EAGLE MINE ANNUAL REPORT – 2016 EAGLE …...Eagle Mine Annual Report – 2016 April 14, 2017-ii- \\DHINRICHS-990\Projects \CBS Eagle \Annual Rpts \Annual Rpt 2016\ 2016AnnualReport.docx

$Page 1: EAGLE MINE ANNUAL REPORT – 2016 EAGLE …...Eagle Mine Annual Report – 2016 April 14, 2017-ii- \\DHINRICHS-990\Projects \CBS Eagle \Annual Rpts \Annual Rpt 2016\ 2016AnnualReport.docx$
EAGLE MINE ANNUAL REPORT – 2016 EAGLE MINE SITE MINTURN, COLORADO Prepared for: CBS Operations Inc. April 14, 2017 9400 Station Street, Suite 300 Lone Tree, Colorado 80124

Eagle Mine Annual Report – 2016 April 14, 2017

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TABLE OF CONTENTS Page

1.0 INTRODUCTION ................................................................................................ 1-1

2.0 SURFACE WATER MONITORING AND DATA SUMMARY ............................ 2-1 2.1 Monitoring Stations ................................................................................. 2-1 2.2 Hydrology ............................................................................................... 2-2

2.2.1 Eagle River ................................................................................. 2-3 2.2.2 Tributaries ................................................................................... 2-4

2.3 Water Quality Trends .............................................................................. 2-5 2.3.1 Eagle River Water Quality .......................................................... 2-5 2.3.2 Tributary Water Quality ............................................................... 2-6

2.4 Load Source Evaluation ......................................................................... 2-7

3.0 EAGLE MINE WATER MONITORING AND DATA SUMMARY ....................... 3-1 3.1 Mine Water Levels .................................................................................. 3-1 3.2 Mine Water Sampling ............................................................................. 3-1 3.3 Eagle Mine Seeps .................................................................................. 3-2 3.4 Mill Level Seeps ..................................................................................... 3-2 3.5 Liberty No. 4 Well ................................................................................... 3-3

4.0 GROUNDWATER MONITORING AND DATA SUMMARY .............................. 4-1 4.1 Belden Area ............................................................................................ 4-1 4.2 Rock Creek ............................................................................................. 4-1 4.3 CTP Upgradient Groundwater Diversion Trench (UGDT) ...................... 4-2 4.4 CTP Groundwater Extraction .................................................................. 4-2

5.0 SUMMARY OF SITE ACTIVITIES ..................................................................... 5-1 5.1 Deliverables, Reports, and Letters Completed and Submitted to

EPA and CDPHE .................................................................................... 5-1 5.2 Pipeline Operation and Maintenance ..................................................... 5-1 5.3 CDPHE Spill Line Reports ...................................................................... 5-1 5.4 Site Inspections and Audits .................................................................... 5-2 5.5 WTP Operation and Maintenance .......................................................... 5-2 5.6 Liberty Well No. 4 (LIB-4) Operation and Maintenance .......................... 5-4 5.7 Community Involvement and Community Relations ............................... 5-5 5.8 Planned 2017 Activities and Submittals ................................................. 5-5

6.0 REFERENCES ................................................................................................... 6-1


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LIST OF TABLES

Tables are located at the end of the section in which they are referenced Table 2-1 Eagle River Cadmium Concentrations and Loads 2012–2016 Table 2-2 Eagle River Copper Concentrations and Loads 2012–2016 Table 2-3 Eagle River Zinc Concentrations and Loads 2012–2016 Table 2-4 Rock Creek Dissolved Metal Concentrations and Loads 2012–2016 Table 2-5 Cross Creek Dissolved Metal Concentrations and Loads 2012–2016 Table 2-6 Zinc Loading Summary 2012–2016

LIST OF FIGURES

Figures are located at the end of the section in which they are referenced

Figure 1-1 Eagle Mine Site

Figure 2-1 Surface Water Monitoring Locations and Eagle River Basin Segments Figure 2-2 Eagle River Mean Daily Flow, Station E-12A: 2016 vs. 2015 vs. Average Figure 2-3 Eagle River Flow by Season at Station E-12A Figure 2-4 Cross Creek Mean Daily Flow, Station T-18: 2016 vs. 2015 vs. Average Figure 2-5 Eagle River Seasonal Water Quality, Dissolved Zinc: Sept-2015 to Sept-

2016 Figure 2-6 Dissolved Zinc Concentrations in Eagle River Segment 5 Figure 2-7 Comparisons of Dissolved Zinc, Cadmium, and Copper in the Eagle River to

Chronic Ambient Water Quality Standards Figure 2-8 Dissolved Zinc Concentration Station T-10: Rock Creek Figure 2-9 Dissolved Zinc Concentration Station T-18: Cross Creek Figure 2-10 Dissolved Metal Concentrations in Cross Creek, Segment 7b Figure 2-11 Zinc Peak Loading, 2016

Figure 3-1 Eagle Mine Water Level Figure 3-2 Approximate Mine Seep/Adit Locations

Figure 4-1 Belden Area Groundwater Well Locations Figure 4-2 East Trench Monitoring Well ET-1 Water Levels


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APPENDICES

Appendix A Surface Water Data A-1 Eagle River Water Quality Report, Eagle Mine Site, January through

December 2016 A-2 Eagle River Flow Relationships

Appendix B Mine Water Data B-1 Eagle Mine Drawdown (MDD), Eagle Mine Site, January through

December 2016 B-2 Groundwater and Mine Water Quality Report B-3 Liberty Well No. 4 Water Quality Report, Eagle Mine Site, 2016

Appendix C Groundwater Data C-1 Groundwater Elevation Data, Eagle Mine Site, January –December 2016 C-2 CTP Groundwater Extraction System, Eagle Mine Site, January –

December 2016 C-3 Upgradient Groundwater Diversion Trench, Eagle Mine Site, 2016

Appendix D Spill Reports March 8, 2016


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1.0 INTRODUCTION

This Annual Site Monitoring and Activity Report (Annual Report) was prepared by NewFields on behalf of CBS Operations Inc. (CBS) and provides a summary of environmental data collected during the 2016 calendar year at the Eagle Mine (Site) near Minturn, Colorado. The Site location is shown on Figure 1-1. The Annual Report also summarizes design, construction, inspection, operation and maintenance, monitoring and community relation activities conducted in 2016 in connection with the Site.

This Annual Report is a deliverable listed in Table A of the Final Statement of Work - Part A (Appendix B) for the Operable Unit No. 1 Partial Consent Decree, Civil Action No. 95-N-2360 (D. Colorado) (CD/SOW). This Annual Report also satisfies the requirement for an annual monitoring report specified in the Consent Decree, Order, Judgment and Reference to the Special Master for Civil Action No. 83-C-2387 (D. Colorado), Remedial Action Plan, as amended (CD/RAP).

Monitoring activities, data summaries, interpretation and analysis of selected data, and summaries of Site activities are provided in the following sections:

• Section 2 Surface Water Monitoring and Data Summary

• Section 3 Eagle Mine Water Monitoring and Data Summary

• Section 4 Groundwater Monitoring and Data Summary

• Section 5 Summary of Site Activities.

Figures and tables are presented at the end of each section.

Figure 1-1 Eagle Mine Site



2.0 SURFACE WATER MONITORING AND DATA SUMMARY

This section provides a summary of surface water monitoring activities at the Site for the reporting period, Fall 2015 through Fall 2016 (fall monitoring occurs in either September or October). Surface water monitoring was originally conducted in accordance with the requirements of the Surface Water Sampling and Analysis Plan (Dames & Moore 1996). The monitoring activities have changed over the years and the scope for each year is submitted beforehand in a memorandum for Surface Water and Groundwater Monitoring for the subject year (NewFields 2016). Surface water monitoring for 2016 was finalized with Colorado Department of Public Health and Environment (CDPHE) and U.S. Environmental Protection Agency (EPA) on March 2, 2016.

2.1 Monitoring Stations

The Colorado Water Quality Control Commission (WQCC) has established water quality standards for segments of the upper Eagle River and its major tributaries. The four mainstem segments are described by WQCC as:

• 2 – Mainstem of the Eagle River from the confluence with Turkey Creek to the compressor house bridge at Belden

• 5a – Mainstem of the Eagle River from the compressor house bridge at Belden to the Highway 24 Bridge near Tigwon Road

• 5b – Mainstem of the Eagle River from Highway 24 Bridge near Tigwon Road to the confluence with Martin Creek

• 5c – Mainstem of the Eagle River from the confluence with Martin Creek to the confluence with Gore Creek.

Additionally Segment 7, Cross Creek, was subdivided into the following two segments:

• 7a – Cross Creek mainstem to the Minturn Middle School

• 7b – Cross Creek from the Minturn Middle School to the confluence with the Eagle River.

Surface water monitoring stations (Figure 2-1) for the Site were established in 1985 at the outset of the remedial investigation, corresponding closely with locations used by the US Geological Survey (USGS) in studies prior to 1985. The following Eagle River stations were monitored at least once during the reporting period:

• E-3 Eagle River above Belden (background location – Segment 2)

• E-10 Eagle River above Rock Creek (Segment 5a)



• E-12A Eagle River below Old Tailings Pile/Rex Flats (Segment 5a)

• E-15 Eagle River below Cross Creek (Segment 5b)

• E-22 Eagle River above Dowds Junction (Segment 5c).

The following two tributaries to the Eagle River at the Site were monitored:

• T-10 Rock Creek at mouth (tributary to Segment 5a)

• T-18 Cross Creek near mouth (Segment 7b; tributary to Segment 5b).

Other Eagle River tributaries at the Site are, in downstream order, Roaster Pile drainage, Fall Creek, Bishop Gulch, and Two Elk Creek. These tributaries enter the Eagle River between Red Cliff and Minturn but are no longer monitored for water quality or stream flow. Years of sampling data confirm that these tributaries are not metal loading sources to the Eagle River.

For the reporting period, Eagle River and tributary water quality samples were collected pursuant to the methods in the 2016 Monitoring Plan. Surface water quality samples collected in March, April, and October were analyzed for total arsenic and dissolved cadmium, copper, and zinc, as well as for calcium and magnesium for hardness calculations. Field measurements consisted of pH, temperature, and specific conductance.

Stream flow in the Eagle River was monitored using the USGS stream gage at station E-12A (09064600). Stream flows at non-E-12A stations are calculated using historical relationships developed over many years. These historical flow relationships were established between each station and the flow measurement recorded at the station E-12A stream gage. Flow in Rock Creek was manually estimated. For Cross Creek, the USGS stream gage “Cross Creek near Minturn” (09065100) discharge rating data are used to estimate flow for station T-18.

Water quality data and measured or estimated stream flow are presented with the associated water quality data in Appendix A-1. Equations for the estimated flow rates for non-measured stations based on the station E-12A measured flow (USGS gage 09064600) are included in Appendix A.

2.2 Hydrology

Included in this section are background information on the hydrologic monitoring program, a comparison of 2015 and 2016 stream flows to historical conditions, and a discussion of stream flow during water quality sampling events.



The Eagle River and its tributaries exhibit a large seasonal fluctuation in stream flow each year that is typical of most high-elevation watersheds in the central Rocky Mountains. Eagle River stream flow at the Site is illustrated in the hydrograph shown in Figure 2-2.

Eagle River watershed topographic elevation ranges from 8000 ft mean sea level (MSL) at the Site to over 14,000 ft MSL at the headwaters of the Eagle River, with precipitation greater in the higher elevations. From November through April each year, a seasonal snowpack accumulates in the watershed with greater snow accumulation at higher elevations. During the winter, mean daily temperatures are typically below freezing and stream flow in the Eagle River and its tributaries is at a minimum. The Eagle River winter base flow period extends from November to March each year and stream flow typically ranges from about 30 to 40 cubic feet per second (cfs). Small fluctuations in Eagle River stream flow occur during winter because of ice freezing and thawing on the river channel bed and banks.

Site snowpack begins to melt in March and April, followed by snowmelt from progressively higher elevations in the watershed through June each year. In May, Eagle River flow is usually dominated by high-elevation basin-wide snowmelt upstream from the Site. Large diurnal flow fluctuations occur because of daily snowmelt during this period. Peak flows in excess of 800 cfs are common in the Eagle River at the Site during the spring runoff period. Stream flow recedes from July through October each year, with periodic flow increases resulting from summer rainfall-runoff events.

2.2.1 Eagle River

USGS records continuous stage height readings at a stream gage located at station E-12A (see Figure 2-1). The stream gage is at an elevation of 8080 ft MSL and represents a drainage area of 186 square miles.

The stream gage is operational during ice-free periods (eight months each year) from about March 15 to November 15 and collects estimated measurements during the ice periods. The channel at the stream gage typically becomes ice-covered in November and ice on the controls affects the stage height readings throughout the winter months. According to USGS criteria, the gage records are considered good (90 percent of the daily discharges are within 10 percent of their true value) except for records estimated during ice periods, which are fair (within 15 percent). Discharge during ice periods is estimated from direct stream flow measurements and stage height measurements that are corrected for ice effect.

A preliminary discharge rating has been developed for the Eagle River at the station E-12A stream gage and its accuracy is evaluated regularly using current discharge measurements. The USGS is involved in the operation and maintenance of the gage through a cooperative agreement with Eagle County and CBS. The USGS publishes mean daily discharge data



on a real-time basis on their website http://waterdata.usgs.gov/co/nwis for USGS station 09064600.

Figure 2-3 presents the 2015-2016 flow year divided into three flow periods: winter low flow, spring/summer high flow, and fall low flow. The dates when samples were collected are labeled on Figure 2-3 and are marked to indicate the sampling entity: “S” for CBS, “e” for River Watch or Eagle River Water & Sanitation District. Sample results for the latter two organizations are provided by Eagle River Watershed Council; the selection of which organization’s data is used in this report is primarily based on data availability (all analytes from one organization) and lowest detection limits.

Eagle River stream flow at the Site was well above average during the peak flow period in 2016 (see Figure 2-2). Stream flow (26 to 47 cfs) was normal through the winter of 2015-2016 (see Figure 2-3). Flows rose with the normal flow pattern through March, April, and May. Flows did not rise steeply from the normal flow until June 2, 2016. The flows through June were much higher than normal. On May 1, 2016, the Upper Colorado River Basin snowpack, as estimated by the Natural Resources Conservation Service (NRCS), was 112 percent of normal compared to 68 percent in 2015 (NRCS 2016). The highest river flow recorded for the season was on June 6, 2016 at 1,210 cfs at station E-12A. By July 16, 2016, the daily average flows were below 150 cfs, approximately the same as average/normal flows. High flows were observed within the typical 90-day high flow window. Stream flow continued with normal flows into the fall (dropping to 34 to 45 cfs).

2.2.2 Tributaries

Rock Creek is a perennial tributary entering the Eagle River between stations E-10 and E-11 (see Figure 2-1), draining approximately 1.5 square miles. Flow measurements are estimated visually, with a bucket and stopwatch, or calculated using the measured rate of flow (in feet/sec) for the 48-foot-long, 72-inch diameter culvert at the base of Rock Creek (T-10) at the confluence with the Eagle River. Rock Creek flows typically increase from snowmelt beginning in March or April with peak flows occurring in May or June. In 2016, Rock Creek flow contributed typically around 1 percent (0.5 to 1.6%) of the Eagle River flow.

