Malakoff Diggins State Historic Park Humbug Creek Watershed Assessment and Management Recommendations DRAFT. Presentation to DTMC January 15, 2014

Transcription

1 Malakoff Diggins State Historic Park Humbug Creek Watershed Assessment and Management Recommendations DRAFT Presentation to DTMC January 15, 2014

2 Legacy Mines in California Map by California Department of Conservation 2007

3 Get the Mercury Out: Strategic Mercury Clean up Targets Upland sources such as hydraulic and hard rock mines that are contaminated with mercury. Operational Capacity Reservoirs where mercury laden sediments accumulate. DRAFT Conceptual Design by Courtney Chatha for The Sierra Fund 3/1/2013

4 Regional approach to Abandoned Mine Clean-up CABY IRWMP Partners USFS DPR NID SYRCL YWI Submitted Proposal in March 2012 for 5.4 M Sierra Fund SNC project (200k ends 2014)

5 Malakoff Diggins State Historic Park Humbug Creek Watershed Assessment and Management Recommendations DRAFT Presentation to DTMC Mining Toxins Working Group January 15, 2014

6 Acknowledgements California State University Chico; Dave Brown and students Sierra Nevada Conservancy; Lynn Campbell USGS; Charlie Alpers, Jacob Fleck, Jenny Curtis, Jim Howel Sonoma State University; Mark Selverston Holdrege and Kull; Jason Muir State Parks; Tamara Sasaki Syd Brown Rick Humphreys John Lane Kyle Leach Reviewers: Tamara Sasaki, Syd Brown, Jason Muir, Rick Humphreys, Stephen McCord, Victor Izzo, Kendra Zamzow, Charlie Alpers

7 Scope of Assessment 1. Cultural Resource Survey 2. Environmental Assessment 3. Management Recommendations Purpose of Assessment: Inform management and remediation at Malakoff Diggins State Historic Park

8 Environmental Assessment Critical Questions Water Quality Critical Questions Biotic Sampling Critical Questions Erosion, Deposition and Soil Conditions in the Pit Critical Questions Soil Quality Conditions Critical Questions Purpose of Assessment: Inform management and remediation at Malakoff Diggins State Historic Park

9 Key Features and Orientation 1) The Malakoff Diggins hydraulic mine pit 2) Hiller Tunnel 3) North Bloomfield Tunnel 4) Air shafts that are associated with the North Bloomfield Tunnel 5) Diggins Creek which drains the pit into Humbug Creek

10 Water Quality Critical Questions What is the Water Quality Problem? How could the Pit be a source of contamination? Where in the Pit is the contamination? Other water quality problems?

11 Water Quality Critical Questions What is the Water Quality Problem? CQ1: What is the annual sediment and mercury load in Humbug Creek? How much of that load is from storm events? CQ2: Is mercury in Humbug Creek transported primarily as particulate bound mercury rather than in its dissolved form? CQ3: Is the quantity of suspended sediment in Humbug Creek directly correlated with mercury concentration in Humbug Creek? CQ4: Is Diggins Creek a significant source of sediment, mercury and/or other metals to Humbug Creek? How is the water quality at the Gage3 site different than the Road1 site?

12 Humbug Creek Water Sampling Sites Road 1 Hiller 2 Gage 3 Water Quality Sampling Plan

13 Road 1 Humbug Creek Hiller 2 Diggins Creek Gage 3 Humbug Creek and Diggins Creek

14 Discharge (cfs) Discharge (cfs) Humbug Discharge and Sample Dates for Water Year /13/11 12/3/11 12/23/11 1/12/12 2/1/12 2/21/12 3/12/12 4/1/12 4/21/ /23/12 11/12/12 1/1/13 2/20/13 4/11/13 5/31/13 Date Humbug Discharge and Sample Dates for Water Year 2013 Date

15 Discharge (cfs) Pressure Transducer-Stage Discharge Relationship y = x R² = Logger Pressure Transducer a) ISCO Automatic Sampler b) Axiom H2 Data Logger c) DTS-12 Turbidity Sensor d) SDI-12 Pressure Transducer TSS (mg/l) y = x R² = TSS and Turbidity 24.9, Turbidity (NTU) Particulate Mercury (ng/l) Particulate Mercury and Turbidity y = x R² = Turbidity (NTU)

16 Discharge (cfs) Humbug Discharge TSS Calculation Data for Water Year /13/11 12/3/11 12/23/11 1/12/12 2/1/12 2/21/12 3/12/12 4/1/12 4/21/12 Date 2,000,000 1,800,000 1,600,000 1,400,000 1,200,000 1,000, , , , ,000 0 TSS (mg/s) Time Period Start End Days Discharge (AF) Sediment Load (ton) Mercury Load (g) g Mercury per day WY /15/11 4:00 PM 4/27/12 11:45 AM , January 23rd, 2012 Storm 1/18/12 9:30 PM 1/30/12 5:30 PM February 13th, 2012 Storm 2/11/12 6:15 PM 2/16/12 9:15 AM March 2, 2012 Storm 2/26/12 4:15 PM 3/7/12 4:15 PM March 16th, 2012 Storm 3/12/12 7:15 AM 3/26/12 2:45 PM Percent Storm 38% 61% 61% WY /1/12 12:00 AM 3/7/13 1:30 PM , Dec 2nd, 2012 Storm 11/27/12 2:30 PM 12/14/12 2:30 PM Percent Storm 20% 49% 49%

