Laserfiche WebLink
Coal Basin Tract <br /> August 18, 1996 <br /> mally flows about 1 cubic foot per <br /> second (cfs) , but remnants of precast <br /> concrete pipe (24"D x 41L) can be found <br /> over 500 feet downstream around a curve <br /> from the road crossing. <br /> 2) - The twin porals are located in the <br /> NW/4 of Section 15, T. 10S. , R.89W. , 6th <br /> PM. The concern is the eventual clog- <br /> ging and stoppage of water from the <br /> newly installed plastic pipe. Plan and <br /> cross-section views of the proposed <br /> remedial action are shown in Figure 4 . <br /> A 48 inch diameter plastic pipe has <br /> been set on pea-sized gravel in each <br /> portal and will be grouted into a cin- <br /> der block wall. A 2: 1 soil embankment <br /> covering the pipe and portal entrance A A' <br /> will be revegetated. The two pipes <br /> will be joined into one at a point <br /> about 50 feet from the embankment. A <br /> settling pond will be constructed at fro. Ritter, 1276 <br /> the end of the pipe. The 48 inch dia- <br /> meter will allow entrance to check for FIGURE 3 A bend in the <br /> any blockage from sediment and rock. creek with helical flow <br /> Two bulkheads were established by Mid- similar to the situation <br /> Continent prior to abandoning their at the base of the scarp <br /> mining activity in Coal Basin. The face. <br /> water level behind the southern portal <br /> is about 4 feet and the wall is damp. <br /> The northern portal is oozing water liberally and the water level <br /> is about 5 feet high. <br /> 3) - There are several established roads which were used during the <br /> mining phase. Numerous additional trails were created during <br /> exploration which are still usable by ATVs. The roadway <br /> alignments have many steep embankments due to the location of the <br /> coal seams and the topography. Seeps and avalanche chutes are <br /> present at the higher elevations. The potential for more <br /> subsurface water flow and yearly avalanches is high. <br /> CONCLUSIONS <br /> 1) - There will always be the possibility that some undetermined <br /> volume of material will slide into Dutch Creek. The chance of this <br /> happening because debris flows in this drainage is probably slight <br /> because of the low frequency of severe debris flows. The chance of <br /> 5 <br />