CLAYBASED GROUTING DEMONSTRATION PROJECT Activity III Project 2

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CLAY-BASED GROUTINGDEMONSTRATION
PROJECTActivity III Project 2
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PROBLEM

• Influx of water through subsurface fracture and
  vein systems intersects underground mine
  workings.
• As the water flows through the fracture system it
  contacts sulfide ore zones.

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PROJECT OBJECTIVE

• Reduce and/or eliminate the influx of water into
  the underground mine system using select source
  control materials.

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SOURCE CONTROL TECHNOLOGY

• Eliminate water from the acid generation equation
• Eliminates transport mechanisms from mobilizing
  the metals/nonmetals.
• Long-term fix which is more cost effective than
  treatment in perpetuity.

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CLAY-BASED GROUT SELECTION

• Comprised of environmentally sound elements
• kaolinitic/illitic clays
• binders
• proprietary additives

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CLAY-BASED GROUTING DEMONSTRATIONPHASE II

• Phase II was canceled (4/95).
• Technology developer claimed only 40 of the
  grout injection was completed during Phase I of
  the project.

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CONCLUSIONS

• Flow decreased by approximately 30 at the mine
  portal.
• The ASARCO earthen dam held a greater percentage
  of water after the grout injection.
• Core drilled areas (SITE/SAIC 1998) showed gt80
  grout coverage.
• Hydraulic testing (SITE/SAIC 1998) resulted in
  "no flow". Only one area allowed flow of 4 gpm
  in a grouted area.

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Underground Mine Source Control Demonstration
Project

• Activity III Project 8

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PROBLEM

• Influx of water through subsurface fracture and
  vein systems intersects underground mine
  workings.
• As the water flows through the fracture system it
  contacts sulfide ore zones.

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PROJECT OBJECTIVE

• Reduce and/or eliminate the influx of water into
  the underground mine system using select source
  control materials.

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Underground Mine Workings on Initial Investigation
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Miller Mine Located in Montana
Miller Mine
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Miller Mine Project Site
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Miller Mine Lower Adit
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Lower Settling Pond at the Miller Mine
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Drift W-2 Drift W-1
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Site Characterization

• Water Quality
• Monitored Weather Conditions
• Monitor Underground Flows within the Mine
• Underground Geologic Survey
• Performed Geophysical Survey of Surface and in
  Underground Workings
• Performed Water Injection Tests
• Performed Dye Tests

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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. Elasticity and strength
• 4. Injectability
• 5. Compatibility
• 6. Freeze-Thaw and Wet-Dry Cycling

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Materials Testing of Source Control Materials
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Field Emplacement

• Grout was placed over W-1 Drift
• Using Water/Dye Test predetermined the amount of
  Grout Injected into each core hole
• Core holes were drilled over and under the
  underground mine workings and perpendicular to
  the fracture system.
• A closed-cell, expandable, Hydro Active Combi
  Polyurethane Grout from de neef Construction
  Chemicals, Inc. was selected for the Project

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Emplacement of the Grout Injection Rod and
Inflatable Packer System
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Grout Tank System
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Plan Map of the Miller Mine Underground Workings
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Drift W-2 Drift W-1
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Field Emplacement (cont.)

• Used inflatable packer system
• Injected water with grout at a 11 ratio
• Dyed grout blue for visibility in W-1 Drift
• Injection pressures between 60 - 160 psi
• Injected a total of 192 gallons of grout

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Dyed Grout
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Map Showing the Grout Injection Holes
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Application Problems and Causes

• Small drifts limited drilling locations
• The remote location required more
  mobilization/prep time
• The additional water was injected to activate the
  grout
• Colder underground conditions increased the grout
  activation time

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Monitoring Results

• Decreased Water Flow from Drift W-1
• Water Quality of all Flows Remains Constant
• Flow from Drift W-2 remains Constant

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Flow at W-1 Flume
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Conclusion and Recommendations

• The application of the polyurethane grout did
  decrease the amount of flow from W-1.
• The water quality was not improved at W-1 due to
  the grout emplacement.
• The flow into the underground workings moved to a
  non-grouted area.
• Using a source control technology will reduce but
  in most cases not eliminate the influx into the
  underground mine workings.