2014-02-24_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 2013, 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 2013. 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 return to "normal." Analysis of the 2013 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 drainage, until streamflows subside. Naturally occurring slideblocks exist in the Elk Creek headwaters and no doubt contribute additional sediment loading. Of particular note is the effect of the mine recovery boreholes. Mine recovery dewater borehole #1 intitiated pumping on June 3, 2013 @ —500 gpm. The second dewater borehole #2 was installed and pumping began on July 3, @ -400 gpm. Borehole #1 contined @400 gpm. Elevated levels of TDS from naturally occurring alkalinity were noted in the E -1 sampling. The additional pumping flows extended the 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, 2014. The 2011 elevated TR Iron seemed to be tied to elevated TSS and appeared to return to "normal" in 2012 and 2013.An analysis of the data suggests there is no adverse impact of the Elk Creek Mine to Lower Elk Creek. E -2- Upper 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 2012 chloride level appeared to be an anomally, and returned to "normal" in 2013. An analysis of the limited 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