Acidic Mine Water, Fire Road Mine Minto, NB Atlantic Reclamation - - PowerPoint PPT Presentation

Investigation of Spot Treatments for Pockets of Acidic Mine Water, Fire Road Mine Minto, NB

Atlantic Reclamation Conference NBCC Miramichi October 16th, 2018

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The STOZA Corp. Team

• Members
• Troy Dobson, EIT
• Andrew Floyd
• Zach McDougall, Dual MIT
• Otillia McLaughlin
• Spencer Wastle
• Mentors
• Dr. B. Broster, P.Geo
• Dr. J. Day, P.Geo P.Eng
• Gilman Violette, P.Eng
• Steven Rossiter, Dual MIT
• Dr. K. Butler, P.Geo P.Eng
• Dr. N. Susak, P.Geo

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Introduction

• Fire Road Mine opened in 1982
• ~50 000 tons of coal produced
• Coal extracted from seam ~0.5m thick
• Mine active for 4 years until pH levels

declined to 3 and was subsequently shut down

• At end of operations, mine was ~120

ha and disturbed area totalled ~300 ha

• Currently being treated with a hydrated

lime

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Introduction

• Geological Background

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Introduction

• Acid mine drainage
• Acidic water created by the reaction of sulphide

minerals when exposed to air and water

• Naturally formed in common sulphide minerals
• The oxidation of pyrite is the most common

producer of acid mine drainage due to its high sulphur content

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Problem Statement

• The purpose of this design report is to investigate possible in

situ solutions for areas of high acidity, and perform a cost analysis of the possible solutions.

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• Conduct a site visit to collect

field data and evaluate site conditions.

• Examine possible in situ

solutions to treat localized areas of high acidity

• Quantify and incorporate

these solutions with the current site treatment plan

• No surficial disturbance
• Must be within current

solution parameters

• Not interfere with the

hydrogeological dynamics

• Work within seasonal

constraints on the mine site

• Complete work within the
• utline of the team schedule

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Requirements Constraints

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Field Work

• November 4th, 2017
• Electromagnetic geophysical survey using an EM31
• Remarked the geophysical survey lines for

reproducibility

• Water level, temperature and conductivity

measurements

• 4 water samples collected from standing water on site
• 2 soil samples from problematic areas (wells 3 & 17)
• 1 soil sample from non-problematic area (well 27)
• November 17th, 2017
• Slug testing 10 wells chosen based on pH data from

GEMTEC reports

• Delineating standing water on site

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Field School Spring 2018

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• Follow up EM-31 and ERI surveys were

completed in April 2018

• ERI – Electrical Resistivity Imaging an

array of electrodes connected to a central power supply measures voltage drop across electrodes to create a pseudo cross-section.

• Data is subsequently inverted with

software and user defined parameters to create a geologically reasonable cross-section

• Very different groundwater conditions

with extensive standing water and high volume recharge of clean meteoric water

Geophysical Analysis

• The geophysical survey was done using

a Geonics EM-31 Ground Conductivity Meter, a Juniper Systems Data Logger and a Garmin GPS.

• A total of 7 surveys lines were

conducted over the anomalous area of high acidity.

• Standing water delineated with Garmin

GPS

• Used for comparison of previous

geophysical work

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Geophysical Analysis Suite

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• 2014: Peak of 42 mS/m
• 2017: Peak of 40 mS/m, similar

anomaly size, smaller maximum

• Site continues to improve over

time

STOZA Corp November 4th, 2017 survey area

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Geophysical Analysis Suite

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• Standing water shows no correlation with areas
• f high apparent conductivity
• Peak near Well #17
• Soil samples taken from anomalously high

apparent conductivity zones

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Field School Spring 2018, EM-31

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• Results replicated in different

environmental conditions across the site.

• Peak value around 40mS/m
• Maximum conductivity

centered around well 17

Field School Spring 2018, ERI

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Bench Scale Experiment

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A bench scale testing program was conducted to develop a solution to treat the areas of anomalously high acidity Choice of solutions based on:

• Locally sourced
• Economically viable
• Previous success with

treating acid mine drainage (AMD) The proposed treatments included

• Biosolids - WWTP
• Seafood compost - Envirem Organics Inc.
• Hydrated lime sludge

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Bench Scale Experiment

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• Same volume of soil was used for each column
• Same volume of solution was used for each

column

• The experiment ran for 3 weeks
• 140 mL of water weekly
• Water collected on a fixed schedule

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Bench Scale Experiment

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Bench Scale Testing

The following tests were performed throughout and at the end of the bench scale experiments:

• pH
• Water chemistry analysis
• Trace element and total dissolved solids analysis
• utsourced to Research and Productivity Council

(RPC)

• Soil chemistry analysis
• Portable X-Ray Fluorescence (PXRF)

