BLASTING

                                   WHAT’S

                                   CAUSING

                                          ALL

                                   THESE

                                   PROBLEMS?

 The Surface Mining Control and Reclamation Act was passed to stop coal mines from “damaging the property of citizens…(and) creating hazards dangerous to life and property by degrading the quality of life in local communities.”

“It is the purpose of this Act to …(b) assure that the rights of surface landowners and other persons with a legal interest in the land…are fully protected’’ and “(m) where ever necessary, exercise the full reach of Federal constitutional powers to insure the protection of the public interest through effective control of surface coal mining operations.”

Penny Loeb

December 1, 2000

INTRODUCTION     

             When I picked up my yearly list of complaints from DEP in March 2000, I discovered just as many blasting complaints as in previous years, and at mines I had never heard of. So I decided to find out if there is any difference between the blasts that people complain about and those that they don’t.

            I collected data on 1,134 blasts at nine mines of various sizes. Of these, 369 had caused problems—such as vibration or noise or dust—for nearby residents. In about three-quarters of the problem blasts, they did differ in some significant way from the blasts that did not cause problems. The differences varied by mine, and not all applied to any one mine. The specifics are discussed under the sections on each mine. But general characteristics include: air blasts over 115 dB, larger shallow binder shots, low-frequency shots, large amounts of explosive per delay, blasts that exceed the scaled-distance formula, cast blasting, two or more shots at the same time, and larger shots closer to homes.

            Experts say that other factors can cause blasts to be troublesome as well, including the way explosives are placed in holes, brand of explosive, and misfirings. These could not be determined from the information available.

            This analysis is based on a database of the information on the blasting logs. Blasting logs contain two pages of information on each blast, including: time, location, number of holes, amount of explosive per hole, blast design and length of delays between holes. Sometimes there will also be information on ground vibration, air blast levels and frequency from seismograph readings. Some mines are required to seismograph all blasts, while others have been seismographed by DEP after complaints from residents.

            I determined which blasts caused problems in two ways. Some resulted in complaints to DEP. Others were noted on lists kept by people living near the mines. In every community except one, I got a list kept by at least one resident.

            The regulations say the director can give the public access to the blasting logs. But they don’t require copies, so Libby Lindsay (a retired miner and summer intern at the West Virginia Organizing Project) and I had to take laptops to the mines. When we had to sit on boxes and use pails as tables in the guard shack at White Flame (the first mine), we thought we were in for a rough summer. Fortunately, accommodations improved, but varied greatly. Paynter Branch required us to go to a lawyer’s office in Charleston and assigned a young secretary to watch. Pen Coal had a supervisor hand us each blasting log, one by one, and asked for a copy of the data.

            For all mines but one, we used the time period of the beginning of 1999 through Spring 2000. The other mine had ceased blasting for part of 1999 so we also looked at older records. We entered every blast that generated a complaint to DEP. We tried to enter at least two full months of blasts during the months when there were the most problems. That way we could compare blasts that were problems to others that were placed nearby at the same time of year. Ideally, we would have tried to gather another 500 blasts, but our time was limited with each mine. We have gone back to as many mines as possible and checked the data.

            I have spoken with seven blasting experts, read both the OSM and DEP blasting manuals, reviewed studies and court testimony and have discussed my findings with DEP and officials at the mines. I asked all the mines for a response. Paynter Branch, Bandmill and Mingo Logan did not respond. Pen Coal officials and I are still trying to set a date for an interview.

            This study is about both nuisance problems and damage. The law gives citizens the right to enjoyment of their property. Yet, in every community where there is blasting, there are certain shots that cause houses to shudder, items on walls and shelves to shake. The blasts can be very loud or cause a lot of dust. At most mines, these types of blasts only occur about a dozen days out of the month. The others don’t bother people.

            In fact the Secretary of the Interior stated in the Federal Register, when OSM issued its blasting regulations in 1983, that citizens’ health and safety should be protected as to “create the least discomfort.” “OSM believes that prevention of excessive noise, especially in populated and residential areas, is within the ambit of ‘health and safety or welfare.’”

            The coal company officials, and to some extent DEP officials, sometimes dismiss the people who claim problems as “chronic complainers.” Sure these people exist. But I am confident that the people from whom I got complaints had legitimate problems and did not exaggerate.

            My purpose was not to determine exactly what made those blasts problematic. There is not enough information on the logs for such precise findings, nor do I have the expertise. What I wanted to find out is whether there is enough suggestion of difference to warrant further study.

