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HomeMy WebLinkAbout05-17 CommentsMethodology and Purpose of Pre -Blast purveys at the Middletown Operation WHAT IS THE PURPOSE OF A PRE -BLAST SURVEY? As the narne implies, the pre -blast survey is a visual inspection of selected structures located adjacent to proposed blasting activities. While off-site effects of commercial blasting such as that proposed for the Middletown expansion are expected to pose no threat to existing structures, it has been historically documented that when the perception of blasting reaches new or additional property owners, it is human nature to pay additional attention to one's property. Decades of research performed by the US Bureau of Mines as well as other investigative groups, have fully documented not only the impact of blasting on structures, but also the impact of ambient environmental conditions. While blast effects typically remain well below the effects of various environmental forces, stress caused by everyday exposure to various weather events regularly places strain on construction materials above their ability to resist impact. In other words, these studies have documented what every homeowner already knows, houses, over time, will develop cracks and defects. Q EXHIBIT W J W Q H �_ J Environmental Effects Comparison With Blast Vibration 91 --- __ _ N 7 O Q . 5 . W IIle N = CL U o ------ -- - - -12-- 0 � - 0 4 -— v>— — - - ..._ — - — -J �+ N L° 3 ----------- - --- --- - ----- - --- — > to m 0 Inside Exterior Inside Exterior Wind Middletown Humidity Humidity Temp Temp Gusts Blast Changes Changes Change Change (Avg.) Environmental Effect Oriard, 1992 With the property owner paying close attention to the structure upon the perception of blasting operations, minor, threshold cracks that may have previously gone unnoticed now become the focus of attention. The question becomes,- "were they there before the blasting started"? The pre -blast survey has become a standard practice for mine and quarry expansion to remove as much doubt regarding the effect, or lack of effect, of blasting on the community as possible. By documenting the condition of a structure before it is exposed to transient ground vibration energy from blasting, a baseline of condition can be developed to aid both the property owner, as well as the mine operator, in determining cause and effect associated with blasting. HOW IS A PRE -BLAST SURVEY CONDUCTED? The pre -blast survey is a relatively simple process requiring no effort on behalf of the property owner other than providing access to his or her home for about one to two hours. The inspector will ask to be given access to both exterior and interior walls, floor and ceiling surfaces, looking for any observable cracks, separations, settlement or other feature that would be considered a change from standard building conditions. Most of the cracks found in residential structures are easily observed at window and door openings, wall junctions and ceiling tape joints. Whenever a crack is found, the inspector will document the location of the crack and its characteristics by taking a photograph or videotape of each observed area. In addition to the photograph, a written description of each crack will be made, providing the location of the crack, length/width features and any other observations deemed of interest. After reviewing all interior surfaces, a similar survey of the exterior of the structure will be performed, using the same simple technique of inspecting observable surfaces and documenting any change in condition with photographs and or videotape. In addition, basic information regarding the structure (age, additions, major repairs, etc.) will be requested similar to what is done for a home purchase inspection. At the conclusion of the survey, the inspector will create a written report containing all of the photographic documentation, as well as the written narrative identifying the location and characteristics of each photograph. A copy of this report will be provided to the property owner. For a typical 3,000 ft2 residential home, a complete survey can be completed in less than two hours. HOW MANY TIMES WILL MY PROPERTY BE SURVEYED? In most cases, a single survey is performed when it is projected that approaching blast operations will become perceptible to the property owner. Because of the impact of environmental forces on any structure over time, it is not appropriate to survey structures if prolonged periods of time will elapse prior to the commencement of blasting in the area. In operations such as Middletown, it would be expected that perception of blasting activities would occur when blasting operations are at a distance of approximately 3,000 feet from blasting operations. Given the phasing of mining activities at Middletown, this would mean that some existing and future structures might not require a pre -blast survey for many years. Sometimes arrangements are made with property owners to have all adjoining properties surveyed upon the receipt of the new mine permit as a means of providing everyone with a general baseline of structure condition at the commencement of general mining activities associated with the permit. An agreement is then made to allow for a second survey when blasting activities reach perceptible levels if a time period greater than six months has elapsed since the initial survey. As all blasting operations are monitored with approved seismic monitoring equipment, no additional surveys will be required. HOW DO I KNOW THE SURVEY IS IMPARTIAL? This is one of the cases where anything that is done with regard to the pre—blast survey that is substandard or incorrectly done will aid the property owner. The primary error that is made with regard to a survey is to miss an existing crack or condition that should be documented. Logic would indicate that this only works in the property owner's favor as, in essence, the structure contains pre-existing cracks that have not been documented, leaving the possibility that they may be claimed as blast related at a later date. I know of no manipulation of a pre -blast survey that can be done that would aid the mine operator in any way. The pre -blast survey is an effective tool in providing the property owner and the mine operator with a baseline reference for the condition of the community prior to blasting. While it needs to be stressed that continued exposure to environmental forces will, over time, show some change in the condition of any structure, the pre -blast survey is still an effective means of establishing guidelines prior to blasting activities. WELL GUARANTEE AGREEMENT Carmeuse Lime & Stone, its