2012-02-28_REVISION - M1980244 (69)

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Mr. David A. Kidd, P.E. 29 September 1993 Page 2 The remaining sections of this letter report present: (1) a description of the configuration of the test specimens; (ii) the testing procedures; and (iii) the test results. CONFIGURATION OF THE TEST SPECIMENS An interface direct shear test series was conducted to evaluate-the interfaces between the overliner, geornemorane. and tailings materials. The test series consisted of four interface direct shear tests with each test conducted at a different level of normal stress ranging from 50 to 300 psi (350 to 2,100 kPa) using a freshly prepared test specimen. Table 1 summarizes the general testing conditions that were used for the interface direct shear test series. The configuration of the test specimens used in the test series, from top to bottom, was as follows: • crushed rock overliner; • 80 -mil (2 -mm) thick Gundle smooth VLDPE geomembrane; and • iron clad tailings. Bulk samples of the overliner, geomembrane, and iron clad tailings used in the testing program were provided to GeoSyntec by Golder. Golder also provided information on the compaction characteristics of the iron clad tailings. TESTING PROCEDURES The interface direct shear testirg was performed in general accordance with the American Society for Testing and Materials (ASTM) Standard Test Method D 5321, "Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear Method." The tests conducted at normal stresses ranging from 50 to 150 psi (350 to 1,050 kPa) were conducted in a large direct spear GL3458/GEL93234 GEOSY`TEC CONSULTANTS