Source Control Surface Waste Pile Demonstration Project

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Source Control - Surface Waste Pile Demonstration
Project

• Activity III, Project 10

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Problem

• Acid Mine Drainage can be formed when surface and
  groundwater infiltrate surface waste piles that
  are placed in drainages.
• The result is increased metals loading and
  suspended solids in surface waters, erosion, and
  reduced pH.

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Project Objective

• In situ stabilization and/or encapsulation of a
  surface waste pile

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Peerless Mine Located in Montana
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Peerless Mine Surface Waste Pile
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Materials Testing

• 50 source control materials were tested to ASTM
  standards when applicable. Material Testing
  Included
• 1. Permeability
• 2. Acid Resistance
• 3. Applicability
• 4. Compatibility
• 5. Freeze-Thaw and Wet-Dry Cycling
• 6. Elasticity and strength

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Materials Testing of Source Control Materials
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Field Emplacement

• Two Problem Areas - Surface Water and Groundwater
  
• Groundwater Technology - Hydraulic Barrier
  (Surface Water Collection Trench and French Drain
  System)
• Surface Technology - Spray Applied Cover

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Construction of Water Collection Trench and
French Drain
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Water Collection Trench and French Drain
Construction
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Spray-Applied Capping Material

• Easy to spray-apply at site
• Reduces water and wind erosion
• Can be applied on webbed jute fabric or on the
  surface of the pile

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Primary Spray Coating
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Spray-Applied Urethane Material
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Final Spray-Application for the Surface Waste Pile
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Peerless Surface Waste Pile Ready for Top Soil
and Vegetation Application
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Application Problems and Causes

• Pinholes in wet areas
• Low temperatures caused curdling effect and
  increased viscosity
• Sagging on slopes
• Application without jute fabric
• Difficult to spray disturbed soil and around
  large rock

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Conclusion and Recommendations

• The application of the French drain and the
  Spray-applied urethane cover did improve the
  water quality at the Peerless Mine.
• The French drain intercepted much of the
  groundwater.
• The Spray-applied cap decreased infiltration and
  increased erosion control.

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Activity III Project 12SULFATE-REDUCING
BACTERIAREACTOR DEMONSTRATION
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Introduction

• Thousands of abandoned mines in the Western U.S.
  discharge water, commonly called acid mine
  drainage (AMD), that is usually formed in the
  mine where sulfide bearing minerals, particularly
  pyrite, are exposed to oxygen and water as
  described by the following chemical reaction
• FeS2 15/4 O2 7/2 H2O ---gt Fe(OH)3
  2SO42- 4H

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Project Scope

• Conventional treatment strategies for AMD are not
  feasible.
• However, sulfate reducing bacteria (SRB) are
  capable of increasing the pH and reducing the
  load of dissolved metals in the effluent
• Three bioreactors were built at the Calliope
  site.

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Construction Overview

• Three reactors were constructed in the Fall of
  1998.
• Two bioreactors contain a passive pretreatment
  section to increase pH of water before the AMD
  enters the bioreactor chamber. Such a setting
  will enable evaluating the effect of inducing an
  optimal pH and EH into AMD on the efficiency of
  the SRB.

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Bioreactors Components

• Each bioreactor consists of discrete
  chambers each filled with either organic carbon,
  crushed limestone, or cobbles.
• For the pretreatment section, a chamber with cow
  manure was included to lower the EH of AMD.
• Crushed limestone provides buffering capacity to
  increase the pH of AMD in the pretreatment
  section.
• Cobbles, placed in the primary treatment section
  of the bioreactor, constitute a stable substrate
  for bacterial growth.

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Results
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The pH of treated AMD has been in the range of
7 - 10
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.Temperature of AMD changes seasonally with the
temperature of air.
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Oxidation-reduction potential (Eh) of the
influent has always been above 50 mV.
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Microbial Capping Barrier for the Control of
Acid Mine Drainage
Activity III Project 14
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Microbial Capping Barriers
Surface application or subsurface injection of
bacteria and nutrient solutions.
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Microbial Capping Barrier
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Microbial Capping Barrier
O2
H20
C6H12O6
O2 C6H12O6
CO2 H2O
AEROBIC
C6H12O6 H2O
C2H3O2 H2 CO2
Fermentative
ANAEROBIC
C2H3O2 SO42-
H2S HCO3
M2 S2-
MS?
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Microbial Capping Barrier Demonstration

• Column Testing
• Crescent Mine tailings, initiated January, 1999
• Fox Lake tailings, initiated October, 1999
• Mammoth tailings, initiated March, 2000
• Field demonstration at Mammoth Site
• Construction of test cells complete
• Treatment to begin in Spring, 2000

