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<br />' ~S ~ <br />i~i <br /> <br /> <br />1 <br /> <br /> <br />1 <br />1 <br />1 <br /> <br />1 <br /> <br />1 <br />LJ <br />1 <br />1 <br />1 <br />Southwestern PoNaad Cement <br />Mining Impacts on Montgomery School <br />SHB AGRA Project E93-7038 <br />Page 7 <br />ground). The baseline survey will be followed by a blast monitoring program that includes <br />ground vibration and air overpressure recording at the school or an alternative location between <br />the school building and the blast location. Compliance with the 0.25 in/sec peak ground vibration <br />is to be met at the monitoring location. <br />Annual site assessments of the school's structural fabric will be made, including extensive <br />photography from the same datum points as the baseline photos for comparison. This will be <br />done to determine if secondary impacts are developing. If impacts result from blasting, <br />Southdown will consult with the SHPO and Boulder County to establish the parameters of a <br />mitigation program for the Montgomery School that preserves, to the fullest extent possible, the <br />architectural fabric and character of the building. The program for monitoring and protection <br />of the Montgomery School will be incorporated specifically into the Cultural Resources <br />Management Plan for Dowe Flats and by reference into the contemplated programmatic <br />agreement between Southdown, Boulder County and the Colorado SHPO that will govern the <br />mine project's cultural resources program. <br />Historic masonry is vulnerable to a number of types of deterioration. Deterioration results from <br />trapped moisture, salts and climatic cycles with variants between freezing and thawing, <br />pollutants, cleaning agents, poor repair, incompatible mortar use in repointing, weathering and <br />vibrations, amongst other factors. In addition the composition of the stone including a "natural <br />inconsistency and layered composition" can also accelerate deterioration. A body of literature <br />(Levine, 1991; Mack, 1984; Powers, 1988; Sabnia, 1985; Smith, 1984 and U.S. Congress, <br />1986) has arisen from experts working with preserving historic masonry. These studies all <br />indicate that if proper care is taken, historic masonry buildings can easily and effectively be <br />preserved. Many documented problems occur from poor preservation and stabilization, often <br />posing a greater threat than the impact agents the conservationists are trying to combat. For <br />example, if cracks appear in the mortar joints of the Montgomery School, mortar testing and <br />analysis will be done before any repointing is started to assure material compatibility. This will <br />avoid one of the most common problems in masonry stabilization. Testing, monitoring and <br />conservation measures to be implemented, are detailed in the Cultural Resource Management <br />Plan (CRMP). <br />SHB AGRA and WHS feel that if apre-construction/pre-blast analysis of the school, including <br />structural review and extensive photo-documentation, is done and Southdown, depending on the <br />results of that survey, adopts vibration standards as proposed herein and carries out a monitoring <br />program for the structure as currently contemplated, then the plan for the school and its <br />protection from undue degradation caused by mining will be adequate based on currently <br />available information. <br />' , AG RA <br />Earth & Environmental Group <br />