Geotechnical Report

                                                METHOD OF ROCK DESCRIPTION USED ON LOGS

CLASSIFICATION AND INFERRED STRATIGRAPHY
Rock is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.

 STRENGTH
                                  Point Load
   Symbol           Term         Index, Is(50)                                       Field Guide
                                    (MPa)
      VL             Very         0.03 to 0.1      Material crumbles under firm blows with sharp end of pick; can be peeled
                     Low                           with knife; too hard to cut a triaxial sample by hand. Pieces up to 30 mm
                                                   can be broken by finger pressure.
       L             Low           0.1 to 0.3      Easily scored with a knife; indentations 1 mm to 3 mm show in the specimen
                                                   with firm blows of pick point; has dull sound under hammer. A piece of core 150
                                                   mm long by 50 mm diameter may be broken by hand. Sharp edges of core may
                                                   be friable and break during handling.
      M            Medium           0.3 to 1       Readily scored with a knife; a piece of core 150 mm long by 50 mm diameter
                                                   can be broken by hand with difficulty.
      H              High              1 to 3      A piece of core 150 mm long by 50 mm diameter cannot be broken by hand but
                                                   can be broken with pick with a single firm blow; rock rings under hammer.
      VH             Very           3 to 10        Hand specimen breaks with pick after more than one blow; rock rings under
                     High                          hammer.
      EH          Extremely            >10         Specimen requires many blows with geological pick to break through intact
                    High                           material; rock rings under hammer.
Relationship between Is(50) and UCS (unconfined compressive strength) will vary with rock type and strength, and
should be determined on a site-specific basis. UCS is typically 10 to 30 x Is(50), but can be as low as 5.

ROCK MATERIAL WEATHERING
    Symbol                     Term                                                  Field Guide
                                                   Soil developed on extremely weathered rock; the mass structure and
                              Residual
      RS                                           substance fabric are no longer evident; there is a large change in volume
                                Soil               but the soil has not been significantly transported.
                            Extremely              Rock is weathered to such an extent that it has soil properties - i.e. it either
      EW
                            Weathered              disintegrates or can be remoulded, in water.
                                                   Whole of rock is discoloured, usually by iron staining or bleaching to the
                                                   extent that the colour of the original rock is not recognizable. Rock strength
                      Highly
 HW                                                is significantly changed by weathering. Porosity may be increased by
                     Weathered
                                                   leaching, or may be decreased due to deposition of weathering products in
                                   Distinctly
           DW                                      pores.
                                   Weathered
                                                   Whole of rock is discoloured, usually by iron staining or bleaching to the
                    Moderately                     extent that the colour of the original rock is not recognizable; but shows little
 MW
                    Weathered                      or no change of strength from fresh rock.

                             Slightly              Rock is slightly discoloured but shows little or no change of strength relative
      SW
                            Weathered              to fresh rock.
      FR                       Fresh               Rock shows no sign of decomposition or staining.
 ABBREVIATIONS FOR DEFECT TYPES AND DESCRIPTIONS
Defect Type                                      Coating or Infilling                    Roughness
   BP       Bedding parting                        Cn     Clean                             POL      Polished
   X        Foliation                              Sn     Stain                             S        Smooth
   C        Contact                                Vr     Veneer                            SL       Slickensided
   L        Cleavage                               Ct     Coating or Infill                 S        Smooth
   JT       Joint                                  Clay   Clay                              RF       Rough
   SS/SZ    Sheared seam/zone (Fault)              Fe     Iron oxide                        VR       Very rough
                                                   Qz     Quartz                        Planarity
   CS/CZ    Crushed seam/zone (Fault)
   DS/DZ    Decomposed seam/zone                                                           PR     Planar
   IS/IZ    Infilled seam/zone                                                             UN     Undulating
   S        Schistocity                                                                    ST     Stepped
   V        Vein
   DB       Drilling break



                                                                                                                               Rev3
                                                                                                                        October 2017