Abstract
In order to solve the problem of moving rig quickly and reducing labor intensity in the mine face with trackless transportation conditions, a solution of rubber wheel drill which meets the ...working conditions is put forward. The drilling rig adopts the configuration of double power and double system, the power comes from the engine when moving, to achieve walking, steering, braking and temporary stability, relocation and transfer of high efficiency and flexibility, the power comes from the motor when drilling, to achieve rotation, feed and auxiliary Angle adjustment, safe and pollution-free construction. After the assembly and debugging of the whole machine, ground simulation test and underground industrial test were carried out on the rig. The test results show that the rig has strong maneuverability, one person can complete the moving walking, the maximum walking speed is 20km/h, and the steering is flexible and the braking is safe. The maximum depth of drilling hole construction is 318m, the target area hit rate reaches 77.8%, the working performance is stable, the hydraulic system is stable, and all parameters meet the design requirements. The equipment provides new technical equipment for the mine drilling construction with trackless transportation conditions.
The aim of the study was to develop a modified drilling method (MDM) for a bench drilling machine to enhance the drilling task performance. The MDM and the present drilling method (PDM) were ...evaluated for the subjects of varying age groups (21–30, 31–40 and 41–50 years) while performing the drilling task for different work durations (3, 6 and 9 min) in the sitting and standing working postures. The performance parameters used were metal removal rate (MRR) and perceived discomfort score (PDS). Drilling load required to perform the task and endurance time were also determined for both PDM and MDM. Thirty male subjects were selected to perform the drilling task on a mild steel block at a drilling speed of 700 rpm. The results of the study showed that there was an increase in MRR by more than 140% using MDM. PDS was also reduced appreciably at different body segments using the proposed system. The results of the study further revealed that there was a substantial decrease in the drilling load required to perform the task and a considerable increase in the endurance time.
•Present Drilling Method (PDM) caused awkward posture of arm resulting in MSDs.•A Modified Drilling Method (MDM) was proposed for bench drilling machine.•MRR and PDS were used to evaluate and compare the PDM and MDM systems.•Awkward posture was effectively removed using the Modified Drilling Method.•Productivity enhanced to more than 140% and discomfort was reduced by upto 60%.
This paper sets forth a geomechanics framework for assessing the energy efficiency of rotary percussive drilling using the energy criterion, which has been proposed by Victor Oparin for volumetric ...destruction of high-stress rocks having nonuniform physico-mechanical properties. We review the long-term research and development in the specified area of science and technology, including research and development projects implemented at the Institute of Mining, Siberian Branch of the Russian Academy of Sciences. A new modified expression of Oparin's dimensionless energy criterion of volumetric rock destruction k is introduced. The range of in situ values is determined for the energy criterion of volumetric rock destruction at the optimized energy efficiency of rotary percussive drilling. The temporo-spatial intervals of geotechnical monitoring are found to control pneumatic drilling energy efficiency at subsoil use objects in Russia. The integrated experimental, theoretical and geotechnical approach to the comprehensive investigation of real-time processes of rock fracture in rotary percussive drilling using the energy concept possesses the necessary geomechanical performance-and-technology potential to create the next level geotechnical monitoring of drilling systems for various purposes, including determination of physico-mechanical properties and the stress-strain analysis of rock mass in full-scale drilling.
Zusammenfassung
Ein 78 Jahre alt gewordener Mann hatte sich 8 Bohrlochverletzungen am Hirnschädel bei später diagnostiziertem Aneurysma cerebri beigebracht. Als wahrscheinlichstes Motiv für die ...außergewöhnliche Tat ist ein Vernichtungskopfschmerz anzunehmen. Nach 5‑tägiger Überlebenszeit trat der Tod im Multiorganversagen mit akutem Myokardinfarkt unter Therapiebegrenzung ein. Eine Fremdeinwirkung konnte ausgeschlossen werden.
Matrix cracking, fibre damage, increased hole surface roughness, delamination, circularity, and thermal deterioration, among other things, all occur throughout the drilling process, reducing hole ...quality. The most concerning of the unfavorable effects is delamination. Delamination can be reduced and hole quality improved by using the optimum cutting parameters and drill bit type. When drilling glass fiber/nano granite powder reinforced epoxy composites, the influence of drill bit coating material, drill bit speed, and drill bit feed rate on surface quality is investigated. The Taguchi L9 rotationally symmetric array is used to develop the experiments. As a result, to coincide radial drilling parameters of the process and response parameters, the statistical analysis of the experimental results is done using ANOVA. The results of the tests show that, high spindle speeds and a bronze oxide coated drill bit produce better hole quality and are also the most important factors influencing the drilled hole quality.
Thin coal seam mining is a development direction to solve the problem of energy supply at this stage, which cannot be realized by small working space, low automation, and drilling deviation. In this ...paper, a nonlinear adaptive backstepping controller based on a disturbance observer is proposed and used on a coal auger for position tracking control to achieve directional drilling. Firstly, a nonlinear dynamic model for the deflection control mechanism is built with the consideration of parameter uncertainties and external disturbances. Then, the parameter uncertainty and external disturbance are regarded as a system compound disturbance. Furthermore, a disturbance observer is designed to estimate the system compound disturbance and a nonlinear adaptive backstepping controller was proposed to compensate the system compound disturbance. The upper bound of the compound disturbance, which can effectively reduce the chattering in the directional control process, cannot be obtained easily. A stability analysis of the DCM (deviation control mechanism) with the proposed controller is proved based on the Lyapunov theory. Finally, an electro-hydraulic servo displacement control experimental system with matlab xPC target rapid prototyping technology and a prototype experiment system is established to verify the effectiveness of the proposed control strategy. The experimental results indicate that the proposed controller can yield more satisfactory position tracking performance, such as parameter uncertainties and external disturbances, than the conventional proportion integral derivative (PID) controller and an adaptive backstepping controller. Using the control strategy, technical breakthrough on horizontal directional drilling can be realized for thin coal seam mining.
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