Drilling engineering is a high input and risk underground project, which needs the real-time down-hole diagnosis and forecast technique. Drilling string vibration signals contain full and complex vibration waves, which contains the vibration of the drilling string by itself, the vibration stimulated by the interaction of bit and the formation, the vibration induced by colliding between drill st...

The study of faulting and earthquake processes requires direct and near-fi eld observations at the focal depth. Deep mines provide a unique opportunity to make such observations. The linked DAFSAM (Drilling Active Faults Laboratory in South African Mines)-NELSAM (Natural Earthquake Laboratory in South African Mines) projects focus on building an earthquake laboratory in deep gold mines in South...

The design of cement slurry for horizontal wellbores is challenging as it must present very high quality cement slurry properties e.g. zero free water, less than 50 cc API fluid loss value, appropriate rheology and yield point for effective displacement, adequate compressive strength, which is critical for lightweight slurries, and finally stable cement column behind casing. The main objective ...

In rock drilling, bit wear is a major factor in determining bit life, the cost of drilling and may significantly influence the drilling method selected for given rock type. Effective control of bit wear can yield significant cost savings. Prediction of cuttability or drillability requires an understanding of the cutting action and the mode of wear and their interaction with the rock propertiesW...

BACKGROUND Optimal tunnel placement is critical in anterior cruciate ligament reconstructive surgery, yet the method used to drill the tunnels may compromise their placement. HYPOTHESIS An independent drilling method versus a conventional transtibial drilling method will place tunnels in different locations and produce reconstructions with different kinematics. STUDY DESIGN Controlled labor...

The purpose of this study was to compare the performance of chemomechanical caries removal (CMCR) with that of conventional drilling for efficacy of caries removal, time spent, morphological changes and microhardness of surface dentin, and microleakage of subsequent restorations. Forty-six carious deciduous molars were randomly divided into two groups: one each for caries removal by (1) CMCR an...

a r t i c l e i n f o In many mining, civil, and petroleum engineering applications diamond bit drilling is widely used due to high penetration rate, core recovery and its ability to drill with less deviation. Recently, many research have been conducted to estimate the penetration rate of diamond drilling which can be considered as one of the most important parameters in project planning and co...