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Use of Explosives, Blasting
Blasting is an integral part of surface mining operations. To uncover coal reserves, the rocks overlying the coal are broken with explosives and excavated with various types of large earth-moving equipment. Without blasting, a vital part of the nation's energy reserve would be inaccessible. Blasting is one of the most frequent complaints received by OSM.
The Surface Mining Control and Reclamation Act of 1977 (SMCRA) requires that coal mining be conducted in a manner that prevents injury to people and damage to public or private property during blasting. The side effects of blasting are “flyrock” (a rock or rocks flying through the air during a blast), ground vibrations, and “airblast” (a concussion that moves through air following any type of explosive detonation). The most dangerous and apparent of these is flyrock. Injury or death to people and property damage may happen when a piece of rock is thrown beyond the permit boundary. The blaster is responsible for preventing flyrock and controlling ground vibration and airblast. OSM oversees the only national program to certify blasters. Blaster training provided by the States addresses the control of flyrock, vibrations, and airblast by the appropriate use of explosives and hazard recognition in the field.
Ground vibrations and airblast causes people's homes to shake. People feel their houses shake and may associate damage to their homes as being a direct result of the blasting at surface coal mines. Homeowners may receive compensation for or repair of damage caused by coal mining blasting. Some property damage identified may pre-date the blasting and is caused by other natural factors (e.g., structure aging, poor foundation, normal stresses, runoff control, etc.) or improper construction. These damages are not the responsibility of the coal company.
Some coalfield citizens claim that the OSM regulations do not adequately protect their homes and property. OSM set limits based on scientific studies that reasonably protect most typical residential structures. When the blasting limits are exceeded, violations are written. Occasionally, damage to homes is possible at vibration levels below the limits, particularly when structures aren’t representative of typical structures (e.g. adobe, log, or mobile homes). In these situations, the States are responsible for investigating the damage claim and/or adjusting limits to prevent further damage.
People are sensitive to blasting vibrations and can feel blasts that are as little as 2% of the legal vibration limits. Thus, blasting that shakes their homes, but is within legal limits may often annoy people. Depending on person’s sensitivity, any given blast may be offensive. While OSM does not regulate this potential annoyance, the regulations do recognize that people need advance warning that such sensations may be forthcoming. The rules require audible signals (to residents within ½ mile) that warn of impending blasts and notification of the blasting schedule that specifies blasting times. Additionally, homeowners can ask questions about the blasting during the pre-blasting survey of their home (required for residents within ½ mile of coal mining permit boundaries).
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