Feb 17, 2016 — productive operations within urban drilling and blasting environments. The authors, contributors and Blasting Mat Construction .
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Best Practices Guide for Urban Blasting Operations – 1st Edition 2 Document Information This 1 st Edition Best Practices Guide for Urban Blasting Operations is produced by the Western Canada Chapter of the International Society of Explosives Engineers . Best practices and guidelines detailed in this publ ication have been developed by utilizing the knowledge, experience and contributions of a wide variety of dri lling, blasting and related industry professionals from throughout North America. This document is the resultant work of our Urban Blasting Committee and is intended to promote safe and productive operations within urban drilling and blast ing environments. The authors, contributors and publis hers have undertaken their best efforts in preparing this document and make no warranty of any kind, express o r implied, with regard to its content. Please see our website at www.iseewest.org for the latest document update or for information on how to participate in our organization. Document Updates This document was revised on May 05, 2016 and supersedes all previous editions. The Best Practices Guide for Urban Blasting Operations 1 st Edition was approved for release by the Urban Blasting Committee on May 17, 2016. The Urban Blasting Committee of the Western Canada Chapter of the ISEE has primary responsibility for amendments to this Best Practices Guide for Urban Blasting Operations and will update this document on an annual basis. Disclaimer Every effort has been made to ensure that this Best Practices Guide for Urban Blasting Operations serves to promote safe and productive operations within urban drilling and blasting environments. All information, statements and recommendations offered in this document are provided in good faith and in the inte rest of promoting the safety and health of workers, the public, and the interests of urban blasting stakehold ers. This document cannot describe and/or be comprehensive for all urban blasting situations and circumstances. It should not be viewed, construed o r assumed as being completely comprehensive in identifying and addressing all urban blasting situati ons. It is intended to serve as a general guideline for best practices. The Western Canada Chapter of the International Society of Explosives Engineers accepts no responsibility for the application of this best prac tices guide or recommendations contained within this document. It is incumbent on the Blaster to evaluat e these best practices and determine if they are applicable for the field conditions encountered in th eir specific urban blasting situation. Ultimately, the s afety of urban blasting activities rests with the Urban Blast er and the employers. The Western Canada Chapter of the International Society of Explosives Engineers does not guarantee th e quality, accuracy, or completeness of the informatio n provided, and is not responsible for any direct, indi rect, special, incidental or consequential damage or any other damages whatsoever and howsoever caused, arising out of or in connection with the reliance upo n the information provided in these materials. Blasters undertaking urban blasting operations utilizing these best practice guidelines do so at their own risk. For more detailed blasting related information, please consult the 18 th Edition of the ISEE Blasters™ Handbook or other useful reference documents detailed in Appendix C. Urban Blasting Committee Mike Witham, Chairperson T & A Rock Works Inc. Ron Elliott International Blasting Consultants Ltd. Mark Grigons Suncor Energy Inc. Alastair Grogan Grogan Rock Consulting Ltd. Paul Jeannotte Orica Canada Inc. Chris Sherbinin K.C. Drilling & Blasting Ltd. Andy Wells Western Grater Contracting Ltd. This list represents the membership at the time the Urban Blasting Committee was balloted on the final text of this first edition. Since that time, changes in the membership may have occurred. Contact Information The Urban Blasting Committee may be contacted at iseeurbanblastingcommittee@hotmail.com.
