ITEM 208 rock blasting
208.02 Regulations on the Use of Explosives
208.03 Product Specifications
208.05 Blasting Plan Submittal
208.06 Production Holes
208.07 Blasting Test Sections
208.08 Safety Procedures
208.10 Cushion (Trim) Blasting
208.11 Sliver Cuts
208.13 Blasting Consultant
208.14 Pre-Blast Condition Survey
208.15 Vibration Control and Monitoring
208.16 Airblast and Noise Control
208.18 Flyrock Control
208.19 Public Meetings
208.20 Record Keeping
208.21 Method of Measurement
208.22 Basis of Payment
Controlled blasting refers to the controlled use of explosives and blasting accessories in carefully spaced and aligned drill holes to produce a free surface or shear plane in the rock along the specified excavation backslopes. Controlled blasting techniques include presplitting, cushion (trim) blasting, and sliver cut blasting.
If the designed cut slope is steeper than 1:1 and deeper than 5 feet (1.5 m), use controlled blasting techniques, even if the main excavation is ripped or excavated. In rare instances, the Department will specify presplitting for 1 to 1 slopes. For all slopes that do not require controlled blasting techniques, rake, excavate, hoe ram, or mechanically shape these slopes to obtain a neat and smooth appearance.
Production blasting refers to the rock fragmentation blasts resulting from more widely spaced production holes drilled throughout the main excavation area adjacent to the controlled blast line. Detonate production holes in a controlled delay sequence.
208.02 Regulations on the Use of Explosives. Perform all blasting operations according to all applicable Federal, State, and local laws and regulations, and the provisions of 107.09. These regulated blasting operations include but are not limited to the following:
A. Storage and handling of explosives, blasting agents, and detonators.
B. Use of explosives in character and amount as allowed.
C. Storage plan, including the type of magazine or explosive storage facility to be used on the job site.
D. Record keeping, placarding, safe distances, and all other requirements concerning storage.
E. Obtaining and displaying magazine permits.
If evaporation occurs or if improperly mixed, bulk explosives (such as ammonium nitrate and fuel oil) may not contain the proper amount of diesel oil. Low diesel oil drastically reduces the energy content of the explosive and commonly produces reddish brown or yellow fumes upon detonation even in dry blast holes.
Use products conforming to manufacturers’ specifications. Ship the manufacturer recommended expiration dates with the products delivered to the project. Do not use any blasting product that is either excessively old or in a deteriorated condition. Cease all work until the product’s age or quality is determined.
208.04 Stabilization. Remove or stabilize rock along the cut face that is loose, hanging, or creates a potentially dangerous situation during or upon the completion of the excavation in each lift. Do not drill the next lift until this work is performed.
208.05 Blasting Plan Submittal. Submit three copies of the Blasting Plan to the Engineer and one copy of the Blasting Plan to the Office of Construction Administration for review at least two weeks before beginning drilling and blasting operations, or at any time the drilling and blasting methods change. If the drilling and blasting methods change, submit four copies of the changed sections one week prior to the work.
The Blasting Plan shall include, at a minimum, the following:
A. General details of the drilling and blasting patterns and controls proposed to use for both the controlled and production blasting.
B. Station limits of proposed shots. Critical distances to structures. Place the pre-blast survey limits detailed in 208.14 on the Right-of-Way or plan view sheets.
C. One plan and section view for each main excavation cut showing the proposed typical range of drill patterns including a range of values for the free face, burden, blast hole spacing, blast hole diameters, blast hole angles, lift heights, and subdrill depths.
D. A typical loading diagram showing the type and amount of explosives, primers, and initiators and location and depth of stemming.
E. Typical range of initiator sequence of blast holes including delay times and delay system.
F. Manufacturers’ data sheets for all explosives, primers, and initiators to be employed.
G. Use the blaster’s plan form or the blasting plan forms in FHWA Publication FHWA-HI-92-001 Rock Blasting and Overbreak Control. Adapt these forms to meet the project requirements.
