Compiled Reference Documents - MCU25/0091 (As Published)

                                                  TERMS FOR ROCK MATERIAL STRENGTH & WEATHERING AND
                                                  ABBREVIATIONS FOR DEFECT DESCRIPTIONS
    ROCK MATERIAL STRENGTH CLASSIFICATION                                 AS1726—2017

    Symbol          Term               Uniaxial         Point Load                                                Field Guide
                                                       Strength Is (50)
                                    Compressive
                                                           (MPa)
                                   Strength (MPa)
    VL        Very Low             0.6 to 2            0.03 to 0.1        Material crumbles under firm blows with sharp end of pick. Pieces up to 30 mm thick can
              Strength                                                    be broken with finger pressure.

    L         Low Strength         2 to 6              0.1 to 0.3         Easily scored with knife. Indentations 1 mm to 3 mm show in the specimen with firm
                                                                          blows of the pick point. A piece of core 150 mm by 50 mm may be broken by hand. Sharp
                                                                          edges of core are friable and break during handling.

    M         Medium               6 to 20             0.3 to 1           Readily scored with a knife. A piece of core 150 mm by 50 mm can be broken by hand
              Strength                                                    with difficulty.

    H         High Strength        20 to 60            1 to 3             A piece of core 150 mm by 50 mm cannot be broken by hand but can be broken by a pick
                                                                          with a single firm blow. Rock rings under hammer.

    VH        Very High            60 to 200           3 to 10            Hand specimen breaks with pick after more than one blow. Rock rings under hammer.
              Strength

    EH        Extremely High       Above 200           Above 10           Specimen requires many blows with geological pick to break through intact material. Rock
              Strength                                                    rings under hammer.

           = Diametral Point Load Test                  = Axial Point Load Test

    CLASSIFICATION OF MATERIAL                        AS1726—2017
    WEATHERING
         Symbol                   Term                                                                  Field Guide
    RS                  Residual Soil (Note 1)        Material is weathered to such an extent that it has soil properties. Mass structure and material texture and
                                                      fabric of original rock are no longer visible but the soil has not been significantly transported.

    XW                  Extremely Weathered           Material is weathered to such an extent that is has soil properties. Mass structure and material texture and
                        (Note 1)                      fabric of original rock are still visible.

    HW                  Highly Weathered (Note 2) The whole rock mass is discoloured, usually by iron staining or beaching to the extent that the colour of the
                                                  original rock is not recognizable. Rock strength is significantly changed by weathering. Some primary miner-
                                                  als have weathered to clay minerals. Porosity may be increased by leaching, or may be decreased due to
                                                  deposition of weathering products in pores.

    MH                  Moderately Weathered          The whole of the rock material is discoloured, usually by iron staining or bleaching to the extent that the
                        (Note 2)                      colour of the original rock is not recognizable, but shows little or no change in strength from fresh rock.

    SW                  Slightly Weathered            Pock is partially discoloured with staining or bleaching along joints but shows little or no change of strength
                                                      from fresh rock.

    FR                  Fresh                         Rock shows no signs of decomposition of individual minerals or colour change.

    Note 1              The term ‘Extremely Weathered rock’ is misleading as the material has soil properties. The word ‘rock’ should be replaced with the name
                        of the original rock of the word ‘material’, eg. Extremely Weathered granite or Extremely Weathered material.

    Note 2              Where it is not possible to distinguish between ‘Highly Weathered’ and ‘Moderately Weathered’ rock the term ‘Distinctly Weathered’ may
                        be used.
                           DEFECT TYPE/DESCRIPTION                                           DEFECT PROFILE                          DEFECT ROUGHNESS
                                                                                   Symbol               Description                       DESCRIPTION
    B           Bedding Parting               V           Vein
                                                                                   PL                   Planar
                                                                                                                             Symbol               Description
    J           Joint                         HB/DB       Handling/Drilling        St                   Stepped
                                                          Break                                                              Sl                   Slickenside
                                                                                   Un                   Undulating
    EW          Extremely Weathered           C           Contact                                                            Sm                   Smooth
                                                                                        DEFECT INFILL DESCRIPTION
                Seam
                                                                                   Symbol               Description          Ro                   Rough
    FZ          Fracture Zone                 L           Cleavage                                                           Vertical Boreholes - The dip
                                                                                   Cn                   Clean: No visible
                                                                                                        coating              (inclination from horizontal) for the
    CZ/S        Crushed Zone/Seam             X           Foliation                                                          defect is given.
                                                                                   Sn                   Stain: Coated 1 to
                                                                                                        3 mm               Inclined Boreholes - The inclination
    IS          Infilled Seam                 S           Schistocity                                                      is measured as the acute angle to the
                                                                                   Vr                   Veneer: < 1 mm     core axis.
    SZ/S        Sheared Zone/Seam                                                  Ct                   Coating: 1 to 3
                                                                                                        mm




Document Set ID: 24031832
Version: 1, Version Date: 14/08/2025