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Crescent Mine Site
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Crescent Mine Site

• Elevated elements
• silver 32.6 mg/kg
• lead 4,570 mg/kg
• cadmium 3.67 mg/kg
• zinc 618 mg/kg
• copper 356 mg/kg

data from the Montana Department of State Lands
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Crescent Tailings Sulfate-Reducing Bacteria vs
Time
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Fox Lake Tailings

• Elevated elements
• Aluminum 50 ppm
• Cobalt 0.3 ppm
• Copper 2 ppm
• Manganese 4 ppm
• Sulfur 720 ppm
• Zinc 20 ppm

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Fox Lake Mine Site
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Conclusions from Column Tests

• Nutrient treatments were effective for decreasing
  oxidation-reduction potential.
• Nutrient treatment of acid-producing tailings
  resulted in an effluent pH increase.
• Nutrient treatments were effective for
  stimulating Sulfate-Reducing bacteria within the
  tailings.

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Mammoth Tailings Site

• Elevated elements
• Aluminum 400-1400 mg/kg
• Arsenic 167-572 mg/kg
• Copper 70-2500 mg/kg
• Lead 10-100 mg/kg
• Manganese 10-1000 mg/kg
• Zinc 20-222 mg/kg

data from the Montana Department of State Lands
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Upper Mammoth Tailings Site
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Upper Mammoth Tailings
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Mammoth Tailings Field Test

• Test cells
• Lined to ensure accurate measurement of influent
  and effluent water volume and quality.
• Treatment cell
• Will receive biocapping treatment beginning in
  Spring, 2000.
• Control cell
• Will be treated with an equivalent amount of
  water to treatment cell.

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Test Cell Schematic
Water supply line
Control valve
Totalizing Flowmeter
Distribution laterals
Effluent Holding Tank
Lined test cell
Totalizing Flowmeter
Buried process control boxes
System effluent line
Surface Drainage
Effluent Valve
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Test Cell Excavation
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Liner Drain Field Installation
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Completed Test Cell
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Mammoth Field Test Status
Test cells constructed Background data
collected Initial nutrient treatment
applied Additional monitoring treatments will
be applied after Spring thaw
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Technology Benefits

• Natural biological process
• In-situ treatment
• Low application costs
• Complete treatment - acidity, metals
• Stabilization of tailings for revegetation

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Tailing Source Control Demonstration Project

• Activity III, Project 15

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Problem

• Wind and water erosion are a major problem
  because of the fine particle size of the tailings
  material.

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Mammoth Tailings Site
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Mammoth Tailings Site
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Project Objective

• Demonstrate the applicability of source control
  technologies for in situ stabilization and/or
  encapsulation of a surface waste pile to prevent
  the influx of water, whether precipitation and/or
  groundwater, thus decreasing AMD formation and
  the erosion of the tailings material.

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Project Phase Approach

• Phase I - Mine Site Selection and Site
  Characterization
• Phase II - Materials Testing and Selection
• Phase III - Field Emplacement, Long-term
  Monitoring and Technology Evaluation

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The Mammoth Tailings Site
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Showing the Erosion Channels at the Mammoth
Tailings Site
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Site Characterization

• Monitor Weather Conditions
• Monitor Soil Moisture
• Perform Soil Analysis (Physical and chemical)
• Perform Air Monitoring
• Perform Erosion Testing

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Materials Testing

• Source control materials were tested to ASTM
  standards when applicable. Material Testing
  Included
• 1. Permeability
• 2. Acid Resistance
• 3. Erosion Testing
• 4. Compatibility
• 5. Freeze-Thaw and Wet-Dry Cycling
• 6. Elasticity and strength

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Materials Testing of Source Control Materials
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Field Emplacement

• Field Emplacement be performed during the Summer
  2000
• The demonstration will consist of placing a
  background and a test plot side-by-side.

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Conclusion and Recommendations

• The demonstration will be performed at the
  Mammoth Tailings Site
• Field Emplacement will occur during the Summer
  2000
• At least two test plots will be used, a
  background and a test plot
• A decision on the materials tested will be made
  during April and May 2000

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Support to SITE Mercury Project/In Situ Mercury
Stabilization Technologies Demonstration
Project Activity III, Project 19
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Background

• The In Situ Mercury Stabilization Technologies
  Demonstration Project will show the effectiveness
  of various technologies for in situ treatment and
  stabilization for mercury-contaminated mine waste
  material.

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Objectives

• The primary goal of the project is to conduct
  comparative mercury stabilization tests using
  mercury-contaminated material.

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Status

• The Sulphur Bank Mine has been identified.
• Characterization is being conducted

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Clear Lake / Hermon Pit
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Hermon Pit (Lake)