In a subsequent submittal, submit one Detailed Plan for all test sections. (Submit or fax at least 24 hours before the shot.) Detail the specific proposed amounts of materials and work described in 208.05.A through 208.05.G above on this Detailed Plan.
The Blasting Plan submittal is for quality control, informational, and record keeping purposes. The review of the Blasting Plan does not relieve the Contractor of the responsibility for using existing drilling and blasting technology and for obtaining the required results.
If specified in the Contract, use an approved blasting consultant, conforming to 208.13, to assist with the blast design and to ensure that the Blasting Plan is carried out on the project.
208.06 Production Holes. Perform all production blasting, including blasting carried out in conjunction with the blasting test section requirements of 208.07, according to the following requirements:
A. Drill the production blast holes on the patterns and to the depths submitted in the Blasting Plan and Detailed Plan, as specified in 208.05, but not exceeding a depth of 60 feet (18 m). Drill the production blast holes within two blast hole diameters of the staked collar location. If the blaster does not drill the production holes then the blaster shall inspect the holes and review the drilling logs prior to loading the holes.
B. Deepen or clean-out blast holes if they are plugged or unable to be fully loaded. Check and measure blast holes before any explosives are loaded into any of the holes to eliminate any safety hazard resulting from drilling near loaded holes.
C. Maintain a burden distance that is equal to or less than the bench height in order to control the blasting effects.
D. Drill the row of production blast holes immediately adjacent to the controlled blast line on a plane approximately parallel to the controlled blast line. Drill the production blast holes no closer than 6 feet (2 m) to the controlled blast line. Drill the bottom of the production holes no lower than the bottom of the controlled blast holes except by the amount of subdrilling used in the production holes. Do not exceed 6 3/4 inches (170 mm) in diameter for the production blast holes. Delay the detonation sequence of the production holes toward a free face.
E. Maintain a stemming depth of at least 0.7 times the burden distance. If water is present or when blasting within 200 feet (61 m) of a structure, use crushed No. 8 coarse aggregate for holes less than 4 inches (100 mm) in diameter and crushed No. 57 coarse aggregate for holes 4 inches (100 mm) in diameter and larger for the stemming material. Use the coarse aggregate gradations of Nos. 8 and 57 gradations on Table 703.01-1. If gravel is used, use crushed material with a minimum of two mechanically fractured faces on 60 percent of the material. In other locations, the Contractor may use drill cuttings for stemming, if it does not compromise the shot integrity.
F. Take all necessary precautions in the production blasting to minimize blast damage to the rock backslope.
G. Drill a line of buffer holes on a parallel plane adjacent to the presplit holes if presplit results are not satisfactory and production holes are damaging the presplit line. Drill the buffer hole 3 ± 1 inch (75 ± 25 mm) in diameter. Drill the line of buffer holes approximately 3 feet (1 m) from the presplit line, and space 3 to 5 feet (1 to 1.5 m) center-to-center. Do not load the buffer holes with more than 50 percent of the full explosive load that could be placed in a 3-inch (75 mm) production hole. Delay the detonation sequence toward a free face.
208.07 Blasting Test Sections. Before commencing full-scale blasting operations, demonstrate the adequacy of the proposed Blasting Plan. Drill, blast, and excavate short test sections to determine which combination of methods, hole spacing, and charge works best. Use a test section with lengths up to 150 feet (45 m) for presplitting and 120 feet (36 m) for production blasting when field conditions warrant.
Do not exceed a production hole depth of 30 feet (9 m) for the first test section.
Begin the controlled blasting tests for presplitting with the controlled blast holes spaced 36 inches (900 mm) apart, then adjust, if needed, until the spacing for full-scale presplit blasting operations is approved. A new test section is required to increase the spacing for the presplitting to a maximum of 48 inches (1200 mm).
Perform two test sections on every project. Use explosive depths greater than 20 feet (6.1 m) for these test sections. Use one test section for controlled blasting and one test section for production blasting.
Apply the requirements specified for controlled and production blasting operations to the test section blasting.
