2011-09-16_HYDROLOGY - M1981185 - Laserfiche WebLink

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In regard to whether the Idaho #1 Mine Portal is mine drainage: Based on available information, the water coming out of the portal is not a natural spring or seep, but flows out of a historic (collapsed) mine portal, and therefore the drainage is associated with a man -made disturbance (mine portal). In a 1993 EPA letter (often referred to as the Dotson Letter or the Fraser Memo), the EPA clearly outlines its stance regarding hard rock mines, point sources, historic drainage and NPDES permits. The following are exerpts from that letter: 1. Point Sources at Hard Rock Mines a. Historic Adits "Mine adits are clearly point sources as defined under Section 502(14) of the CWA....defines the term "point source" as any discernable confined and discrete conveyance including but not limited to any pipe, ditch channel, tunnel, conduit... from which pollutants are or may be discharged....Following this definition, discharges from mine adits at historic or active mines are point sources and are required to have an NPDES permit if pollutants are being discharged to waters of the United States." b. Groundwater Hydrologically Connected to Surface Water "..mines had seeps or other groundwater discharges to surface water which were not authorized in the facility's NPDES permit. There were also some mines without an NPDES permit which had claimed to be "non- discharging "....were found to be discharging through seeps and water control structures....are now being required to obtain NPDES permits...It is therefore EPA's position that seeps and other groundwater discharges hydrologically connected to surface water from mines, either active or inactive, are discharges from point sources and are subject to regulation through an NPDES permit." 2. Historic Mining "Clearly as discussed in 1.a above, discharges from abandoned mine adits are point sources which require a traditional (rather than a stormwater) NPDES permit...EPA's current permit writing practices and priorities incorporate historic mine drainage into NPDES permits for active mines if the active mine influences the pollution discharged from the historic area. In addition, if the active mine owns or has control over an adjacent historic mining area, the active mine must also apply for an NPDES permit to control the discharge from the inactive area." 3. Stormwater vs. Traditional NPDES "It is our position that any point source discharge of pollutants not directly associated with a precipitation or snow melt event, (i.e. dry weather flows), must be permitted under a traditional NPDES permit. This means any dry weather flow from mine adits, seeps, french drains and culverts are mine drainage or process water and cannot be covered by a stormwater permit....Also during wet weather flows, most of the areas at an active mine must be covered by traditional NPDES requirements because stormwater was included in the developing the effluent guidelines regulations." Because the water in question flows out of a mine portal, the discharge is associated with a mining activity. As clearly shown in the above statements, this water must be covered under a process water (individual, non - stormwater) permit as it: 1) is a point source; 2) is included regardless of whether it is drainage from an adit or is a seep /spring; and 3) although it is a historic discharge it is included in an area where active mining is being planned and such mining may influence the discharge or is in an adjacent area for which the permittee owns or has control over. Additionally, the Division of Reclamation Mining and Safety (DRMS), at this time, is considering the water to be mine drainage. Based on communication with DRMS, the water has been characterized as mine drainage in numerous documents including: 1) DRMS 3 1T1 adequacy letter for AM -01 to Idaho Mill, M- 2006 -069, June 8, 2009, page 1, item 2; 2) DRMS 5 adequacy letter for AM -01 to Idaho Mill, M- 2006 -069, August 11, 2009, page 4, item 7;