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CONCLUSIONS <br /> The monitoring results show that methane concentrations exceed 5%in several probes <br /> this quarter. For the most part, the probes exceeding 5%methane are along the north half <br /> of the landfill. The moisture from this winter has revealed that there are water blockages <br /> in the header pipes of the gas extraction system. The accumulation of water is due to <br /> some settlement of perimeter slopes and subsequent sagging of header pipes. These <br /> blockages have effectively cut off pressure to the north half of the landfill. This is <br /> a logical explanation for the increased levels and positive pressures in probes on the <br /> north half of the site. Currently, the County is investigating all problems and making <br /> necessary repairs. The probes are monitored in accordance with Waste Board protocol <br /> of purging one probe volume prior to taking a reading. The County has calculated the <br /> volume of gas that constitutes a probe volume for each probe. A time has been calculated <br /> for each probe using the manufacturers' pump rate information for the GEM 500. Once <br /> the time has been reached indicating that one probe volume has been purged, a reading is <br /> taken if the levels are constant. If the levels are changing at the end of the purge, a <br /> reading is not taken until the levels have stabilized. <br /> Monitoring will continue with the next monitoring event in April 1999. Further <br /> monitoring will help determine if the results from this quarter are anomalous due to <br /> needed repairs and perimeter gas concentrations are under control, or if the higher <br /> concentrations will continue. <br /> S:\WES\HL\GAS\lSTQU99G.wpd <br /> 4 <br />