For controlled blasting and for production blasts within 10 feet (3 m) of the finished slope, do not drill ahead of the test shot area until the test section has been excavated and the results evaluated. If the test shots are unsatisfactory, revise methods as necessary to achieve the required results. Unsatisfactory test shot results include an excessive amount of fragmentation beyond the indicated lines and grade, excessive flyrock, or violation of other requirements within Item 208.
If the drilling and blasting methods do not produce the desired result of a uniform slope and shear face, within the tolerances specified, drill, blast, and excavate short sections, not exceeding 150 feet (45 m) in length for a presplit line or 120 feet (36 m) for a production hole line, until a technique produces the desired results.
The blasting consultant shall witness the test sections drilling and loading operations and be present when all test sections are shot. The time spent witnessing these operations is considered part of the time required to observe the loading, drilling, and blasting operations, as specified in 208.13.
Define the limits of the blasting area where there is a flyrock danger. Control the access to the blasting area to prevent the presence of livestock or unauthorized persons at least ten minutes before each blast.
Notify all employees in the area that a blast shall be fired with a one minute signal. After the blast is over, sound an “all clear” signal so all employees in the area understand that all blasting operations are finished.
One minute before the blast, sound three long signals, lasting five seconds, on an air horn or siren. For the all “clear” signal, sound one long signal, lasting at least five seconds, to indicate that all blasting has ceased.
Fill out the Department’s Blast Site Security Plan Form (CA-EW-11).
B. Lightning Protection. Furnish, maintain, and operate lightning detection equipment during the entire period of blasting operations and during the periods that explosives are used at the site. Use equipment similar or equal to the Thomas Instruments SD250 Storm Alert as manufactured by DL Thomas Equipment, Keene, New Hampshire. Install the equipment when approved. If the lightning detection device indicates a blasting hazard potential, evacuate personnel from all areas where explosives are present. If a lightning detector indicates a blasting hazard, perform the following:
1. Clear the blasting area of all personnel.
2. Notify the Engineer of the potential hazards and precautions to be taken.
3. Terminate the loading of holes and return the unused explosives to the day storage area.
4. If blast holes are loaded and would pose a hazard to traffic if detonated, close the roads until the lightning hazard has passed.
5. When the hazard dissipates, inform the Engineer that production blasting can continue.
C. Check for Misfires. Observe the entire blast area for a minimum of five minutes following a blast to guard against rock fall before commencing work in the cut. The five minute delay between blasting and not allowing anyone but the blaster to enter the area is needed to make sure that no misfires have occurred.
During the five minute delay, the blaster is responsible for going into the shot area and checking all the holes to make sure that they have detonated. If any holes have not fired, the blaster shall handle these misfires before others enter the work area.
Halt the blasting operations if the methods being employed result in the required slopes not being in a stable condition or the safety and convenience of the traveling public is jeopardized.
1. If the system was energized and no charges fired for electric systems, test the lead wire continuity before inspection of the remainder of the blast. For nonelectric systems, check the lead in or tube to make sure that detonation has entered the blast area.
2. If an inspection of the electrical trunkline or lead in tubing-line indicates that there is a break in the line or if the tubing did not fire, repair the system and refire the blast. If the inspection indicates that the trunkline has fired, and misfired charges remain, the blaster shall do the following:
a. Exclude all employees except those necessary to correct the problem.
b. Close traffic, if a premature explosion could be a hazard to traffic on nearby roads.
c. Correct the misfire in a safe manner. If the misfire poses a problem that the blaster cannot safely correct, the Contractor shall call a consultant or an explosive company representative skilled in the art of correcting misfires to correct the problem.
208.09 Presplitting. Perform all presplitting, including that carried out in conjunction with the blasting test section requirements of 208.07, according to the following requirements:
A. Completely remove all overburden soil and loose or decomposed rock along the top of the excavation for a distance of at least 30 feet (9 m) beyond the end of the production hole drilling limits, or to the end of the cut, before drilling the presplitting holes.
