(A) Blasting logs shall be prepared by the mining operation and shall be maintained for a period not less than five years after a blasting event.
(B) Copies of blasting logs shall be given to the LGU within five working days upon request.
(C) Information to record in a blasting log includes:
(1) Name, signature and license number of the blaster in charge of the blast;
(2) Specific blast location, including address, bench and station number if applicable;
(3) Type of blasting operation;
(4) Date and time of the blast;
(5) Copy of information provided to the city prior to blasting, as required in § 158.035 of this chapter;
(6) Meteorological conditions, including temperature inversions, wind speed and directions as can be determined from the United States Weather Bureau and ground-based observations;
(7) Diagram of the blast layout and the delay pattern;
(8) Number of holes;
(9) Hole depth and diameter;
(10) Spacing of holes;
(11) Burden;
(12) Maximum holes per delay;
(13) Maximum pounds of explosives per delay;
(14) Number, type and length of stemming used between decks;
(15) Total pounds and type of explosives per each delay;
(16) Distance to nearest inhabited building not owned by the applicant;
(17) Type of initiation used;
(18) Seismographic and airblast records, which shall include all of the following:
(a) Type of instrument and last laboratory calibration date;
(b) Maps of the exact location of monitoring instrument(s);
(c) Records of the date, time and distance from the blast;
(d) Trigger levels for ground and air vibrations; and
(e) The vibration and airblast levels recorded.
(19) Particle velocity should be recorded in three mutually perpendicular directions.
(D) In the event that seismograph monitoring exceeds standards identified in either the blast plan or local permit, the company will notify the city within one working day.
(E) The water resource management plan should address potential nitrate contamination due to blasting.
(F) Whenever explosives are used, they shall be of such character and in such amount as is permitted by state and local laws and ordinances and all respective agencies having jurisdiction over them.
(G) The regulatory requirements of OSHA safety and health standards, 29 C.F.R. part 1926, subpart U, “Blasting and Use of Explosives”, shall be applied.
(H) Operators will use all industry standard measures to control fly rock with the intent that fly rock not leave the mine property.
(I) Prior to any blasting event at the excavation and mining site, the mining operation is responsible for giving notice of the impending blasting event by displaying a fluorescent flag and legible sign within 100 feet of all public roads bordering the blasting site.
(J) Untreated ANFO should not be used in blastholes with standing water in the bottom. Water- proof blasting agents such as emulsions or gels, developed to prevent the release of nitrates into the ground water, should be used in blastholes with standing water at the bottom.
(K) The maximum single component peak particle velocity resulting from construction activity should not exceed the safe blasting criteria established in Office of Surface Mining recommendations, OSM Alternative Blasting Level Criteria (modified from Figure B1, R1 8507, U.S. Bureau of Mines). This criteria allows a constant peak particle velocity (ppv) of 2.0 inches per sec (ips) above 30 Hz. Below 30 Hz, the maximum velocity decreases at a rate equivalent to a constant peak displacement of 0.01 inch to 11 Hz. Between 11 Hz and 4 Hz the maximum velocity is 0.75 ips. Below 4 Hz, the maximum velocity decreases at a rate equivalent to a constant peak displacement of 0.03 inch.
(L) Appropriate vibration levels shall be used where there is the presence of fragile or extremely fragile historically significant buildings or sites. The following table is to be used as a guideline but limits shall be determined ultimately based on:
(1) Proximity of the resource to the blasting site and on site (ground conditions) and the anticipated travel of damaging vibrations;
(2) The level of significance of a resource as determined by its official listing on any federal, state or local register and as by the City Council; and
(3) Level of protection afforded to the resource by its official listing on any federal, state or local register.
Structure and Condition | Maximum PPV (in/sec) | |
Transient Sources | Continuous/Frequent Intermittent Sources | |
Extremely fragile historic structures, ruins or monuments | 0.12 | 0.08 |
Fragile buildings | 0.2 | 0.1 |
(M) The mine operator shall provide a notification to all property owners within a one-half mile of the mine site at least 15 days prior to blasting activity occurring. A copy of the notification shall also be sent to the city along with a list of those being sent the notification. For blasting anticipated to occur for more than one day within a one-month period, one notification with the anticipated dates will suffice. The notification shall include:
(1) The date(s) or range of dates that blasting is anticipated to occur;
(2) The contact information including a contact person, a phone number and an address for questions to be addressed during business hours;
(3) An offer to property owners for a pre-blast survey which shall:
(a) Be performed by an independent, credentialed third party at the expense of the operator;
(b) Consist of a record on paper, video or an unalterable electronic file to document the condition of a dwelling, structure or water well before the commencement of blasting activity; and
(c) Provide a record of inspection of the condition of a well and/or structure including the interior and exterior as requested by the owner.
(4) A written statement that the survey must be requested in writing which shall identify the structures and/or well to be surveyed; and
(5) A written statement indicating that all surveys completed will be available upon request of the property owner within a 72-hour period after the request is made.
(N) The City Engineer shall inspect, review and monitor all blasting operations.
(Prior Code, § 345.06)