Laserfiche WebLink
<br />I <br />l~ <br /> <br />!J <br />~ <br /> <br />I <br />I <br />I <br />l <br />I <br />L <br />!~ <br />> <br />, <br /> <br />I <br />l <br /> <br />~ <br />r;. <br />I' <br />, <br /> <br />tte <br />[ <br /> <br />4.3 Channel Conditions <br /> <br />As discussed in Section 4.1, the Ralston Creek valley at the mine site <br />has been altered to provide a working area for mine facilities and operations. <br />The fi 11 has been placed on the west side of the va 11 ey; the creek has been <br />channelized on the easterly side of the valley. An exception to this situation <br /> <br />occurs near the upstream end of the mine site where a storage yard and heliport <br /> <br />have been constructed in an indentation in the east slope of the canyon. <br /> <br />The channel through the site has slopes ranging from 1.2 percent upstream <br /> <br />of the Water Treatment Pl ant Site to over 3 percent near the guard shack at <br /> <br />the downstream end of the mine facilities. Channel top widths are generally <br />30 to 35 feet and depths range from three feet to six feet. <br /> <br />The channel bed is composed of gravel and cobbles with occasional <br /> <br />boulders. Many of the fragments are angular, indicating they may be from the <br /> <br />waste rock fi 11 used for the site. The 1 eft (east) bank of the channel is <br /> <br />composed of the natural rock outcropping with some brush. The right (west) <br />bank is composed of the fill material. <br /> <br />The fill consists of waste rock from the mining operation. It is com- <br /> <br />posed of gravel to cobble size fragments with lesser quantities of sand and <br /> <br />silt locally. There is also timber and other debris present in the fill. <br /> <br />The fill is in a loose to very loose condition. Underlying the fill is <br />alluvium of varying thickness and bedrock. <br /> <br />4-3 <br />