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Bench Scale - Water Chemistry

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1 2 3 4 5 6 7 8 0.5 1 1.5 2 2.5 3 3.5

pH Time (Weeks)

pH Analysis from Bench Scale Test

1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0.5 1 1.5 2 2.5 3 3.5

TDS (Mg/L) Time (Weeks)

Total Dissolved Solids from Bench Scale Test

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Bench Scale - Water Chemistry

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Comparing Trace Elements of Problematic Soil to Treatments at Week 3

Element Problematic Soil - Seafood Compost Problematic Soil - Hydrated Lime Problematic Soil - Biosolids Removed (ppm) Added (ppm) Removed (ppm) Added (ppm) Removed (ppm) Added (ppm)

Aluminium

• 3.71
• 2.53

0.31

• Boron

0.15

• 0.25
• 0.21
• Cadmium

0.10

• Calcium

430.00

• 407.00
• 31.00

Copper 73.01

• 73.61
• 4.50

Iron 1653.80

• 1469.00
• 150.00
• Lead

3.70

• 3.73
• 0.67

Lithium

• 0.10
• Magnesium

32.30

• 28.50
• 1.30

Manganese 9.10

• 4.74
• 1.20
• Nickel

2.20

• 2.21
• 0.82
• Potassium

63.30

• 63.80
• 18.10
• Sodium
• 81.00

38.80

• Strontium

0.52

• 0.49
• 0.15
• Zinc

190.93

• 189.07
• 14.00

Note: Detection limit for analysis was in ppb. To be considered for added and removed columns, the ion's concentration must be greater than ±0.1 ppm to be significant.

• Water chemistry

tested by RPC using Inductively Coupled Plasma Mass Spectrometry (ICP- MS)

• Columns are a

comparison of elements in the problematic soil sample minus the elements in each of the solutions

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Bench Scale - Water Chemistry

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• Absolute concentration of metal ions reported in each solution at Week 3

100 200 300 400 500 600 700 800 900 1000 Al Fe K Ca Pb Mg Mn Zn Concentrations (ppm)

Effluent Water Chemistry Comparison

Seafood Compost Hydrated Lime Sludge Control

Fe ≈ 1680 ppm

Problematic Soil

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Bench Scale - Soil Chemistry

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10000 20000 30000 40000 50000 60000 70000 80000 Al Fe K S Si Concentration (ppm)

Problematic Soil Pre and Post Leaching

Pre Leach Post Leach

• PXRF data from the problematic soil pre- and post-leaching
• Post-leaching shows lower concentrations of elements as they have been

mobilized and carried out by the water

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Bench Scale - Soil Chemistry

• PXRF data comparing the soil columns of the solutions to the problematic soil
• Post-leaching shows an improvement in soil chemistry as a higher concentration
• f elements remained in the soil with treatment

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10000 20000 30000 40000 50000 60000 70000 80000 Al Fe K S Si

Concentration (ppm)

Problematic Soil and Solutions Post Leach

Problematic Soil Pre Leach Problematic Soil Post Leach Hydrated Lime Sludge Post Leach Biosolid Soil Post Leach Seafood Compost Soil Post Leach

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Hydrogeology Models

• 3D Surface Topography
• Water table topography

(unconstrained)

• Vector plots
• 1st Derivative water table

plots

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3D Surface Topography Map

1:6400

25 0m 100m 200m 300m Water table elevation set at 125m above CGVD2013 (Geodetic Sea level)

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Water Table Topography

Contours marked at 1m elevation change.

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N E

UTM NAD 83 NB Stereographic

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125m

Flow Direction

Water table slopes assuming homogeneous site conditions. Significant shallowing in troubled regions.

UTM NAD 83 NB Stereographic 27

E

m/m

N

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1st Derivative Water Table

Visualizes the change

• f the water table
• slope. Colour

variation showing greatest rate of change in slope.

UTM NAD 83 NB Stereographic 28

E N

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Conclusions

• The goal of the project was to find a viable

solution that is economically feasible and can be locally sourced.

• Seafood compost is the best practical spot

treatment based on its results in the bench scale tests and the analysis of the data collected in the field.

• Slope of the water table is relatively flat at the

two hotspots, allowing direct application of solution to soil.

• The application method assumes vertical

infiltration for spot treatment through permeable soil.