Cross Creek is a perennial tributary entering the Eagle River between stations E-13B and E-15 (see Figure 2-1) draining approximately 34.2 square miles. Stream flow (measured at USGS station 09065100 or T-18) ranges from less than 5 cfs during the winter season to peak flows between 150 and 200 cfs in May and early June. In 2016, Cross Creek flows was similar to the Eagle River with average flows in the winter and early spring and then peak flows delayed from May to June (maximum flow of 403 cfs on June 23, 2016). Flows dropped below average by the end of June 2016 (see Figure



2-4). In 2016, Cross Creek flow contributed approximately 18 percent of the Eagle River flow during the winter, 30 percent during high flow, and 26 percent during fall low flow.

2.3 Water Quality Trends

Through a cooperative process involving all major stakeholders, water quality standards (WQS) were developed for the Colorado Water Quality Control Division (the Commission) that are protective of the aquatic community (macroinvertebrates and brown trout) expected in Segment 5 of the Eagle River and Cross Creek. The WQS were put in place on January 1, 2009, replacing the Temporary Modifications to the table value standards (TVS) provided in Regulation No. 33. The following sections discuss water quality data at the monitored stations focusing on dissolved levels of zinc, cadmium, and copper.

2.3.1 Eagle River Water Quality

Table 2-1 through Table 2-3 present the dissolved concentrations for cadmium, copper, and zinc, respectively, for the past five years, 2012 to 2016. These tables present the concentrations for Eagle River monitoring stations E-3, E-10, E-12A, E-15, and E-22. The tables also present the associated load for the CBS measured concentrations by monitoring station (see Section 2.4 for discussion of load within the river). Flow and chemical results for 2016 are provided in Appendix A.

Dissolved zinc concentrations for the Eagle River are plotted in Figure 2-5 for the reporting period September 2015 to October 2016. The WQS by segment of the Eagle River are plotted on Figure 2-6 and are compared to the monitoring station dissolved zinc concentrations. ERWSD also collect surface water samples monthly at E-12A (Station 950) and E-15 (Station 3291). These data were used to supplement Figures 2-5 and 2-6 in the months for which CBS had not collected samples as well as providing additional data for the Spring months.

Higher dissolved zinc concentrations are typically observed in the river during early snowmelt periods in March and April and may extend into May. Generally by May each year, warm temperatures generate snowmelt in the upper Eagle River basin at higher elevations above the Site and a large increase in stream flow occurs, with peak flows typically occurring in May or June. The increased stream flow from higher elevations above the Site results in lower metal concentrations.

Graphical representation of concentration data for dissolved zinc, cadmium, and copper is provided in Figure 2-7. These plots show concentrations for the Eagle River stations over the 2016 period.



As discussed in previous annual reports, the source of increased zinc concentrations in the Spring is believed to be from a groundwater surge in the Belden area. This typical Spring increase can be seen in the Segment 5 stations, depicted on Figure 2-6. All measured zinc concentrations within the Site (Segments 5a and 5b) were below the WQS for all sampling events, with the exception of the April 15, 2016 (ERW&S) and April 19, 2016 (CBS) sampling events for station E-12A. These exceedances correspond with an increase in river flow and a drop in hardness. As shown in Figure 2-7 the results are below WQS when an average hardness is used to calculate the WQS. The zinc concentration at station E-3 measured on April 19, 2016 was above the WQS for Segment 2 (Figure 2-7). The dissolved zinc concentration at station E-22 was also just above the WQS during the April 19, 2016 sampling event (Figure 2-6 and Figure 2-7). Again as noted in the E-12A graph, the hardness of the river water (as reflected in the WQS) was dropping as the snowmelt began to increase the flow. The average hardness measured during the Spring at station E-22 for 2016 was lower (approximately 100 mg/L) versus previous averages (124 mg/L for the 2009-2012 average). The lowest hardness concentration for 2016 was measured on April 19, 2016 at 76 mg/L.

Dissolved cadmium concentrations, shown in Figure 2-7, are below the standards for the high metal season, with one exception at station E-3. Copper concentrations, shown in Figure 2-7, were also below standards at all stations within the Site, with the exception of station E-15 on March 23, 2016. The source of increased copper at station E-15 has not been identified. Next year’s sample results will be reviewed to determine if the 2016 copper result is an outlier or if the condition is persistent.

All metal concentrations (cadmium, copper, and zinc) at station E-3 on April 19, 2016 were above the respective WQS for Segment 2.

2.3.2 Tributary Water Quality

Trends in dissolved zinc concentrations for Rock Creek and Cross Creek are discussed in the following sections. Table 2-4 and Table 2-5 present the dissolved concentrations for cadmium, copper, and zinc for the past five years, 2012 to 2016, in Rock Creek (T-10) and Cross Creek (T-18), respectively. The tables also present the associated load for the measured concentrations by monitoring station (see Section 2.4 for discussion of load within the river). Flow and chemical results for the reporting period are provided in Appendix A.

Rock Creek

Water samples have been collected routinely from the mouth of Rock Creek (T-10) since March 1989. Dissolved zinc results for station T-10 from March 1989 to September 2016 are presented in Figure 2-8.



Water quality in Rock Creek is influenced by large seasonal fluctuations in stream flow, seepage from the Eagle Mine, and waste-rock pile runoff. Metal concentrations typically increase in April during early spring snowmelt runoff and decrease rapidly in May and June as basin-wide stream flow increases. Concentrations typically remain low during the summer months except during rainfall-runoff events. Concentrations increase in fall and winter under reduced stream flow conditions.

Significant improvements in Rock Creek water quality have occurred since 1989. Factors contributing to a continued decrease in metals concentrations in Rock Creek include lowering the mine pool elevation, collection and treatment of mine seepage and groundwater in lower Rock Creek at the RX-3 well, and the diversion and treatment of runoff/seepage from the hillside below Waste Rock Pile No. 8.

Cross Creek

Dissolved metal concentrations have been routinely measured near the mouth of Cross Creek (T-18, see Figure 2-9) since September 1990. The zinc concentration at station T-18 dropped significantly in 1996 following the remediation of the Maloit Park wetlands. As seen in Figure 2-10, all detected metal concentrations are below WQS for Segment 7b.

2.4 Load Source Evaluation

In this section, dissolved zinc load in the river is used to quantify the contribution from point and non-point metal sources. Dissolved zinc load is calculated by multiplying the dissolved zinc concentration (in mg/L) by the flow (in cfs), and converting the units into pounds per day (lbs/day) using a conversion factor of 5.4. In this manner, the dissolved zinc load was calculated for each of the monitoring stations for which flow can be measured or estimated (Table 2-3 through Table 2-5).

Inherent in each computation of load is the calculated error associated with the measurement of metal concentration and stream flow (up to ±25 percent analytical error and ±10 percent flow error). In the analysis of loading by stream segment, it is assumed the computed load incorporates these errors and, as such, retains a compounded error of at least ±20 percent.

Sampling stations located on the mainstem Eagle River bracket the potential metal sources. These sources include tributary inflows from Rock Creek and Cross Creek, in addition to predominately groundwater inflow from the Belden, Old Tailings Pile (OTP)/Rex Flats, and Consolidated Tailings Pile (CTP) areas. Using discrete river segments, the difference in metal load between two stations can be calculated. The amount of load contributed by measured or “accounted” tributary inflows is known. After subtracting the accounted load, the load difference is referred to as the “unaccounted” load. A positive unaccounted load (load increase) includes groundwater and/or diffuse



surface-water inflow that are not measured. These are sometimes referred to as non-point source loads. A negative unaccounted load (load decrease) can result from losses of flow to groundwater, or from decreases in metal concentration through attenuation processes such as chemical precipitation or adsorption.

Table 2-6 provides a data summary of the dissolved zinc loading by Eagle River segment for a five-year period of 2012 through 2016. A discussion of peak spring zinc loading by river segment for the sample date April 19, 2016 is provided below, using Figure 2-11 presenting the yearly peak Spring loads for reference.

Background (E-3)

The calculated dissolved zinc load at E-3 (41 lbs/day) represents the background zinc load entering Segment 5a from Segment 2. The source of the background zinc in Segment 2 is thought to be runoff from the numerous smaller mines and associated waste rock piles located along the Eagle River between Red Cliff and Belden. These mines and piles are not associated with the Eagle Mine Site.

Belden (E-3 to E-10)

Upper Segment 5a or Belden segment extends downstream from Segment 2 (station E-3) to station E-10 above Rock Creek. The calculated dissolved zinc load after subtracting background is 55 lbs/day. Investigations indicate that the primary source of the zinc load is groundwater perched in the waste rock and railroad ballast located in Belden. Runoff from the waste rock may contribute to periodic metal loads during spring and summer.

Fall Creek contributes on the order of 10 to 20 percent of the Eagle River flow in this segment. Past studies document that Fall Creek contributes negligible amount of metals, and this tributary metal load is assumed zero for purposes of load accounting (Dames & Moore 1998).

Rock Creek (E-10 to E-12A)

Lower Segment 5a or Rock Creek segment receives tributary inflow from Rock Creek and Bishop Gulch and groundwater from Rock Creek and the OTP/Rex Flats area. Historical data shows that Bishop Gulch does not contribute significant zinc load to the Eagle River. This segment typically shows a small increase in zinc load relative to the Belden segment.

The calculated dissolved zinc load increased by 5.9 lbs/day, after subtracting Rock Creek, which contributed 18 lbs/day. In past years, the source of the zinc has been



attributed to groundwater baseflow from Rock Creek alluvium, groundwater baseflow from Belden segment alluvium, and groundwater seepage from the OTP/Rex Flats area.

CTP (E-12A to E-15)

Segment 5b brackets the CTP and receives flow from Cross Creek, the largest tributary within the Site. Two Elk Creek, a perennial tributary, and discharge from the WTP also flow to the Eagle River in this segment; however, historical data show that the dissolved zinc load contributed by these sources is negligible. The calculated dissolved zinc load increased by 19 lbs/day, after subtracting Cross Creek, which contributed 3.3 lbs/day. Investigations indicate that the source of the zinc is primarily groundwater baseflow from OTP/Rex Flats and the CTP.

Table 2-1Eagle River Cadmium Concentrations and Loads

2012 - 2016

E- 3 E-10 E-12A E-15 E-22 E- 3 E-10 E-12A E-15 E-22Date

Eagle River Flow (cfs) at

E-12A

Cadmium Load (1,2)

(lbs/day)Dissolved Cadmium Concentration (1)

(mg/L)

3/12/12 0.00005 ** 0.00049 0.00061 25 0.01 ** 0.07 0.083/19/12 0.00045 36 0.093/26/12 0.00005 ** 0.00035 0.00044 0.00027 85 0.02 ** 0.16 0.20 0.204/3/12 0.00036 116 0.234/10/12 0.00005 ** 0.00010 0.00014 0.00005 ** 144 0.03 ** 0.08 0.11 0.064 **4/17/12 0.00022 103 0.1210/18/12 0.00005 ** 0.00014 0.00018 0.00015 0.00017 28 0.01 ** 0.02 0.03 0.03 0.033/12/13 (3) 0.00026 0.00028 0.00015 0.00016 9 0.02 0.01 0.00 0.003/22/13 0.00010 ** 0.00030 0.00032 0.00021 0.00023 12 0.01 ** 0.02 0.02 0.01 0.014/5/13 0.00035 0.00074 0.00074 0.00055 0.00043 38 0.06 0.16 0.15 0.16 0.134/19/13 0.00024 0.00066 0.00100 0.00053 0.00044 33 0.04 0.12 0.18 0.13 0.115/3/13 0.00045 0.00074 0.00110 0.00064 0.00053 130 0.28 0.53 0.77 0.74 0.619/30/13 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 86 0.02 ** 0.02 ** 0.02 ** 0.04 ** 0.04 **3/20/14 0.00018 0.00070 0.00040 0.00043 0.00037 31 0.03 0.12 0.07 0.10 0.094/3/14 0.00024 0.00110 0.00100 0.00078 0.00063 38 0.04 0.24 0.21 0.23 0.194/17/14 0.00032 0.00081 0.00093 0.00064 0.00059 143 0.22 0.63 0.72 0.82 0.759/24/14 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 67 0.02 ** 0.02 ** 0.02 ** 0.03 ** 0.03 **3/13/15 0.00014 0.00034 0.00031 0.00022 0.00019 38 0.03 0.07 0.06 0.07 0.063/27/15 0.00030 0.00045 0.00052 0.00033 0.00032 80 0.11 0.20 0.22 0.23 0.224/13/15 0.00004 0.00009 0.00012 0.00017 0.00017 143 0.03 0.07 0.09 0.22 0.224/27/15 0.00006 0.00021 0.00042 0.00030 0.00019 139 0.04 0.16 0.32 0.37 0.2410/19/15 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 0.00005 ** 34 0.02 ** 0.02 ** 0.02 ** 0.03 ** 0.03 **3/9/16 0.00009 0.00023 0.00190 0.00023 0.00020 40 0.02 0.05 0.41 0.07 0.06

3/23/16 (3) 0.00042 0.00310 0.00027 0.00023 49 0.11 0.82 0.11 0.094/7/16 0.00013 0.00036 0.00460 0.00038 0.00030 64 0.04 0.13 1.59 0.21 0.164/19/16 0.00039 0.00057 0.00750 0.00056 0.00050 91 0.17 0.28 3.69 0.44 0.409/23/16 0.00005 ** 0.00012 0.00350 0.00005 ** 0.00005 ** 42 0.01 ** 0.03 0.79 0.02 ** 0.02 **

Notes:

1) Blanks indicate station was not sampled on designated date.

Concentrations marked with ** were not detected and reported concentration is estimated and reported at 1/2 the detection limit through 2014. In 2015 the reporting limit was lowered to the Laboratory's MDL. Load is calculated using this full MDL concentration.

2) Load was calculated using the flow for the designated station and the flow relationship to the E-12A gage (see Appendix A). Loads calculated with flows greater than 100 cfs are flow driven and are italicized3) Samples were not collected at E-3 due to unsafe ice/river access conditions.

