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Analytical investigations of the accuracy of the small diameter tool-joint tapered thread made by a lathe machining

Abstract

The drill string consists of connected drill pipes and other elements. The connection is carried out by screwing of the drill string elements with the help of tool-joint tapered thread. The operational characteristics of the drill pipes depend of the manufacture precision of these tool-joints mostly. The accuracy of the thread is regulated by the accuracy of its profile and the accuracy of its pitch diameter value. The accuracy of the tapered thread manufacturing on the lathe in its depending on the values of the geometric parameters of the lathe tool and the values of deviations of its installation relatively to the workpiece axis is investigated. It is proved that for the tapered thread of form VI profile used for connection of drill pipes with the diameter from 30 mm to 44 mm the most influential factor, in relation to the accuracy of the thread profile is the value of the rake angle. Application of the rake angle value up to −5° according to the research data leads to a deviation from the specified profile of 0.3°, which is more than 35% of the declared standard tolerance on deviations from the profile. Also, the influence of the back rake angle value on the value of the deviation from the standard pitch diameter of the thread is proved. It is proved that the magnitude of the tangential displacement of the nose of the cutter relatively to the axis of the thread up to −0.2 mm can cause a deviation of the profile angle of 0.18°, which is 27% of the standard tolerance.

Open access
Application of fiber optic FBG techniques in analysis of strain in engineering machines

Abstract

The paper presents the use of fiber optic FBG strain sensors for analysis of deformations of machines and devices including those used in mining techniques. FBG strain sensors have many advantages over classic strain measurements using electro resistance strain gauges. They are characterized by a significant measurement accuracy of up to 1 mm, a service life of up to 30 years, the possibility of measuring large deformations of up to 8%, significant fatigue life, the possibility of building measurement networks and, something extremely important in mining – intrinsic safety, because the operating medium is white light. The entire measurement system based on the optical interrogator was also discussed. It enables conducting both static and dynamic measurements. The results of the strain research for an engineering machine, in which the loads had exceeded 800 T, were reported.

Open access
Application of friction braking devices in drum shaft hoists

Abstract

This article presents the problem of emergency braking in mining shaft hoists equipped with drum. The industrial applications of friction devices and mobile fender beams concerned only friction shaft hoists. For drum devices, it is necessary to use braking devices both in the shaft tower and its sump. The impact of such a solution on the construction of braking devices and on the braking process itself is the subject of the paper.

Open access
Application of neural networks to the prediction of gas pollution of air

Abstract

The issue of projecting the air pollution levels is quite essential from the viewpoint of the necessity to adopt specific prevention measures intended to reduce the pollution concentration in the air. One can apply certain machine learning methods, including neural networks, to build pollution concentration models. Neural networks are characterised by the fact that they can be used to solve the relevant problem when we face shortage of data, or we do not know the analytical relationship between input and output data. Consequently, neural networks can be applied in a number of problems. This paper discusses a possibility to apply neural networks to the prediction of selected gas concentrations in the air, based on the data originating from the measurement networks of the Polish State Environmental Monitoring System, combined with local meteorological data. Forecast results have been presented here for SO2, NO, NO2, and O3 in various locations. The author also discusses the accuracy of the respective forecasts and indicates the relevant contributing factors.

Open access
The application of the integrated production assets management system in the Polish Mining Group Inc.

Abstract

The management of the production assets in the Polish Mining Group Inc. is geared towards achieving strategic aims through the unification of the obtained machines/devices, their practical use while maintaining them in the proper technical condition, adhering to proper maintenance-renovation procedures, reserves optimization as well as final recycling with no re-use in the production cycle. The following paper presents the functioning of the IT support in the production assets management, geared towards the integration with other areas of technical and economic activities of the Group. The modular structure of the integrated IT system makes it possible to gradually implement the successive solutions functioning within the Group as well as in the surrounding local areas, ensuring the suitability to the current needs of the organization and the system users.

Open access
Areas of industrial damages in upper Silesian industrial region versus recultivation or revitalization ?

