Laserfiche WebLink
<br />5.0 SURFACE WATER MIGRATION PATHWAY <br />The Rito Seco River flows through the Battle Mountain Gold San Luis Project permit area. <br />Overland flow coming into contact with the reclaimed historic heap leach pad and the <br />current mine pits and waste rock areas enters the Rito Seco River. Aqueous and <br />sediment samples were collected from the Rito Seco River at locations upstream and <br />downstream of site operations. Sediment sample BM-SE-06/MHBS45 was collected from <br />the unnamed drainage pathway downstream of the milt/tailings facility (Fgure 3). <br />Release Data <br />Surface water samples collected from the Rito Seco River indicate elevated levels of <br />aluminum, iron and manganese at locations downgradient of mining operations. The <br />aluminum concentration detected in Rito Seco water at station BM-SW-03/MHCR73 is <br />greater than three times the concentration detected in sample BM-SW-01/MHCR71 <br />collected from upstream of site operations. tt is anomalous that sample BM-SW- <br />02/MHCR72 collected upstream of sample BM-SW-03/MHCR73 and downstream of site <br />operations did not contain aluminum at a concenrtration greater than three times the <br />adjusted background value (fable 1). Manganese and iron were also detected at <br />concentrations exceeding three times background concentrations in RRo Seco surface <br />water at locations downgradient of site operations. The iron concentration reported for <br />sample BM-SW-03, 1,090 micrograms per liter (pg/L), exceeds the freshwater Aquatic <br />Water Quality Criteria (AWQC f AALAC) of 1,000 pg/L for iron (SCDM, 1994). <br />Sediment samples collected from the RRo Seco and the unnamed drainage downgradient <br />of the mill-tailings facility did not contain elevated metals concentrations. <br />Cyanide was not detected in any of the aqueous or sediment samples collected during <br />this S1. Previous detections of cyanide and mercury in Rito Seca River water <br />downgradient of site operations, as discussed in the SAP (MK, 1995), were not <br />reproduced with analysis of SI samples. <br />T~raets <br />The RRo Seco River bed contains a variety of wetland types downstream of the Battle <br />Mountain Gold operating permit boundary. Seasonally flooded, palustrine scrub-shrub <br />type wetlands occur along the RRo Seco within and beyond the permit boundary (USDI, <br />1992)(Fgure 1). Recent beaver dam construction was noted along the Rito Seco channel <br />a~ao~aeaal~mraomvx - 6 - M.. 4 or/ro/oel <br />ti <br />