Table 2-2Eagle River Copper Concentrations and Loads

2012 - 2016

E- 3 E-10 E-12A E-15 E-22 E- 3 E-10 E-12A E-15 E-22

Copper Load (1,2)

(lbs/day)Dissolved Copper Concentration (1) (mg/L)DateEagle River Flow (cfs) at

E-12A 3/12/12 0.0025 0.0033 0.0026 25 0.30 0.48 0.353/19/12 0.0036 36 0.703/26/12 0.0026 0.0033 0.0041 0.0031 85 1.1 1.5 1.9 2.34/3/12 0.0043 116 2.74/10/12 0.0027 0.0029 0.0028 0.0027 144 1.9 2.3 2.2 3.54/17/12 0.0034 103 1.9

10/18/12 0.001 ** 0.001 ** 0.001 ** 0.001 ** 0.001 ** 28 0.13 ** 0.16 ** 0.15 ** 0.20 ** 0.20 **3/12/13 (3) 0.0026 0.001 ** 0.001 ** 0.001 ** 9 0.2 0.05 ** 0.03 ** 0.03 **3/22/13 0.002 ** 0.002 ** 0.002 ** 0.002 ** 0.002 ** 12 0.11 ** 0.15 ** 0.13 ** 0.11 ** 0.11 **4/5/13 0.0078 0.0080 0.0052 0.0039 0.0039 38 1.4 1.7 1.1 1.2 1.24/19/13 0.0064 0.0078 0.0085 0.0042 0.0228 33 1.0 1.5 1.5 1.0 5.75/3/13 0.0069 0.0089 0.0114 0.0092 0.0074 130 4.3 6.3 8.0 11 8.69/30/13 0.001 ** 0.001 ** 0.001 ** 0.0021 0.0025 86 0.41 ** 0.47 ** 0.46 ** 1.6 1.93/20/14 0.0045 0.0058 0.0023 0.0025 0.0023 31 0.66 1.0 0.39 0.58 0.534/3/14 0.0046 0.0061 0.0044 0.0036 0.0034 38 0.83 1.3 0.90 1.1 1.04/17/14 0.0073 0.0072 0.0077 0.0059 0.0061 143 5.0 5.6 5.9 7.5 7.89/24/14 0.001 ** 0.0028 0.001 ** 0.0020 0.001 ** 67 0.32 ** 1.0 0.36 ** 1.1 0.57 **3/13/15 0.0032 0.0035 0.0028 0.0024 0.0020 38 0.58 0.75 0.57 0.71 0.593/27/15 0.0071 0.0067 0.0062 0.0051 0.0048 80 2.7 3.0 2.7 3.5 3.34/13/15 0.0062 0.0051 0.0050 0.0039 0.0038 143 4.2 4.0 3.9 5.0 4.94/27/15 0.0068 0.0058 0.0061 0.0044 0.0041 139 4.5 4.4 4.6 5.5 5.1

10/19/15 0.0009 0.0018 0.0013 0.0013 0.0010 34 0.1 0.3 0.24 0.3 0.33/9/16 0.001 ** 0.0027 0.0028 0.0010 0.0010 40 0.2 0.6 0.60 0.3 0.3

3/23/16 (3) 0.0050 0.0062 0.0292 0.0064 49 1.4 1.6 12 2.64/7/16 0.0042 0.0048 0.0050 0.0038 0.0040 64 1.3 1.7 1.7 2.1 2.24/19/16 0.0137 0.0080 0.0061 0.0057 0.0058 91 6.0 4.0 3.0 4.5 4.69/23/16 0.001 ** 0.001 ** 0.0013 0.001 ** 0.001 ** 42 0.20 ** 0.24 ** 0.29 0.33 ** 0.33 **

Notes:



2) Load was calculated using the flow for the designated station and the flow relationship to the E-12A gage (see Appendix A). Loads calculated with flows greater than 100 cfs are flow driven and are italicized3) Samples were not collected at E-3 due to unsafe ice/river access conditions.

Table 2-3Eagle River Zinc Concentrations and Loads

2012 - 2016

E- 3 E-10 E-12A E-15 E-22 E- 3 E-10 E-12A E-15 E-22


E-12A

Zinc Load (1,2)

(lbs/day)Dissolved Zinc Concentration (1)

(mg/L)Date

3/12/12 0.026 0.230 0.316 25 3.1 33 433/19/12 0.245 36 483/26/12 0.025 0.131 0.158 0.120 85 10 61 73 884/3/12 0.178 116 1114/10/12 0.029 0.040 0.064 0.055 144 20 31 50 714/17/12 0.117 103 6510/18/12 0.010 ** 0.047 0.095 0.057 0.055 28 1.3 ** 7.6 14 12 113/12/13 (3) 0.113 0.166 0.121 0.110 9 6.6 8.2 3.2 2.93/22/13 0.010 ** 0.157 0.129 0.140 0.129 12 0.6 ** 12 8.4 7.5 6.94/5/13 0.105 0.231 0.288 0.243 0.222 38 19 49 59 72 664/19/13 0.067 0.223 0.445 0.377 0.231 33 11 42 79 94 585/3/13 0.154 0.235 0.370 0.266 0.215 130 96 167 260 308 2499/30/13 0.010 0.028 0.041 0.033 0.035 86 4 13 19 24 263/20/14 0.043 0.259 0.197 0.196 0.176 31 6 46 33 45 414/3/14 0.059 0.306 0.342 0.251 0.220 38 11 65 70 74 654/17/14 0.101 0.209 0.248 0.171 0.168 143 69 163 192 219 2159/24/14 0.005 ** 0.038 0.032 0.032 0.040 67 1.6 ** 14 12 18 233/13/15 0.029 0.128 0.153 0.111 0.113 38 5 27 31 33 343/27/15 0.098 0.180 0.225 0.166 0.156 80 37 79 97 115 1084/13/15 0.035 0.063 0.088 0.068 0.068 143 24 49 68 87 874/27/15 0.027 0.074 0.128 0.111 0.066 139 18 56 96 138 8110/19/15 0.009 0.048 0.065 0.047 0.039 34 1.4 9.2 12 12 10

3/9/16 0.026 0.092 0.214 0.143 0.106 40 5.0 21 46 45 333/23/16 (3) 0.185 0.208 0.191 0.152 49 51 55 76 61

4/7/16 0.057 0.140 0.175 0.188 0.165 64 17 50 60 102 894/19/16 0.095 0.192 0.243 0.179 0.179 91 41 96 119 142 1429/23/16 0.010 0.043 0.067 0.054 0.043 42 2.0 10 15 18 14

Notes:


3) Samples were not collected at E-3 due to unsafe ice/river access conditions.


2) Load was calculated using the flow for the designated station and the flow relationship to the E-12A gage (see Appendix A). Loads calculated with flows greater than 100 cfs are flow driven and are italicized

Table 2-4Rock Creek Dissolved Metal Concentrations and Loads

2012 - 2016

Cadmium Copper Zinc Cadmium Copper ZincDate

Dissolved Metal Load (3)

(lbs/day)Flow (2)

(cfs)

Dissolved Metal Concentration (1)

(mg/L)

3/12/12 0.0031 0.0044 1.9 0.19 * 0.0032 0.005 2.03/26/12 0.0119 0.0225 6.22 0.28 0.0180 0.034 9.44/10/12 0.0046 0.0115 2.12 0.59 * 0.0146 0.036 6.7

10/18/12 0.0025 0.0026 1.53 0.16 * 0.0022 0.002 1.33/12/13 0.0039 0.0023 2.65 0.13 0.0027 0.002 1.93/22/13 0.0044 0.0040 2.61 0.02 * 0.0005 0.000 0.34/5/13 0.0032 0.0152 1.67 0.06 * 0.0010 0.005 0.54/19/13 0.0072 0.0176 4.21 0.45 0.0175 0.043 10.25/3/13 0.0144 0.0354 6.66 0.45 0.0350 0.086 16.29/30/13 0.0029 0.0056 1.22 0.41 * 0.0064 0.012 2.73/20/14 0.0029 0.0031 1.74 0.20 * 0.0031 0.003 1.94/3/14 0.0031 0.0043 1.61 1.45 0.0243 0.034 12.64/17/14 0.0054 0.0201 2.07 1.00 0.0292 0.109 11.29/24/14 0.0028 0.0035 0.96 0.45 0.0068 0.009 2.33/13/15 0.0027 0.0082 1.48 0.55 0.0080 0.024 4.43/27/15 0.0067 0.0289 2.76 0.95 0.0344 0.148 14.24/13/15 0.0030 0.0218 1.30 0.71 0.0115 0.084 5.04/27/15 0.0032 0.0196 1.31 0.71 0.0123 0.075 5.0

10/19/15 0.0028 0.0035 0.81 0.22 0.0033 0.004 1.03/9/16 0.0039 0.0057 2.01 0.22 0.0046 0.007 2.43/23/16 0.0028 0.0087 1.56 0.78 0.0118 0.037 6.64/7/16 0.0022 0.0095 1.05 1.00 0.0119 0.051 5.74/19/16 0.0063 0.0135 2.93 1.11 0.0378 0.081 17.69/23/16 0.0020 0.0044 0.95 0.22 0.0024 0.005 1.1

Notes:

3) Load was calculated using the flow for the designated station and concentration presented in table. Loads marked with ** are based on estimated concentrations when metal was not detected.

1) Concentrations marked with ** were not detected and reported concentration is estimated and reported at 1/2 the detection limit through 2014. In 2015 the reporting limit was lowered to the Laboratory's MDL. Load is calculated using this full MDL concentration.2) T-10 flow measured at the station or if marked with * estimated using a relationship with T-18 (using T-18 flow measured at USGS station 09065100 until July 2009). Flows after July 2009 are estimated using field measurements when conditions allowed. Comparisons to the T-18 relationship to estimated T-10 flows indicate the relationship has a high bias during dry years.

Table 2-5Cross Creek Dissolved Metal Concentrations and Loads

2012 - 2016

Cadmium Copper Zinc Cadmium Copper ZincDate

Dissolved Metal Load (3)

(lbs/day)Flow (2)

(cfs)

Dissolved Metal Concentration (1)

(mg/L)

3/12/12 0.0002 0.001 ** 0.173 5 0.0044 0.028 ** 4.83/26/12 0.00005 ** 0.0023 0.038 16 0.0043 ** 0.199 3.34/10/12 0.00005 ** 0.0028 0.0265 36 0.0097 ** 0.544 5.210/18/12 0.00005 ** 0.001 ** 0.0567 11 0.0030 ** 0.059 ** 3.43/12/13 0.00011 0.001 ** 0.1820 3 0.0017 0.015 ** 2.83/22/13 0.00010 ** 0.002 ** 0.1200 3 0.0015 ** 0.029 ** 1.74/5/13 0.00011 0.0023 0.0799 6 0.0037 0.077 2.74/19/13 0.00005 ** 0.0021 0.0726 5 0.0012 ** 0.051 1.85/3/13 0.00011 0.0044 0.0551 31 0.0184 0.74 9.29/30/13 0.00005 ** 0.0038 0.0189 42 0.0113 ** 0.86 4.33/20/14 0.00005 ** 0.0025 0.0640 5.7 0.0015 ** 0.077 2.04/3/14 0.00005 ** 0.0010 0.0497 7.8 0.0021 ** 0.042 2.14/17/14 0.00005 ** 0.0027 0.0348 28 0.0076 ** 0.41 5.39/24/14 0.00005 ** 0.0035 0.0202 29 0.0078 ** 0.55 3.23/13/15 0.000042 ** 0.0014 0.0614 7 0.0016 ** 0.053 2.33/27/15 0.000042 ** 0.0033 0.0235 19 0.0043 ** 0.34 2.44/13/15 0.000042 ** 0.0021 0.0223 26 0.0059 ** 0.29 3.14/27/15 0.000042 ** 0.0019 0.0208 27 0.0061 ** 0.28 3.0

10/19/15 0.000042 ** 0.0035 0.0660 7.3 0.0017 ** 0.14 2.63/9/16 0.000050 ** 0.0010 0.0595 4.7 0.0013 ** 0.03 1.53/23/16 0.000050 ** 0.0015 0.0669 6.9 0.0019 ** 0.06 2.54/7/16 0.000050 ** 0.0019 0.0438 12 0.0032 ** 0.12 2.84/19/16 0.000050 ** 0.0023 0.0404 15 0.0041 ** 0.19 3.39/23/16 0.000050 ** 0.0010 0.0648 8.8 0.0024 ** 0.048 3.1

Notes:

3) Load was calculated using the flow for the designated station and concentration presented in table. Loads marked with ** are based on estimated concentrations when metal was not detected.

1) Concentrations marked with ** were not detected and reported concentration is estimated and reported at 1/2 the detection limit through 2014. In 2015 the reporting limit was lowered to the Laboratory's MDL. Load is calculated using this full MDL concentration.2) T-18 flow measured at USGS station 09065100. Flows from August 2009 through November 2010 (when the gage was not operating) are estimated on day of sampling. Flows during ice over could not be estimated with accuracy and are not reported.

Table 2-6Zinc Loading Summary

2012 - 2016

Entire Segment

Rock Creek Load

Without Rock Creek Load

Entire Segment

Cross Creek Load

Without Cross Creek Load

Zinc Loading for Eagle River (lbs/day) (1)

Segment 2 (Background)

Upper Segment 5a

(Belden)

Lower Segment 5a (Rock Creek) Segment 5bDate


E-12A

3/12/2012 25 3.1 30 10 2.0 7.6 NM 4.8 NA3/26/2012 85 10 51 11 9.4 1.9 16 3.3 12.64/10/2012 144 20 12 19 6.7 12 21 5.2 1610/18/2012 28 1.3 6.3 6.8 1.3 5.5 -2.9 3.4 -6.33/12/2013 9 NM 6.6 1.6 1.9 -0.3 -5.0 2.8 -7.73/22/2013 12 0.6 11 -3.2 0.32 -3.6 -0.9 1.7 -2.64/5/2013 38 19 30 9.7 0.52 9.1 13 2.7 104/19/2013 33 11 31 38 10.2 27 15 1.8 135/3/2013 130 96 71 93 16.2 77 48 9.2 399/30/2013 86 4.1 9.3 5.5 2.7 2.8 5.3 4.3 1.13/20/2014 31 6.3 39 -13 1.9 -15 12 2.0 104/3/2014 38 11 55 4.7 13 -7.9 4.3 2.1 2.24/17/2014 143 69 94 29 11 17 27 5.3 229/24/2014 67 1.6 12 -2.2 2.3 -4.5 6.7 3.2 3.53/13/2015 38 5.2 22 29 4.4 24 -23 2.3 -263/27/2015 80 37 42 4.6 14 -10 31 2.4 284/13/2015 143 24 25 -16 5.0 -21 54 3.1 514/27/2015 139 18 38 -7.0 5.0 -12 89 3.0 8610/19/2015 34 1 8 2.7 1.0 1.8 0.1 2.6 -2.53/9/2016 40 5 16 25 2.4 23 -1.1 1.5 -2.63/23/2016 49 NM 51 4.5 6.6 -2.1 21 2.5 194/7/2016 64 17 32 11 5.7 5.2 41 2.8 384/19/2016 91 41 55 23 18 5.9 22 3.3 199/23/2016 42 2.0 8.2 5.0 1.1 3.9 2.6 3.1 -0.4

Notes:

NM - Not MeasuredNA - Not applicable - if a tributary load could not be measured, it as not applicable to present the Segment load "without" the tributary.

Lower Segment 5a is the load measured at E-12A minus the load measured at E-10. When the Rock Creek load (T-10) is removed, the remaining gain/loss is from unaccounted sources.Segment 5b is the load measured at E-15 minus the load measured at E-12A. When the Cross Creek load (T-18) is removed, the remaining gain/loss is from unaccounted sources and the WTP (which is typically small approximately 0.2 lbs/day).

Segment 2 or Background is the measured load at E-3.

1) Individual zinc loads are presented on Table 2-3 for the Eagle River stations and Tables 2-4 and 2-5 for the tributary stations Rock Creek (T-10) and Cross Creek (T-18), respectively. Zinc Loading for a segment is calculated using the stations listed below.

Upper Segment 5a or Belden is the load measured at E-10 minus the background load (E-3).