successors or assigns (hereinafter referred to as "MINE OWNER") guarantees to the undersigned Owner that it will replace or replenish the Owner's existing privately owned domestic -use water well(s) under the following circumstances: Any water well negatively impacted in such a way as to render it unsuitable for its existing use, on property within 1,500 feet of any parcels being actively quarried and dewatered by MINE OWNER located at its Middletown plant (hereinafter referred to as the MINE OWNER Facility) by depleting a well, lowering the water surface below the pump or negatively intercepting the groundwater flow to the well. If at some future date MINE OWNER expands the MINE OWNER Facility and the active mining operations into other adjoining properties not currently zoned for earth materials extraction, then this Well Guarantee Agreement will be automatically expanded to include all parcels within 1,500 feet from those areas. MINE OWNER will repair the problem by lowering the pump, deepening the well. drilling a replacement well. and/or installing an appropriate water quality treatment system at no cost to the Owner. The undersigned Owner, in accepting this guarantee. agrees to the following conditions: The Owner grants permission to MINE OWNER or its representative to inspect and evaluate the current condition of the well as part of a baseline water well inspection survey. The Owner grants permission to MINE OWNER or its representative to perform water level measurements of the well or collect water quality samples (in addition to the baseline water well inspection survey) on an as needed basis for the purpose of creating background data for the well, and to assess potential complaints. The Owner agrees to notify within twenty-four (24) hours of discovery of the reduction of water supply, depletion of the well or degradation in water quality so that MINE OWNER and a third - party hydrogeologist (as a Licensed Professional Geologist in the State of Virginia) can verify and/or document any occurrences noted during quarrying at the MINE OWNER Facility that may have contributed to the reduction of water supply or well depletion. The third -party hydrogeologist shall document the reduction of water supply, depletion of the well or degradation in water quality. Further, the hydrogeologist will make a determination as to the cause of the reduction of water supply, depletion of the well or degradation in water quality only for purposes of determining the appropriate repair or remediation. MINE OWNER shall be responsible for supplying temporary potable water for human consumption, and potentially. water hauling for other uses (as appropriate) until the problem is corrected. MINE OWNER shall be allowed by the Owner to evaluate the well and conduct such reasonable tests as it deems necessary to verify the cause of the reduction of water supply, depletion of the well or degradation in water quality. MINE OWNER agrees to bear all reasonable expenses that result from said reduction of water supply or well depletion; including, but not limited to temporary potable water supply for human consumption, household use, water hauling for other potential uses (as appropriate), well and pump modification, new well construction, and legal fees expended in implementing this Well Guarantee Agreement. The owner shall notify MINE OWNER prior to undertaking remedial activities or incurring expenses that later may be borne by MINE OWNER. Repair costs due to worn or defective pumps, electrical cabling, and piping are specifically a EXHIBIT W W J UJ 5A Q J J Q excluded from this guarantee. The terms of the Well Guarantee Agreement are binding during the active life of the said MINE OWNER Facility, including one year following cessation of mining activities. Upon the expiration of one year following completion of quarrying activities at the MINE OWNER Facility, this Well Guarantee Agreement shall be considered null and void. Owner: Date: MINE OWNER: Title: Date: Local homeowners within 1,500 feet of the property line of the proposed expansion will be invited to take part in a pre -expansion survey of their domestic water wells. Within days after rezoning is approved, each property owner within the 1,500 ft. radius of the proposed expansion will be sent an informational newsletter explaining the purpose of the Survey. A second letter, which will include a short scheduling form for owners to fill out and return to Carmeuse Lime & Stone, will be sent out within days after the newsletter, and a public information meeting will be held as a follow up. As the scheduling forms are received, the property owners will be contacted by Carmeuse personnel to coordinate a day and time that is convenient to conduct the survey. The Survey generally will consist of a short, in-person or phone, interview with the resident, property owner, or other knowledgeable party to gain information on the history of their well. The interview will followed by a physical inspection of the well. This includes obtaining the water level, pump setting depth and total depth. Existing driller's logs will also be examined. All sampling will be conducted in accordance with governing approved testing procedures for potable water wells. Field parameters measured at the time of collection include pH, Specific Conductance, Temperature, and Turbidity. The samples will be packed in ice and transported under chain -of -custody to a third party, accredited analytical laboratory for analysis. The samples will be analyzed at the laboratory for pertinent biological and chemical constituents. These include Total Coliform, Alkalinity, Chloride, Sulfate, Nitrate, Phosphorus, Potassium, Sodium, Magnesium, Calcium, Iron, and Manganese. Each well will also be tested to determine its Specific Capacity, which will be used as a baseline for well yield estimations at that particular location. Well water at each respective well will be purged at a measured flow rate (variable for each well) for a specific time interval (also variable for each well) using the existing pumping system currently in place. The water level in each well will be measured during the testing period. Typically the well will be purged at a flow rate of less than 5 to 10 gallons per minute for approximately 30 minutes or less. The Specific Capacity for each test will be calculated using the average pumping rate during the test divided by the water level drawdown incurred at the well during the test. Copies of the resulting reports will be provided to the property owner, as well as being maintained by Carmeuse and the designated third party performing the evaluation. a EXHIBIT W W a J J Q