2016-05-04_REVISION - M1977300 - Laserfiche WebLink

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and mine waste dumps have been further identified in the area. Surface geologic mapping, supported by an evaluation of aerial photographs available for the site, was performed so that individual geotechnical units could be delineated and characterized for the purpose of this study. The geotechnical mapping performed within this study was also used to provide data on the general stability of the area. The results of geotechnical mapping are shown on Plate 2, Geo- technical Map. In this map, the area of interest was divided into several geotechnical units that are important for the scope of work. Following is a brief description of these geotechnical units: Man-made fills cover a considerable area on the southern part of the property where most of the mine surface facilities are located. They appear to be spread over most of the alluvial valley of Ralston Creek; minor fills have been constructed along the road on the northern end of the property. Fills consist predominantly of cobbles and gravels. Waste piles are located in the northern part of the property, on both sides of Ralston Creek. For the purpose of this report, they are called East and West piles. Alluvial sediments of Ralston Creek occur along the creek within the entire area covered by this study. The width of alluvial deoosits is limited on the northern end of the property and increases toward the south. The maximum width of the alluvial sediments is ap- parently at the location of the mine and other surface facilities, although the alluvium is obstructed by the cover of the man-made fills. Alluvial sediments are also covered by both waste piles; an attempt was made to indicate the original alluvial boundaries on the geotechni- cal map. The alluvial deposits consist predominantly of cobbles and gravels with some sand. The color of the sediments is medium brown. Alluvial soils are frequently well-sorted , forming lenses of similar - 7 -