SUBSURFACE LANDFILL FIRE SUPPRESSION AND MONITORING
                        A Case Study at the Campbell Mountain Landfill, Penticton, British Columbia

Phase 1 Construction.
As mentioned previously, Phase 1 consisted of the installation of an impervious clay cap over the landfill crest in conjunction with shotcrete seals along the fractured bedrock found at the edges of the ravine. Phase 1 was constructed by Kedon Waste Services Ltd. of Penticton, with shotcrete work being subcontracted to Silver Springs Ventures Ltd. of Kelowna, B.C. Phase 1 was completed in May 1998.

In order to achieve a shotcrete seal that would be effective in preventing air from entering the North Ravine through the fractured bedrock, a shotcrete seal was applied over a three metre width; the bottom of the seal was one metre below the existing ground level elevation while the top was one metre above the final clay cap elevation. The first step was therefore to excavate a one metre deep by two metre wide trench along the edges of the ravine to gain access to the entire area of coverage.

The bedrock was thoroughly cleaned using a high pressure air gun and or water gun prior to the shotcrete being installed. The shotcrete itself consisted of Type 50 cement, water, fine aggregate, a quick curing admix and fibre reinforcing.

After the shotcrete was given sufficient time to cure, the excavated areas were backfilled using local till, and then the clay was installed. Once the clay cap was in place, protective 15.2 cm square steel monuments with lockable lids were installed over each of the monitoring wells and the Thermistor strings were permanently installed in the appropriate wells.

Because a membrane cap was being contemplated directly over the clay cap, if the clay did not achieve the desired seal (Phase 2), the original plan was to hold off on applying the final biosolids cover. By mid summer however, desiccation of the clay cap was noted due to the extremely hot temperatures encountered during the summer f 1998, and it was recommended that the final cover be installed more as an insulation barrier than a vegetative cover.

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