            The mines usually abide by the regulatory limits of 1 inch/second ground movement and 133 dB air blast. Vibration is supposed to be minimized by separating the explosions of each delay by at least 8 ms. Mines usually use a “scaled-distance formula.” This limits the amount of explosive per delay period. For example, the limit for a blast 2,600 feet from the closest protected structure is 2,234 pounds per delay period. The closer a mine gets to a house, the less explosive per delay is allowed. The formula does not have to be followed if a seismograph is at the closest house.

            When a citizen files a complaint, the DEP inspector, in nearly every case, will write that blasting was within the regulations and go away, leaving angry citizens. They feel as if they are in the Twilight Zone. How can the inspector say blasting is being done properly when their house shakes? Some inspectors have even pinpointed types of blasts that cause problems under these limits, especially air blasts above 115 dB (these are explained in the analysis of each mine below). Yet, DEP and OSM refuse to look beyond these standards.

            The regulations are based on research done 15-20 years ago by the Bureau of Mines. None was done in West Virginia, and research was with smaller blasts and partly on a new house built specifically to test blasting. Two recent bodies of research have been developed that refute the accepted limits. (I can supply copies to anyone who wishes).

            Sam Kiger, Dean of Engineering at the University of Missouri, was the expert for the Bim blasting case, which was tried in court in Boone County in March 1999. Kiger is an international expert in protecting federal buildings from blasting damage. After examining 6,000 blasting logs, he testified that there is about a 95 percent chance of damage at a vibration limit of .5 inches/second, if you count each of the holes shot (50 on average) as a separate vibration. In the Bim case, he also testified that low-frequency waves (2 Hz-11 Hz) generated by some blasts can be more damaging. The frequencies can match that of a house and amplify the shaking.

             Freda Harris, who had a blasting case with a mine in Indiana, gathered many documents during the case and subsequent FOIAs of OSM. She wrote a manual for Citizens Coal Council. One of her most intriguing findings was that there can be “hot spots” in a community where the geography can make blasts worse. She emphasizes that damage and vibrations can feel worse if a house’s natural frequency is approximately between 4 Hz and 12 Hz. The above-ground part of the house often vibrates more than the ground outside and the foundation. Yet, the DEP/OSM standard is based on ground vibration.

            Most of the blasting studies of the Bureau of Mines were done by the David Siskind. The FOIAs provided much correspondence between Siskind and other experts, some of it quite critical. A top official of Vibra-Tech, a leader in designing blasting technology, said: “Any criteria…which ignores the frequency of a structure and the frequency content of the ground motion is overly simplistic…Your criteria, as proposed, will neither protect the interest of the citizen and the homeowner, nor will it protect the blaster from alleged damage claims.”

            After the Bureau of Mines was shut down by Congress, Siskind became a private consultant. He testified for the coal company that lost the Bim case. The majority of the blasting cases have overturned his studies, and thereby the limits used by DEP and OSM. As he wrote an OSM official on June 17, 1997: “The battles I am now seeing are not 0.5 in/sec versus 1.0 in/sec. Complainants are trying to dismiss all the science as biased, wrong or nonapplicable. For the most part, they are succeeding in ways that pay off.”

            Interestingly, the DEP “Surface Mine Blasting Study Guide” acknowledges that the response of the human body is greater at lower frequencies: “This explains why people file complaints even when the blasting is conducted at safe (no damage) levels.”

The guide recommends seven ways to possibly reduce ground vibration, including: use less explosive per delay, increase the length of delay, detonate the blast away from houses, increase the scaled distance formula. Interestingly, many of the problem blasts violated one of those seven recommendations.

            The study guide also notes that blasting complaints will be likely when air blasts exceed 115 dB. It has nine recommendations on how to reduce air blasts, including using enough cover over the explosives in the holes, avoid cloudy days and temperature inversions and avoid open sides in the direction of homes. Again these were often disregarded during problem blasts.

            DEP regulations give the Director the power to order mines to reduce blasts to prevent harm. The regulation currently reads: “The director may prohibit blasting on specific areas where it is deemed necessary for the protection of public or private property, or the general welfare and safety of the public.”

            DEP has tried to strengthen the language in revised regs now before the Legislature: “The director may prohibit blasting or prescribe alternative distance, vibration and air blast limits on specific areas, on a case by case basis, where research shows it is necessary, for the protection of public or private property, or the general welfare and safety of the public.”

            At DEP’s public hearing in August, the industry submitted criticisms, and Mike Mace, director of the new Office of  Explosives and Blasting,  thinks it might not pass the legislature. Even if it passes, the question is will it ever be used.

