Section 880-X-10C-.34 - Use of Explosives: Control of Adverse Effects (Alabama Administrative Code)

§ 880-X-10C-.34. Use of Explosives: Control of Adverse Effects

(1) General requirements. Blasting shall be conducted to prevent injury to persons, damage to public or private property outside the permit area, adverse impacts on any underground mine, and change in the course, channel, or availability of surface or ground-water outside the permit area.

(2) Airblast.

(a) Limits.

1. Airblast shall not exceed the maximum limits listed below at the location of any dwelling, public building, school, church, or community or institutional building outside the permit area, except as provided in Rule 880-X-10C-.34(5).

Lower frequency limit of measuring Maximum level, system, in Hz (3 dB) in dB

O.1 Hz or lower-- flat response 1.... 134 peak

2 Hz or lower-- flat response.... 133 peak

6 Hz or lower-- flat response.... 129 peak

C-weighted-- slow response 1.... 105 peak dBC.

1 Only when approved by the Regulatory Authority.

2. If necessary to prevent damage, the Regulatory Authority shall specify lower maximum allowable airblast levels than those of Paragraph 2(a)1. above for use in the vicinity of a specific blasting operation.

b. Monitoring.

1. The operator shall conduct periodic monitoring to ensure compliance with the airblast standards. The Regulatory Authority may require airblast measurement of any or all blasts and may specify the locations at which such measurements are taken.

2. The measuring system shall have an upper-end flat-frequency response of at least 200 Hz.

(3) Flyrock. Flyrock traveling in the air or along the ground shall not be cast from the blasting site --

(a) More than one-half the distance to the nearest dwelling or other occupied structure;

(b) Beyond the area of control required under Rule 880-X-10C-.33(3), or

(c) Beyond the permit boundary.

(4) Ground vibration.

(a) General. In all blasting operations except as otherwise authorized in Paragraph (e) below, the maximum ground vibration shall not exceed the values approved in the blasting plan required under Rule 880-X-8F-.07. The maximum ground vibration for protected structures listed in this section shall be established in accordance with either the maximum peak-particle-velocity limits, the scaled distance equation, or the blasting-level chart of this section; or by the Regulatory Authority pursuant to this Rule. All structures in the vicinity of the blasting area, not listed in this section, such as water towers, pipelines and other utilities, tunnels, dams, impoundments, and underground mines, shall be protected from damage by establishment of a maximum allowable limit on the ground vibration, submitted by the operator in the blasting plan and approved by the Regulatory Authority.

(b) Maximum peak particle velocity.

1. The maximum ground vibration shall not exceed the following limits at the location of any dwelling, public building, school, church, or community or institutional building outside the permit area:

Distance (D), from Maximum Scaled distance the blasting site, allowable peak factor to be in feet particle applied without velocity (Vmax) seismic for ground monitoring 2 vibration, in inches/seconds 1

0 to 300............ 1.25 50

301 to 5,000........ 1.00 55

5,001 and beyond.... 0.75 65

1 Ground vibration shall be measured as the particle velocity. Particle velocity shall be recorded in three mutually perpendicular directions. The maximum allowable peak particle velocity shall apply to each of the three measurements.

2 Applicable to the scaled distance equation of Rule 880-X-10C-.34(4)(c)1.

2. A seismographic record shall be provided for each blast.

(c) Scale-distance equation.

1. An operator may use the scaled-distance equation, W= (D/Ds)2 to determine the allowable charge weight of explosives to be detonated in any 8-millisecond period, without seismic monitoring; where W = the maximum weight of explosives in pounds; D = the distance, in feet, from the blasting site to the nearest protected structure; and Ds = the scaled-distance factor, which may initially be approved by the Regulatory Authority using the values for scaled-distance factor listed in this section.

2. The development of a modified scaled-distance factor may be authorized by the Regulatory Authority on receipt of a written request by the operator, supported by the seismographic records of blasting at the mine site. The modified scale-distance factor shall be determined such that the particle velocity of the predicted ground vibration will not exceed the prescribed maximum allowable peak particle velocity of this section, at 95-percent confidence level.

(d) Blasting-level chart.

1. An operator may use the ground vibration limits in Figure 1 to determine the maximum allowable vibration.

2. If the Figure 1 limits are used, a seismographic record including both particle velocity and vibration-frequency levels shall be provided for each blast. The method for the analysis of the predominant frequency contained in the blasting records shall be approved by the Regulatory Authority before application of this alternative blasting criterion.

(e)

1. The State Regulatory Authority shall reduce the maximum peak particle velocity allowed, if it determines that a lower standard is required because of density of population or land use, age or type of structure, geology or hydrology of the area, frequency of blasts, or other factors.

2. Upon the request of a municipality or fifteen (15) citizens of a municipality who are being affected by blasting operations of a surface mine, the State Regulatory Authority shall solicit and consider public comments from those being affected in determining the necessity of more stringent standards. The State Regulatory Authority may require the blaster to decrease the maximum peak particle velocity of ground motion, at the nearest dwelling, public building, school, church, commercial or institutional building to as low as 0.5 inch per second. Seismographic monitoring may be required at the site of the complaint nearest the blast. The final written determination of the State Regulatory Authority, including any proposed standards, or the failure of the State Regulatory Authority to act within a reasonable time, shall be reviewed by the Commission. The Commission, if requested by the municipality, twenty-five (25) citizens of the municipalities or any affected licensee, shall hold a public hearing in the manner specified in Chapter 880-X-5. The Commission shall affirm or reverse the written determination or refer it to the State Regulatory Authority for further specific inquiries.

(f) The Regulatory Authority may require an operator to conduct seismic monitoring of any or all blasts or may specify the location at which the measurements are taken and the degree of detail necessary in the measurement.

(5) The maximum airblast and ground vibration standards of this section shall not apply at the following locations:

(a) At structures owned by the permittee and not leased to another person.

(b) At structures owned by the permittee and leased to another person, if a written waiver by the lessee is submitted to the Regulatory Authority before blasting.

Graph 1 al2201

See Graph at http://www.alabamaadministrativecode.state.al.us/docs/graphics/aladmn/AL2201.jpg

Blast Vibration Frequency Hz

Figure 1. Alternative blasting level criteria

(Source: Modified from figure B-1,

Bureau of Mines R18507)

Figure 1. Alternative blasting level criteria (Source: Modified from figure B-1, Bureau of Mines R185071

Figure 1. Alternative blasting level criteria (Source: Modified from figure 8-1. Bureau of Mines R185071)

See Figures at http://www.alabamaadministrativecode.state.al.us/docs/graphics/aladmn/AL2201.jpg

Author:

Statutory Authority: Code of Ala. 1975, §§ 9-16-71, 72, 73, 74, 75, 76, 80, 84, 90, 92, 97.

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