B. Remove potentially dangerous boulders or other material located beyond the excavation limits.
C. Drill the presplit holes 3 ± 1 inch (75 ± 25 mm) in diameter.
D. Control the drilling operations by using proper equipment and technique to ensure that no hole deviates from the plane of the planned slope by more than 12 inches (300 mm) either parallel or normal to the slope.
E. Extend presplit holes a minimum of 30 feet (9 m) beyond the limits of the production holes to be detonated, or to the end of the cut as applicable.
F. Drill the presplit holes for any individual lift to a vertical depth of less than or equal to 30 feet (9 m). Demonstrate that the blast can stay within the above tolerances and produce a uniform slope. If more than 5 percent of the presplit holes are misaligned in any one lift, reduce the depth of the lifts until the 12-inch (300 mm) alignment tolerance is met.
G. If a cut height requires more than one lift or if there is a slope change (for example, when changing from a 1:1 slope to a 0.75:1 slope), use a maximum 2-foot (0.6 m) offset between lifts for drill equipment clearances. Begin the presplit blast hole drilling at a point that allows for the necessary offsets and adjust to compensate for any drift that may occur in the upper lifts. Move the controlled blast line back if required to accommodate for these conditions.
H. The Contractor may drill 2 feet (0.6 m) below ditch bottom to remove the toe berm.
I. Before placing charges, determine if the hole is free of obstructions for its entire depth. Exercise all necessary precautions so that the placing of the charges will not cause caving of material from the walls of the holes.
J. Drill hole conditions may vary from dry to filled with water. Use whatever types of explosives and blasting accessories necessary to accomplish the specified results.
K. Use a maximum diameter of explosives that is not greater than one-half the diameter of the presplit hole.
L. Do not use bulk ammonium nitrate and fuel oil (ANFO) in the presplit holes.
M. Use only standard explosives manufactured especially for presplitting in the presplit holes.
N. If using a continuous column cartridge type of explosives with detonating cord, assemble and affix the detonating cord according to the explosive manufacturer’s instructions. Furnish a copy of the instructions to the Engineer.
O. The Contractor may make the bottom charge of a presplit hole larger than the line charges but not large enough to cause overbreak. Place the top charge of the presplitting far enough below the collar, and reduce the charge sufficiently, to avoid overbreaking and heaving.
P. Stem the upper portion of all presplit holes, from the topmost charge to the hole collar. Use stemming material conforming to the stemming specified for the production holes in 208.06.
Q. As long as equally satisfactory presplit slopes are obtained, either presplit the slope face before drilling for production blasting or presplit the slope face and production blast at the same time, provided the presplitting drill holes are fired first. If required to reduce ground vibrations or noise, delay the presplit holes, except that the hole-to-hole delay must be less than 25 milliseconds.
R. Do not deviate the presplit slope face more than 1 foot (0.3 m) from a plane passing through adjacent drill holes, except where the character of the rock is such that irregularities are unavoidable. Measure the 1-foot (0.3 m) tolerance perpendicular to the plane of the slope. Do not encroach on the roadbed with any portion of the slope.
S. Use the same diameter and drilled in the same plane and to the same tolerance as the presplit holes when using unloaded and unstemmed guide holes between presplit holes.
T. Detonate the presplit line before detonating any production holes, except when the closest horizontal distance between the production line and presplit line is greater than 50 feet (16 m).
208.10 Cushion (Trim) Blasting. If the horizontal distance from the cut face to the existing rock face is less than 15 feet (4.5 m), the Contractor may use cushion blasting instead of presplitting. Perform cushion blasting according to 208.09, except as follows:
A. Detonate along the cut face after the detonation of all production holes.
B. Between the trim line and the nearest production row, use a difference in delay time of 25 to 75 milliseconds.
208.11 Sliver Cuts. For sliver cuts, pioneering the top of cuts and preparing a working platform to begin the controlled blasting and drilling operations may require unusual working methods and use of equipment. Use angle drilled holes or fan drilled holes during the initial pioneering operations to obtain the desired rock face. Apply the hole diameter requirements for controlled blasting for pioneering work. Do not exceed a hole spacing of 36 inches (900 mm).
