Physical modeling of joint's spacing and filling effects on drilling efficiency in mines

Drilling in rocks is the initial stage in extraction operation. Therefore recognition of correct parameters which are interfering on drilling and studying the qualitative and quantitative effects of every one of them would result affects the technical and economical aspect of extraction operation. In the previous studies on drilling, parameter are mainly related to rock material characteristics such as hardness, texture, grain size, density and abrasion were considered. However, in this study rock mass reaction was aimed. For this purpose in order to study the drilling in jointed rocks with different filling materials and spacing of 10, 20, 30, 50 and 100 centimeters, physically modeled in laboratory by using concrete blocks. The models were drilled and the time of drilling was recorded. Results obtained from drilling in the physical models reveal that with reduction in spacing, drilling time is increased exponentially and with reduction in size of filling material, drilling time is increased logarithmically and drilling efficiency is decreased.