The 3-D Imaging of Drill Core for Fracture Mapping

The Rock Quality Designation (RQD) is a widely used indicator of rock mass strength. This proof of concept research is a step toward the semi-automatic computation of the RQD and is based on 3-D imaging procedures and algorithms to detect fractures in drill core.The images were acquired with a 3-D laser digitizer. Each image file is a point cloud of spatially referenced measurements in Cartesian space. Variations in the z coordinate were used to detect fractures in profile. Natural fractures were distinguished from mechanical breaks by measuring the angle and quantifying the roughness of the fracture trace. The algorithm measured intact lengths of core for the RQD calculation. Established image processing tools were tested on 3-D data. 3-D core models were made.This 3-D approach measures changes in the core surface, not highlights and shadows as with 2-D methods. Limitations arise when there is no detectable change in z.