Geological mapping of entry roof in mines.

摘要

Although strata types and approximate thickness of strata can be obtained from the geological exploration materials of the mine, these do not meet the requirements for roof bolting design because of the ever-changing roof geological properties, including rock strength, discontinuity distribution, and thickness of rock strata. In order to obtain such geological information in a timely manner, the technology of geological mapping of the roof in the mine, which uses the drilling parameters acquired during the drilling process, has been proposed. The study in this dissertation attempts to map the roof geology by developing a new drilling parameter, drilling hardness, to detect the locations of interfaces between rock layers and discontinuities, and to classify the rock types.; In conjunction with the laboratory test, the drilling mechanical model (DMM) and the drilling hardness were successfully developed based on the principle of energy equilibrium. It was found that the values of the monitored drilling parameters were affected by multiple factors, such as rock properties, friction between the drill bit and the rock, energy lost and adjustment of the hydraulic system of the drilling machine. By considering the energy lost, the contact area and friction between the drill bit and rock, the derived drilling parameter, drilling hardness and its slope can be used to effectively detect the locations of interfaces between rock layers. Also, the criteria for using the slope to determine whether it is an interface or a discontinuity were developed. On average, the errors in interface location between the predicted ones and these shown by borehole camera scope and actual core logs are 1.37 inches at Mine A and 1.22 inches at Mine B, respectively.; In addition, the algorithm for classifying/predicting rock type using discriminant analysis was also determined. However, the requirement of obtaining a core log first in order to build the training data for each rock type and updating the group data if roof geology changes significantly limits the applicability of this technology and makes it unfeasible in applying this discriminant analysis in the field.