Figure 2-1 Surface Water Monitoring Locations and Eagle River Basin Segments

Source: USGS station 09064600 accessed at http://waterdata.usgs.gov/co/nwis Figure 2-2

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT

Mea

n D

aily

Flo

w (c

fs)

Eagle River Mean Daily FlowStation E-12A: 2016 vs 2015 vs Average

2016 2015 Average (1989-2014)

Eagle River Flow by Season at Station E-12A

Figure 2-3

e e e S

0

100

200

11/15 11/22 11/29 12/6 12/13 12/20 12/27 1/3 1/10 1/17 1/24 1/31 2/7 2/14 2/21 2/28 3/6 3/13

Mea

n D

aily

Flo

w (c

fs)

Eagle River Winter FlowStation E-12A: 15-Nov to 15-Mar

"S" Indicates sample collected by CBS"e" indacates sampled by ERW&S/RiverWatch

Estimated Flow Values, Ice Affected 11-Nov through 6-Apr

e S S e S

e

e

e0

100200300400500600700800900

1,0001,1001,2001,3001,4001,500

3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25 6/1 6/8 6/15 6/22 6/29 7/6 7/13 7/20 7/27

Mea

n D

aily

Flo

w (c

fs)

Eagle River Spring/Summer FlowStation E-12A: 16-Mar to 31-Jul

Current YearAverage

Estimated Flow Values, Ice affected through 6-Apr

e S e e0

100

200

300

400

500

8/1 8/8 8/15 8/22 8/29 9/5 9/12 9/19 9/26 10/3 10/10 10/17 10/24 10/31

Mea

n D

aily

Flo

w (c

fs)

Eagle River Fall FlowStation E-12A: 1-Aug to 31-Oct3

Source: USGS station 09065100 accessed at http://waterdata.usgs.gov/co/nwis Figure 2-4

0

100

200

300

400

500

600

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT

Mea

n D

aily

Flo

w (c

fs)

Cross Creek Mean Daily FlowStation T-18: 2016 vs 2015 vs Average

2016 2015 Average (1989-2014)

Figure 2-5

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

1-Sep 27-Oct 22-Dec 16-Feb 12-Apr 7-Jun 2-Aug 27-Sep

Con

cent

ratio

n (m

g/L)

Eagle River Seasonal Water QualityDissolved Zinc: Sept-2015 to Oct-2016

E-3 E-10 E-12A E-15 E-22

E-12A and E-15 data are supplemented with data collected by RiverWatch and ERW&S

Dissolved Zinc Concentrations in Eagle River Segment 5

Figure 2-6

Segment 5a

Segment 5b

Segment 5c

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

9/1/15 10/31/15 12/30/15 2/28/16 4/28/16 6/27/16 8/26/16 10/25/16

Dis

solv

ed Z

inc

Con

cent

ratio

n (m

g/L)

E-10

E-10 WQS for 5a

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

9/1/2015 10/31/2015 12/30/2015 2/28/2016 4/28/2016 6/27/2016 8/26/2016 10/25/2016

Dis

solv

ed Z

inc

Con

cent

ratio

n (m

g/L)

E-15

E-15* WQS for Seg 5b**** WQS equations vary by season for this Segment - Pink for Spring (Jan-Apr) and Purple for non-Spring (May-Dec). LIne is dashed between the two equations

WQS are based on equations found in Table 3 of CCR 33, effective 1/1/2009 and were calculated using the hardness of the corresponding sample.

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

9/1/2015 10/31/2015 12/30/2015 2/28/2016 4/28/2016 6/27/2016 8/26/2016 10/25/2016

Dis

solv

ed Z

inc

Con

cent

ratio

n (m

g/L)

E-12A

E-12A* WQS for 5a

*E-12A and E-15 data are supplemented with data collected by RiverWatch and ERW&S

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

9/1/15 10/31/15 12/30/15 2/28/16 4/28/16 6/27/16 8/26/16 10/25/16

Dis

solv

ed Z

inc

Con

cent

ratio

n (m

g/L)

E-22

E-22 WQS for Seg 5c

Comparisons of Dissolved Zinc, Cadmium, and Copper in the Eagle River to Chronic Ambient Water Quality Standards

Figure 2-7

** WQS for dissolved zinc shown for Segment 5b is the January-April WQS as this is appropriate comparison for all but September's sample. See Figure 2-6 for comparison of individual samples to the seasonal standards.

* Average Hardness for each station was calculated using data from 2009-2012 and used in WQS calculation; equations vary by Segment.

DL DL DL DL DL0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

E- 3 E-10 E-12A E-15 E-22

Con

cent

ratio

n (m

g/l)

Dissolved Copper

3/9/16 3/23/16 4/7/16 4/19/16 WQS* DL

Segment 2 Segment 5a Segment 5b** Segment 5c

DL DL DL DL DL0

0.00020.00040.00060.0008

0.0010.00120.00140.0016

E- 3 E-10 E-12A E-15 E-22

Con

cent

ratio

n (m

g/l)

Dissolved Cadmium

3/9/16 3/23/16 4/7/16 4/19/16 9/23/16 WQS* DL


concentrations are estimated below the detection limit (DL); Non-detects are graphed at 1/2 DL

0

0.1

0.2

0.3

0.4

E- 3 E-10 E-12A E-15 E-22

Con

cent

ratio

n (m

g/l)

Dissolved Zinc

3/9/16 3/23/16 4/7/16 4/19/16 9/23/16 WQS*


Figure 2-8

0102030405060708090

100110120130140150160170180190200

Con

cent

ratio

n (m

g/L)

Dissolved Zinc ConcentrationStation T-10: Rock Creek

240

Figure 2-9

0.00.10.20.30.40.50.60.70.80.91.01.11.21.31.41.51.61.71.81.92.0

Con

cent

ratio

n (m

g/L)

Dissolved Zinc ConcentrationStation T-18: Cross Creek

Dissolved Zinc, Cadmium, and Copper Concentrationsin Cross Creek, Segment 7b

Figure 2-10

Segment 7b - Cross Creek

0.00

0.05

0.10

0.15

0.20

9/1/15 10/31/15 12/30/15 2/28/16 4/28/16 6/27/16 8/26/16 10/25/16

Con

cent

ratio

n (m

g/L)

Dissolved Zinc

T-18 WQS for Seg 7b*

* All WQSs are based on equations found in Table 3 of CCR 33, effective 1/1/2009 and were calculated using the hardness of the sample. WQS equations vary by season for this Segment - Pink for Spring (Jan-Apr) and Purple for non-Spring (May-Dec). LIne is dashed between the two

0.0000.0010.0020.0030.0040.0050.0060.007

9/1/15 10/31/15 12/30/15 2/28/16 4/28/16 6/27/16 8/26/16 10/25/16

Con

cent

ratio

n (m

g/L)

Dissolved Copper

T-18 WQS for Seg 7b**

** All WQS are based on equations found in Table 3 of CCR 33, effective 1/1/2009 and were calculated using the hardness of the sample.

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

9/1/15 10/31/15 12/30/15 2/28/16 4/28/16 6/27/16 8/26/16 10/25/16

Con

cent

ratio

n (m

g/L)

Dissolved Cadmium

T-18 WQS for Seg 7b**

** All WQS are based on equations found in Table 3 of CCR 33, effective 1/1/2009 and were calculated using the hardness of the sample.

ZINC PEAK LOADING2016MINTURN

BELDEN

E-3

CTP

E-15142 lbs/day

REX

OTP

119 lbs/day

T-10 18 lbs/day

3.3 lbs/day T-18

96 lbs/dayE-10

E-12A

DateBack-

ground (E-3)

Belden(E-3 to E-10)

Rock Creek(T-10)

Rock Creek(E-10 to E-12A

Less T-10)

Cross Creek(T-18)

CTP(E-12A to E-15

Less T-18)

3/26/2012 +10 +51 +9.4 +1.9 +3.3 +13

4/5/2013 +19 +30 +0.5 +9.1 +2.7 +10

4/17/2014 +69 +94 +11 +17 +5.3 +22

3/27/2015 +37 +42 +14 -10 +2.4 +28

4/19/2016 +41 +55 +18 +5.9 +3.3 +19 41 lbs/day

WP-8

GILMAN

Segment Peak(1) Zinc Loading Summary in lbs/day

Figure 2-11(1) Peak is based on largest measured load at E-10 during the Spring (March or April)



3.0 EAGLE MINE WATER MONITORING AND DATA SUMMARY

Eagle Mine water monitoring activities conducted in 2016 included the following:

• Measuring mine water levels.

• Collecting mine water samples.

• Monitoring mine seepage flow.

• Pumping the Mill Level seepage.

These monitoring activities and related data are summarized in this section. Activities conducted at the Liberty No. 4 well, which intercepts clean water prior to flowing into the Eagle Mine, are also summarized in this section.

3.1 Mine Water Levels

The mine pool level was measured in the Wilkesbarre shaft in Gilman until 1998. Beginning in July 1998 and continuing until 2002, the mine water level was measured from a reference point set in the Bleakhouse Mine workings (elevation 8503.8 ft MSL). Since 1992, mine water has been released at the Adit No. 5 bulkhead and gravity drained through a pipeline to the WTP for treatment (the MDD). Since 2002, the mine water levels have been monitored using a pressure transducer in the MDD pipeline. The Wilkesbarre shaft is not deep enough to access mine pool levels below 8498 ft MSL. Graphical representations of the mine pool level for 1992 through 2016 and for 2015 and 2016 are presented in Figure 3-1.

As seen in Figure 3-1 the mine pool elevation was falling at the end of 2015 due to the combination of the MDD and the Liberty well groundwater withdrawals. By April 7, 2016, the mine pool elevation had fallen 7.62 feet, from 8456.20 ft MSL on December 21, 2015 to 8448.58 ft MSL. The Spring snowmelt and lack of the Liberty well groundwater withdrawal for the month of June caused the mine pool to rise 13.85 feet to 8462.44 ft MSL on July 27, 2016. After the snowmelt period, the combination of the MDD and the Liberty well groundwater withdrawals again reduced the mine pool elevation 6.93 feet to 8455.51 ft MSL as measured on October 27, 2016. On October 26, 2016, the Liberty well pump stopped and could not be restarted. Without the Liberty well and the MDD flowing at approximately 175 gpm (2016 average) the mine pool again rose 6.70 feet or to 8462.20 ft MSL as measured on December 29, 2016.

3.2 Mine Water Sampling

In the 1990s, mine pool seepage through rock fractures was a significant source of metals, especially in the Rock Creek drainage where the flooded workings of the Bleakhouse Mine were leaking through highly fractured Cambrian quartzite. Mine pool



seepage ceased to be a major source of metal loading since the inception of the MDD program and control of the mine pool level below 8500 ft MSL. Operational history has demonstrated that as long as the elevation of the mine pool is maintained below 8500 ft MSL, most of the seeps are eliminated.

Mine water has been historically sampled directly from the mine pool via the Wilkesbarre shaft, from the bulkhead valve in Adit 5, and from the MDD at the Rock Creek vault. No mine water samples were collected in 2016.

3.3 Eagle Mine Seeps

The Eagle Mine began filling with water in 1984 when the mine dewatering pumps were turned off. The mine filled and eventually began leaking water in the Rock Creek area in September 1989. Subsequently, monitoring stations were established. Since 1990, seepage has been collected and piped to the WTP for treatment. Seepage stations are shown on Figure 3-2. Flow at collected seeps S-5 (Adit 5 bulkhead), S-6 (Adit 6 bulkhead), and S-TT (Tip Top bulkhead) is typically monitoring on a daily or weekly basis, unless access is difficult in the winter.

3.4 Mill Level Seeps

In the Spring, melting ice and snow collects in the mine workings that house the underground mill between the Newhouse level (8483 ft MSL) and the Copper Tipple Loading Tunnel (8397 ft MSL) or about 40 feet topographically above the Eagle River. When the mine and mill were operating, water that accumulated in the Mill Level was pumped out for treatment. At present, the so-called Mill Level water picks up elevated metal concentrations due to contact with ore and concentrates in the underground mill. Once the Mill Level water reaches its maximum level of 10 inches or so, it leaks outside the mine through old pipelines, fractures in the bedrock, and tunnels that serviced the mill. Mill Level seepage probably recharges the shallow groundwater in the Copper Tipple Trench area. A dedicated electric sump pump on the Mill level was used to dewater the Mill Level pool over the year. A total of 45,900 gallons was pumped to the treatment plant.

Date of Pumping Volume of water removed 6/2/2016 3,000

6/15/2016 15,000 6/28/2016 3,900 7/15/2016* 24,000

One sample of Mill Level water was collected in 2016 (indicated by asterisk). The July 15, 2006 sample was tested for total arsenic, cadmium, copper, and zinc. The sample results are included in Appendix B.



3.5 Liberty No. 4 Well

Since 1990, CBS has investigated means to reduce inflow to the Eagle Mine, thereby allowing better control of the mine pool level and, eventually, reduce flow to the WTP. From these investigations, it was concluded that the most feasible method to reduce recharge to the mine is to stop or reduce flow entering on the 19 Level, via exploratory drift 19-5-E-3. It was estimated that 200 gpm or more of fresh water continuously recharges the drift via core holes drilled horizontally from the tunnel into the Leadville Dolomite. An 890-foot-deep well (Liberty No. 4 or LIB-4) intersected the tunnel in July 1998.

On September 1, 1999, EPA issued an Explanation of Significant Differences (ESD) describing EPA’s decision regarding this mine pool component of the remedy for the Site. The ESD, which is an addition to the 1993 Record of Decision, required installation of a pumping system at the Liberty No. 4 well. After delays due to securing an easement for power and pump problems, the Liberty No. 4 well began pumping on October 30, 2001. CDPHE phased out the general “MINDI” permit COG-600000 and replaced it with Individual Permit CO-0048952 in October 2014, under which the well is currently operating.

Water samples, field parameters, and flow measurements are taken in accordance with CDPHE Permit No CO-0048952. Discharge from the well is measured weekly using an in-line flow meter that records both instantaneous flow and total gallons. In early December 2015, a discrepancy was identified between the total gallons pumped, developed using the instantaneous readings and the run time, and the totalizer reading on the meter1. Cleaning the flow meter did not resolve the discrepancy; therefore, the meter was replaced in 2016.

Chronological list of key dates in 2016:

• January to early March 2016 – flow 150 gpm • Totalizing meter replaced on February 3, 2016 • Flow gradually increased beginning March 1, 2016 to 192 gpm by April 1, 2016 • Flowed at 192 gpm until end of April 2016; specific conductance increases to

577 umhos/cm and flow decreased to 150 gpm • Zinc sample collected to verify zinc content in discharge; late April 2016 • Zinc results were normal, flow turned back up to 175 gpm on May 19, 2016 and

up to 190 gpm by end of May 2016 • Pump out of service during June 2016 • Pump replaced on June 30, 2016; flow 150 gpm • Meter piping reworked and meter calibrated on August 26, 2016 • Flow 150 gpm until pump seized on October 26, 2016 • No discharge since October 26, 2016

1 For calculation purposes and permit reporting, the higher of the two flow measurements was used



In 2016, 57,900,114 gallons were pumped from the Liberty No. 4 well to Willow Creek, compared to 72 million gallons in 2015. Field parameters and sample results are provided in Appendix B. All permit requirements were met.

Eagle Mine Water Level(measured in the Bleakhouse tunnel)

Figure 3-1

8440.00

8450.00

8460.00

8470.00

8480.00

8490.00

8500.00

8510.00

8520.00

8530.00

8540.00

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Elev

atio

n (f

t am

sl)

Mine Pool 1992 - 2016

8440.00

8450.00

8460.00

8470.00

8480.00

8490.00

8500.00

8510.00

2015 2016 2017

Elev

atio

n (f

t am

sl)

Mine Pool 2015 - 2016

Figure 3-2 Approximate Mine Seep/Adit Locations



4.0 GROUNDWATER MONITORING AND DATA SUMMARY

Section 4 presents an historical background of the groundwater monitoring activities conducted at the Site. Also discussed in this section are the groundwater extraction and diversion systems that were operated in 2016. The Rock Creek groundwater extraction system (siphon) is discussed with the Rock Creek groundwater in Section 4.2. Section 4.3 presents the operation summary of the upgradient groundwater diversion trench (UGDT) at the CTP. Section 4.4 presents the operation summary of the CTP groundwater extraction trenches.

