July 29, 2005 Prepared by: Golder Associates Inc. November 2006 Prepared for: Energy Fuels Resources Corporation 44 Union Boulevard, Suite 600 Lakewood, Colorado 80228 Submitted by: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado 80228
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July 29, 2005053-2348
Prepared by:
Golder Associates Inc.
November 2006 063-2191
073-81694.0001September 2008
Prepared for:
Energy Fuels Resources Corporation44 Union Boulevard, Suite 600
Lakewood, Colorado 80228
Submitted by:
Golder Associates Inc.44 Union Boulevard, Suite 300
Lakewood, Colorado 80228
Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO USA 80228 Telephone: (303) 980-0540 Fax: (303) 985-2080
OFFICES ACROSS AFRICA, ASIA, AUSTRALIA, EUROPE, NORTH AMERICA AND SOUTH AMERICA
PHASE 2 GEOTECHNICAL FIELD AND LABORATORY TEST PROGRAM
PIÑON RIDGE PROJECT MONTROSE COUNTY, COLORADO
Submitted to:
Energy Fuels Resources Corporation 44 Union Boulevard, Suite 600 Lakewood, Colorado 80228
Submitted by:
Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado 80228
2.0 PHASE 2 FIELD EXPLORATION PROGRAM ............................................................. 2 2.1 Drill Hole Exploration Program – Equipment & Methods ................................................. 2 2.2 Drill Hole Exploration Program – Observations................................................................. 4
2.2.1 Evaporation Pond Area ................................................................................................ 5 2.2.2 Tailings Cell Areas ....................................................................................................... 5 2.2.3 Ore Pad Areas ............................................................................................................... 6
2.3 Test Pit Exploration Program .............................................................................................. 6
LIST OF APPENDICES Appendix A Work Plan for the Phase 2 Field Exploration Program Appendix A-1 Work Plan Appendix B Geotechnical Field Exploration Program Results Appendix B-1 Drill Hole Logs Appendix B-2 Core Photos Appendix B-3 Packer Tests Appendix B-4 Test Pit Logs Appendix C Laboratory Test Results Appendix C-1 Index Testing Appendix C-2 Compaction Testing Appendix C-3 Consolidation/Collapse Testing Appendix C-4 Permeability Testing Appendix C-5 Triaxial Testing Appendix C-6 Interface Shear Strength Testing Appendix C-7 Soil-Water Characteristic Curve Testing Appendix D Product Data Sheets Appendix D-1 Bentonite for Permeability Testing Appendix D-2 Geosynthetic Materials Appendix E Liquefaction Evaluation Appendix E-1 Liquefaction Assessment Using SPT Data
evaporation ponds will be shallow, and liner stability is not considered a major concern. Interface
shear testing was conducted to evaluate the following interfaces:
• 60-mil textured high density polyethylene (HDPE) geomembrane manufactured by Poly-Flex Inc. (Poly-Flex) versus drainage geocomposite (representative of the primary or secondary geomembrane liner in the tailings cells in contact with the Leak Collection and Recovery System [LCRS] layer on the cell slopes);
• 60-mil textured HDPE geomembrane manufactured by Poly-Flex versus the following geosynthetic clay liners (GCL):
o Bentomat CLT manufactured by CETCO Lining Technologies (CETCO), with clay side against the geomembrane (a liner system considered for the tailings cells secondary composite liner); and
o Bentomat ST manufactured by CETCO, with woven side against the geomembrane (a liner system considered for the tailings cells secondary composite liner).
• GCL materials versus native compacted soil materials, as follows:
o Bentomat CLT manufactured by CETCO, with laminated HDPE side against soil (a liner system considered for the five-acre ore pad); and
o Bentomat DN manufactured by CETCO, with white nonwoven side against soil (a liner system considered for the five-acre ore pad, but also representative of the GCL adjacent to the subgrade for the tailings cells).
Data sheets on the various geosynthetic materials tested are included in Appendix D. A
double-composite liner system is being considered for construction of the tailings cells and
evaporation ponds, while a single liner system is being considered for the 5-acre ore pad.
It is important that the tests are conducted based on the anticipated conditions in the field, i.e., the test
specimen should be representative of final construction by using the soils planned for underliner
construction, as well as the specific geomembrane liner material planned for construction. Interface
shear testing is used to evaluate the friction angle with respect to translational failure along the liner
system (i.e., geomembrane / GCL; geomembrane / drainage geocomposite; or GCL / compacted soil
interface). The following section presents the results of the interface shear testing as well as the
sample construction, test procedures, and test results.
Where applicable, soil materials were air dried prior to testing. After air drying, the soils were
moisture treated to approximately the optimum moisture content as determined by a standard Proctor
test performed for this material and allowed to hydrate. The soils were compacted to approximately
95 percent of the standard Proctor maximum dry density.
Test Procedure
The interface shear testing was performed in general accordance with the ASTM Standard Test
Method D5321, “Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and
Geosynthetic Friction by the Direct Shear Method.” All tests were conducted at normal stresses of
20, 40, and 80 psi in a direct shear device containing an upper and lower shear box.
Testing Program
The interfaces tested were as described above. The interface shear strength test is performed by
constructing the configuration in the laboratory, placing a normal load onto the configuration, and
shearing the sample at a rate of 0.04 to 0.2 inches per minute (in/min). The tests involving use of soil
materials were allowed to consolidate under the normal load for 12 hours prior to shearing, while the
geosynthetic-only tests were consolidated only 15 minutes prior to shearing.
Test Results
Results of the interface shear tests are summarized as follows:
• Textured geomembrane versus drainage geocomposite: Peak friction angle of 21.2 degrees with residual friction angle of 14.8 degrees;
• Textured geomembrane versus GCL: Peak friction angles ranging from 20.0 to 23.2 degrees with residual friction angles ranging from 12.7 to 13.1 degrees;
• HDPE-laminated GCL versus soil: Peak friction angle of 25.1 degrees with residual friction angle of 13.3 degrees; and
• Reinforced GCL versus soil: Peak friction angle of 35.5 degrees with residual friction angle of 30.5 degrees.
The results of interface shear strength testing are presented in Appendix C-6.
This report has been prepared exclusively for the use of Energy Fuels Resources Corporation (EFRC)
for the specific application to the Piñon Ridge Project. The engineering analyses reported herein
were performed in accordance with accepted engineering practices. No third-party engineer or
consultant shall be entitled to rely on any of the information, conclusions, or opinions contained in
this report without the written approval of Golder and EFRC.
The site investigation reported herein was performed in general accordance with generally accepted
Standard of Care practices for this level of investigation. It should be noted that special risks occur
whenever engineering or related disciplines are applied to identify subsurface conditions. Even a
comprehensive sampling and testing program implemented in accordance with a professional
Standard of Care may fail to detect certain subsurface conditions. As a result, variability in
subsurface conditions should be anticipated and it is recommended that a contingency for
unanticipated conditions be included in budgets and schedules.
Golder sincerely appreciates the opportunity to support EFRC on the Piñon Ridge Project. Please
contact the undersigned with any questions or comments on the information contained in this report.
Respectfully submitted, GOLDER ASSOCIATES INC. Kimberly Finke Morrison, P.E., R.G. James M. Johnson, P.E. Senior Project Manager Principal and Project Director KFM/dls
6 CCR 1007-1, Part 18 – “State Board of Health Licensing Requirements for Uranium and Thorium Processing”, specifically Appendix A (Criteria relating to the operation of mills and the disposition of the tailings or wastes from these operations).
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