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OURAY SILVER MINES <br /> fill the mixing, storage and day tanks to operate the mill. Chemical <br /> inventory will be staged at the warehouse in Ouray. However, as is <br /> discussed in response to comment 5.a below, OSMI may need to use the mill <br /> reagent room for temporary storage of chemicals. Day tanks are located in <br /> either the reagent room or in the mill tunnel. <br /> b. The comment section in Table I has been updated with correct volumes and <br /> the locations of tanks are noted in the comments column. Day tanks for most <br /> chemicals are located in the mill tunnel. <br /> c. The day tank is storing mixed chemicals that are used in the milling process. <br /> Day tanks are located in the back of the mill area and were not included in <br /> the secondary containment calculations. The mill tunnel is 288 feet long and <br /> is graded away from the portal at 1% creating 129,000 gallons of <br /> containment. <br /> d. Based on our discussion with DRMS on June 9, 2021, we understand the <br /> intent of DRMS's comment is concern with the capacity of secondary <br /> containment due to the space potentially occupied by dry chemical storage <br /> such as bags of lime or totes. To respond to this concern, OSMI has calculated <br /> the area of the dry chemicals stored in the secondary containment and used a <br /> volumetric conversion to convert to gallons. This conversion is provided in <br /> Table 5. As shown on drawing 700-GA-02 section 2, Lime, CuSO4, ZnSO4, <br /> and Sodium Metabisulfite are stored in totes on racks and do not occupy space <br /> in the secondary containment.Xanthate is the only dry chemical that is not on <br /> an elevated rack and will occupy space in the secondary containment. <br /> 3. In order to track the volume of reagent chemicals on site please commit to <br /> submitting a quarterly milling activity report. Said report would include the tons <br /> of ore processed, volume of chemicals used to process the ore and a balance sheet <br /> describing the chemicals shipped to the site, consumed during mining and <br /> containers that were disposed of. <br /> Response: The mine will be tracking information regarding reagent use as part of normal <br /> business activity and such information will be made available to DRMS during normal <br /> quarterly inspections. <br /> 4. The adequacy response provided to question #3 states that `'There are no known <br /> byproducts created from the combination of any of the 4 chemicals that are in the <br /> '`common area" of the reagent room. SDS sheets do not indicate that it is <br /> dangerous to mix these substances together." However MSDS Sheets lists the <br /> 3 Page <br />