4.1 Belden Area

Several years of water level measurements in seven Belden area monitoring wells indicate that the water table rises in the spring in response to recharge from snowmelt. This rise in the local water table in the Belden area is commensurate with a seasonal increase in the zinc concentration in the Belden reach of the river.

Based on recent sampling, groundwater in the Belden area is moderately acidic (pH range 2.8 to 5.8) and contains elevated concentrations of sulfate, zinc, and other metals leached from sulfide minerals within undifferentiated mineralized source materials in the area and from seepage from the Mill Level of the Eagle Mine.

In 2006, CBS and NewFields proposed to meet the anticipated WQS in Segment 5a by extracting and treating groundwater in Belden. System performance reports (NewFields 2007a, 2007b, 2007c; and 2008) document data collected from Belden wells and the as-built information for the groundwater collection trench constructed in 2007 (this trench is referred to as the Copper Tipple Trench). Figure 4-1 presents the location of the Belden groundwater wells and the Copper Tipple Trench.

A total of 45,900 gallons of water was pumped to the treatment plant from the Mill Level in Belden to maintain a low water level (see Section 3.4) and reduce groundwater recharge.

4.2 Rock Creek

Groundwater within Rock Creek canyon colluvium, also called baseflow, is a source of metal loading to Segment 5a downstream from station E-10. In October 1992, a groundwater extraction system consisting of four, 4-inch diameter wells was installed at a narrow bedrock constriction in lower Rock Creek Canyon near seep S-2. These extraction wells are spaced approximately 15 feet apart and are approximately 15 feet deep with the well bottom in granite. A gravity siphon was installed in one extraction well (RX-3) on June 23, 1993 that has the ability to remove approximately 1 gpm. The siphon was



restarted on April 26, 2016 and ran sporadically (well had to be re-primed almost daily) through June 1, 2016 when water in well was insufficient to maintain the siphon flow.

The EDS-3 pumping well, located at the base of Rock Creek in the colluvium, operated at approximately 12 gpm from April 5, 2016 through May 12, 2016 to intercept shallow groundwater entering the river from Rock Creek.

4.3 CTP Upgradient Groundwater Diversion Trench (UGDT)

The UGDT was originally installed in the late 1980s, but its use was discontinued in 1990 due to elevated metal concentrations in the discharge. Section 9.0 of the CD/SOW required an analysis of the need to reactivate or reconstruct the UGDT. CBS requested reopening the UGDT in 1997 because the CTP cap was complete and water quality of the groundwater in the nearby DT wells was good. In March 1999, CDPHE and EPA agreed that operation of the UGDT benefited the reestablishment of wetland vegetation in Maloit Park and increased the efficiency of the north groundwater extraction trench. The UGDT has flowed seasonally since that time.

The UGDT outfall was flowing at approximately 3 gpm by late-March 2016 and flowed until mid-summer. The UGDT was dry by late July 2016. Monitoring data of flow and field parameters are presented in Appendix C.

4.4 CTP Groundwater Extraction

Two extraction trenches at the CTP intercept groundwater and route it to the WTP surge ponds for treatment. The combined flow from the east groundwater extraction trench and north groundwater extraction trench is measured at the surge ponds by a totalizing meter. Run times are recorded for each of the pumps.

The flow rate from the two trenches was reduced in late 2012 and early 2013 compared to previous years. Partial pipeline blockages were identified and the force main and east trench collection pipe were jetted in 2013. With the replacement of the east trench surface plumbing and jetting in September 2014 the flow rate when both pumps are operating increased to 130 gpm. For 2016, the combined production (both trenches) was approximately 10,536,774 gallons. While the production is slightly less than the average annual production for the last 10 years (12,800,000 gallons), it is consistent with the previous two years (2014 and 2015). The 2016 volume from the trenches represents approximately 9 percent of the total volume treated at the WTP in 2016. Monthly production figures are provided in Appendix C.

Water levels at the east trench are monitored in well ET-1 to assess the effectiveness of pipe cleaning and pumping. Water levels are measured in situ with a HOBO water level



transducer. ET-1 is also manually measured with a water level meter weekly to calibrate the HOBO and to bridge data gaps when the HOBO data is downloaded. The HOBO was pulled from the well in early June 2016 and not replaced until November 2016 due to instrument issues that required sending both the HOBO and its communication shuttle in for maintenance and data retrieval. The 2016 water elevations (non-HOBO) are provided in Appendix C.

An ET-1 water level profile is included as Figure 4-2. High water levels in ET-1 in the Spring are not unusual due to significant recharge from snowmelt. The ET-1 water level peaked during the week of April 6, 2016 and remained high until April 22, 2016. No major maintenance issues were identified in 2016.

Figure 4-1 Belden Area Groundwater Well Locations

Figure 4-2

7982

7983

7984

7985

7986

7987

7988

7989

7990

Wat

er E

leva

tion

(Ft.-

MSL

)

East Trench Monitoring Well ET-1 Water Levels

solid line measured by water level pressure transducer (HOBO) and dashed line by water level meterHOBO measurement are not corrected for atmospheric pressure but rather calibrated to the water level meter



5.0 SUMMARY OF SITE ACTIVITIES

Section 5.0 contains a summary of the key submittals and the significant activities that occurred in 2016.

5.1 Deliverables, Reports, and Letters Completed and Submitted to EPA and CDPHE

• Discharge monitoring reports (DMRs) were filed monthly per the permit requirements for CO-0048952 (Lib-4) and CO-0042480 (WTP).

• Surface Water and Groundwater Monitoring Plan for 2016, dated February 24, 2016 was approved on March 2, 2016.

• 2015 Pipeline Inspection and Maintenance Report, dated March 2016.

• Annual Report for Eagle Mine Site – 2015, dated April 6, 2016.

• Ramboll Environ submitted a formal response on June 10, 2016 to a Compliance Advisory regarding a potential effluent violation for dissolved zinc during the March 2016 DMR reporting period.

• Eagle Mine 2016 Annual Inspection Completion of Recommended Actions, dated October 22, 2016.

• A formal response to the ERWSD and UERWA letter dated October 16, 2016 that provided comments to the 2015 Pipeline Inspection and Maintenance Report was submitted to CDPHE on December 5, 2016.

5.2 Pipeline Operation and Maintenance

• Periodic inspections and maintenance were conducted. Annual maintenance activities were documented in a report 2016 Pipeline Maintenance and Repair submitted in January 2017.

5.3 CDPHE Spill Line Reports

As required by the Emergency Response/Contingency Plan (Environ 2014) all releases from the site are reported to the CDPHE Spill Line. One minor release occurred at the Site in 2016 (March 8, 2016). The related spill report forms for this incident are included in Appendix D. These reports include the initial spill report, as recorded by the Spill Line and the follow-up report, prepared by Ramboll Environ.



• During the daily site inspection on March 8, 2016, a manhole along the mine road to Belden was found to be leaking. The CDPHE Spill Hotline was contacted immediately upon discovery. The manhole is part of the conveyance system and is located approximately 2,000 feet north of the Mine Drawdown (MDD) vault at Rock Creek. The manholes located upstream and downstream of this manhole were not leaking. The cause of the leaking manhole was likely an obstruction within the pipeline downstream of the manhole, which caused the pipeline to back up and leak out of the air relief valve on the pipe located in the manhole. When the leak was discovered, the MDD flow was reduced and the air relief valve was closed which stopped the release. The volume released is unknown but initially conservatively estimated at less than 2,000 gallons, but based on further evaluation is was likely much less (less than 500 to 1,000 gallons). Only a small fraction of the water released entered the Eagle River. The pipeline was jetted on March 9, 2016 to remove the obstruction.

5.4 Site Inspections and Audits

• General site inspections were performed during weekdays with observations recorded on Daily Inspection Forms.

• CDPHE’s annual site inspection was conducted on April 22, 2016.

• An inspection of the WTP was performed by CDPHE on May 26, 2016. No Major Findings or Other Findings were identified in the WTP Inspection Report received dated June 20, 2016.

• Eagle River Fire Department performed their annual inspection of the WTP on June 29, 2016.

• Audit of the Liberty well was performed by CDPHE on July 14, 2016.

• EPA toured the Site on July 21, 2016 with new EPA attorneys.

• Tri-County Fire performed the annual inspection of the WTP fire extinguishers on October 19, 2016.

• Xcel Energy performed a Facility Energy Assessment on October 27, 2016.

5.5 WTP Operation and Maintenance

• The WTP treated 116,357,758 gallons of water, generating approximately 1,908 cubic yards of dewatered sludge. The sludge was placed in the lined Sludge Cell.



• The major plant maintenance activities included.

o New sludge press cloths were installed.

o The lime feed system auger broke on January 1, 2016. Parts were obtained and a welder repaired the auger on January 6, 2016.

o A new squeeze water pump was installed in June 2016.

o A new acid pump was installed on July 26, 2016.

o The road to the WTP from Tigwon Road was graded on August 12, 2016.

o The sludge cell was graded in September 2016 using a bulldozer in preparation for winter operation.

o Electrical repairs and maintenance were performed throughout the year on various WTP components.

o Air compressor repairs and maintenance were performed throughout the year.

o Hach performed routine maintenance and calibration of all Hach monitoring equipment in January and July 2016.

• Other activities included.

o Ramboll Environ and NewFields replaced the high pressure discharge hose in the North Trench sump manhole on March 18, 2016.

o A new pressure gauge was installed in the North Trench sump on March 30, 2016.

o Spot spraying of thistle was performed by Native Habitat around the Site on July 6, 2016.

o Repair activities to the UGDT as required by the CDPHE following the annual site inspection were performed during the weekly inspections throughout the spring and early summer.

o A presentation was given to students at the Vail Ski and Snowboard Academy at Maloit Park on October 26, 2016.

o Water in the sludge cell remaining from snowmelt was pumped from the Sludge Cell into the Lower Pond in August to be treated in the WTP.

o NewFields directed the excavation and removal of accumulated soil from the Tramway Culvert on August 30, 2016. The excavated soil was transported to the Sludge Cell.

o Video inspection of the culvert under Highway 24 that transmits treated water from the WTP to the Eagle River was performed on October 17, 2016 to confirm there were no obstructions in the pipe prior to winter.



o The Sludge Cell was surveyed to quantitatively determine the remaining life of the cell. The remaining volume was determined to be approximately 29,212 cubic yards which equates to over 20 years of storage remaining in the cell.

o An evaluation of the filter press system was performed by the manufacturer on November 17, 2016.

o Non-destructive testing was performed of the WTP tanks on December 1, 2016.

o Additional No Trespassing signs were installed at various locations around the Site.

• Jetting of facility pipelines and structures included the following:

o The pipe between R2 and the clarifier and the tail pipe into the Upper Pond were jetted on February 11, 2016.

o The R1 feed tube was jetted on July 8, 2016.

o The R1 feed tube was jetted on August 25, 2016.

• The Cross Creek Culvert was replaced by CDOT starting in July 2016. Dewatering activities generated water that could not be discharged directly to Cross Creek/Eagle River. Under an agreement with CBS, the contractor transported the water removed from the excavation to the WTP for treatment.

5.6 Liberty Well No. 4 (LIB-4) Operation and Maintenance

• During the year, approximately 57.9 million gallons of water were pumped from the 19-5-E-3 tunnel to Willow Creek.

• The flow reported from the flow meter observed during weekly visits to LIB-4 was variable in January and February 2016. The flow meter was replaced on February 3, 2016, which temporarily resolved the flow measurement issue.

• On June 2, 2016, the LIB-4 was visited for the weekly monitoring. The well was not pumping but the power was on. The pump could not be restarted. Based on the last flow meter reading the pump failed on May 28, 2016. Subsequent maintenance visits to the well site indicated the pump was shorted and was pulled and replaced on June 29-30, 2016.

• Flow measurements of LIB-4 were found to be variable starting in early August 2016. The meter was removed and inspected on August 26, 2016 but did not require cleaning. The meter/pipe was reconfigured to provide straight 10 pipe diameters upstream and 5 pipe diameters downstream of the meter, which resolved the flow measurement issue.



• In response to a concern that an Xcel Energy maintenance power outage in the area may have affected the pump in the LIB -4, an inspection of the well was conducted on October 26, 2016. The pump was not pumping although power was available at the motor. After additional investigations and troubleshooting, it was determined that the pump impellers are jammed. An attempt to pull the pump was conducted on December 1, but the drill rig could not access the well site. The drill rig was rescheduled for March 2017. Therefore, as of December 31, 2016, the well was not operating.

• All discharge permit requirements for CO-00048952 were met during operation.

5.7 Community Involvement and Community Relations

• The Colorado Parks and Wildlife annual fish shock program took place on April 4 through 6, 2016.

• An Eagle River Stakeholders group meeting was held on April 15, 2016 in Avon, Colorado. The primary purpose of the meeting was to introduce the new EPA RPM, Jamie Miller, and to discuss the Battle Mountain Feasibility Study (OU3) and the Eagle Mine status (OU1).

• Ramboll Environ attended the annual Eagle River Valley State of the River community meeting on May 16, 2016 at Colorado Mountain College in Edwards, Colorado.

• Ramboll Environ facilitated a tour of the WTP on August 10, 2016 for members of the Minturn Town Council and the Town Manager.

• An Eagle River Stakeholders group meeting was held on August 17, 2016 in Avon, Colorado. The agenda included the OU3 FS status, OU1 update, the Belden crib wall failure and increased trespassing noted in Gilman.

• CEPHE and EPA presented a status update to the Minturn Town Council on Wednesday September 21, 2016 also attended by Ramboll Environ.

• Ramboll Environ facilitated a tour of the site for Vail Mountain Rescue on September 24, 2016. There were approximately 35 people in attendance including representatives from Vail Mountain Rescue, Eagle River Fire District and the Eagle County Sheriff’s office.

5.8 Planned 2017 Activities and Submittals

• Mine water withdrawal rate will be measured daily as recorded by the SCADA system at the plant and at the totalizing meter on the MDD pipeline located near the mouth of Rock Creek.



• The mine pool elevation will be measured routinely.

• Site personnel will perform general site inspections on weekdays.

• Accumulated water in the Temp Cell and Sludge Cell will be periodically pumped to the WTP surge ponds for treatment.

• Accumulated debris at the Tramway culvert in Belden will be periodically removed.

• Accumulated debris at seep 7 and the WP-8 seep collection facilities will be periodically removed and transported to the Sludge Cell.

• Debris from the beaver dams in upper Rock Creek will be periodically removed and transported to the Sludge Cell.

• Scale will be periodically removed from the pipelines and the sediment traps.

• A 2016 Pipeline Maintenance and Repair report will be prepared for submittal to EPA and CDPHE in 2017.

• A 2016 Annual report will be prepared for submittal to EPA and CDPHE in 2017.

• An FFS Addendum will be prepared in cooperation with EPA and CDPHE quantifying the arsenic load diverted from the river by the alternatives listed in the FFS (NewFields 2013).

• The Lib-4 well will be operated on a full-time basis up to a monthly average of 210 gpm. Samples will be collected to meet the permit requirements.

• The CTP groundwater extraction trenches will continue to operate, pumping groundwater to the WTP surge ponds.

• Rock Creek pumping well EDS-3 will be pumped in the spring to intercept metal load entering the river from Rock Creek.

• The water in the Mill Level in Belden will be removed periodically and treated to maintain a low water level.

• The WTP will continue to operate and upgrades will be made as needed.

• The river and two tributaries will be sampled every other week during March and April, and again in September or October, in accordance with the 2017 Monitoring Plan (NewFields 2017).