208.12 Blaster. Use an experienced blaster in charge of all blasting operations. Use a blaster with at least five years of proven experience in heavy construction or highway rock blasting and with a sufficient amount of proven experience of the type of highway rock blasting required by the Contract.
Before or at the preconstruction conference, submit a resume of the credentials of the proposed blaster. Include in the resume a list of at least five heavy construction or highway rock blasting projects on which the blaster was responsibly in charge of the rock blasting. List a description of the projects, with details of the blasting operations. List the names and telephone numbers of project owners with sufficient knowledge of the projects to verify the submitted information. Obtain approval of the blaster before beginning any drilling and blasting work. Allow 30 days for the review of this documentation. The blaster shall perform the following:
A. Control the ground vibrations by the use of properly designed delay sequences and by using allowable charge weights per delay.
B. Base the allowable charge weights per delay on vibration levels that will not cause damage.
C. Establish the allowable charge weights per delay by carrying out trial blasts and measuring the vibration levels.
D. Independently measure the vibrations and airblast at the closest structure using the criteria and limits set in 208.15 and 208.16. Ensure that only trained and certified personnel set up the seismographs.
E. Use appropriate blast hole patterns, detonation systems, and stemming to prevent venting of blasts and to minimize airblast and noise levels produced by the blasting operations.
F. Carry out the trial blasts according to the blasting test section requirements of 208.07.
G. Report the vibrations (velocity and frequency) and airblasts on both seismographs before the next blast. This report shall denote whether or not these numbers exceeded the allowable set by the vibration specialist.
I. Coordinate and review the blast hole layout and drilling operations.
The blaster, blasting contractor, or the Contractor shall obtain insurance as specified in 107.12. Present a certificate of insurance 10 days before the blasting operations begin.
208.13 Blasting Consultant. If specified in the Contract, retain an experienced and recognized blasting consultant to assist in the blast design. The blasting consultant shall assist in the design of both the controlled and production blasting.
Retain a blasting consultant with at least five years of proven experience in heavy construction or highway rock blasting design and with a sufficient amount of proven experience of the type of highway rock blasting design required by the Contract. The Contractor shall not use a blasting consultant that is an employee of the Contractor, explosives manufacturer, or explosives distributor.
Before or at the preconstruction conference, submit a resume of the credentials of the proposed blasting consultant. Include in the resume a list of at least five heavy construction or highway rock blasting projects on which the blasting consultant was responsibly in charge of the rock blasting design. List a description of the projects, with details of the blast plans and modifications made during the project. List the names and telephone numbers of project owners with sufficient knowledge of the projects to verify the submitted information. Obtain approval of the blasting consultant before beginning any drilling and blasting work. Allow 30 days for the review of this documentation.
The blasting consultant shall observe the loading, drilling, or blasting operations for at least 8 hours per week if these operations are in progress for 40 or more hours per week. The blasting consultant shall witness the drilling, loading and blasting of the first shot in each major cut. At a minimum, the blasting consultant shall witness the drilling, loading and blasting of every 20th shot on the project. The blasting consultant shall write a written report to the Engineer at least once a month detailing the blasting operations. The time spent writing this report is not considered part of the time required to observe the loading, drilling, and blasting operations. The Contractor shall coordinate the blasting consultant’s hours with the Engineer.
208.14 Pre-Blast Condition Survey. If specified in the Contract, conduct a pre-blast survey of any buildings, structures, or utilities within 1500 feet (460 m) or to the nearest structure up to a 1/2-mile (0.8 km) radius of the blasting operations. Use a greater radius if the structures are potentially at risk from blasting damage. The Contractor shall use a survey method acceptable to its insurance company. The Contractor is responsible for any damage resulting from blasting.
If owners or occupants fail to allow access to the property for the pre-blast survey, send a certified letter to the owner or occupant. Make the notification effort and the certified letter part of the pre-blast survey records.
Submit a copy of the pre-blast survey records to the Engineer before beginning the blasting operations at the critical blasting locations.
