§ 19-53. Vibration, blasting.

(a)

Vibration. Explosives shall not be detonated in an active mining area in which ground vibrations in any plane exceed the thresholds at the site of a protected structure as follows:

(1)

.2 or less inches per second peak particle velocity at a 1 or less hz at the site of a protected structure;

(2)

.75 inches per second peak particle velocity at between 1 and 12 hz at the site of a protected structure;

(3)

.8 inches per second peak particle velocity at 13 hz at the site of a protected structure;

(4)

.9 inches per second peak particle velocity at 14 hz at the site of a protected structure; or

(5)

1.0 inch per second peak particle velocity between 15 and 100 hz at the site of a protected structure.

(b)

Air blast overpressure. The conduct of mining operations, including the detonation of explosive charges related thereto, shall not exceed any of the following safe maximum air blast overpressure levels at the site of a protected structure:

Lower Frequency Limit of Measuring System in HZ 3 dB	Measurement Level dB
1 Hz or lower—Flat response	134 peak
2 Hz or lower—Flat response	133 peak
6 Hz or lower—Flat response	129 peak
C-weighted—Slow response	105 peak dBC

 

(c)

Blasting conditions. The following conditions apply to blasting:

(1)

Blasting will be permitted only between the hours of 8:00 a.m. and 5:00 p.m., Monday through Saturday. If an area is deemed to be remotely located from residential areas, the board of county commissioners may permit blasting to occur during all daylight hours, sunrise to sunset. In accordance with applicable federal and/or state safety standards, blasting may occur at any time for a hazardous condition with notice being given to the county on the next business day.

(2)

In instances where the blast site is sufficiently close to a public road so as to constitute a public safety hazard, the mine operator shall temporarily control vehicular traffic during blasting operations by conspicuously posting "Danger! Mine blasting" signs along the blast area where a public or private road is less than two hundred (200) feet distant and at the junction of access roads leading to the blast site. Operators shall be prohibited from allowing rock, debris, or refuse to be blast-propelled from the mine property onto adjacent private property.

(3)

Blast monitor equipment shall be used in accordance with manufacturer's recommendations in order to obtain accurate vibration readings.

(d)

Reporting requirements. The following reporting requirements apply:

(1)

Blasting records, notices of ordinance violations issued, and investigations of complaints for alleged violations, will be maintained by the county.

(2)

Each operator shall monitor and record the daily vibration amplitudes. The operator shall bear the expense of securing the appropriate seismograph or other comparable continuous vibration recording instrument, together with any necessarily associated consulting or interpretive services.

(3)

The operator shall file monthly blast reports with location of the seismograph with the county showing the peak vibrations for each blast occurring during the month. These reports shall be due within thirty (30) days of the end of each month.

(e)

Blasting and user permits. If blasting or any other use of explosives is to be conducted in conjunction with mining operations, the following must be met:

(1)

No permit shall be issued by the County until copies of the Blaster and User Permits required and issued by the State of Florida have been submitted.

(2)

No blasting shall be conducted in conjunction with mining unless such permit copies have been filed with the application.

(Ord. No. 93-13, § C-3, 6-29-93)