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western flank of Taylor Basin surface drainage is impacted by FS 228 road - • . <br />cuts and other former mine working road cuts that traverse the hillside - <br />above and north of the presently disturbed mine zone. The mining area <br />itself intersects the direct flow path of surface water and diverts all <br />overland flow into the main pit azea. Drainage patterns maintained on the <br />lower process azealstaging area insure that all water flowing onto the <br />lower staging area find its way to the lower pit area. Upland diversion <br />ditches installed as planned will divert overland flow south to the southern <br />end of the site prior to diversion to the lower pit or for direct release to <br />Taylor Gulch. The operator prefers diversion to the lower pit for <br />maximum sediment control and water volume release control. In addition <br />to the limitation of overland storm flow acreage on the west flank of <br />Taylor Basin, reconnaissance of the slopes along the eastern flank of ` <br />Taylor Basin resulted in the notation of a number of bulldozer cuts that <br />have been made in the past (prior to mining regulation and most probably <br />related to former annual assessment work) intersect the downhill flow path <br />and divert surface flows towards historic mine workings, talus slopes and <br />related access roads: Please note the number of x's shown on the east <br />flank of Taylor Basin, locating historic mine workings, most associated <br />with road cuts and diversions of surface flow to rock talus slopes. These <br />man made diversions in conjunction with lazge azeas of course talus slopes <br />will substantially reduce overland flow potentials as delivered to Taylor <br />Gulch. Watershed Map Gb will be marked to reflect the extent of affected <br />water~sfled areas within the 390 acre potential watershed flow path. <br />b. Storm projections aze given for Taylor Gulch, not including in-mine <br />drainage. Taylor Gulch isolated from the mining area will be impacted by <br />overland flow delivered from the northern end of Taylor Basin and the <br />eastern flank of Taylor Basin. In mine storm flows will be impacted by <br />overland flows delivered from the western flank of Taylor Basin not <br />intercepted by upland diversions or highwall configuration and tbe <br />disturbed acreage within the mining zone. <br />c. The operator will defer to the Division's projected maximum storm event <br />for design of channel and rip-rap sizing. Channel depth of six feet, six feet <br />wide at bottom and 20' wide at top will be proposed. Rip-rap armoring of <br />no less than 12" and up to 30" will be proposed. Colorado Marble is <br />requesting Division review and comment on final rip-rap and channel <br />design criteria and is requesting Forest Service input for purposes of <br />design review. <br />d. Rip-rap armoring is proposed to be increased to no less than 12" and up to <br />30" in diameter. <br />e. Waste rock berms will built along the western edge of Taylor Gulch to <br />insure separation of drainages. The berms will be constructed to maintain <br />sepazation during maximum storm event and will be proposed to be eight <br />feet higher than Taylor channel bottom, with a flattened top of no less than <br />six feet wide. <br />