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Best Practices Guide for Urban Blasting Operations – 1st Edition 3 Intent and Application This Best Practices Guide for Urban Blasting Operations is intended to outline the guidelines for best pract ices to be utilized in the performance of urban drilling and blasting operations for rock excavation and act as a source document for the development of a Control Blasting Plan. Other operations where explosives are utilized in urban environments such as quarries, open pit mines, demolition, fireworks, special effects, etc. are out side the scope, intent and application of this document. These guidelines are intended to be supplemental to any and all local, municipal, state, provincial and /or federal regulations and represent best practices for urban drilling and blasting operations. Antitrust Statement It is the policy of the Western Canada Chapter of th e ISEE Board of Directors to fully comply and encourage its chapters, sections, committees, and members to comply with the antitrust laws of any recognized jurisdiction. No employee or agent of the Western Canada Chapter of the ISEE or any officer, director or member acting on its behalf, has the authority to engage in any cond uct inconsistent with the antitrust laws of any recogni zed jurisdiction or the guidelines established by the Wes tern Canada Chapter of the ISEE Board of Directors. Terminology This Best Practices Guide for Urban Blasting Operations utilizes industry standard terminology. Numerical Units This Best Practices Guide for Urban Blasting Operations has been developed and is intended for use with metri c units. Throughout the document where metric units are cited, approximate imperial units are provided in parenthesis. e.g.: 500m (1600™). Please note that imperial units in this document ar e provided in generalisation and are not exact conversions. Readers of this document may be required to make the necessary conversions to obtain accurate imperial values to meet their specific need s. Purpose This Best Practices Guide for Urban Blasting Operations has been developed utilizing the knowledge and experience of a wide variety of blasting and industr y related professionals throughout North America. It is the intention of this document to promote safe and productive operations within urban drilling and blas ting environments and to be utilized where deemed useful by stakeholders. The purpose of the Best Practices Guide for Urban Blasting Operations is to: 1. Provide guidelines to protect the safety and hea lth of the public, workers and urban structures within the area of influence by minimizing the following environmental effects of urban drilling and blasting operations: a) Noise/Nuisance, b) Dust, c) Blast Vibration, d) Air Overpressure, e) Flyrock, f) Surface Water Contamination. 2. Advance the science and art of Urban Blasting activities. 3. Identify best practices for drilling and blasting operators to implement while undertaking urban blasting operations. 4. Act as a supplement to applicable local, provinc ial, state, and federal by-laws and/or regulations pertaining to aspects of drilling and blasting activities. 5. Identify best practices to assist drilling and b lasting contractors in maintaining high quality and productive operations. 6. Instill stakeholder confidence in our industry w hile undertaking urban blasting activities in a safe and productive manner.
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Best Practices Guide for Urban Blasting Operations – 1st Edition 4 Table of Contents DOCUMENT INFORMATION .. 2 DOCUMENT UPDATES .. . 2 DISCLAIMER . 2 URBAN BLASTING COMMITTEE 2 CONTACT INFORMATION .. 2 INTENT AND APPLICATION . .. 3 ANTITRUST STATEMENT . 3 TERMINOLOGY 3 NUMERICAL UNITS .. . 3 PURPOSE .. . 3 DEFINITIONS . 6 SCOPE .. 8 URBAN BLASTING LEVELS .. 8 CONTROL BLASTING PLAN .. .. 9 CONTROL BLASTING PLAN DEVELOPMENT . 9 BLAST DOCUMENTATION .. 9 URBAN BLASTING LEVEL 0 .. 11 0 TO 3M (0 TO 10™) .. 11 Definition . . 11 URBAN BLASTING LEVEL 1 >3M TO 10M (10™ TO 3 3™) .. 12 UBL 1 CONTROL BLASTING PLAN . 12 1. Blast Design Guidelines . . 12 2. Peak Particle Velocity .. 12 3. Air Overpressure . 12 4. Blast Hole Diameter . 12 5. Explosives . . 12 6. Detonators 12 7. Flyrock Controls .. 12 8. Pre-Blast Surveys . .. 12 9. Community Notification . 12 10. Blast Monitoring 12 11. Documentation .. 12 URBAN BLASTING LEVEL 2 >10M TO 30M (>33 ™ TO 100™) . 13 UBL 2 CONTROL BLASTING PLAN . 13 1. Blast Design Guidelines . . 13 2. Peak Particle Velocity .. 13 3. Air Overpressure . .. 13 4. Blast Hole Diameter . 13 5. Explosives . . 13 6. Detonators 13 7. Flyrock Controls .. 13 8. Pre-Blast Surveys.. . 13 9. Community Notification . 13 10. Blast Monitoring 13 11. Documentation .. 