Performance Enhancement of DIAdrill Operations
Conventional drilling of rock, in most mining applications, uses the mechanical impact of a metal tool to create the advancing hole. This technique, which has gradually increased in power and thus penetration rate has, however, certain inherent disadvantages. These range from the overall weight of the equipment which must be located at the free face of the hole to the maintenance of alignment over long distances, particularly with smaller diameter holes, where the limitations of thrust delivery through the small diameter rod can limit performance.
Variation of abrasive feed rate with abrasive injection waterjet system process parameters
A new rock excavation method using an abrasive injection waterjet system has been developed to enhance the efficiency and reduce the vibration of tunnel excavation. The abrasive feed rate is an important factor for the cutting performance and the economical efficiency of waterjet-based excavation. In this study, various experiments were performed to explore the effects of major process parameters for both the abrasive feed rate and the suction pressure occurring inside the mixing chamber when the abrasives are inhaled. Experimental results reveal that the abrasive feed rate is affected by geometry parameters (abrasive pipe height, length, and tortuosity), abrasive parameters (abrasive particle size), and jet energy parameters (water pressure and water flow rate). In addition, the relation between the cutting performance and the abrasive feed rate was discussed on the basis of the results of an experimental study. The cutting performance can be maximized when the abrasive feed rate is controlled appropriately via careful management of major process parameters.
Composite monolayer fabrication by an arc-spray process
A single layer (monotape) technique for fabricating complex high-temperature tungsten-fiber-reinforced superalloy composites is proposed. The fabrication of sheets of arc-sprayed monotape 38 cm wide and 122 cm long has been demonstrated. Composites fabricated using the method are shown to have equal tensile strength and a cleaner matrix than composites fabricated from powder metal cloth monotapes, and the present technique is less expensive than the powder metal fabrication techniques.