Notify occupants of local buildings before the commencement of blasting.
208.15 Vibration Control and Monitoring. If specified in the Contract, use vibration control and monitoring if blasting near buildings, structures, or utilities that may be subject to damage from blast induced ground vibrations. The vibration specialist interprets the seismograph records to ensure that the seismograph data is effective in the control of the blasting operations with respect to the existing structures.
Retain an experienced vibration specialist to establish the safe vibration limits. Use a vibration specialist with at least five years of proven experience in monitoring vibrations on heavy construction or highway rock blasting projects and with a sufficient amount of proven experience of the type of highway rock blasting vibration monitoring required by the Contract.
Use a vibration specialist that is an expert in the interpretation of the vibration data. The Contractor shall not use a vibration specialist that is an employee of the Contractor, explosives manufacturer, or explosives distributor.
Before or at the preconstruction conference, submit a resume of the credentials of the proposed vibration specialist. Include in the resume a list of at least five heavy construction or highway rock blasting projects on which the vibration specialist was responsibly in charge of monitoring the rock blasting vibrations. List a description of the projects, with details of the vibration interpretations made on the project. List the names and telephone numbers of project owners with sufficient knowledge of the projects to verify the submitted information. Obtain approval of the vibration specialist before beginning any drilling and blasting work. Allow 30 days for the review of this documentation.
The vibration specialist shall perform the following:
A. Monitor each blast with an approved seismograph located between the blast area and the closest structure subject to blast damage.
B. Use a seismograph capable of recording particle velocity for three mutually perpendicular components of vibration in the range generally found with controlled blasting.
C. Furnish the data recorded for each shot before the next blast and include the following:
1. Identification of instrument used.
2. Name of approved observer and interpreter.
3. Distance and direction of recording station from blast area.
4. Type of ground at recording station and material on which the instrument is sitting.
D. Ensure that the peak particle velocity of each component of the safe limits of the nearest structure subject to vibration damage is not exceeded.
E. The vibration specialist may elect to summarize and report this information monthly, when the blaster measures the vibration and airblast with its own seismograph and reports the measurements on the vibration specialist’s seismographs.
F. Establish what vibration limits are being used and explain why they are being used to the Engineer before blasting begins near structures denoted in the pre-blast survey in 208.14.
G. Stop all operations if the vibration limits are exceeded until the vibration specialist reports to the Engineer that no damage has occurred or will occur and that corrective action has been taken to lower the vibration.
Retain an experienced airblast and noise control specialist. Use an airblast and noise control specialist with at least five years of proven experience in airblast and noise control on heavy construction highway rock blasting projects and with a sufficient amount of proven experience of the type of rock blasting airblast and noise control monitoring required by the Contract. Use an airblast and noise control specialist that is an expert in airblast and noise control. The Contractor shall not use an airblast and noise control specialist that is an employee of the Contractor, explosives manufacturer, or explosives distributor.
Before or at the preconstruction conference, submit a resume of the credentials of the proposed airblast and noise control specialist. Include in the resume a list of at least five heavy construction or highway rock blasting projects on which the airblast and noise control specialist was responsibly in charge of the airblast and noise control of the rock blasting operations. List a description of the projects, with details of the airblast and noise control monitoring made on the project. List the names and telephone numbers of project owners with sufficient knowledge of the projects to verify the submitted information. Obtain approval of the airblast and noise control specialist before beginning any drilling and blasting work. Allow 30 days for the review of this documentation.
The airblast and noise control specialist shall perform the following:
A. Use equipment of the type specifically manufactured for the purpose to make the airblast measurements. Hold peak overpressure below 134 dB at the nearest structure or other designated location. Lower the overpressure limit if it proves too high based on damage or complaints.
B. The airblast and noise control specialist may establish the peak overpressure limits higher than 134 dB. Submit information explaining why higher limits are needed and are safe to the Engineer before blasting begins near structures denoted in the pre-blast survey in 208.14.