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Cost Analysis

Costs Associated with Applying Seafood Compost Treatment to Problem Areas on Site

Apparent Conductivity Cut-off for Area Calculation (mS/m) Area (m2) Cost of Compost $10/ton ($) Cost of Hauling $21.08/ton ($) Cost of Equipment ($) Total Cost ($) 12 24800 $37,855 $79,798 $1,118 $118,770 20 9427 $14,390 $30,334 $732 $45,456 26 1796 $2,741 $5,778 $539 $9,057

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Solution Source Locations

31 Fire Road Mine Envirem Compost Bio-solids

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Environmental Considerations

• In terms of the addition of seafood compost.
• Pros:

1. Aids vegetation growth 2. Create a stable organic soil horizon 3. Prevention of future soil erosion 4. Reduce the amount of water infiltrating in the ground

• Cons:

1. Slight odour 2. Increased presence of rodents, birds, and deer to the site

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Recommendations

• Conduct a hydrogeological investigation to assess the possible water escape along

the hanging wall

• Assess the drainage ditch to ensure its efficiency to prevent possible groundwater

stagnation in problem areas on site

• Further geochemistry and vertical permeability assessments to confirm the viability
• f the proposed seafood compost solution

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References

Monenco Consultants Limited . (1991). Stabilization Plan for the Fire Road Site . Fredericton, NB: Monenco Consultants Limited . Monenco Consultants limited . (1991). Use of Chatham Coke Ash at the Fire Road SIte . Fredericton, NB: Monenco Consultants Limited . NB Coal Limited . (1996 ). Acid Mine Drainage Cover Options and Their Considerations at the Fire Road Mine . Fredericton, NB : NB Coal Limited . NB Coal Limited . (1997 ). Investigation of Metal Hydroxide Solubility from SLudge in Acid Mine Drainage . Minto, NB: NB Coal Limited . NB Coal Limited. (1996 ). Investigation on the Placement of Lime Neutralization on Acid Generating Waste Rock . Minto, NB : NB Coal Limited. New Brunswick Power Coroporation Development Division . (1993 ). Review Of Acid Mine Drainage at NB Coal Ltd.'s Fire Road Site . Fredericton, NB : New Brunswick Power Coroporation Development Division . Phinney, K. (1987). Acid Mine Generation at NB Coal Ltd's Fire Road

• Operation. Minto, NB.

Phinney, K. (1989). Reclamation Study Fire Road Minesite . Fredericton, NB: K.D Phinney. Piercey, S. e. (2014). Analysis of Powdered refrence materials and known samples with a benchtop, field portable X-ray Fluorescence (pXRF) spectrometer: evaluation of performance and potential applications for exploration lithogeochemistry. The Geological Society of LOndon . Ryan Leblanc, A. S. (2014 ). Environmental Characterization of the Fire Road Coal Mine Using Hydrological and Geophysical Investogation Techniques . Fredericton, NB: University Of New Brunswick . Taylor, J. (1996). The Microbiology of Acid Mine Drainage. Three - D Geoconsultants Limited . (1984). The Fire Road - Bog Camp Road 1983-1984 Percussion Drilling Program . Fredericton, NB: Three - D Geoconsultants Limited .

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Al, T., & Butler, K. (2001). Environmental Geoscience, Acid mine drainage in the Minto Coal Fields. Fredericton: Department of Geology.

Al, T., & Butler, K. (2001). Environmental Geoscience, Acid mine drainage in the MInto Coal Fields. Fredericton: Department of Geology. GEMTEC . (1988). Surface and Groundwater Hydrology of the Fire Road Mine Site . Fredericton: GEMTEC .

• GEMTEC. (2014 ). Groundwater Sampling and Analysis June

2013, Former Fire Road Mine SIte . Fredericton : GEMTEC. GEMTEC Consulting Engineers and Scientists. (2010). Groundwater Sampling and Analysis June 2010, Fire Road Mine Site . Fredericton, NB : GEMTEC Consulting Engineers and Scientists. Grace Dearbon Inc. . (1996 ). Evaluation of Options for the Control of AMD Generation at NB Coal Ltd.'s Fire Road Mine Site . Fredericton, NB : Grace Dearbon Inc. . Ian Bragdon, K. H. (2014 ). Fire Road Coal Mine, NB AMD Effects Assessment . Fredericton : University of New Brunswick . Kawatra, S. K., & Eisele, T. C. (2001). Coal Desulfurization: High-efficiency Preparation Methods. Taylor & Francis. Kelsey Cheverie, L. E. (2014 ). 2014 Fire Road Mine Site Preliminary Geochemical & Geophysical Report . Fredericton, NB: Univeristy of New Brunsiwck . LeBLanc, B. R. (2014). Geophysical & Geochemical Investigation on Fire Road Mine ESCI 3713. Fredericton: Univeristy of New Brunswick .

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Acknowledgements

STOZA Corp. would like to thank Michele Coleman of NB power for the opportunity to work on this project, and to the mentors who have helped us throughout its duration.

• Dr. Broster
• Dr. Day
• Mr. Gilman Violette
• Dr. Butler
• Dr. Susak
• Steven Rossiter

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Questions?

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