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Cleats are considered one of the significant permeability-related parameters in coalbed methane (CBM) growth. As critical parameters for CBM extraction, a complete characterisation of cleat distributions and orientation can provide a better tool to indirectly estimate porosity and permeability in coal reservoirs. This chapter presents the outcomes of the production of comprehensive research cleats within Miocene coal seams as part of CBM exploration and development. The majority of data (cross-section view measurement) were collected on mine’s walls. Cleat data were gathered from 16 windows measurement locations with hundreds of cleats were measured from outcrops for several coal seams. Two primary cleat orientations; for face cleats, NNE-SSW and for butt cleats, ESE-WNW. The ratio of low permeability coals appears to have a smaller cleat aperture than high permeability coals. As critical parameters for CBM extraction, a complete characterisation of cleat distributions and orientation can provide a better tool to indirectly estimate porosity and permeability in coal reservoirs.

The correlations between mechanical behaviour, tensile strength, and rock parameters of metasedimentary rock samples in Karak, Pahang’s New Austrian Tunnelling Method (NATM) were statistically evaluated from the rock mechanic laboratory works at the selected sections around 2,000 m of the tunnel (named as NATM-1). According to a statistical analysis, lithotypes, geological structures, and region geology have a significant impact on the mechanical behaviour of the metasedimentary rock. In the Brazilian test, the fracture behaviour of the disc specimens was highly related to the reliability and precision of the experimental data by validations of methods. In this work, the impact of different loading methods and rock lithotypes on the failure mechanism of Brazilian discs was examined utilising five different metasedimentary rock types and three different loading methods. During the loading operation, the strain and displacement fields of the specimens were recorded and evaluated using a computerised strain gauge system. The rock types, according to experimental data, have a significant impact on the peak load and deformation properties of Brazilian discs. With the method below, tensile strength point of a disc specimen is clearly regulated by the material stiffness and tensile–compression ratio. Seismic occurrences have had a substantial impact on changing the rock and exerting forces that may affect its mechanical characteristics as well as its vulnerability to weathering effects or discontinuities. As a result, the goal of this study is to look into the connection between rock mechanics and metasedimentary rock stress analysis in NATM-1, Karak, Pahang.