| This work presents an experimental database encompassing known and suspected factors causing in-the-hole deviation when drilling long production holes at Canadian underground mines.; Using this experimental database and previous studies on the subject, an idealized model of minimal detail but complete structure is proposed using the principles of beam bending, the constraining effect of the drill hole on the drill string and simple relationships for bit rock interaction.; Next, the proposed model is programmed digitally to produce a longhole drill deviation simulator, which is first checked for self consistency and stability and then verified against the experimental field results obtained earlier.; The model's prediction agrees, within the known working limits of the simulator, with the trends observed in the field as regards to the effects of pipe weight, hole inclination, hole length and feed force. In addition, the model's prediction shows the crucial importance of geology on the observed deviation process and the three-dimensional nature of drillhole deviation. Because of its scientific basis, the model can be further developed to include additional factors when required. |