C. Furnish a permanent signed and dated record of the peak overpressure measurements to the Engineer immediately after each shot or use the same reporting procedures and time frames denoted for vibration in 208.15.
D. Stop all operations if the overpressure limits are exceeded until the airblast and noise control specialist reports to the Engineer that no damage has occurred or will occur and that corrective action has been taken to lower the airblast.
208.17 Hydrologist. If specified in the Contract, use a qualified hydrologist to monitor before, during, and after blasting or major excavation the quantity and quality of the water supplies within 1500 feet (460 m) of the blasting or major excavation areas. The water supplies shall include, but not be limited to, all wells, springs, or other water supplies for human consumption.
Retain an experienced hydrologist. The Contractor shall not use a hydrologist that is an employee of the Contractor, explosives manufacturer, or explosives distributor.
Before or at the preconstruction conference, submit a resume of the credentials of the proposed hydrologist. Include in the resume a list of at least five heavy construction or highway projects on which the hydrologist was responsibly in charge of monitoring water quality and quantities. List a description of the projects, with details of the water monitoring or modeling performed on the projects. List the names and telephone numbers of project owners with sufficient knowledge of the projects to verify the submitted information. Obtain approval of the hydrologist before beginning any major excavation, drilling, or blasting work. Allow 30 days for the review of this documentation.
The hydrologist shall perform, at minimum, all of the following:
A. Review the available public records, including Ohio DNR well logs, to obtain background information and to identify the locations and geology of water supplies within 1500 feet (460 m) of the blasting areas or major excavations.
B. Examine private wells, and public and industrial water supplies (as allowed by property owners or occupants), and measure water levels and well depths with a water level meter. Clean the water level meter before and between each use.
C. Collect water quality data (pH, e-coli, specific conductivity, turbidity, sulfur, and iron) from private wells, and public and industrial water supplies to determine the major excavation work or blasting effects on the water supplies by using field instruments.
D. Measure the water quality and water level for a minimum of two times per week for two weeks before, during, and two weeks after major excavation or blasting within 1500 feet (460 m) of the water supplies.
E. Perform an associated field survey of the locations and elevations of wells and springs.
F. Evaluate the need for piezometers to monitor the ground water conditions. Place and monitor the piezometers as necessary.
G. Provide a monitoring plan report detailing the proposed activities, frequencies, testing, and any recommendations for monitoring the water supplies as detailed in 208.17.A through 208.17.F above. Submit this report at least 10 days before beginning the scheduled blasting or major excavation.
H. Provide a monthly report of the conclusions and results of the monitoring plan.
I. Provide a final report on the final condition or effect of the blasting or major excavation on the water supplies. Submit this report within 30 days after the blasting or major excavation is completed on the project.
J. Meet with the Engineer in order to coordinate this work and provide input, update the project schedule, report progress (including completed work and updated schedule), and make recommendations. Allow for ten meetings.
The Contractor is not responsible for damages to the above denoted water supplies if the blasting or excavation is done according to this specification. The Contractor is responsible for damage caused by negligence, vibration or noise above the allowable limits, flyrock, or back break.
208.18 Flyrock Control. Before firing any blast in areas where flying rock may result in personal injury or unacceptable damage to property or the work, cover the rock with blasting mats, soil, or other equally serviceable material to prevent flyrock.
If flyrock leaves the construction site or lands on a traveled road, the Contractor shall cease all blasting operations until the blasting consultant specified in 208.13 reviews the site and determines the cause and solution to the flyrock problem. Before blasting proceeds, submit a written report addressing the following:
A. Why the flyrock left the construction site or landed on a traveled road.
B. What corrective measures were taken to prevent this from reoccurring?
208.19 Public Meetings. If a blasting consultant, vibration specialist, airblast and noise control specialist, or hydrologist are specified in the Contract, make the consultant, specialists, Contractor’s superintendent and blaster available for one day to prepare for and participate in a public meeting organized by the Engineer and conducted by the Contractor to inform the public about anticipated drilling and blasting operations. The consultant and specialists shall be prepared to answer any questions dealing with the magnitude of seismic motion, vibrations, airblast overpressure, flyrock, and water problems that may affect the public.
