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l,.2 CO17CLl'SIC':S wID R~'~1:_~?~D;:TIOt:S <br />Y.ith the co2pletion of this report nearly two years of data have been collected <br />• and anal}•zed. The follo~ning general conclusions have been reached. <br />1) Drainage frog the mire and Stevens Gulch: <br />Drainage from tre mine area can occur during heavy rains or snotirmelt. <br />Past evidence indicates levels of scTe parameters, including total iron, <br />manganese, suspended solids and other parameters discussed in the first <br />semi-annual report, could exceed state and federz? standards within a <br />mixing zone of the North Fork. Runoff from the Gulch abo•re the Q.ine- <br />i*ifluenced area also has the potential for exceeding state and federal <br />standards, as shown by past data. <br />Four sedimentation daTS being constructed in }iestmoreland Canyon are <br />designed to contain runoff Sro:c all storm events of 10 year-2L hour <br />magnitude. (Tt is not clear whether these days ral. contain runoff from <br />~~• heavy accum•.:iated snow malts.) Dissolved an.: suspended materials that <br />aSfect water ovallty and may result in state or federal standards being <br />violated can be expected to be retained in the sedimentation ponds <br />except when their carrying capacity is exceeded. <br />2) The North Fork: <br />Data from the past two years show that existing OSM standards for iron <br />can be exceeded in water originating upstream of ary mine or ccal loadout <br />area related to the Orchard valley mine. Similarly, levels oS aluminum <br />higher than proposed state standards have been shown to originate upstream <br />of tkie l7orth Fork control area. There is no e~-idence to suggest that arty <br />runoff from materials at the coal lcadout area would exceed the propcsed <br />state standard except for mercury. Higher 1e~21s of rercury originating <br />• somewhere between the control station and the next staticn dowrstrean <br />have been observed in past studies. <br />4- 2 <br />