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Mined Land Reclamation Golden Eagle Mine TR-18 June 9, 1992 Page 2 Nalco 7885 Tovi i v ~ inC Enclosed is an updated MSDS sheet for Nalco Enact 9885. Please refer to section 12 Environments) Information. Based on biotesting, Nalco 7885 has a toxicity rating of from EssentislIy non-toxic to slightl}• toxic. This is based on 96 hour static acute test on Rainboca trout snd Sheepshesd minnows, snd 96 hour static acute of Mpsid shrimp and 18 hour static acute with Daphnis magna respectively. Operstion~ Plan Nalco Enact 7883 will be sdded according to the approved plan. Nalco Enact 7885 coil be added to the mine water after the 7883 snd just prior to entering pond 003. Both chemical pumps will be connected to flow monitoring devices to stop chemicsl injection st times of no floc. in the system. Initially the injection rate of 7883 will be reduced to approximately 40Y of the single chemicsl injection rate. Likewise the minimum amount, of 7885 will be injected. These rates tail) be adjusted in response to laboratory determined TSS concentrations to provide s discharge meeting the NPDES requirements. Since the mine pumping system is designed to deliver a constant floc, chile the system is in operation, no flow rate monitoring equipment will be necessary. The system will be monitored continuously during start-up snd daily there after until results of biomonitoring tests have been received. The pond discharge will be sampled weekly as required by the NPDES permit for TSS, total iron, and dissolved aluminum. In addition the pond will be sampled caithin 21-36 hours after initiation of discharge and within 24-36 hours after any increase in the injection rate of Nalco 7885. As indicated on the MSDS ssheets no toxicity is anticipated as s result of using Nalco 7885. However, the next cycle of biomonitoring (wet testing), as required by our NPDES permit, will be commenced within 3-5 days after starting the dual chemical treatment. This period was chosen to allow the sdded chemicals in the discharge to reach a static equilibruim concentration.