"Fracture mechanics would be useful in the design of fragmentation and extraction processes of layered rocks in order to achieve desired sizes and shapes at minimum cost (5). However, fracture mechanics of anisotropic media, such as oil shale, is not well understood due to the complexity arising from the anisotropic nature of material properties (12), heterogeneity, presence of bedding planes, etc. It has become necessary i:o devise accurate and convenient methods for the evaluation of fracture toughness of such materials. Moreover, there is Ii definite need for the establishment of a standard test procedure for the determination of fracture toughness of layered materials. Types of cracks encountered in practical applications of layered materials are general in nature; and is, therefore, the use of numerical methods is more appropriate. Among the various approaches reported to determine the stress intensity factors, use of special elements to represent the stress singularities at the crack tip. and strain energy methods are more prominent. Methods involving the determination of stress intensity factors, fracture toughness, and innovative methods involving discs and half discs are presented."