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.~ <br /> <br /> <br /> <br />RECOMMENDATIONS: <br />1. Because the Incas Mine is a designated mining operation due to processing by <br />cyanidation, groundwater monitoring is recommended. The adit discharge could <br />serve as the monitoring point, and the surface stream serve as the compliance point. <br />Because mining is not conducted six months of the year, the mine should be <br />monitored for a set of indicator parameters at least twice yearly while in operation. <br />Provided any of the indicator parameters (see following) exceeds drinking water <br />standards for any reporting period, follow-up samples should be collected and <br />analyzed immediately. If any ofthe follow-up monitoring sample values exceeds <br />standards, then the operator should furnish to the division within 30 days an <br />explanation of the upset and a plan for compliance to be reviewed and approved by <br />the Division. Coincidentally, the monitoring list should be extended to all regulated <br />parameters, and sampling should begin at the compliance point. <br />Based on site conditions, cyanide use, a simple geological assessment, and review of <br />the water quality data, it is suggested that the first parameters that might appear from <br />a discharge would be cyanide and/or acid mine drainage. For these reasons, it is <br />recommended that the parameters to be monitored include: <br />pH (field and lab) <br />conductivity (report only) <br />SOa <br />CNw,~ <br />Total Dissolved Solids <br />The operator should have a chance to review and comment on this recommended list. <br />3. It is recommended that the Operator furnish a narrative explanation of the low pH of <br />surface water measured in October 1998. <br />4. It is recommended that at least one sample be collected at low flow, either preceding <br />or after the autumn rainy season. <br />5. Numeric protection levels should be established at the drinking water standards <br />values for all parameters. TDS should not exceed USDW values. <br />Please contact me if you have questions or need clarifications. <br />cc: Tom Gillis <br />Bruce Humphries <br />