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Zinc sorbs strongly onto soil particulates. Little water - soluble and exchangeable heavy metals were <br />found in soil irrigated with raw waste water (Schalscha et al. 1982). Although considerable amounts of <br />metals were added to the soil in soluble and exchangeable forms during waste -water irrigation, they were <br />converted into the less chemically active forms (i.e., organically bonded and inorganic precipitates). <br />Further examination showed that zinc accumulation in soil resulting from waste disposal occurred <br />primarily as inorganic precipitates. <br />Zinc is an active reducing agent for many metal ions such as iron (Fe +3) and <br />permanganate (Mn04 ions (Stokinger 1981). As a result of the reducing reactions, the manganese <br />oxides and ferric salts may precipitate and, in the process, may entrap soluble zinc in the precipitate, <br />thereby reducing the zinc concentration in the water phase. <br />1.2 Methods of lowering zinc in the mine discharge: <br />None of the data available shows exactly why the zinc levels are dropping in both the mine water <br />channel and in Sneffels Creek, but it shows that the zinc levels do drop over time and distance. <br />Because of this, Star Mine Operations believes that the best methods for reducing the presence of <br />zinc in the mine water discharged from the tunnel are: a) encourage precipitation of zinc in the <br />Revenue Tunnel mine ditch, b) storage and dilution of mine water in a pond, and c) source control <br />underground by sealing off poor water quality contributions. <br />a) It is believed from the zinc solubility chemistry that the 3700 feet length from the Atlas drift <br />to the Revenue Mine portal can be enhanced with organic material, magnesium rich rocks <br />and other material which will encourage zinc precipitation. Much is already occurring, but <br />SMO can probably improve it by taking these steps. <br />b) It is believed that the residence time within the current pond provides some benefit to the <br />mine water. Zinc is the dissolved metal of most concern at Revenue. Sampling of water <br />before the pond (UG -2) and at the Seep (SW -3) below the pond shows a decrease in zinc <br />values. It is believed that the Seep is the discharge from the pond since they are <br />approximately the same flow rates and no other discharge is visible from the pond. Since <br />this pond will be removed as part of the construction of the Revenue waste pile, a new <br />settling pond will be constructed just east of Sediment Pond 2. The mine water will be piped <br />Revenue Mine August 2012 T - <br />