Surface excavation works in tropically weathered rock are often reported to be challenging due to too many uncertainties such as rock mass and rock material properties, environment, selection of the best excavation method, machine characteristics, cost, and production rate. The heterogeneity of rock mass causes great challenges and difficulties in performing surface excavation work, especially in non-bedded rock mass due exhibits a different nature of profile such as boulders occurrence in the completely highly weathered zone. The objective of this study is to determine the strength index of rock material for assessing the performance of earthwork. Besides that, this study aims to verify the excavation performance of excavating machines involved in the pre-determined rock mass properties. This study involves correlation between rock mass and rock materials with machine productivity data in surface excavation assessment. A selected field test and laboratory testing were conducted at Menang Granite Quarry, Kulaijaya, Johor involving non-beded rock mass. The trial excavation was carried out on site using excavator type CAT349 to confirm determining the hard mass for this area. The result show the Panel 1 and 2 were classified as rock mass which represent fresh to slightly weathered. Hence, recommendation for blasting. Meanwhile, for weathering grade III (Panel 3 and 4), based on field mapping, point load index and machine productivity rate, its hard to categorised the in-situ material between hard or rock mass. Hence, this zone needs to be clarified with other test such as borehole and geophysical survey such as seismic refraction and resistivity. In rock masses with moderate to high weathering, the load index value of strength points and geological characteristics had a significant impact on materials. An extensive study is needed to clarify the selection of excavation methods in relation to tropical granite rock masses’ weathering, geological, and geotechnical features.