• Groundwater sampling of several monitoring wells will be conducted in support of the Five Year Review to be submitted by EPA in 2018.

• A public tour of the site is planned for August 2, 2017



6.0 REFERENCES

Dames & Moore, 1996. Surface Water Sampling and Analysis Plan.

Dames & Moore, 1998. Eagle Mine Annual Site Monitoring and Activity Report 1997.

Environ, 2014. Emergency Response/Contingency Plan, Eagle Mine Superfund Site. March 11.

Natural Resources Conservation Service (NRCS), Snowpack Summary for May 1, 2016 for Colorado. http://www.wcc.nrcs.usda.gov/basin.html

NewFields, 2007a. Eagle Mine Site - Belden Groundwater Extraction System Performance Report. January 19.

NewFields, 2007b. Eagle Mine Site - Belden Groundwater Extraction System Performance Report No. 2. July 25.

NewFields, 2007c. Eagle Mine Site - Belden Groundwater Extraction System Performance Report No. 2, Revision 1. August 21.

NewFields, 2008. Eagle Mine Site - Belden Groundwater Extraction Performance Report No. 3, July 9.

NewFields, 2013. Focus Feasibility Study, Eagle Mine Site, Minturn, Colorado. Prepared for CBS Operations, Inc. January 24, 2013.

NewFields, 2016a. Surface Water and Groundwater Monitoring in 2016, Eagle Mine Site, Minturn, Colorado. Memorandum to CDPHE and EPA prepared on behalf of CBS Operations, Inc. February 24, 2016. Approved on March 2, 2016.

NewFields, 2017. 2016 Pipeline Maintenance and Repair. March 2017.

APPENDIX A SURFACE WATER DATA

A-1 Eagle River Water Quality Data Eagle Mine Site

January through December 2016

Station ID

Sample Date and Time

Station DescriptionFlow

Field Temperature

Field Spec. Cond. @25C

Cadmium Dissolved

Calcium Dissolved

(cfs) (Deg. C) (umhos/cm) (mg/L) (mg/L)

Copper Dissolved

(mg/L)

Zinc Dissolved

(mg/L)

Eagle River Water Quality ReportEagle Mine Site, January through December 2016

Magnesium Dissolved

(mg/L)

Calculated Hardness

(mg/L)

Arsenic Total

(mg/L)

Field Temperature

(Deg. C)

E- 3 EAGLE RIVER ABOVE BELDEN3/9/2016 0.5 154 0.00009 J16 13:35 -- 0.002 UJ 0.0264 6.91 68 0.00053 0.5

3/23/2016 NM NM ----0:00 -- -- ---- -- -- NM4/7/2016 3.2 120 0.00013 J12.5 12:50 -- 0.0042 0.0572 5.56 54 0.0017 3.2

4/19/2016 3.3 140 0.00039 14.8 12:30 -- 0.0137 0.0947 6.01 62 0.0008 3.3 9/23/2016 9.5 178 0.0001 U21.5 12:15 -- 0.002 U 0.01 U8.64 89 0.00043 9.5

E-10 EAGLE RIVER ABOVE ROCK CREEK3/9/2016 0.6 148 0.00023 J15 14:00 -- 0.0027 J 0.0922 6.24 63 0.00096 0.6

3/23/2016 0.3 161 0.00042 17.4 11:22 -- 0.005 0.185 7.48 74 0.00053 0.3 4/7/2016 3.3 119 0.00036 12.7 13:20 -- 0.0048 0.14 5.11 53 0.0053 3.3

4/19/2016 3.5 135 0.00057 14.5 13:00 -- 0.008 0.192 5.89 60 0.00081 3.5 9/23/2016 9.2 166 0.00012 19.6 12:40 -- 0.002 U 0.0434 7.9 81 0.00045 9.2

E-12A EAGLE RIVER BELOW OLD TAILINGS3/9/2016 1 185 0.00038 J18.3 12:40 40 A 0.0019 J 0.214 8.27 80 0.0006 1

3/23/2016 0.1 182 0.00042 19.2 10:25 49 A 0.0031 0.208 8.47 83 0.002 0.1 4/7/2016 6.4 135 0.00039 14.2 14:15 64 A 0.0046 0.175 5.84 59 0.0021 6.4

4/19/2016 3.6 149 0.00062 14.7 12:00 91 A 0.0075 0.243 6.05 62 0.0022 3.6 9/23/2016 10 178 0.0001 20.8 11:15 42 A 0.0035 0.0673 8.47 87 0.00085 10

E-15 EAGLE RIVER BELOW CROSS CREEK3/9/2016 1 291 0.00023 J28.1 12:25 -- 0.002 UJ 0.143 14.2 129 0.00059 1

3/23/2016 0.2 189 0.00027 18.6 9:50 -- 0.0292 0.191 8.25 80 0.0019 0.2 4/7/2016 2.9 219 0.00038 22.7 11:30 -- 0.0038 J 0.188 10.4 99 0.0019 2.9

4/19/2016 3.6 178 0.00056 18.4 11:25 -- 0.0057 0.179 8.03 79 0.002 3.6 9/23/2016 10.3 210 0.0001 U24.4 10:30 -- 0.002 U 0.0536 10.1 102 0.00066 10.3

Appendix A-1: Page 1 of 2

NM or "--" - Not Measured NA - Not Available est - Estimated Flow U - Undetected at stated detection limit J - Estimated ConcentrationFlow for E-12A and T-18 from USGS gages, "e" - est due to ice; A - USGS finalized and P indicates the USGS reported this datum as preliminary and subject to revision.

Station ID


Station DescriptionFlow

Field Temperature

Field Spec. Cond. @25C

Cadmium Dissolved

Calcium Dissolved

(cfs) (Deg. C) (umhos/cm) (mg/L) (mg/L)

Copper Dissolved

(mg/L)

Zinc Dissolved

(mg/L)

Eagle River Water Quality ReportEagle Mine Site, January through December 2016

Magnesium Dissolved

(mg/L)

Calculated Hardness

(mg/L)

Arsenic Total

(mg/L)

Field Temperature

(Deg. C)

E-22 EAGLE RIVER ABOVE DOWDS JUNCT.3/9/2016 2.6 310 0.0002 J28.3 11:45 -- 0.002 UJ 0.106 14.3 129 0.00067 2.6

3/23/2016 0.7 203.2 0.00023 20.4 9:20 -- 0.0064 0.152 8.83 87 0.0019 0.7 4/7/2016 3.1 226 0.0003 23.4 11:00 -- 0.004 0.165 10.3 101 0.0015 3.1

4/19/2016 3.4 173 0.0005 18.1 11:00 -- 0.0058 0.179 7.43 76 0.0023 3.4 9/23/2016 10.9 227 0.0001 U25.4 10:15 -- 0.002 U 0.0429 10.4 106 0.00061 10.9

T-10 ROCK CREEK AT MOUTH3/9/2016 1.5 557 0.0039 42.3 14:05 0.22 est 0.0057 2.01 37.4 259 0.0018 1.5

3/23/2016 0.5 455 0.0028 33.1 11:30 0.78 0.0087 1.56 26.2 190 0.0021 0.5 4/7/2016 8.6 404 0.0022 30.3 13:15 1 0.0095 1.05 23.4 172 0.0036 8.6

4/19/2016 5.9 502 0.0063 39.9 13:10 1.11 0.0135 2.93 31.5 229 0.0017 5.9 9/23/2016 451 8.8 0.002 43.4 12:45 0.22 est 0.0044 0.947 29.5 230 0.0031 451

T-18 CROSS CREEK NEAR MOUTH3/9/2016 0.6 99 0.0001 UJ8.91 12:10 4.7 A 0.002 UJ 0.0595 3.49 37 0.00033 0.6

3/23/2016 0.1 126 0.0001 U11.2 10:05 6.9 A 0.0015 J 0.0669 4.61 47 0.0013 0.1 4/7/2016 2.8 105 0.0001 UJ10.3 11:55 12 A 0.0019 J 0.0438 4.23 43 0.00086 2.8

4/19/2016 3.5 83 0.0001 U8 11:40 15 A 0.0023 0.0404 2.71 31 0.0009 3.5 9/23/2016 11.1 85 0.0001 U8.84 11:00 8.8 A 0.002 U 0.0648 2.77 33 0.00054 11.1

Appendix A-1: Page 2 of 2

NM or "--" - Not Measured NA - Not Available est - Estimated Flow U - Undetected at stated detection limit J - Estimated ConcentrationFlow for E-12A and T-18 from USGS gages, "e" - est due to ice; A - USGS finalized and P indicates the USGS reported this datum as preliminary and subject to revision.

A-2 Eagle River Flow Relationships

\\DHINRICHS-990\Projects\CBS Eagle\Annual Rpts\Annual Rpt 2015\Eagle River Flow Relationships.doc

Appendix A-2

Flow Rates for Eagle River Monitoring Stations

Eagle River Monitoring Station Flow Rate Equations

E-3 - above Belden E-3 Flow = 0.8855 (E-12A Flow) - 0.0872

E-5 - above Fall Creek E-5 Flow = 0.9424 (E-12A Flow) - 2.0748

E-10 - above Rock Creek E-10 Flow = 0.9979 (E-12A Flow) + 1.7100

E-11 - below Rock Creek E-11 Flow = 1.0124 (E-12A Flow) + 1.7416

E-12A - below Old Tailings Pile/Rex Flats E-12A Flow (measured at USGS station 09064600)

E-13B - above Cross Creek E-13B Flow = 1.1390 (E-12A Flow) - 0.2774

E-15 - below Cross Creek E-15 Flow = 1.7333 (E-12A Flow) - 10.918

E-22 – above Dowds Junction E-22 Flow = E-15 Flow (conservative assumption per CDPHE)

The flow at six main stem Eagle River monitoring stations is approximated using a flow rate equation that relates the station flow to that measured at E-12A through interpolation of historical flow records. Graphs used to determine the equation are provided in Eagle Mine Annual Report – 2007, Eagle Mine Site Minturn,

Colorado, prepared by NewFields, February 29, 2008 for CBS Operations Inc.

APPENDIX B EAGLE MINE WATER DATA

B-1 Eagle Mine Drawdown (MDD) Eagle Mine Site

January through December 2016

* Mine water level reading from pressure transducerOpsCalc_201X.xlsxMDD=Discharge Appendix B-1: Page 1 of 6

Table B-1 Eagle Mine DrawdownEagle Mine Site, January through December 2016

Cumulative Average Eagle MineDischarge Discharge Discharge Water Level

Date (gallons/day) (gallons YTD) (gpm) (Ft. MSL)Hours from

Previous Reading1/4/16 221,865 867,275 93.8 1541/5/16 159,387 1,024,338 23.7 111 8,457.12 *1/6/16 125,101 1,185,145 30.8 871/7/16 186,145 1,328,115 18.4 129 8,456.20 *1/8/16 221,017 1,545,295 23.6 153

1/11/16 250,475 2,310,634 73.3 1741/12/16 281,784 2,612,965 25.7 1961/13/16 281,013 2,896,320 24.2 1951/14/16 279,344 3,139,970 20.9 194 8,456.43 *1/15/16 279,355 3,418,549 23.9 1941/18/16 278,679 4,241,814 70.9 1941/19/16 278,658 4,562,464 27.6 1941/20/16 278,695 4,821,805 22.3 1941/21/16 279,557 5,109,516 24.7 1941/22/16 277,823 5,382,130 23.5 193 8,456.20 *1/25/16 289,337 6,231,052 70.4 2011/26/16 246,019 6,504,236 26.7 1711/27/16 277,858 6,768,973 22.9 1931/28/16 276,801 7,046,543 24.1 192 8,456.20 *1/29/16 277,467 7,347,325 26.0 1932/1/16 272,436 8,227,445 77.5 1892/2/16 280,483 8,417,745 16.3 1952/3/16 281,708 8,735,645 27.1 1962/4/16 280,093 9,019,045 24.3 1952/5/16 305,131 9,321,421 23.8 212 8,455.74 *2/8/16 279,449 10,133,765 69.8 1942/9/16 280,980 10,378,842 20.9 195

2/10/16 279,276 10,660,445 24.2 1942/11/16 279,172 10,956,871 25.5 194 8,454.82 *2/12/16 238,185 11,214,408 26.0 1652/15/16 274,639 11,998,845 68.5 1912/16/16 304,551 12,327,718 25.9 2112/17/16 281,723 12,586,160 22.0 1962/18/16 280,567 12,875,884 24.8 195 8,454.35 *2/19/16 284,723 13,132,332 21.6 1982/22/16 281,741 13,987,925 72.9 1962/23/16 281,188 14,310,120 27.5 1952/24/16 281,458 14,617,965 26.3 1952/25/16 278,946 14,895,942 23.9 194 8,453.89 *2/26/16 282,894 15,102,415 17.5 1962/29/16 281,519 16,014,029 77.7 1953/1/16 280,471 16,238,795 19.2 195 8,453.43 *3/2/16 282,460 16,577,355 28.8 196





Previous Reading3/3/16 281,854 16,859,405 24.0 196 8,452.97 *3/4/16 288,098 17,124,895 22.1 2003/7/16 285,256 17,997,105 73.4 1983/8/16 285,901 18,287,970 24.4 1993/9/16 232,092 18,490,245 20.9 161

3/10/16 238,780 18,719,905 23.1 166 8,452.04 *3/11/16 265,471 19,048,978 29.8 1843/14/16 259,028 19,812,570 70.7 1803/15/16 262,388 20,072,225 23.8 1823/16/16 261,911 20,327,770 23.4 1823/17/16 261,932 20,585,155 23.6 182 8,451.12 *3/18/16 277,905 20,864,025 24.1 1933/21/16 260,740 21,647,150 72.1 1813/22/16 261,637 21,874,084 20.8 182 8,451.58 *3/23/16 246,847 22,106,532 22.6 1713/24/16 289,967 22,454,895 28.8 201 8,450.43 *3/25/16 312,824 22,772,064 24.3 2173/28/16 308,716 23,710,645 73.0 2143/29/16 331,391 24,040,195 23.9 2303/30/16 316,874 24,341,665 22.8 2203/31/16 315,230 24,656,895 24.0 219 8,449.74 *4/1/16 320,040 25,003,605 26.0 2224/4/16 318,479 25,918,125 68.9 2214/5/16 314,965 26,227,184 23.6 2194/6/16 284,306 26,555,320 27.7 1974/7/16 284,395 26,801,203 20.8 197 8,448.58 *4/8/16 297,726 27,104,925 24.5 207

4/11/16 297,304 28,011,289 73.2 2064/12/16 293,297 28,288,495 22.7 2044/13/16 210,291 28,496,595 23.8 1464/14/16 207,964 28,730,555 27.0 1444/15/16 247,200 28,917,328 18.1 172 8,448.58 *4/18/16 198,971 29,535,244 74.5 1384/19/16 123,166 29,666,536 25.6 864/20/16 130,908 29,791,535 22.9 914/21/16 154,479 29,969,615 27.7 1074/22/16 153,654 30,093,925 19.4 1074/25/16 170,943 30,628,715 75.1 1194/26/16 102,040 30,723,315 22.3 714/27/16 156,868 30,887,264 25.1 1094/28/16 164,014 31,035,332 21.7 1144/29/16 171,935 31,188,760 21.4 119 8,451.81 *5/2/16 165,093 31,717,861 76.9 115