17 Time Period Start End Days Discharge (AF) Sediment Load (ton) Mercury Load (g) g Mercury per day WY /15/11 4:00 PM 4/27/12 11:45 AM , January 23rd, 2012 Storm 1/18/12 9:30 PM 1/30/12 5:30 PM February 13th, 2012 Storm 2/11/12 6:15 PM 2/16/12 9:15 AM March 2, 2012 Storm 2/26/12 4:15 PM 3/7/12 4:15 PM March 16th, 2012 Storm 3/12/12 7:15 AM 3/26/12 2:45 PM Percent Storm 38% 61% 61% WY /1/12 12:00 AM 3/7/13 1:30 PM , Dec 2nd, 2012 Storm 11/27/12 2:30 PM 12/14/12 2:30 PM Percent Storm 20% 49% 49%

18 Humbug Creek Water Sampling Sites Road 1 Hiller 2 Gage 3 Water Quality Sampling Plan

19 600 Storm Events Humbug Creek WY 2012 and Mercury Concentration ng/l Total Mercury Particulate Mercury Disolved Mercury Road 1 Hiller 2 Gage 3 Road 1 Hiller 2 Gage 3 Road 1 Hiller 2 Gage 3 Road 1 Hiller 2 Gage 3 Road 1 Hiller 2 Gage 3 1/23/2012 2/13/2012 3/14/2012 3/16/ /30/2012

20 Hiller Tunnel Discharge January 2012 Storm 100 µg/l 120 µg/l 300 µg/l Concentration of Total Metal /20/2012 9:05am 01/23/ :40pm 01/27/ :00pm 20 9 µg/l 15 µg/l 0 Copper ug/l Lead ug/l Nickel ug/l Zinc ug/l Iron mg/l CTR CCC CDPH Primary MCL

21 Key Features and Orientation 1) The Malakoff Diggins hydraulic mine pit 2) Hiller Tunnel 3) North Bloomfield Tunnel 4) Air shafts that are associated with the North Bloomfield Tunnel 5) Diggins Creek which drains the pit into Humbug Creek

22 60 Mercury Sources in Humbug Creek 2/13/ Mercury Consentration ng/l Total Mercury Particulate Mercury Disolved Mercury 10 0 Humbug (Road 1) Hiller Tunnel (Hiller 2) Humbug (Gage 3) Lake City Tunnel (LCT) Humbug (DS LCT)) North Bloomfield Tunnel (NBT) Humbug (DS NBT)

23 Water Quality Critical Questions What is the Water Quality Problem? CQ1: What is the annual sediment and mercury load in Humbug Creek? How much of that load is from storm events? CQ 1: the annual sediment load is ~1,000 tons/year and the annual mercury load is 250 g/year. And over half the annual sediment and mercury load in Humbug Creek is from storm events. CQ2: Is mercury in Humbug Creek transported primarily as particulate bound mercury rather than in its dissolved form? CQ2: The mercury in Humbug Creek is primarily in particulate bound form-not dissolved CQ3: Is the quantity of suspended sediment in Humbug Creek directly correlated with mercury concentration in Humbug Creek? CQ3: The particulate bound mercury is highly correlated with total suspended sediment in Humbug Creek at Gage3 site (R 2 =0.88, n=16). CQ4: Is Diggins Creek a significant source of sediment, mercury and/or other metals to Humbug Creek? How is the water quality at the Gage3 site different than the Road1 site? CQ4: Humbug Creek has lower levels of metals upstream of Diggins Creek (Road1) and higher levels downstream of the confluence with Diggins Creek (Gage3). Diggins Creek is a source of impaired water quality to Humbug Creek, it is a source of sediment, mercury, copper, lead, nickel, zinc and iron to Humbug Creek during storm events.. How could the Pit be a source of contamination?...

24 Water Quality Critical Questions Where in the Pit? CQ7: What are the sources of mercury and suspended sediment in the pit? CQ8: Is the source of mercury in the discharge of Hiller Tunnel the mine tailings deposited in the south east end of the pit? CQ9: Is the water entering the pit free of mercury, copper, nickel, and zinc?

25 Water Quality Sampling Plan Dec. 2 nd Pit Storm Sampling Sites

26

27 Dec 2 nd 2012 Instantaneous Discharge (cfs) 44 cfs 12 cfs 26 cfs cfs cfs Where is the water coming from?

28 Dec 2 nd 2012 Instantaneous Discharge (cfs) 44 cfs 9 ppm 12 cfs 1ppm 22ppm 26 cfs 2ppm cfs cfs Where is the mercury contamination?

29 Dec 2 nd 2012 Instantaneous PHg 12 cfs 44 cfs 4,000 ng/s PHg 4,000 ng/s PHg 10,000 ng/s PHg 26 cfs 10,000 ng/s PHg cfs 26,000 ng/s PHg cfs Water (cfs) & [mercury] = Hg loads Where is the mercury coming from?