13 URBAN BLASTING LEVEL 3 >30M TO 100M (>100™ TO 330™) 14 UBL 3 CONTROL BLASTING PLAN . 14 1. Blast Design Guidelines . . 14 2. Peak Particle Velocity .. 14 3. Air Overpressure . .. 14 4. Blast Hole Diameter and Depth .. .. 14 5. Explosives and Detonators 14 6. Flyrock Controls .. 14 7. Pre-Blast Surveys.. . 14 8. Community Notification . 14 9. Blast Monitoring 14 10. Documentation .. 14 URBAN BLASTING LEVEL 4 >100M TO 500M (>330™ TO 1600™) 15 UBL 4 CONTROL BLASTING PLAN . 15 1. Blast Design Guidelines . . 15 2. Peak Particle Velocity .. 15 3. Air Overpressure . .. 15 4. Blast Hole Diameter and Depth .. .. 15 5. Explosives and Detonators 15 6. Flyrock Controls .. 15 7. Pre-Blast Surveys.. . 15 8. Community Notification . 15 9. Blast Monitoring 15 10. Documentation .. 15 BEST PRACTICES FOR URBAN BLASTING ACTIVITIES . .. 16 PLANNED OPERATIONS .. 16 URBAN BLASTING PROJECT MANAGEMENT PROGRAM 16 URBAN BLASTER IN CHARGE .. 16 CONTROLLING FLYROCK . . 17 BLAST DESIGN .. 17 STEMMING .. . 17 BLASTING MATS .. 17 Use of Blasting Mats .. 18 Blast Coverage . . 18 Rigging of Blasting Mats .. 18 Blasting Mat Construction .. 18 USE OF EARTH MATERIAL .. 18
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Best Practices Guide for Urban Blasting Operations Р1st Edition 5 PRE-BLAST SURVEY OF URBAN STRUCTURES .. .. 19 SURVEY GUIDELINES .. . 19 PRE -B LAST SURVEY AREA .. 19 NOTIFICATION AND OFFER TO CONDUCT A PRE -B LAST SURVEY . 19 REFUSAL OF A PRE -B LAST SURVEY 19 POST-BLAST SURVEY OF URBAN STRUCTURES .. 20 DAMAGE CLAIM .. . 20 HISTORIC OR SIGNIFICANT STRUCTURE 20 OTHER CONSTRUCTION OR BLASTING OPERATIONS .. 20 REFUSAL OF A POST -B LAST SURVEY . 20 COMMUNITY NOTIFICATION OF BLASTING OPERATIONS .. .. 21 COMMENCEMENT OF BLASTING NOTIFICATIONS .. 21 INHABITED STRUCTURES & URBAN STRUCTURES .. 21 NOTIFICATION OF SCHOOLS AND MEDICAL TREATMENT FACILITIES .. 21 BLAST NOTIFICATION .. 21 BLAST MONITORING .. 22 VIBRATION AND AIR OVERPRESSURE 22 SEISMOGRAPH SETUP .. 22 VISUAL RECORDING .. .. 22 BLAST MONITORING MATRIX .. . 22 APPENDIX A: USBM ΠFREQUENCY VERSUS PARTICLE VELOCITY . 23 APPENDIX B ΠREFERENCE MATERIALS .. 24 APPENDIX C ΠGENERIC FORM TEMPLATES . 25 SAMPLE CONTROL BLASTING PLAN .. 26 This section intentionally left blank.
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Best Practices Guide for Urban Blasting Operations – 1st Edition 6 Definitions fiA point of safetyfl A location that is secure from fly rock. fiAir overpressurefl A pressure wave in the air between 2 and 500Hz (mostly below 20 Hz) resulting from a blast, usually expressed in decibels (dB(L)) or Pascal (pa). Note: see fiNoisefl. fiArea of influencefl The area that could be actually, potentially or perce ived to be affected by urban blasting operations. Determined by the blaster in charge and measured in meters from the blast ing limit. fiBest Practicesfl Procedures that are generally accepted as being correct o r most effective. “Blaster” A person who is the holder of a valid, applicable Bla ster’s Certificate issued by a municipal, provincial, state , federal or recognized regulatory agency. “Blaster in charge” The blaster who is designated to be in control of al l blasting operations. Is in control of a specific blast event. fiBlasting Consultantfl A blasting professional with a minimum of 5 cumulati ve years of experience working in a consulting role in the bla sting field in an urban environment, an Urban Blasting Manager with specific knowledge and expertise in blast design to meet specific objectives as well as the control of vibrati on and air blast , and who™s experience is acceptable to the appropria te regulatory authority. “Blasting incident” An accident, near miss, close call and/or unintended occurrence caused by or as a result of the use of explo sives, and also includes an unexpected result or problem wit h explosive products. fiBlasting limitfl The boundary to which rock is to be blasted and exca vated. Includes overbreak. “Blasting log” A written record of the fias loadedfl condition of a bla st, including details of the blasting pattern, explosiv e loading and hole timing in sufficient detail that the condition s of the blast could be recreated from the log. It should also cont ain a record of the blaster™s post-blast examination. “Blasting operation” Includes preparing, placing, and firing a charge, handl ing a misfire, and destroying or disposing of explosive mate rials. fiBenchfl A near-horizontal or shallow slope surface at the top of a near- vertical rock face where blast holes are collared. fiBench widthfl The horizontal distance on the bench between the exc avation backslope and the crest of the existing rock face. Ge nerally this dimension defines the width of the rock to be re moved. “Bootleg” The remnant