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' an old air shaft which was constructed of s large diameter, 8' to <br />9', corrugated metal pipe, CMP, bedded in pea gravel. Mine water <br />had seeped up through the old air shaft and partially filled the <br />CMP. The extensive pea gravel bedding allowed the mine water a <br />free flow path to the creek. The CMP wsa removed along with most <br />of its pea gravel bedding. It was fairly obvious that the source <br />of the seeps had been the old air shaft and CMP. <br />Further investigation around the area failed to find additional <br />seeps which might flow into North Thompson Creek. A perforated <br />pipe and gravel packed french drain system was installed across <br />the front of the portal area to collect the drainage from the <br />area. The french drain system, although free flowing, allows <br />water to pond in the old air shaft at the elevation of the invert <br />of the pipe leading to the ponds. Because of this, there wsa a <br />chance some seepage would find its way from the french drain <br />directly to the creek. In order to assure that all of the <br />seepage was collected in the french drain system, a bentonite <br />filled trench was constructed between the french drain and the <br />creek. <br />In order to provide for long term access to the portal area a <br />bridge was installed across North Thompson Creek and the oulvert <br />installed previously wsa removed. The bridge is an old railroad <br />flat car which is long enough to span the creek and strong enough <br />"• 4-66d (New 6-20-88) <br />