2008-05-09_GENERAL DOCUMENTS - M1977285

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detection limits, following approval by the Division. The following parameters may be omitted altogether: D.O., Suspended Solids, Temperature, E. Coli, Total Residual Chlorine, Free Cyanide, Su]fide, and Asbestos. The link for Regulation 31 is: http~//www cdphe state co us/regulations/wgccregs/100231basicstandards1205and1207.pdf. 3) You should communicate with your lab regarding the detection limits required per the Tables referenced above. Please be aware that, unless otherwise instructed, some laboratories will routinely use EPA method 6010 ICP-AES (Inductively Coupled Plasma -Atomic Emission Spectrometry) for water analyses. In some cases, this laboratory method does not yield useful results because its detection limits are at concentrations at or above the relevant water quality regulatory criteria. Arsenic, Selenium, Thallium, and Uranium are some important examples. The important message here is that your lab should be instructed to use a method with detection limits at or below the regulatory standards (limits below the standards are better). The choice of which method to use is yours, but an example of one that appears to meet this requirement for the analytes of interest in hard rock mining is EPA method 6020 ICP-MS (Inductively Coupled Plasma -Mass Spectrometry). 4) This also applies to required leach tests or humidity cell tests. The rock preparation and extraction procedures for leach tests are usually well described in the method. For example, for SPLP (Synthetic Precipitation Leaching Procedure) it is ASTM method 6234-98, and EPA method 1312. This is important since the recommended method of water analysis is usually left open to the discretion of the person analyzing, and justifiably so because the analytical method used will depend on the analyte(s) of interest. Again, please refer to the standards and choose the water analysis method with appropriate detection limits for analyzing leach test extract, appropriate for the standards of the end use. 5) You should provide the details on the testing method proposed on page 5 under Environmental Pathway Analysis for evaluation of the soil geochemical adsorption potential. . 6) For any and all leach tests, such as the Meteoric Water Mobility Test (MWMT) and the soil geochemical adsorption potential, -the list of analytes should include all regulated parameters in Tables 1-4 in Reg 41 for ground water or Tables I-III in Reg 31 for surface water, at the appropriate detection limits. The omissions stated in (1) and (2) above apply for these analyses as well. 7) Also, since some of the parameters that are required to be analyzed have standards that are hardness- based, please instruct the lab to test for hardness in its analyses. 8) The test leachate should be checked for pH and electrical conductivity. Although not required for regulatory purposes, dissolved oxygen and oxidation-reduction potential might also be useful in later geochemical interpretations. This discussion has focused on rock testing, but to expand to field water sampling, if water samples from surface water or ground water will be collected, then the following parameters should be measured immediately in the field during sample collection: pH, electrical conductivity, dissolved oxygen, temperature, and (optional) oxidation-reduction potential. On pages 6 through 8 are the separate items that will be prepared and. submitted as part of the Environmental Protection Plan (EPP), Rule 6.4.20(1) through (19). Subpart 6.4.20(10), Surface Water Control. and Containment Facilities Information, does not appear on the list, though it is applicable and should be part of the EPP. This part would contain information concerning stormwater controls in particular. Please ensure that this and all other applicable parts of the EPP Rules are included.