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Drilling mechanism of three types of rock drill machines. (a) Top hammer drilling; (b) Down the hole drilling; (c) Rotary drilling.
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This report introduced the types of drilling equipment and their operation mechanisms. The state of the art technologies of the Top-hammer drill equipment were investigated and the technology level of Korean drill industry was compared to that of the advanced country. Based on the investigation, the necessity of fusion research and development in t...
Citations
... As the core component of rock drill, the performance of percussion system decides the whole level of rock drill to a great extent. 8,9 However, the structure of percussion system is complicated, and its working process obeys the hydraulic-mechanical-pneumatic coupling laws, 10 which introduces great difficulty in researching on the percussion characteristic of hydraulic rock drill. J Seo and colleagues [11][12][13] developed an analysis model for rock drill using SimulationX software, which was validated by the static calibration and measurement tests of impact frequency and impact energy under three different supply pressure conditions. ...
Considering the insufficiency of numerical study on the percussion characteristic of hydraulic rock drill, which restricts the improvement of efficiency and reliability, a coupling model including the impact piston, spool valve, impact accumulator, and connecting pipelines was established taking into account the oil compressibility, oil leakage, and pressure drop in valve ports. The rebound velocity of impact piston was calculated based on the stress wave theory. The simulation results revealed the coupling mechanism of percussion system. Pressure curves of the piston’s front-chamber and rear-chamber, and valve’s left-chamber and right-chamber were obtained by field rock drilling test. Then, the velocity curve of impact piston was obtained after judging the striking point through the feature of rear-chamber’s pressure spike, so were the rock drill’s impact energy, impact frequency, and impact power. The simulation and experimental results have consistency. And, on this basis, the influence of spool valve’s damping clearance (δ) and pipeline diameters (d1, d2) connecting the impact piston and spool valve on the percussion performance and system cavitation was researched. The results show that the larger δ is better considering reversal time of spool valve, the impact frequency of rock drill, pressure fluctuation, and cavitation relief. But too large δ will cause over quick impact velocity of the spool valve, which may lead to strong vibration and the damage of spool valve. The optimal value of δ is 0.01 mm by comprehensive consideration. The pipeline diameters have an important influence on the pressure fluctuation and negative pressure in rear-chamber. The diameters should be larger than 18 mm to alleviate the cavitation. This article provides means for the design and research of rock drills.
... In particular note, oil sands plants are mainly located in the cold regions of northern Canada. Therefore, the development of energy resources and the construction of underground pipelines in such an extreme environment, needs to use materials that are highly resistant to wear and exhibit excellent hightemperature and low-temperature hardness [4]. The wear of the equipment is an important matter in the general industries from the financial perspective. ...
... If the workpiece material is assumed moving relative to the rubber wheel with a constant velocity as expressed in Eq. (4). Where N is rotational speed and D is diameter of the rubber wheel, respectively. ...
The surge in demand for natural resources has shifted the focus of the international community toward the development of oil sands, shale oil, shale gas and other non-traditional energy sources. In extreme environments, materials used in petroleum gas plant modules are accompanied by various problems caused by low-temperature brittleness such as damage, corrosion and wear. Many researchers have been conducting studies to discover a suitable material whose lifespan could be improved by performing characteristics analyses and performance assessments. In this study, a material characteristics assessment was conducted based on a wear resistance test on materials that are commonly used at oil sands plants. Prior to a wear resistance test, a chemical composition analysis was performed on each of the specimens, and tensile, impact, hardness and corrosion tests were carried out to examine the correlation between their results with the results of the wear resistance test. Each test was performed according to ASTM G 105 standards, and the change in weight according to wear length was analysed for each material to determine the related tendencies. In addition, the results of the wear test were derived by analysing the change in the mass of the specimen before and after the test, and the surface roughness was assessed to analyse the performance related to wear and define the service life. The aim was to use these results to select a material that would be suitable for the abrasive environment of the key equipment and materials of plants.
In order to achieve the purposes of better energy saving and lower fuel consumption under the condition in which load changes frequently and fluctuates dramatically, the energy-saving control strategy of power system is put forward in a hydraulic surface drilling rig. The structure of power system and working conditions of hydraulic surface drilling rigs are described. The mathematical models of the external characteristic for engine, variable pump, and air screw compressor in hydraulic surface drilling rig are presented in detail. Then the control strategy of power system and the fuzzy PID control algorithm to implement this strategy are proposed to control the engine speed in various working states. The simulation analysis and experimental investigation are carried out to study the fuel consumption in the typical operating conditions by using energy-saving control strategy. Results show that the energy-saving control strategy can reduce fuel consumption for the hydraulic surface drilling rig while ensuring that the system performance is not sacrificed.
The impact system of a high frequency rock drill drifter was modeled. The structure and working principle of the impact system are presented. A performance test system was built using the arm and the hydraulic source of excavator. A mathematical model was developed to analyze the nonlinear hydraulic–mechanical coupling performance for the impact system using bond graph. The simulation was done using the mathematical model and relative parameters in the test. The simulation results satisfied the test, which verified the accuracy of the model. The influences of inlet oil flow, pre-charge pressure for accumulator with high pressure and system setting pressure to impact system performance were determined, which provide the theoretical basis to set operation parameters.
This study experimentally validated the reliability of the lab-scale rock drill apparatus and investigated the effect of bit design factors on the performance of drilling. To test drilling efficiency of a drill bit, a testing system was designed and manufactured. Using the testing system, the drilling rates and specific energy of a conventional drill bit and newly proposed drill bit with different button arrangement were compared. The newly proposed model was tested to be superior in drilling performance than that of the conventional model. The testing system developed in this study could be used to predict and test the performance of newly developed drill bit models. Also, the system has to be improved further for measuring more accurate and quantitative data for future drill bit developments. © 2015, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
Drilling accuracy is known to be one of the most important factors determining blasting efficiency in mining by blast operation. Therefore analysing the causes of drilling error and preparing a countermeasure for minimizing drilling error are very important for blasting efficiency and safety. In this study, causes of drilling error are analyzed with dividing them into controllable factors and uncontrollable factors, and relationship between each cause is also comprehended through field measurement and AHP analysis. Finally, effective measures to help lower the drilling error are proposed with the results from weighting analysis for each factor.