30 Water Quality Critical Questions Where in the Pit? CQ7: What are the sources of mercury and suspended sediment in the pit? Mercury at SS5 and SS13, not enough information CQ8: Is the source of mercury in the discharge of Hiller Tunnel the mine tailings deposited in the south east end of the pit? Not enough information CQ9: Is the water entering the pit free of mercury, copper, nickel, and zinc? Not enough information? CQ7, 8, 9: The largest loads of suspended sediment and particulate bound mercury are areas with the highest discharge coming from the north rim outside the pit (SS15 and SS12). Additional sources of mercury are in the eastern end of the pit (SS13 and SS5) and in the relic mine tailings piles (SS4)...Other water quality problems?

31 Water Quality Critical Questions Other water quality problems? CQ10: Is the North Bloomfield Tunnel contributing to degraded water quality in Humbug Creek? CQ11: Is the Red Shaft contributing to degraded water quality in Humbug Creek?

32 Key Features and Orientation 1) The Malakoff Diggins hydraulic mine pit 2) Hiller Tunnel 3) North Bloomfield Tunnel 4) Air shafts that are associated with the North Bloomfield Tunnel 5) Diggins Creek which drains the pit into Humbug Creek

33 Conceptual Model of the North Bloomfield Tunnel and associated air shafts

34 The Red Shaft

35 Total Mercury Particulate Mercury Disolved Mercury Mercury in North Bloomfield Air Shafts 2,270 ng/l THg 0.51 ng/l Dissolved Hg Mercury Concentration ng/l Mouth Shaft 1 Pond Shaft 2 Shaft 3 Hole Shaft 4 Shaft 5 Red Shaft 6 Green Shaft 7 Blocked Shaft 8 Pond 0

36 Metals in North Bloomfield Tunnel and Airshafts µg/l Arsenic Barium Chromium Copper Lead Nickel Zinc 0 Mouth Shaft 1 Shaft 2 Shaft 3 Shaft 4 Shaft 5 Shaft 6 Shaft 7 Shaft 8 Mouth Shaft 1 Shaft 2 Shaft 3 Shaft 4 Shaft 5 Shaft 6 Shaft 7 Shaft 8 units Arsenic 4.2 ND 2.3 ND ND 5 ND ND ug/l Barium ND ND ug/l Chromium ND 0.53 ND 0.75 ND ug/l Copper 0.6 ND ND 1.7 ug/l Lead ND ND ND ND ND ug/l Nickel 90 ND ND ND ND ug/l Zinc 13 ND ND ND ND ND ug/l

37 Water Quality Critical Questions Other water quality problems? CQ10: Is the North Bloomfield Tunnel contributing to degraded water quality in Humbug Creek? CQ11: Is the Red Shaft contributing to degraded water quality in Humbug Creek? CQ10 & 11: The North Bloomfield Tunnel has elevated total metal concentrations of mercury, nickel and barium. Shaft 5 (the Red Shaft) has elevated levels of mercury, arsenic, nickel, and zinc.

38 MANAGEMENT RECOMMENDATIONS Reduce Turbidity in Humbug Creek Reduce Metal Contamination in Humbug Creek Reduce Erosion in the Pit Address Physical Hazards WHERE? HOW? 1) Hydraulic Mining Pit 2) Red Shaft 3) North Bloomfield Tunnel water and metals 4) North Bloomfield Tunnel-physical hazards

39 1) Hydraulic Mining Pit Management of Sediment and Metals Discharge Option 1 A) No Action Option 1 B) Divert Surface Water Inflow to Hydraulic Pit Option 1 C) Stabilize Hydraulic Pit Option 1 D) Retain Sediment in Hydraulic Pit Option 1 E) Dewater Hydraulic Pit Option 1 F) Treat the Discharged Water

40 Divert Surface Water Inflow

41 Treat Discharge Water from the Pit

42 Proposed Detention Basin the Pit

43 2) Shaft 5 (Red Shaft) Management of Water and Metals Discharge Option 2 A) No Action Option 2 B) Plug Shaft Option 2 C) Apply Discharge to Land Option 2 D) Treat the Discharged Water

44 Boardwalk

45 3) North Bloomfield Tunnel Outfall Management of Water and Metals Discharge Option 3 A) No Action Option 3 B) Plug Outfall Option 3 C) Apply Discharge to Land Option 3 D) Treat the Discharged Water

46 4) North Bloomfield Tunnel and Ventilation Shafts Management of Physical Hazards Option 4 A) No Action Option 4 B) Fence Hazardous Features Option 4 C) Plug Hazardous Features

47 4) North Bloomfield Tunnel and Ventilation Shafts Shaft 2 Shaft 3 Shaft 4

48 4) North Bloomfield Tunnel and Ventilation Shafts

49 Summary of Management Strategies

50 CURRENT STATUS Working Group review of report - Revise and Finalize Fill Critical data Gaps Preliminary Engineering Evaluation of remediation actions Permit and Fund remediation action(s) DOC Physical hazards funds