of a blast hole which did not properly brea k when the blast was initiated; also called socket, butt o r button. fiBuffer holesfl Buffer holes are a line or lines of holes, adjacent to and generally parallel to the final wall, with a reduced burden and/or spacing and/or diameter and/or explosive load, designed to help limit the potential for damage behi nd the final face. fiBurdenfl The distance between the blasthole and the nearest free face. fiControl blastingfl The highly planned and controlled use of explosives and accessories in carefully spaced, aligned, loaded and delayed drill holes to achieve specified environmental and ph ysical blast requirements. fiControl blasting planfl The blasting plan developed for a site that specifie s in what manner blasting operations are to be undertaken. fiControl blast reportfl The report that documents specified criteria of each b last performed under a Control Blasting Plan. “Charge” Explosive materials which may or may not contain a p rimer, and which are placed for the purpose of detonation. “Danger area” An area in which there may be danger to persons or prop erty from flying material, vibrations, air overpressure, dust or other hazardous environmental conditions resulting from dri lling and blasting activities. “Day box” An unlicensed explosives storage facility that is n ot used for overnight storage. fiDelayfl Delay time period before detonation. “Detonator” Explosive device used to detonate commercial explos ives. “Explosive” A substance that is made, manufactured or used to prod uce an explosion or detonation, including but not limite d to blasting explosives, pyrotechnic devices and accessories conta ining explosives; fiFlyrockfl The unintended throw and ejection of rock, mats and /or other material from a blast. fiFree facefl The rock face that provides relief for a blast.
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Best Practices Guide for Urban Blasting Operations – 1st Edition 8 Scope An urban blasting operation is defined as any drilli ng & blasting operation for rock excavation undertaken wi thin 500m (1600™) of any building, structure, and/or utility (urban structure). This Best Practices Guide for Urban Blasting Operations outlines guidelines and best practices for considerat ion in urban drilling and blasting activities. These guidelines are not intended to supersede any federal, state, provincial, or local regulations per taining to drilling, blasting and/or the use of explosive mat erials or other activities. Ultimately, the safety of urban blasting activities rests with the Urban Blaster and their employer. Urban Blasting Levels It is generally accepted that the prevalence of risk involved in blasting activities increases proportiona lly to the reduction in distance to urban structures. Based on this relationship, the establishment of di stance related guidelines can mitigate the negative risks associated with vibration, air overpressure, flyrock and other related urban blasting issues. Therefore, it is considered necessary to classify urban drilling and blasting guidelines according to their location rela tive to urban structures. For the purpose of this guide, urban blasting activi ties are classified, by distance, into five separate categ ories called Urban Blasting Levels (UBL). Urban blasting levels are categorized as follows: Urban Blasting Level 0 UBL 0 – 0m to 3m (0 to 10™) distance from any urban structure. Urban Blasting Level 1 UBL 1 Œ greater than 3m to 10m (>10™to 3 3™) distance from any urban structure. Urban Blasting Level 2 UBL 2 Œ greater than 10m to 30m (>33 ™ to 100™) distance from any urban structure. Urban Blasting Level 3 UBL 3 Œ greater than 30m to 100m (>100™ to 3 30™) distance from any urban structure. Urban Blasting Level 4 UBL 4 Œ greater than 100m to 500m (>33 0™ to 1600™) distance from any urban structure
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Best Practices Guide for Urban Blasting Operations – 1st Edition 9 Control Blasting Plan The purpose of the Control Blasting Plan is to docum ent the hazards and risks associated with an Urban Blastin g Project and to document project specifics to ensure that risks and hazards are mitigated. Blast designs should never compromise safety, and safety goals must have the highest design priority. For each urban blasting level, the following best pra ctice items are outlined as part of the Control Blasting Pla n: 1. Blast Design 2. Peak Particle Velocity 3. Air Overpressure 4. Maximum Blast Hole Diameter 5. Maximum Blast Hole Length 6. Explosives 7. Detonators 8. Fly Rock Control 9. Pre-Blast Survey 10. Community Notification 11. Blast Monitoring 12. Blast Documentation Control Blasting Plan Development When developing a project Control Blasting Plan, tw o primary goals should be considered: safety goals and operational goals. It is to be acknowledged under thi s Best Practices Guide for Urban Blasting Operations that whenever safety goals conflict with operational goal s, safety must have the highest priority. The Control Blasting Plan should be developed, documented and communicated to the Blaster in Charge prior to the commencement of all urban blasting operations. The Control Blasting Plan should includ e the following information: 1. Project name, location, purpose and anticipated volume/quantities, Prime Contractor and number of workers. 