2015-04-06_REPORT - C1981022 - Laserfiche WebLink

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The information is collected in order to aid in analyzing 1) potential water depletions and 2) potential for injury to any Bear Creek water rights. Due to return of more seemingly "favorable" precipitation conditions in 2014, Bear Creek stream flows ceased during the usual mid June timeframe. A spike in 2011 total iron levels appeared tied to TSS and seemed "normal" in 2014. A spike in 2012 chloride level occurred for no apparent reason. Some 2009, 2010 and 2011 reduced levels of sodium, calcium, conductivity, TDS, and bicarbonate alkalinity appeared to remain at historic levels. The orthophosphate spike remains under the minimal 0.09 mg/1 level. Here the importance in the role of the scale of the Y axis seems to predominate. Analysis of the 2014 data, as well as subsidence monitoring and observations in the field, suggests no significant anomalies or any indication of adverse effects attributable to mining activities. E -1- Lower Elk Creek Surface water monitoring point E -1 - Lower Elk Creek, an ephemeral drainage, is monitored as a down gradient site to verify that the Elk Creek Mine and the surface facility located at Somerset does not have an adverse affect on the quality of runoff in the drainage. During spring snowmelt, elevated levels of TSS and Total Recovered Iron are routinely encountered, presumedly from natural upstream erosion in the unstable Elk Creek drainage, until streamflows subside. Naturally occurring slide blocks exist in the Elk Creek headwaters and no doubt contribute additional sediment loading. Of particular note is the possible lingering effects of pumping the two mine recovery boreholes #1 and #2 during 3 months in 2013. Elevated levels of TDS from naturally occurring alkalinity were noted in the E -1 sampling during 2013. The additional pumping flows extended the 2013 runoff period in Elk Creek. Elevated dissolved solids raised conductivity measurement during pumping, but quickly returned to "normal" after pumping was terminated on September 9, 2013. 2014 data indicate no lingering effects from the pumping. An analysis of the data suggests there is no adverse impact of the Elk Creek Mine to Lower Elk Creek. E -2- Ubner Elk Creek Surface water monitoring point E -2 - Upper Elk Creek, an ephemeral drainage, is monitored to verify that the Elk Creek mine does not have an adverse affect on the quality of runoff in the drainage. In addition, the site will serve as an up- gradient site to monitor Elk Creek prior to entering the OMLLC surface facility. See the above comments for site E -1 for the discussion on the dewater recovery boreholes. An elevated September 2014 chloride level appears to be an anomaly, as the down dip site does not show a similar chloride level. An analysis of the data suggests there is no adverse impact of the Elk Creek Mine to Upper the upper Elk Creek site or this segment of Lower Elk Creek in particular. S -1 — Upper Sanborn Creek and S -2 — Lower Sanborn Creek Surface water monitoring points S -1 - Upper Sanborn Creek and S -2 — Lower Sanborn Creek were established to monitor the flow in ephemeral Sanborn Creek above and below the disturbed area of the Sanborn Creek Mine site. Historically, Sanborn Creek also received mine water