Md. Code Regs. 26.21.01.21

Current through Register Vol. 51, No. 22, November 1, 2024

Section 26.21.01.21 - Blasting

A. General.

(1) The permittee shall comply with all applicable local, State, and federal laws and regulations and with this regulation in the use of explosives. To the extent this regulation is more restrictive than other applicable law or regulations, this regulation shall control.

(2) The permittee is responsible for insuring that blasting is conducted by a person licensed under Article 38A, §§ 26-36, Annotated Code of Maryland.

(3) The permittee shall conduct blasting so as not to cause injury to persons, damage to public or private property, adverse impacts on an underground mine, or adverse changes in the course, channel, or availability of ground or surface waters.

(4) The Department may prohibit blasting in specific sensitive areas if necessary for public safety.

(5) The Department may require a seismographic record of any blast.

(6) Explosive weight limitations prescribed in Regulation .22B(2) of this chapter do not apply to any detonation when every person owning or controlling potentially affected residences, buildings, or structures within 1,300 feet of the permit area executes a written statement of consent, and that consent is submitted to the Department before detonation.

(7) The permittee shall post a permanent sign, at least 2 feet by 3 feet in size at the entrance of the property, stating "Warning-Blasting Area" in legible letters.

(8) The air blast and ground vibration limits specified in this regulation are considered the threshold below which blasting damage is unlikely to occur. The Department may require an evaluation of any blast site by a vibration consultant and, if necessary, impose more stringent limits to protect property outside the permitted area and not within the permittee's ownership or control, or to protect public safety.

(9) After receipt and review of an application for a permit for a new surface mining operation, or for expansion of a surface mining operation permitted before the enactment of these regulations, the Department may specify a potential impact area and may require a pre-blast survey, to be submitted before any blasting. The pre-blast survey shall document any pre-blasting damage and other physical factors that could reasonably be affected by the blasting.

(10) Assessment of structures such as pipes, cables, transmission lines, wells, and other water systems shall be limited to surface conditions and other readily available data. Special attention shall be given to the pre-blasting condition of wells and other water systems used for human, animal, or agricultural purposes, and to the quantity and quality of the water.

B. Air Blast Effects.

(1) The maximum allowable air blast at any inhabited building may not exceed 130 decibels peak when measured by an instrument having a flat frequency response (±3 decibels) over the range of 6 to 200 hertz.

(2) The maximum allowable air blast at any uninhabited building may not exceed 140 decibels peak when measured by an instrument having a flat frequency response (±3 decibels) over the range of 6 to 200 hertz.

(3) When blasting is of a continuing nature, 124-130 decibels shall be the caution range.

(4) When the air blast effects are consistently within the caution range, the blasting procedures shall be changed to reduce the decibel level on subsequent blasts in order to protect property outside the permitted rea and not within the permittee's ownership or control, or to protect public safety.

(5) The permittee shall employ a person who is competent to use an approved instrument that has been calibrated in accordance with the manufacturer's recommendations for determining compliance with this section.

Md. Code Regs. 26.21.01.21