            Darcy White, assistant chief of the Office of Explosives and Blasting, agrees that blasts can be refined and reduced a bit. She has found that the frequency problem can be eased by lengthening the delay periods between blasts. This would eliminate a lot of the problems. But she sees it as a continual negotiation between inspectors and the mines. Never, she thinks, will DEP have the authority to order the changes that are needed. The sad thing is that these aren’t major changes. Nor would they result in much slowing of production.

            The response of homes can be measured before blasting. Response Spectra Analysis is a mathematical procedure that takes into account the structure’s natural forces and the amplitudes and frequencies transmitted by a blast. This requires firing test blasts first. Vibra-Tech’s West Virginia office offers this service, which they sometimes use when blasting will be near a hospital or computer operations. One hole is fired for a week, and vibrations measured. Mines don’t use it, the Vibra-tech official said. “If the speed limit is 55mph, would you drive 50 mph,” he said, explaining that mines only do the legal minimums.

            OSM actually considered requiring Response Spectra Analysis, but rejected it in 1983 as too expensive.

            The other weakness of the DEP system is that inspectors don’t know the scope of the blasting problems. Only a small percentage of the problematic blasts get reported to DEP. Some people don’t know who to call or even that DEP exists. Others give up after being told repeatedly that the blast “was in compliance.” Within two hours, I can find the person(s) in a community keeping lists of the blasts. But there is no DEP policy requiring inspectors to regularly canvass a community for problems with a mine

            From this study, it appears that blasting could be moderated enough to reduce problem blasts by at least 50 percent. With the recent appropriation of additional state and federal money for DEP, the blasting office will hire about a dozen blasting inspectors. If inspectors had a complete record of all the problem blasts at every mine, they could require modifications in the blasting until the problems abate.

            Clinton Evans, engineer for an explosives firm in southwestern Virginia, is regarded as one of the leading experts on blasting in the Kentucky, West Virginia and southwestern Virginia area. He has been a blaster since 1976, and his firm supplies powder to Tri-County and advises the mine occasionally. It is also doing the blasting for the Route 10 widening in Man. The firm does blasting at surface mines, though none currently in West Virginia.

            He offered many insights on why certain kinds of blasts can cause problems and kinds of improvements that can be made. He agreed that there are things that can be done to make blasting less bothersome. I will explain what he said about some of the most common problems

            Binder shots, which have short holes (generally less than 10-feet deep), frequently result in loud air blasts, which cause complaints. Mines use these when they have to shoot a narrow layer of overburden to reach coal. The top coal layer is usually fairly deep (50-100 feet below the top of the mountain). Then there can be a few coal seams close together with just a little cover. The holes are so short that there is no room for adequate cover to absorb the sound. The best way to cope is to use gravel to cover the explosive instead of the drill cuttings normally used. His firm uses gravel for binder shots on construction jobs. But it would be practically impossible for coal companies to absorb that cost, he said. Barry Doss, the chief engineer for West Virginia operations for Addington, said that mines tend to use binder shots with too many holes because they are so easy to drill. The data shows that smaller binder shots generally don’t cause problems.

            Evans said that they concentrate much more on the effects of the low frequencies than on per particle velocity. The per-particle reading almost never goes higher than .3 inches, well below the regulatory limit of 1 inch per second. However, just as Sam Kiger and Freda Harris determined, the low frequencies are bothersome. “We try to change to a higher frequency so don’t get as high a jolt,” he explained. DEP recognizes that lengthening the delays can raise the frequency. However, Evans also tries decreasing the burden a foot at a time, and then possibly the spacing as well.

            Air blasts that exceed 115 dB frequently cause complaints. He said the best time to shoot when there is a potential for air blast is from noon until 2 p.m. because temperature inversions and clouds are least likely. However, a lot of mines like to shoot at shift changes around 4 p.m. Another way to reduce air blasts is to slow down the delays down the rows. The data shows at least half the mines use 9ms delays down the rows. He said those short delays can actually end up, depending on the design of the blast, being less than the regulatory limit of 8 ms between delays. Some mines use these very quick row shots to cast the overburden. This saves a lot of time and reduces the cost of moving the overburden. The explosion just tosses the material away from the coal.

            There needs to be better training of both blasters and inspectors, he said. “One of the biggest problems in the industry,” he said, “Is that we have a lot of explosive companies with well-trained people, but more intensive training of the blasters at the sites needs to be done.” There will be times with difficult blasts, he said, that blasters will need advice from explosives companies. However, their resources are stretched thin, as well. Larger mines will generally get more attention just because they do more blasting.

He recommends that at least some of the new blasting inspectors at DEP have worked as blasters. He also advises aggressive public outreach, which is what his company does when they start blasting in a new area.

Continue to in-depth analyses of blasting problems in nine communities:

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