speed. Instrument used to measure and record seismic wave data using a ground motion sensor. Measuring instrument that monitors movements across cracks in a structure. Influence Factors Blast Duration Vibration Velocity Soil Composition Precise Location of Work Schedule Citizens seem more concerned when blasting is of longer duration. The higher the vibration velocity, the greater the likelihood of impact on building structures. Some types of soil conduct vibrations more efficiently than others. Blasting carried out to the north of the mine site is more likely to be noticed by nearby residents. Blasting is always carried out at the same times between a.m. and 2 a.m. and between 3 p.m. and 4 p.m. in order to reduce the startle response. Even if citizens are informed of blasting, some are still startled by the vibrations since blasting can occur at any time during either timeframe. Identified Vibration Source Blasting Blasting is carried out at various locations in the pit. The farther the blasting is to the north, the more it is noticed by citizens. Blasting may be carried out no more than twice daily, between a.m. and 2 a.m. and between 3 p.m. and 4 p.m., if the winds are favourable. Blasting may include one or several continuous blast sequences, whose total duration may not exceed 5 seconds. The concept of continuity was imposed so that there would not be three 5-second blasts with 5-minute intervals over a period of one hour, which would increase the startle response in residents. However, blast sequences within a 5-second interval may be separated by an interval of a few seconds. 2

3 FACT SHEET VIBRATION AND STRUCTURAL INTEGRITY Solutions Already Implemented at the Mine Site The CMM Team continuously works to improve its practices to reduce the vibration level and mitigate its possible impacts. The following measures have been taken to date at the CMM site. Solution #. Quality Assurance Procedures Quality assurance procedures for blasting methods and practices have been improved The goal of the clear and precise protocols is to ensure operational consistency and thus limit the potential for human error Solution #2. Use of Electronic Detonators Electronic detonators allow for better control of blast sequence synchronization and effectiveness of explosives, while limiting vibration generation One goal is to optimize blasting quality through better detonation control Solution #3. Blast Modelling I-Blast software enables engineers to anticipate blast results based on external influence factors, such as the type of rock and location Solution #4. Decking Decking reduces vibration intensity and the number of blasts required Solution #5. Call Citizens Before Blasting A call program has been implemented to give citizens a twominute warning of blasts When a complaint is followed up, the resident concerned is given the option of signing up for the call program The goal of this approach is to limit the effects of the startle response Solution #6. Call the Presbytery The Community Relations Team calls the Presbytery twice a week to ensure that religious ceremonies are not disrupted by potential blasting vibration CMM obtains the ceremony schedule and delays planned blasts when there are church ceremonies With modelling, blasting technical parameters can be modified and blasting can even be delayed if the likelihood that standards will be exceeded is too great 3 This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants. The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.

4 Solutions Already Implemented in the Town of Malartic The following measures have been taken to date outside the mine site, in the Town of Malartic. Solution #7. Notice Board Announcing Upcoming Blasts Two notice boards have been installed at either end of the town limits to inform people of the blasting schedules. The goal is to inform residents and people passing through Malartic of blasts with a view to reducing the startle response. Solution #8. Blasting Application Posted on the Mine s Website A blasting application has been posted on CMM s website in order to keep citizens informed of upcoming blasts, cancellations and results. The goal is to provide citizens will real-time information. This tool was implemented at the request of citizens who wanted to be informed of blast results. This is an additional tool that reduces the impact of the startle response. Solution #9. Seismographs Vibrations are measured by seven seismographs located throughout the town since 204. The Ministry selected the locations. The goal is to ensure that standards are complied with and to validate if improvements are conclusive. The enhanced program, and data collection and analysis continue. 4

5 FACT SHEET VIBRATION AND STRUCTURAL INTEGRITY Solution #0. Program on Perceived Blasting Effects This program compares residents perceptions during blasting with technical data. CMM Team members, equipped with portable seismographs, visit residents who are taking part in the program to experience the blasting with them, in real time. After the blasting, residents are invited to share their perceived vibration intensity and the effect of the startle response. The evaluations are then compared with the technical data gathered by the seismographs. This program has led to improved practices at the mine. For example, it revealed that blast sequences that start in the north and end in the south create a stronger startle response in residents. Sequences are now planned to go from south to north. Solution #. Control Home Program Four homes were fitted with instruments in 204 to assess the impact of vibrations on structures. The data gathered over the past two years will be compiled so that results can be compared over time and by season. The goal is to acquire the knowledge needed to determine if available studies can be applied to our surroundings. Solution #2. Fissurometer Monitoring Program Seventeen fissurometers were installed on 4 buildings in 200, before mining began. Eight to nine readings were taken from each instrument between 200 and 204. Monitoring is now done every two weeks to assess crack growth in the buildings. Based on the data gathered, seasonal temperature variations seem to have a greater impact on buildings than building proximity to the mine. Type of Movement Shifting Number of Fissurometers Percentage per Movement No movement 0 mm 2 2% Very little movement < mm 7 4% Little movement <.5 mm 5 29% Slight movement < 2.5 mm 3 8% Total 7 00% Solution #3. Building Inspection Program A building inspection program, underway since the mining project was announced and before mining began, targets homes located within a radius of 50 m from the pit and some control buildings in the town. CMM plans to continue these inspections every four or five years. The goal is to monitor the potential impact of operations on buildings. 5 This fact sheet is a synthesis tool designed to provide food for thought for collaborative workshop participants. The information it contains has no official value and shall not be construed as CMM undertakings, directions or positions.

6 Solution Evaluated and Found to be Inconclusive Solution #4. Inspection Mandates Damage Complaint Follow-up A building inspection procedure has been implemented for structural damage complaints. During the procedure, an inspection and a report are prepared by an architect or an engineer. The goal is to analyze the cause of the damage. Because experts determine only the cause of the damage, the procedure fails to address the concerns of citizens who are keen to know if vibrations caused by mining operations do or do not accelerate the normal deterioration of their home s structure. Potential Vibration Sources from the Mine Extension and Road Deviation Project The project s potential vibration impacts are the same as current impacts. Some citizens fear that future blasting carried out in the Barnat pit will be closer to residential neighbourhoods, but that is not the case. Modelling has shown no increase in impacts on residents due to vibrations that could be caused by mining operations. 6