2014-06-16_HYDROLOGY - P2013002 - Laserfiche WebLink

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Ms. Angela Bellantoni June 9, 2014 Page 3 • Any drainage from the mine area will flow down gradient to the Dawson monitoring points, where the drainage water will be detected at either one of the Dawson ground or surface water monitoring points. • Because there are no wells in the topographical vicinity of the actual mine excavation, it is not necessary to monitor ground water conditions in and topographically adjacent to the mine itself. • There are other mine workings in the area. The locations of the ground water monitoring points should detect the influences of the existing mine workings that drain to the monitoring points during the baseline monitoring period, such that changes resulting from the Zephyr mine can be determined independently from existing mine workings. • There is complex structural geology including major geologic faults in the vicinity of the proposed monitoring points. We do not believe that the geologic faults will impact the function of the monitoring points, because the targeted well depths are shallow and will intercept ground water and surface water draining from the mine site despite geologic structure in the drainages. There is no evidence that the faults at this location function as conduits to ground water flow. • Available borehole data indicate that there is no ground water present at the mine location. Therefore, any ground water monitoring down gradient of the mine will simply provide baseline data that can be used to detect impacts from mine surface activities and any mine drainage should it occur. • We understand that ground water monitoring is not required because the mine will not intercept ground water. Nevertheless, we have recommended one ground water monitoring point for the purposes of establishing baseline data at the Dawson location. Sqrface Water MonitoringPoints • Locations are geographically close to the mine excavation areas and intended to capture surface drainage from the mine sites. • Proposed surface water monitoring points will generally be dry, but they are strategically located to capture any surface water runoff or mine drainage that may result from the mine. • Monitoring locations will effectively monitor and detect any surface water influences that may impact downstream locations. • There are other mine workings in the area. The locations of the surface water monitoring points should detect the influences of the existing mine working during the baseline monitoring period, such that changes resulting from the Zephyr mine can be determined independently from existing mine workings. Proposed Monitoring Point Locations Based on our field observations, land use considerations, and the hydrological and geological research completed, we propose that three surface water monitoring points and one ground water monitoring point are implemented. The proposed locations are presented on Figure 2 and Table 1. We believe that the locations should be accessible for monitoring and construction (drilling) purposes, and suggest that Zephyr confirm whether or not these points are located on property owned by or accessible to Zephyr. We understand that the ground water monitoring point is not required because the mine will not intercept ground water. Nevertheless, we have recommended the ground water monitoring point to provide baseline ambient ground water data which may detect impacts at the Dawson site, where impacts to ground water have potential to occur as a result of mining activities. Two surface water monitoring points at the Dawson pad site are proposed, one intended to intercept drainage directly occurring from the mine and pad area, and another intended to intercept surface water draining from adjacent lands, some of which have active mine workings and tailings.