Previous Reading5/3/16 230,893 31,914,280 20.4 1605/4/16 229,334 32,184,225 28.3 1595/5/16 230,035 32,398,285 22.3 160 8,452.04 *5/6/16 257,839 32,666,867 25.0 1795/9/16 254,437 33,434,595 72.4 177

5/10/16 255,955 33,686,995 23.7 1785/11/16 255,897 33,948,756 24.6 1785/12/16 253,789 34,165,005 20.4 176 8,452.97 *5/13/16 229,933 34,404,519 25.0 1605/16/16 37,956 34,517,595 71.5 265/17/16 848,516 35,460,390 26.7 5895/18/16 262,133 35,721,613 23.9 1825/19/16 284,822 35,996,545 23.2 1985/20/16 263,919 36,267,795 24.7 183 8,454.35 *5/23/16 262,281 37,062,835 72.8 1825/24/16 262,601 37,309,935 22.6 1825/25/16 263,278 37,558,221 22.6 1835/26/16 261,849 37,841,345 26.0 182 8,455.05 *5/27/16 265,203 38,083,895 21.9 1845/31/16 263,180 39,135,700 95.9 1836/1/16 262,806 39,413,654 25.4 1836/2/16 287,237 39,671,968 21.6 199 8,457.36 *6/3/16 270,583 39,974,495 26.8 1886/6/16 271,285 40,791,175 72.3 1886/7/16 260,970 40,998,682 19.1 181 8,458.97 *6/8/16 166,265 41,183,074 26.6 1156/9/16 293,879 41,501,035 26.0 204 8,459.90 *

6/10/16 292,031 41,778,870 22.8 2036/13/16 290,357 42,662,040 73.0 2026/14/16 292,296 42,940,939 22.9 2036/15/16 253,719 43,204,525 24.9 1766/16/16 301,928 43,511,695 24.4 210 8,461.28 *6/17/16 300,213 43,793,145 22.5 2086/20/16 299,991 44,655,827 69.0 2086/21/16 299,602 45,006,195 28.1 2086/22/16 311,400 45,318,460 24.1 2166/23/16 311,164 45,611,473 22.6 216 8,461.97 *6/24/16 310,243 45,939,383 25.4 2156/27/16 310,250 46,864,099 71.5 2156/28/16 306,798 47,131,695 20.9 2136/29/16 286,963 47,463,695 27.8 1996/30/16 308,548 47,826,667 28.2 2147/1/16 300,045 48,071,495 19.6 208 8,462.44 *





Previous Reading7/5/16 301,679 49,284,495 96.5 2097/6/16 301,213 49,578,805 23.4 2097/7/16 301,002 49,888,795 24.7 209 8,461.74 *7/8/16 302,246 50,172,780 22.5 210

7/11/16 215,275 50,817,110 71.8 1497/12/16 302,767 51,104,739 22.8 2107/13/16 299,016 51,434,695 26.5 208 8,461.51 *7/14/16 305,899 51,716,165 22.1 2127/15/16 288,066 52,019,635 25.3 2007/18/16 277,461 52,863,195 73.0 1937/19/16 214,382 53,055,692 21.6 1497/20/16 207,674 53,309,371 29.3 1447/21/16 82,959 53,392,445 24.0 587/22/16 128,604 53,521,496 24.1 89 8,461.51 *7/25/16 45,072 53,649,700 68.3 317/26/16 45,111 53,688,044 20.4 317/27/16 45,250 53,737,411 26.2 31 8,462.44 *7/28/16 48,292 53,788,118 25.2 347/29/16 166,321 53,944,390 22.5 1168/1/16 205,392 54,574,688 73.6 1438/2/16 264,267 54,829,045 23.1 1848/3/16 261,037 55,098,965 24.8 1818/4/16 263,426 55,358,915 23.7 1838/5/16 262,244 55,607,500 22.7 182 8,461.74 *8/8/16 260,503 56,404,025 73.4 1818/9/16 261,484 56,706,729 27.8 1828/10/16 257,479 56,930,235 20.8 1798/11/16 258,860 57,173,815 22.6 180 8,461.28 *8/12/16 256,285 57,422,625 23.3 1788/15/16 254,542 58,194,914 72.8 1778/16/16 257,932 58,440,845 22.9 1798/17/16 258,710 58,718,419 25.7 1808/18/16 255,065 58,976,495 24.3 177 8,460.59 *8/19/16 258,190 59,228,947 23.5 1798/22/16 263,082 60,019,107 72.1 1838/23/16 252,199 60,275,684 24.4 1758/24/16 250,822 60,529,990 24.3 1748/25/16 248,700 60,772,645 23.4 173 8,460.13 *8/26/16 258,332 61,023,801 23.3 1798/29/16 256,263 61,794,370 72.2 1788/30/16 295,018 62,109,875 25.7 2058/31/16 301,983 62,421,295 24.8 2109/1/16 301,387 62,680,195 20.6 209 8,459.43 *





Previous Reading9/2/16 303,680 62,969,745 22.9 2119/6/16 303,179 64,215,095 98.6 2119/7/16 303,749 64,557,867 27.1 2119/8/16 299,020 64,816,395 20.7 208 8,458.74 *9/9/16 258,322 65,053,190 22.0 179

9/12/16 254,533 65,845,425 74.7 1779/13/16 255,079 66,094,481 23.4 1779/14/16 253,199 66,350,845 24.3 1769/15/16 254,294 66,590,835 22.6 177 8,458.28 *9/16/16 253,399 66,850,393 24.6 1769/19/16 251,750 67,610,015 72.4 1759/20/16 251,764 67,856,009 23.4 1759/21/16 249,799 68,093,665 22.8 1739/22/16 252,306 68,345,971 24.0 175 8,457.82 *9/23/16 253,905 68,613,100 25.2 1769/26/16 255,163 69,377,348 71.9 1779/27/16 254,648 69,644,375 25.2 1779/28/16 260,440 69,900,836 23.6 1819/29/16 266,196 70,176,645 24.9 185 8,457.36 *9/30/16 257,557 70,401,113 20.9 17910/3/16 255,475 71,186,165 73.7 17710/4/16 255,474 71,448,735 24.7 17710/5/16 256,385 71,666,840 20.4 17810/6/16 255,340 71,943,458 26.0 177 8,456.66 *10/7/16 252,334 72,196,668 24.1 175

10/10/16 251,755 72,965,220 73.3 17510/11/16 251,829 73,201,135 22.5 17510/12/16 251,445 73,502,345 28.7 17510/13/16 248,824 73,725,595 21.5 173 8,456.43 *10/14/16 256,949 73,952,745 21.2 17810/17/16 254,846 74,718,167 72.1 17710/18/16 254,181 74,971,465 23.9 17710/19/16 253,108 75,199,965 21.7 17610/20/16 254,976 75,493,010 27.6 177 8,455.74 *10/21/16 256,840 75,761,087 25.0 17810/24/16 254,660 76,504,200 70.0 17710/25/16 254,609 76,765,881 24.7 17710/26/16 253,292 77,049,075 26.8 17610/27/16 256,844 77,277,381 21.3 178 8,455.51 *10/28/16 252,276 77,531,759 24.2 17510/31/16 253,927 78,306,765 73.3 17611/1/16 253,738 78,546,759 22.7 17611/2/16 289,663 78,849,095 25.1 201





Previous Reading11/3/16 264,700 79,116,185 24.2 184 8,456.89 *11/4/16 255,140 79,366,895 23.6 17711/7/16 250,350 80,081,262 68.5 17411/8/16 181,234 80,268,915 24.8 12611/9/16 264,628 80,540,894 24.7 184

11/10/16 245,199 80,852,160 30.5 17011/11/16 244,418 81,048,373 19.3 170 8,458.05 *11/14/16 239,377 81,746,721 70.0 16611/15/16 241,460 82,011,656 26.3 16811/16/16 242,080 82,236,084 22.3 16811/17/16 242,016 82,472,554 23.4 168 8,458.74 *11/18/16 249,234 82,728,365 24.6 17311/21/16 249,153 83,500,565 74.4 17311/22/16 249,233 83,744,086 23.4 17311/23/16 249,378 83,991,905 23.9 17311/28/16 249,798 85,227,713 118.7 17311/29/16 248,036 85,459,730 22.5 17211/30/16 220,291 85,692,871 25.4 15312/1/16 197,911 85,889,545 23.9 137 8,460.13 *12/2/16 205,984 86,093,097 23.7 14312/5/16 212,449 86,744,165 73.5 14812/6/16 212,938 86,938,471 21.9 14812/7/16 233,700 87,163,245 23.1 16212/8/16 261,449 87,445,029 25.9 182 8,460.82 *12/9/16 249,314 87,692,785 23.9 173

12/12/16 253,314 88,450,088 71.7 17612/13/16 249,587 88,700,715 24.1 17312/14/16 251,427 88,951,967 24.0 17512/15/16 250,376 89,212,775 25.0 174 8,461.28 *12/16/16 250,714 89,469,235 24.6 17412/19/16 253,212 90,224,300 71.6 17612/20/16 251,775 90,459,115 22.4 17512/21/16 251,986 90,717,226 24.6 17512/26/16 252,376 92,001,013 122.1 17512/27/16 252,137 92,262,780 24.9 17512/28/16 250,197 92,470,756 20.0 17412/29/16 250,890 92,746,212 26.3 174 8,462.20 *12/30/16 252,061 93,025,405 26.6 175

B-2 Mine Water Quality Report Eagle Mine Site

2016

Appendix B-2 Mine Water Quality

Parameter units

MILL-3 7/15/2016 14:50Arsenic Total Rec. 0.0172 mg/LCadmium Total Rec. 0.606 mg/LCopper Total Rec. 1.47 mg/LZinc Total Rec. 525 mg/L

Mine Water Quality ReportEagle Mine Site

January - December 2016

Concentration

MILL-3 is a sample of the periodically pumped water from the Mill Level Zinc Dryer Room of the Mill; discharge is located at the Service tunnel

B-3 Liberty Well No. 4 Water Quality Reports Eagle Mine Site

2016

Station ID and Description


Field pHField Temp.

Field Spec. Cond. @25C TSS

Selenium Pot. Diss.

Zinc Pot. Diss

(SU) (Deg. C) (umhos/cm) (mg/L) (mg/L) (mg/L)TDS

(mg/L)Chloride(mg/L)

Hydrogen Sulfide(mg/L)

Copper Pot.Diss(mg/L)

Arsenic Total

(mg/L)

Lead Pot. Diss.

(mg/L)

Cadmium Pot. Diss.

(mg/L)Mercury(mg/L)

Pump Rate(GPM)

Liberty Well No. 4 Water Quality ReportEagle Mine Site, January - December 2016

LIB- 4 LIBERTY WELL AT WILLOW CREEK1/6/2016 7.84 11.4 439 5 U 0.0025 13:10 254 0.5 U0.72 0.0027 0.0043 0.00033 0.000059 0.0776 0.0062 171 est

1/15/2016 7.87 10.7 459 -- --9:24 -- ---- -- ------ ----141 est1/20/2016 7.68 12.3 440 5 U 0.0027 9:35 -- ---- 0.002 0.0017 0.00018 -- 0.057 --73 est1/27/2016 7.66 12.2 464 -- --13:10 -- ---- -- ------ ----73 est2/3/2016 7.69 11.2 437 -- --13:30 -- ---- -- ------ ----146 2/9/2016 7.74 12.8 439 5 U 0.0026 13:30 -- --0.71 0.002 0.0023 0.00016 -- 0.0603 --140

2/19/2016 7.67 12.6 432 -- --10:35 -- ---- -- ------ ----139 2/25/2016 7.64 13.4 426 5 U 0.0026 13:00 -- ---- 0.0021 0.0021 0.00021 -- 0.0612 --151 3/1/2016 7.69 13 430 -- --12:45 -- ---- -- ------ ----151

3/10/2016 7.65 13.6 431 5 U 0.0029 14:00 -- --0.69 0.0025 0.0013 0.0001 U-- 0.0608 --161 3/15/2016 7.66 12.2 439 -- --16:11 -- ---- -- ------ ----161 3/22/2016 7.58 13.5 441 5 U 0.0029 14:00 -- ---- 0.0021 0.0028 0.0003 -- 0.0851 --175 3/29/2016 NM NM NM -- --13:16 -- ---- -- ------ ----0 4/1/2016 7.63 12.8 442 -- --14:15 -- ---- -- ------ ----185 4/6/2016 7.54 13.7 452 5 U 0.0027 14:05 -- --0.75 0.0027 0.0026 0.00018 -- 0.0747 --191

4/14/2016 7.53 14.1 466 -- --14:00 -- ---- -- ------ ----192 4/21/2016 7.53 14.6 461 -- --15:15 -- ---- -- ------ ----193 4/27/2016 7.43 13.5 577 5 U 0.0028 12:45 -- ---- 0.0024 0.0022 0.00023 -- 0.113 --192 5/3/2016 7.51 13.8 428 -- --12:40 -- ---- -- ------ ----152

5/11/2016 7.52 13.2 411 5 U 0.0028 13:56 -- --0.73 0.0021 0.0021 0.00029 -- 0.0609 --152 5/11/2016 NM NM NM -- --14:00 -- ---- -- ------ ----175 5/19/2016 7.56 14.6 420 -- --14:21 -- ---- -- ------ ----176 5/19/2016 NM NM NM -- --14:22 -- ---- -- ------ ----186 5/24/2016 7.5 13.9 440 5 U 0.0024 10:30 -- ---- 0.0023 0.0024 0.00031 -- 0.109 --185 5/24/2016 NM NM NM -- --11:40 -- ---- -- ------ ----190 5/28/2016 NM NM NM -- --19:27 -- ---- -- ------ ----0

6/2/2016 NM NM NM -- --17:24 -- ---- -- ------ ----0

Appendix B-3 Liberty Well No. 4 Water Quality: Page 1 of 2

U - Undetected at stated detection limit J - Estimated value

Station ID and Description


Field pHField Temp.

Field Spec. Cond. @25C TSS

Selenium Pot. Diss.

Zinc Pot. Diss

(SU) (Deg. C) (umhos/cm) (mg/L) (mg/L) (mg/L)TDS

(mg/L)Chloride(mg/L)

Hydrogen Sulfide(mg/L)

Copper Pot.Diss(mg/L)

Arsenic Total

(mg/L)

Lead Pot. Diss.

(mg/L)

Cadmium Pot. Diss.