Abstract

Areas of industrial damages require elaborating efficient methods of reclamation and revitalization. A region of Poland, where process of degradation is particularly visible is Upper Silesian Industrial Region. Areas in the zone of many-years influence of Huta “Miasteczko Śląskie” are characterized by norm-exceeding concentration of heavy metals. The area in its direct surrounding was defined as industriogeneous desert. In 2017 on three designated testing grounds with diversified degree of contamination (see: map) of joint area of 1.5 ha, planted were jointly 6550 seedlings of chosen species of trees and bushes which were likely to survive in those conditions. In the first vegetative season, despite extremely long-lasting drought and high temperatures, the seedlings showed high survivability. It amounted 82% on industriogeneous desert (testing ground C) and 90-95% on forest testing grounds (A and B). Maples stood out among other trees with proper development and condition. The highest seedlings, especially mountain ash, birch and European red elder already in August had burnt top shoots and numerous necroses on leaves. Introduction of plants – hyperaccumulators of heavy metals, especially on industriogeneous desert will influence positively on condition and development of seedlings in future vegetative seasons.

Open access
Assessment of efficiency in reduction of dust concentration in mineral processing plants using the state-of-the-art technical measures

Abstract

Airborne coal dust hazard at the workplaces in hard coal processing plants in Poland is presented. The methods for dust control in coal processing plants are discussed. The results from testing the dust control efficiency at the workplaces are given. The test results of airborne dust concentration are analysed as well as advantages and disadvantages of used technical measures are indicated.

Open access
Asymmetrical mini disk tools – possibilities of use and directions for further development

Abstract

The paper presents a new solution of asymmetrical mini disk tools for mining head of roadheader designed for hard and very hard rock mining. In the first part the benefits of disk tools used in TBM's and special tunneling machines were presented. Next part presents the results of works and laboratory tests performed for developing of new solution of asymmetrical mini disk tools. On the basis of these results new mining head equipped with mini disk tools with a complex trajectory was designed. The results of field tests with different constructional and material solutions of asymmetrical mini disk tools were presented. The directions for further development were described.

Open access
An attempt to increase technological capabilities of laboratory vibratory mills by changing the construction of chamber

Abstract

The paper presents the issues related to the grinding process in the vibration mills with low vibration frequency. These mills are rated among devices with high energy of impacts with much wider potential of industrial use than the classic gravitation mills. In vibratory mills there is an unfavorable decrease in the intensity of the grinding process along with the increase in the chamber diameter, which makes it impossible to achieve high performance of such devices. One of the ways to reduce or eliminate this occurrence is to intensify the load movement inside the chamber – this is the subject of this article. The article shows that in a vibrating mill of periodic action it is possible to increase its technological capabilities by application of an appropriate cylindrical component permanently installed inside the milling chamber. The paper also presents an attempt to increase the technological capabilities of a laboratory continuous vibratory mill.

Open access
Components of an innovative electro-control system for undeground mining – analysis

Abstract

In the era of Industry 4.0, coal companies began to reach for new innovative technologies that increase work safety and their possible use affects the economic improvement of companies. One of them is to equip a powered roof support section with an electrohydraulic control system with a monitoring system that tracks operating parameters. The development of a monitoring system for a powered roof support is a key investment in new longwall complexes. It allows rapid diagnostics of status of the support. Currently used system designed to control the powered roof support are based on blocks of manually controlled distributors. The pilot control is currently the leading control that properly functions in all conditions, allowing to adapt to the requirements resulting from the construction of the section. A number of tests and analyses must be conducted prior to introducing the new control based on an innovative approach into operation. The basic research has focused on identifying the user interface that will potentially be the solution for the entire system. The user has defined how the driver should look like and how it will be operated and maintained. The results of the first series of tests on the elements of an innovative electronic control system of the powered roof support enabled to develop a prototype version. The assumptions for the system were verified during the conducted development studies. The article presents preliminary results of development research for devices included in the innovative control system of the powered roof support.

Open access