Sustainable Land Development Today - July/August 2008 - (Page 33) I Specific nature of the subsidence ground movement and the foundation loading; I Structural response of the foundation; I Structural and architectural response of the structure(s). The greater the integration and understanding of these factors along with ingenuity, the more efficient and the less conservative the design rendered. For example, where the potential subsidence was determined to be limited, mine grouting would be necessary and a subsidence-resistant design of the foundation and superstructure could be cost-effective. Also, where the project site is fairly large, and there is some flexibility in the location of surface structures, a surface risk map can be prepared. Using this map, structures can be more strategically placed. This can significantly reduce the cost of development by reducing the subsidence mitigation needed. In approaching the potential damage from subsidence at the site one can: I Ignore the possibility of mine subsidence; I Implement subsidence resistant measures at the ground surface; I Employ mine stabilization measures with or without making the structure itself more subsidence resistant. Obviously, the more pro-active the approach one takes against subsidence the lower the risk but the greater the cost. Ignoring the possibility of subsidence can subject the proposed structures to a range of potential damage from minor to very severe intensities depending upon the project site. Taking cost-effective, surface-resistant measures can significantly reduce the level of damage under certain circumstances especially if the exposure to subsidence movements is mild. If, however, the structure is exposed to a significant subsidence event, major damage can result despite taking some surface mitigation measures. Although more costly, mine stabilization measures will significantly reduce to virtually eliminate the subsidence potential and the risk of subsidence depending upon what methodology is used. Certain mine stabilization measures in combination with surface abatement can provide even more protection against subsidence. In closing, developers are confronted with an uncommon risk assessment when contemplating building above an underground mine. This situation can be problematic and can alone result in whether the project is viable or not. In other words, the advice obtained from a mining consultant can make a considerable difference in development potential. SLDT About the author: Dr. Gennaro G. Marino, P.E. has been working in the field of coal mine stability and subsidence for 30 years. He has authored over 70 technical publications on the subject. Dr. Marino can be reached at gmarino@meacorporation.com or 217-3842288. For more information about MEA visit http://meacorporation.com/. Innovative Stormwater Management Products Up-Flo™ Filter, developed by Hydro International, is a high-rate media filtration system capable of targeting a wide range of pollutant types. Up-Flo™ Filter offers distinct advantages in solving today's stormwater management issues. • • • • Reduced purchase and installation costs Smaller structure for reduced footprint Standard manhole or retrofit applications All-in-one treatment train capability Perk Filters can be installed in existing drop inlets, installed as a catch basin system at individual inlets or as a centralized modular treatment system installed on-line or off-line. • Modular, scalable design • Addresses wide array of pollutants • Highly effective media filter performance • Easy, low cost installation and maintenance Evolving Stormwater Management Solutions Enhanced Gravity Separation in a Compact Configuration Our separator offers an innovative and economic alternative for BMP implementation in new and retrofit applications where land area necessitates compact, effective treatment for removal of suspended pollutants from stormwater runoff. • Fits industry-standard manholes or vaults • Economical installation • Ease of maintenance • Vector control Contact us today to learn more about these exciting systems for complete stormwater management. Call 1-800-579-8819 Visit our web site at: www.kristar.com S i n c e 19 9 3 Circle 136 • or www.SLDTonline.com/webcard www.SLDTonline.com 33 http://meacorporation.com/ http://www.kristar.com http://www.kristar.com http://www.SLDTonline.com/webcard http://www.SLDTonline.com
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