A. Daily Explosive Material Consumption. Keep a daily record of the transactions at each storage magazine. Update inventory records at the close of every business day. Show on the records the class and quantities received and issued and total remaining on hand at the end of each day. Check the remaining explosive inventory each day and report any discrepancies that would indicate a theft or loss of explosive material.
B. Report of Loss. If a loss or theft of explosives occur, report all circumstances and details of the loss or theft immediately to the nearest Bureau of Alcohol, Tobacco and Firearms, as well as to the local law enforcement authorities and the Engineer.
C. Daily Drilling and Blasting Logs. On a weekly basis, provide a daily log of the drilling and blasting operations. Update the log at the close of each business day.
Fill out the Department or blaster’s drilling form to document the following: burden, spacing, bench height, hole depth and diameter, and subdrill depth. Document additional information about the drilling such as voids, mud seams, air pressure loss and lack of cuttings. The driller shall give this form to the blaster and the Department.
Document on the blasting log the number of blasts, times and dates of blasts, the blasting locations and patterns, and all of the following information:
1. Station limits of the shot.
2. Plan and section views of drill pattern including free face, burden, blast hole spacing, blast hole diameters, blast hole angles, lift height, and subdrill depth.
3. Loading diagram showing type and amount of explosive, primers, and initiators and location and depth of stemming.
4. Initiators sequence of blast holes including delay times and delay system in each blast hole.
5. Trade names and sizes of all explosives, primers, and initiators employed.
6. Signature of the blaster in charge.
7. Use the blaster’s blasting form or the Blasting Report form in FHWA Publication FHWA-HI-92-001 Rock Blasting and Overbreak Control. Adapt these forms to meet the project requirements.
The drilling and blasting logs are for quality control, informational, and record keeping purposes. Review of the blast log by the Engineer does not relieve the Contractor of responsibility for the accuracy and adequacy of the drilling and blasting log.
D. Video Recording of Blasts. Record video of each blast. Index the recordings in a manner that permits easy and correct identification of each blast. Submit copies of the blast recordings on a weekly basis. If submitting the video recordings as electronic data files, furnish them in a video format acceptable to the Engineer and capable of being viewed on the Department’s computers.
208.21 Method of Measurement. The Department will measure Presplitting by the number of square yards (square meters) along the slope face of the cut. The horizontal measurement will begin at the first hole and end at the last hole of the cut, and the vertical slope measurement will be along the sloped drill hole.
208.22 Basis of Payment. The Department will not make separate payment for the production blasting operations. Payment for the production blasting is incidental to the other work items in the Contract requiring blasting. The Department will pay for additional excavation volume resulting from the 2-foot (0.6 m) offsets at the Contract unit price for Item 203 Excavation. The Department will pay for the removal of this material beyond the excavation limits under 109.05.
The Department will pay lump sum for all work for the Pre-Blast Condition Survey, Blasting Consultant, Airblast and Noise Control, Vibration Control and Monitoring, and Hydrologist. The same person or consultant may perform the pre-blast survey, vibration control and monitoring, airblast and noise control, and the work required of the hydrologists. The Department may make intermediate payments based on the percentage of the work completed for Pre-Blast Condition Survey, Blasting Consultant, Airblast and Noise Control, Vibration Control and Monitoring, or Hydrologist.
Payment for guide holes is incidental to Presplitting. Payment for all of controlled blasting is included in the payment for Presplitting.
The Department will pay for stabilization under 109.05 if caused by geology. The Department will not pay for stabilization if caused by the Contractor’s blasting operations.
The Department will pay for the placement and monitoring of piezometers according to 109.05.
The Department will pay for accepted quantities at the contract prices as follows:
Item Unit Description
208 Square Yard Presplitting
208 Lump Sum Pre-Blast Condition Survey
208 Lump Sum Blasting Consultant
208 Lump Sum Airblast and Noise Control
208 Lump Sum Vibration Control and Monitoring
208 Lump Sum Hydrologist