2. The name of the blasting firm and of the person responsible for the blast design, including a record of experience and statement of qualifications. 3. The name of the applicable Urban Blasting Manager and/or Urban Blaster including a record of experience and training. 4. Suggested certifications, permits, authorizations and/or regulatory approvals for the project. First Aid Assessment and Emergency Response Plan. 5. Distance to urban structures, roads/highways, property line, other site works, access conditions, ramps, prevailing wind conditions. 6. Results of the Risk/Hazard Assessment and detail s on how risks/hazards will be mitigated. i.e.: PPE, traffic control, blast guarding, etc. 7. Nature of the material which includes type of ro ck, relative hardness, joint orientation and direction, adverse jointing and the potential for back break. 8. Fragmentation requirements of the owner. 9. Seismic modeling for nearest urban structure, including distance, anticipated peak particle velocity and suggested monitoring locations. 10. Blast design considerations, number of holes to be blasted, maximum number of holes per blast and anticipated number of blasts for the project. 11. Drill hole diameter. Minimum and maximum hole depth, burden and spacing, stiffness ratio, explosive type, load, powder factor and collar, type and length of stemming material, detonator type, blast hole timing. 12. Flyrock control. Matting instructions. 13. Pre-Blast survey requirements and structures identified to be surveyed. 14. Stakeholder identification and community notification requirements. Blast Documentation It is best practices for the Urban Blaster to documen t fulfillment of the Control Blasting Plan in sufficie nt detail in which to recreate a written record of the fias loadedfl condition of a blast. The individual blast report sh ould include: 1. A blast sketch with north arrow, typical section view, number of holes and hole depth. 2. Explosive loading details, hole timing, powder factor. 3. Fly rock control measures. 4. Monitoring results, PPV, frequency and air overpressure for each monitoring location. 5. Documentation of the blast results and details o f the post-blast examination. All blast documentation should be reviewed by the Urban Blasting Manger. Detail any amendments made to the Control Blasting Plan to ensure safety and proj ect objectives are met.
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Best Practices Guide for Urban Blasting Operations – 1st Edition 10 Best Practices Urban Blasting Level 0 0m to 3m (0 to 10™) Urban Blasting Level 1 >3m to 10m (>10™ to 3 3™) Urban Blasting Level 2 >10m to 30m (>3 3™ to 100 ™) Urban Blasting Level 3 >30m to 100m (>100 ™ to 330 ™) Urban Blasting Level 4 >100m to 500m (>330™ to 160 0™) Blast Design & Control Blasting Plan Please see Urban Blasting Level 0 section of this document on Page 11. · Urban Blasting Manager with 7 or more years of experience suggested to review Control Blasting Plan · Suggested oversight from an independent Blasting Consultant · Urban Blasting Manager with 5 or more years of experience suggested to design, develop and accept site Control Blasting Plan · Certified Urban Blaster suggested to design, develop site Control Blasting Plan · Certified Urban Blaster suggested to design, develop site Control Blasting Plan if blasting activities are within 500m (1600 ™) of school, hospital or clinic Peak Particle Velocity & Frequency Response · Blast designed to 50 mm/sec (2 inches/sec) or in accordance with the USBM table in Appendix A · Blast designed to 35 mm/sec (1.4 inches/sec) or in accordance with the USBM table in Appendix A · Blast designed to 25 mm/sec (1 inch/sec) or in accordance with the USBM table in Appendix A · Blast designed in accordance with the USBM table in Appendix A Air Overpressure · Maximum 134dBL · Maximum 134dBL · Maximum 134dBL · Maximum 134dBL Blast Hole Diameter · Suggested 45mm (1 ¾fl) blast hole diameter maximum · 70mm (2 ¾ “) blast hole diameter suggested maximum · 75mm (3fl) blast hole diameter suggested maximum · At the discretion of the Urban Blaster Blast Hole Length · Governed by charge weight