(mg/L)Mercury(mg/L)

Pump Rate(GPM)

Liberty Well No. 4 Water Quality ReportEagle Mine Site, January - December 2016

6/30/2016 7.68 13.9 409 5 U 0.0028 14:22 228 0.5 U0.69 0.0019 0.0039 0.00035 0.0000038 0.0815 0.002 U148 7/7/2016 7.58 14.5 396 -- --13:00 -- ---- -- ------ ----149

7/12/2016 7.66 14.3 412 5 U 0.003 13:33 -- --0.66 0.002 0.0021 0.00015 -- 0.0627 --149 7/19/2016 7.61 14.3 406 -- --18:51 -- ---- -- ------ ----149 7/26/2016 7.69 14.5 409 5 U 0.0026 11:39 -- ---- 0.0021 0.0021 0.00013 -- 0.067 --149 8/2/2016 7.63 14.9 400 5 U 0.002 14:21 245 0.5 U0.66 0.0026 0.0022 0.00026 0.0000045 0.0691 0.00049 U149 8/9/2016 7.63 14.8 423 -- --14:10 -- ---- -- ------ ----149 est

8/19/2016 7.73 13.8 404 -- --12:04 -- ---- -- ------ ----149 est8/24/2016 7.64 14.1 404 5 U 0.0025 13:05 -- ---- 0.0023 0.0021 0.00019 -- 0.0604 --153 est8/26/2016 7.62 13.8 405 -- --11:35 -- ---- -- ------ ----150 8/30/2016 7.59 14 393 -- --13:05 -- ---- -- ------ ----150 9/7/2016 7.59 14.4 393 5 U 0.0026 13:30 -- --0.7 0.0023 0.002 0.00019 -- 0.056 --150

9/14/2016 7.57 14.1 389 -- --12:20 -- ---- -- ------ ----149 9/21/2016 7.55 14.2 393 5 U 0.0029 13:00 -- ---- 0.0022 0.0023 0.00026 -- 0.0589 --156 est9/27/2016 7.61 14 394 -- --12:35 -- ---- -- ------ ----154 10/4/2016 7.58 13.1 401 -- --12:25 -- ---- -- ------ ----154

10/12/2016 7.6 13.9 401 5 U 0.0026 14:50 242 0.5 U0.74 0.0023 0.0021 0.00023 0.0000052 0.0509 0.002 U154 10/21/2016 7.63 13.1 405 -- --11:15 -- ---- -- ------ ----154 10/24/2016 7.59 13.7 399 5 U 0.0033 13:30 -- ---- 0.002 0.002 0.0002 -- 0.06 --154 10/26/2016 NM NM NM -- --14:39 -- ---- -- ------ ----0

Appendix B-3 Liberty Well No. 4 Water Quality: Page 2 of 2

U - Undetected at stated detection limit J - Estimated value

APPENDIX C GROUNDWATER DATA

C-1 Groundwater Elevation Data Eagle Mine Site

January – December 2016

Well ID DATEMeasuring Point

Elevation (ft Depth to

Water (feet) Elevation (ft MSL)

Groundwater Elevation Data Eagle Mine Site, January - December 2016

BTS-13/22/2016 8,381.18 12.10 8,369.084/5/2016 8,381.18 No Access, snow

ET- 11/5/2016 7,993.37 9.90 7,983.471/7/2016 7,993.37 10.05 7,983.32

1/14/2016 7,993.37 10.10 7,983.271/28/2016 7,993.37 10.20 7,983.172/9/2016 7,993.37 10.20 7,983.17

2/18/2016 7,993.37 10.05 7,983.323/4/2016 7,993.37 9.80 7,983.57

3/10/2016 7,993.37 9.95 7,983.423/31/2016 7,993.37 8.40 7,984.974/5/2016 7,993.37 6.96 7,986.41

4/21/2016 7,993.37 7.50 7,985.874/28/2016 7,993.37 8.95 7,984.425/5/2016 7,993.37 9.50 7,983.87

5/12/2016 7,993.37 9.05 7,984.325/20/2016 7,993.37 9.30 7,984.075/26/2016 7,993.37 9.15 7,984.226/3/2016 7,993.37 9.10 7,984.276/7/2016 7,993.37 8.30 7,985.07 Transducer pulled

6/16/2016 7,993.37 8.50 7,984.877/1/2016 7,993.37 9.12 7,984.257/7/2016 7,993.37 9.30 7,984.078/3/2016 7,993.37 9.90 7,983.47

8/11/2016 7,993.37 9.85 7,983.528/18/2016 7,993.37 10.00 7,983.378/25/2016 7,993.37 10.00 7,983.379/1/2016 7,993.37 10.05 7,983.329/8/2016 7,993.37 9.92 7,983.45

9/15/2016 7,993.37 10.00 7,983.379/23/2016 7,993.37 10.40 7,982.9710/6/2016 7,993.37 10.10 7,983.27

10/20/2016 7,993.37 10.05 7,983.3210/27/2016 7,993.37 10.00 7,983.3711/3/2016 7,993.37 10.08 7,983.29

11/11/2016 7,993.37 10.08 7,983.2911/17/2016 7,993.37 10.08 7,983.2911/22/2016 7,993.37 10.10 7,983.2712/1/2016 7,993.37 10.10 7,983.2712/8/2016 7,993.37 10.04 7,983.33

12/15/2016 7,993.37 10.10 7,983.2712/29/2016 7,993.37 10.08 7,983.29

Appendix C-1 Groundwater Elevation Data: Page 1 of 1

C-2 CTP Groundwater Extraction System Eagle Mine Site

January – December 2016

Notes:North and East Trenches combined total gallons is measured via a flow meter at the surge pond.

Appendix C-2

Month Tot. Gallons Pumped per Month

Cumulative Gallons Pumped

for the Year

Cumulative Gallons Pumped

CTP Groundwater Extraction SystemEagle Mine Site, January - December 2016

January 667,450 667,450 404,586,209February 714,926 1,382,376 405,301,135March 832,961 2,215,337 406,134,096April 1,292,699 3,508,036 407,426,795May 1,187,165 4,695,201 408,613,960June 1,029,981 5,725,182 409,643,941July 889,869 6,615,051 410,533,810August 905,477 7,520,528 411,439,287September 767,778 8,288,306 412,207,065October 771,817 9,060,123 412,978,882November 741,260 9,801,383 413,720,142December 735,391 10,536,774 414,455,533

C-3 Upgradient Groundwater Diversion Trench Eagle Mine Site

2016

Appendix C-3

(gpm) (ft.) (Std Unts) (Deg. C) (umhos/cm)>6.0 * <950 *

UGDT Flowed from 3/??/16 to 7/27/16March-16 under snow4/5/2016 3 flume snowed in4/15/2016 ~5 6.9 3.8 5374/28/2016 3-5 7.0 5.4 5025/5/2016 2-4 7.0 6 4735/12/2016 2-3 7.1 6.8 4845/20/2016 2 7.1 7.4 5075/26/2016 <2 7.0 7.8 5136/4/2016 ~1 7.1 8.8 5096/8/2016 ~1 7.0 9.3 512

6/17/2016 ~1 7.1 9.9 5206/24/2016 <1 7.1 -- --7/1/2016 <1 7.1 11.9 5297/7/2016 <1 7.1 12.5 540

7/13/2016 <1 7.1 12.7 5427/27/2016 Dry

Note*Operational/maintenance standard - action required, see O&M PlanTemperature & SPC measured on 6/24/16 was rejected after review of the data and probe maintenanced

Upgradient Groundwater Diversion TrenchEagle Mine Site, 2016

Monitoring Location Date

Flow Stage/ Level Field pHField

TemperatureField Spec.

Cond. @ 25C

APPENDIX D SPILL REPORTS

Colorado Department of Public Health and Environment Incident / Spill / SSO Release Reporting Water Quality Control Division Five (5) Day Reporting Form

Revised September 2014 Incident Reporting Hotline 1-877-518-5608 Page 1 of 3

Field Services – Grand Junction 222 South 6th Street, Room 232 Grand Junction, CO 81501 Telephone: 970-248-7150 Fax: 970-248-7198 Contact email: [email protected]

Field Services – Pueblo 140 Central Main, Suite 300 Pueblo, CO 81003 Telephone: 719-295-5060 Fax: 719-543-8441 Contact email: [email protected]

Field Services – Denver 4300 Cherry Creek Dr. South, B2 Denver, Colorado 80246-1530 Phone: 303-692-3650 Fax: 303-782-0390 Contact email: [email protected]

Reporting Form: Incident / Spill / Sanitary Sewer Overflow (SSO)

The Water Quality Control Division distinguishes between reporting requirements for spills that occur with respect to activities that result in a discharge that is authorized under a CDPS permit and those that are not. Reporting and management of spills that occur with respect to activities resulting in a discharge authorized under a permit should be performed in accordance with the specific requirements of that permit. If the permit does not require a 5-day report, please provide the information below in writing. For non-permitted activities, or in the case of an activity where a permit does not address reporting of or response to a given spill, please submit this written response to the Water Quality Control Division within five (5) working days of the date of the event. If sufficient space is not provided, please attach other sheets. Please send the completed form with signature via fax or email to the Division’s Field Services office indicated above. If you have any questions please contact the Division’s Field Services Engineer at your earliest convenience. The Field Services County list is available at: http://www.colorado.gov/cdphe/wqcd (Contacts, Inspection services contacts, then Field services contacts).

Prior to the five (5) working day deadline, you may request an extension to submit the report if sample analyses justifiably are going to require more time to analyze than the reporting time allows. To request an extension please send an email to the Division’s Field Services Engineer for the County that the incident / spill / SSO took place or to the email listed above.

Incident Background Information

County Eagle Incident / Spill Number (Division provided) and Spill Date 2016-0120 3/8/16

Type of Incident / Spill / SSO (check one)

Sanitary Sewer Overflow/Reuse Petroleum Product Chemical

WW Treatment Plant Bypass or Upset (through an authorized outfall point) Combined Sewer Overflow Biosolids

Unplanned potable water release (e.g., water line break) Other

Contact Information Potentially Responsible Party (PRP): Contact Name Russ Cepko

Potentially Responsible Party (PRP): Company / Agency CBS Operations, Inc.

PRP Phone / Fax Phone: 412-642-2569 Fax: 412-642-3014

PRP email address [email protected]

CDPS Permit Number: CO-0042480 CDPS Permittee Name: CBS Operations, Inc. Reported by (if not PRP): Contact Name David Heinze

Reported by (if not PRP): Company / Agency Ramboll Environ US Corp

Reported by (if not PRP): Phone / Fax

Phone: 303-382-5474 Fax: 303-382-5499

Reported by (if not PRP): email address [email protected]

Incident Information: Please provide the following information. A Incident / spill / SSO source, cause, and event description.

Response: The release occurred on March 8, 2016 at the Eagle Mine Superfund Site. During the daily site inspection, it was discovered that a manhole was leaking. The manhole is part of the conveyance system and is located along the mine road to Belden, approximately 2,000 feet north of the Mine Drawdown (MDD) vault at Rock Creek. The manholes located upstream and downstream of this manhole were not leaking. The cause of the leaking manhole was likely an obstruction within the pipeline downstream from the manhole which caused the pipeline to back up and leak out of the air relief valve on the pipe located in the manhole. When the leak was discovered, the MDD flow was reduced and the air relief valve was closed which stopped the release. The pipeline was jetted on March 9, 2016 to remove the obstruction.

B Material released (e.g., untreated wastewater, biosolids, specific chemicals or products) and estimated total quantity (e.g., gallons). Please attach MSDS for any and all chemicals or products involved in spill or release.



Response: Material released was mine water from the Eagle Mine that was being conveyed from the mine to the water treatment plant. The volume released is unknown but was initially conservatively estimated at <2,000 gallons but based on further evaluation it was likely much less (<500 to 1,000 gallons).

C Actual or estimated dates and times of the event, including duration and actual date and time spill was fully controlled/stopped. If release is still occurring, the date and time the release is expected to be stopped. Response: The duration of the leak is unknown. Based on the visual evidence of the area upon discovery of the release (minor volume of ponded water around the manhole, minor distance the release traveled at the edge of the road which melted the snow, limited staining from mine water, etc.), it likely (conservatively) started in the morning hours of March 8, 2016 and was stopped upon discovery at 2:30 PM that day.

D Location of release (e.g., address, lat/long, road name and mile marker).

Response: The release occurred at the manhole labeled #16 on the east side of the gravel road approximately 2,000 feet north (downstream) of the MDD vault.

E Describe measures taken or planned to contain, reduce, and clean up spill or release.

Response: The MDD flow was immediatley reduced which stopped the release. The pipeline in this area was jetted the day following discovery of the release to remove the obstruction in the pipe. After snowmelt, if stained soil is visible in the area of the release it will be excavated and relocated to the sludge cell at the Water Treatment Plant.

F Steps taken or planned to prevent reoccurrence of the event.

Response: The pipeline in this area was jetted to remove the obstruction in the pipe to prevent reoccurence of the event. The pipeline will continue to be monitored in accordance with inspection requirements at the Site.

Incident Impact to State Waters (As defined in § 25-8-103(19), C.R.S.). Examples of State waters include: perennial streams, intermittent or ephemeral gulches, ditches, ponds, lakes, reservoirs, irrigation canals, wetlands, stormwater conveyances (when they discharge to surface water), and groundwater. G Did flow or materials reach surface waters of the State? If so, please describe the path of flow to State waters and which

State water body was impacted (e.g., spill impacted a storm drain which was directly connected to Cherry Creek, Colorado River, etc.). If yes, what quantity of material (e.g., gallons) reached the surface water and what was the resulting impact? Response: An unkonwn volume of released water entered the Eagle River. It was initially conservatively estimated that approximately less than half the water that was released reached the river (i.e., <1,000 gallons) but closer inspection revealed that only a fraction of that amount reached the river. Closer inspection revealed that orange-stained mine water released from the manhole did not extend beyond the east edge of the road (opposite side of road from the River). Ponded water present in the area included snowmelt. A berm of snow created from plowing was present on the west side of the road above the river and there were no locations where the snow was melted (i.e., a significant release of ~60 degree Faherenheit water would have melted the snow as it flowed down the slope into the river).

H Were any water quality samples or other samples taken? If so, please describe sampling process and attached results.

Response: Samples were not collected as they were not required in the Site Emergency Response Plan based on the size of the release.

I Did flow or materials reach groundwater of the State? If so, please describe the path of flow to State waters and which State water body impacted (e.g, spill soaked into ground and wet soil was not excavated). If yes, what quantity of material (e.g., gallons) reached the ground or groundwater and what was the resulting impact? Response: Released water likely migrated to groundwater beneath the east side of the road in the area of the release. The volume of material released is unknown but was likely less than 500 to 1,000 gallons.

J Did the incident include any of the following (check if yes)? If so, please include additional details below.

Toxic Chemical Release Fish Kill

Response: The mine water contains metals such as zinc, lead, cadmium and copper. The release was less than the 15 GPM threshold established in the Site Emergency Response Plan which is the conservative limit established at low flow conditions where releases below this threshold have been demonstrated to have little measurable effect on the downstream water users. The Eagle River was well above its assumed low flow which forms the basis for the flow limits for notification.

Incident Impact to Areas or Water Users

K Did the incident / spill / SSO impact any areas (e.g., public use areas including parks or swim beaches) or downstream



water users (e.g., public water suppliers, irrigation diversions)? Please list impacted areas and/or users, their location, and potential impacts. Response: Released water ponded around the manhole, migrated along the gravel road and eventually a very small portion of the released water entered the Eagle River. Downstream water users are located several miles from the release area (the closest water intakes for the Eagle River Water and Sanitation District are located more than 6 miles downstream of the release). As previously discussed, the release was less than the 15 GPM threshold established in the Site Emergency Response Plan which is the conservative limit established at low flow conditions where releases below this threshold have been demonstrated to have little measurable effect on the downstream water users. The Eagle River was well above its assumed low flow which forms the basis for the flow limits for notification.

L How were the impacted area users (e.g., park patrons) and downstream water users notified (e.g., signs posted, list downstream users contact via phone). Response: The Eagle Mine site CDPHE Remedial Project Manager was notified immediately upon discovery of the release followed by a notification to the CDPHE Spill Hotline.

I hereby certify that the information presented above is accurate and complete.

Date Company Typed Name and Title Signature

3.11.16 Ramboll Environ US Corporation

David J. Heinze David J Heinze

Documents

EAGLE MINE ANNUAL REPORT – 2016 EAGLE …...Eagle Mine Annual Report – 2016 April 14, 2017-ii- \\DHINRICHS-990\Projects \CBS Eagle \Annual Rpts \Annual Rpt 2016\ 2016AnnualReport.docx