Potential environmental health impacts in Alaska Kendra Zamzow - PowerPoint PPT Presentation

� � Potential environmental health impacts in Alaska Kendra Zamzow Alaska Collaborative on Health and the Environment April 30, 2014

ARD � ARD in underground tunnel at Kensington D Chambers Y ellowboy East Fork Carson river, CA, 1969. Lahontan Regional Water Quality Board www.swrcb.ca.gov/rwqcb6 2

pH, redox (reduction-oxidation) � Rock types: sulfides, oxides, silicates, carbonates � PAG, NAG, Acid drainage, metal leaching � Element symbols: � Arsenic As Aluminum Al Selenium Se Manganese Mn Antimony Sb Copper Cu 2 - Sulfate SO 4 Cadmium Cd Iron Fe Zinc Zn Forms of iron: Mercury Hg Fe 2 + , Fe 3 + dissolved iron Fe(OH) 3 yellowboy (solid) Fe 2 0 3 rust (solid) FeS iron sulfide (solid) 3

Acid r rock k drai ainage ge We Wetlands Neutral Drai ainage age ARD in underground tunnel at Kensington D Chambers 4

A mine: two waste streams pit/ tunnels economic Market Mill Uneconomic tailings waste rock (finely ground ore, process chemicals) 5

“Rock” is a mixture of many materials. For the purposes of � mine waste treatment, rock is categorized as potentially acid generating rock (PAG), non-acid generating rock (NAG) PAG Sulfides NAG Carbonates Oxides, silicates, iron carbonate 6

PAG: Acid dissolves Contaminant release is not dependent on the ore being mined -- it’s dependent on what is in the rock matrix � Iron, Aluminum, Manganese � Copper, zinc, cadmium � Lead, Mercury 7

the only chemistry equations in this slideshow Oxygen and water act on pyrite � Iron sulfide + O 2 + H 2 O = Fe 2+ + sulfate + 2 H + Bacteria convert iron ions � Fe 2+ � Fe 3+ Iron and water acting on pyrite � produces a great deal of acid Iron sulfide + Fe 3+ + H 2 O � Fe 2+ + sulfate + 16 H + Perry Canyon, NV 2007 8

NAG: Metal “leaching” Some elements in the rock matrix dissolve better under higher pH and oxidizing conditions � Selenium � Arsenic � Antimony � Molybdenum 9

Impacts along stream length PAG Aluminum Acid flocs metals Iron East Fork Carson river, CA, 1969. Lahontan Regional Water Quality Board www.swrcb.ca.gov/rwqcb6 (Copper, Zinc, Armor Mercury, Iron, Aluminum) Fe, A metals precipitate based on pH and concentration pH Iron Aluminum 10

Impacts along stream length NAG Alkaline metals (Selenium, Fe, A Arsenic, Antimony) metal cycling pH 11

Acid drainage: Formosa Mine, Oregon Copper zinc mine. 1910-1937 and � 1989-1993. Then bankrupt. Contaminated 18 miles of coho � salmon and steelhead habitat. 1994 remedial actions made � some areas worse. Became a Superfund site in 2007. Still working on a final cleanup plan. Releases 4-13 million gallons of � acid drainage every year. U.S. EPA, Fact Sheet: Formosa Mine, Douglas County Oregon, March 2007, http://www.epa.gov/region10/pdf/sites/formosamine/Formosa_Mine_FS_2_12.pdf. Several documents available at ttp://yosemite.epa.gov/r10/cleanup.nsf/5c8919bc41f032578825685f006fd670/2e0107830190476a882571f0006623b0!OpenDocume nt 1 2

Metal leaching: Selenium, Beal Mt Mine, Montana Operated from 1989-1998. Went bankrupt. � Not predicted to harm water. � Selenium in the waste rock seeps into groundwater. Selenium in trout � is high enough to cause reproductive failure and birth defects. 13

Mixed drainage: Mt. Nansen, Yukon Mt. Nansen, Y ukon, Canada. Gold mine. 1997-19 9 9. � o Oxide and sulfide tailings deposited together. Operator went bankrupt. o Cu, As, Cd, Zn o Government installed water treatment plant that cost $500,000 per year. Company bond: $4 45,000. o T ails need to be kept saturated to prevent oxidation of arsenopyrite leading to acid drainage – but water needs to be drained to prevent dam failure. o T otal closure and treatment estimated to cost $23 million Personal review of documents for the Little Salmon/Carmacks First Nation. Many documents available at http://www.emr.gov.yk.ca/aam/mount_nansen.html 14