per delay to meet suggested PPV limit · Governed by charge weight per delay to meet suggested PPV limit · Governed by charge weight per delay to meet suggested PPV limit · Governed by charge weight per delay to meet suggested PPV limit Explosives · Packaged explosive to a max 38mm (1 1/2 fl) diameter · ANFO/bulk products not recommended below critical hole diameter for product. · Packaged explosive to a max 50mm ( 2fl ) diameter · ANFO/bulk products to be utilized in accordance with manufacturers specifications · At the discretion of the Urban Blaster · ANFO/bulk products to be utilized in accordance with manufacturers specifications · At the discretion of the Urban Blaster · ANFO/bulk products to be utilized in accordance with manufacturers specifications Detonators · Electronic detonators suggested · Electronic detonators suggested Type of detonator utilized at the discretion of the Urban Blaster · Type of detonator utilized at the discretion of the Urban Blaster · Type of detonator utilized at the discretion of the Urban Blaster Fly Rock Control · Adequate Blast Design · Use of a confinement device and/or clear crushed rock stemming · Adequate blast matting or earth fill · Adequate Blast Design · Use of a confinement device and/or clear crushed rock stemming · Adequate blast matting or earth fill · Adequate Blast Design · Use of a confinement device and/or clear crushed rock stemming · Adequate blast matting or earth fill · Adequate Blast Design · Use of a confinement device and/or clear crushed rock stemming · Blasting mats suggested within 300m (1000™) · Adequate blast mating or earth fill Pre -Blast Survey · Suggested for all urban structures within 30m (100™) of the blasting limits · Suggested for all inhabited structures within 75m (250™) of the blasting limits · Suggested for all inhabited structures within 75m (250™) of the blasting limits · At the discretion of the Urban Blaster Community Notification · 48 hours notification for all inhabited structures within 30m (100™) of the blasting limits · Blasting schedule to be coordinated with schools, hospitals and clinics within 150m (500™) of blasting limits · 48 hours notification for all inhabited structures within 75m (250™) of the blasting limits · Blasting schedule to be coordinated with schools, hospitals, and clinics within 150m (500™) of blasting limits · 48 hours for all inhabited structures within 100m (330 ™) and/or School/Hospitals within 300m (1000™) of the blasting limits · Blasting schedule to be coordinated with schools, hospitals and clinics within 300m (1000™) of blasting limits · 48 hours for School/Hospitals within 500m (1600™) of the blasting limits. · Blasting schedule to be coordinated with schools, hospitals and clinics within 500m (1600™) of blasting limits Monitoring · Follow ISEE Field Practice Guidelines for Seismographs. · Monitoring at the 2 nearest urban structures. · Follow ISEE Field Practice Guidelines for Seismographs. · Monitoring at the 2 nearest urban structures. · Follow ISEE Field Practice Guidelines for Seismographs. Monitoring at the 2 nearest urban structures. · Follow ISEE Field Practice Guidelines for Seismographs. · Monitoring at the nearest urban structure. Additional monitoring as suggested
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Best Practices Guide for Urban Blasting Operations – 1st Edition 11 Urban Blasting Level 0 0 to 3m (0 to 10™) Definition Urban Blasting Level 0 (UBL 0) is defined as drillin g and blasting activities occurring from 0 meters to 3 met ers distance from any urban structure. Urban blasting operations classified UBL 0 are highly specialized and involve a significant risk of proper ty damage that may be beyond the control of the Urban Blaster. Blasting operations undertaken at Urban Blasting Leve l 0 represent the highest potential for damage to an u rban structure. This work must only be attempted by highl y trained blasters who are skilled in close-in blastin g work and are capable of carrying out the work safely. Oth er methods of rock removal such as hydraulic splitting, or use of expanding grouts should be considered as an alternative. Blasting operations conducted at UBL 0 should be conducted in close consultation with civil, structu ral and/or geotechnical engineers. UBL 0 operations may require an assessment of building structures and a review of geological conditions, as suggested, to ensure that blasting operations can be carried out safely in close proximi ty to urban structures. The risks associated with blasting at UBL 0 need to be communicated to the project owner and/or general contractor and a determination made as to who will assume these risks. This section intentionally left blank.
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