Mixed drainage: Red Devil? Underground mercury mine operated � 1930s to 1971 As, Sb, Hg � Sulfides and carbonate present. � Groundwater at 20-30’ deep is neutral pH � and oxidized. Shannon and Wilson, 2007. Me mo to BLM, 56 pg. Recent sampling of surface stream found � low pH, yellow-orange water. Cleanup plans ongoing � Ann-Marie Palmieri, DEC 15

Fish are affected by different elements or at different concentrations People ug/ L Fish ug/ L Iron Habitat 1,000 none -- � � � 87 Suffocation Aluminum none -- � � � 3 “Drunk” None -- Copper � � � 5 Deformities Selenium Hair, nails 50 � � � -- None Antimony Heart, GI 6 � � � Growth 150 Heart, 10 Arsenic � � � Cancer Nerves, � 0.8 Mercury � reproduction Nerves 2 � Wate r quality standards for drinking wate r or fre shwate r aquatic life . From ADEC, 2008, Alaska wate r quality crite ria 16 manual for toxic and othe r de le te rious organic and inorganic substance s. De ce mbe r.

Donlin’s mine economic pit Uneconomic Mill Market Arsenic Antimony Arsenic, Antimony Selenium Manganese Sulfate Mercury, Cyanide, Sulfate NAG + PAG 17 http://www.donlingolde is.com/BackgroundDocume nts.aspx

Donlin’s end of life Pit lake T reatment In pe rpe tuity Arsenic, Antimony Manganese Arsenic Mercury, Moly Antimony Cyanide, Sulfate Selenium Sulfate 18

control Acid Drainage and Metal Leaching PAG rock � o chemically neutralized (usually with lime) o prevent oxygen from reaching it (place it underwater, place geotextile covers and/ or soil for vegetation over it) NAG rock � o may need to be covered to decrease leaching 19

Control systems Cover waste rock. � Red Dog, Alaska (1989- current). Lead-zinc mine. Sulfate (total dissolved solids) issues. Covering waste rock to reduce water infiltration. Chemical water � Co-mix PAG and NAG + Chemical treatment � treatment Donlin -- more PAG than NAG – mix waste rock together to Red Dog. ARD. PAG rock will neutralize. require chemical water treatment, probably liming. Chemical water treatment of waste rock runoff for As, Sb, Mn, Hg. Good method for Se removal not yet identified. 2 0

Perpetual treatment costs Equity Silver, BC (1980-1994) – � Silver mine. ARD. Government holds a $50 million bond for perpetual treatment of Cu, Cd, Zn from waste rock. Red Dog, Alaska (1989-current). � Currently bonded for $305 million (up from $21 million in 2005), expecting $10 million per year for perpetual water treatment. Silverton, CO – ARD. Needs a $ 1 2 -$ 17 million water treatment plant. $ 1 million per year to operate. Former � operator has offered $ 6 .5 -$ 10 million. Leviathan mine, CA – ARD. About $ 2 0 million spent setting up treatment systems. $ 1 -$ 2 million per year to � operate. 21

The rock matrix, not the metal being mined, influences � whether the material is acid generating or not Metals can be released under acid and neutral-alkaline � conditions Legacy mines may cost a lot of money to treat � Modern mines plan for treatment, but perpetual treatment � requires large bonds. It may be many decades before we know if predictions were accurate and if mitigating control systems work as planned. 2 2

Kendra Zamzow C ENTER FOR S CIENCE IN P UBLIC P ARTICIPATION (CSP2) kzamzow@ csp2.org 907-746-80 6 5 CS P 2 2 3

acid mine drainage cycle (1) Weathering (pyrite oxidation w/ O 2 ) (2) Bacterial cycling of Fe 2+ and Fe 3+ acid drainage from waste rock, Leviathan mine. K. Zamzow Red iron reactions (1) FeS 2 (s) + 7/2 O 2 + H 2 O = Fe 2+ + 2SO 42- + 2 H + (3) Gunky rusty precipitate (2) 4Fe 2+ + O 2 + 4H + = 4Fe 3+ + 2H 2 O (4) Pyrite oxidization (Fe 3+ ) (3) Fe 3+ + 3H 2 O = Fe(OH) 3 + 3H + (4) FeS 2 (s) + 14 Fe 3+ + 8 H 2 O = 15 Fe 2+ + 2SO 42- + 16 H + 7 0 2 + 28 Fe 2+ + 28 H + --> 28 Fe 3+ + 14 H 2 O Iron oxidizing bacteria Pyrite oxidation 4SO 4 2- + 30 Fe 2+ + 32 H + <-- 28 Fe 3+ + 16 H 2 O + 2 FeS 2 24 24