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  • Author: Piotr Cheluszka x
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Piotr Cheluszka

Abstrat

This article discusses the issue of selecting a pick system for cutting mining machinery, concerning the reduction of vibrations in the cutting system, particularly in a load-carrying structure at work. Numerical analysis was performed on a telescopic roadheader boom equipped with transverse heads. A frequency range of the boom’s free vibrations with a set structure and dynamic properties were determined based on a dynamic model. The main components excited by boom vibrations, generated through the process of cutting rock, were identified. This was closely associated with the stereometry of the cutting heads. The impact on the pick system (the number of picks and their arrangement along the side of the cutting head) was determined by the intensity of the external boom load elements, especially in resonance zones. In terms of the anti-resonance criterion, an advantageous system of cutting head picks was determined as a result of the analysis undertaken. The correct selection of the pick system was ascertained based on a computer simulation of the dynamic loads and vibrations of a roadheader telescopic boom.

Open access

Marian Dolipski, Piotr Cheluszka and Piotr Sobota

The article presents the outcomes of extensive computer investigations the purpose of which was to identify the impact of cutting heads’ rotational speed on the load applied on the cutting heads drive as well as on the efficiency and energy consumption of the cutting process. The investigations were performed based on a simulation of the rock cutting process within a wide range of rocks’ compressive strength with a roadheader transverse head equipped with 80 conical picks. Variations were taken into consideration in the rotational speed of the cutting heads and variations in the factors connected with the properties of the drives driving the cutting heads on the load condition of the cutting system and on the energy consumption of the cutting process.

The computer simulations carried out indicate that a reduction is possible in the energy consumption of cutting the rocks with low workability by decreasing the cutting heads’ rotational speed thus preventing also the excessive load on the cutting heads drive. Possibilities are presented along with a concept of the heads‘ automatic speed adjustment according to the power utilised in the cutting process.

Open access

Marian Dolipski, Piotr Cheluszka, Piotr Sobota and Eryk Remiorz

Abstract

The key working process carried out by roadheaders is rock mining. For this reason, the mathematical modelling of the mining process is underlying the prediction of a dynamic load on the main components of a roadheader, the prediction of power demand for rock cutting with given properties or the prediction of energy consumption of this process. The theoretical and experimental investigations conducted point out – especially in relation to the technical parameters of roadheaders used these days in underground mining and their operating conditions – that the mathematical models of the process employed to date have many limitations, and in many cases the results obtained using such models deviate largely from the reality. This is due to the fact that certain factors strongly influencing cutting process progress have not been considered at the modelling stage, or have been approached in an oversimplified fashion.

The article presents a new model of a rock cutting process using conical picks of cutting heads of boom-type roadheaders. An important novelty with respect to the models applied to date is, firstly, that the actual shape of cuts has been modelled with such shape resulting from the geometry of the currently used conical picks, and, secondly, variations in the depth of cuts in the cutting path of individual picks have been considered with such variations resulting from the picks’ kinematics during the advancement of transverse cutting heads parallel to the floor surface. The work presents examples of simulation results for mining with a roadheader’s transverse head equipped with 80 conical picks and compares them with the outcomes obtained using the existing model.

Open access

Marian Dolipski, Piotr Cheluszka, Eryk Remiorz and Piotr Sobota

Abstract

Initial chain tension in armoured face conveyors, in which operating conditions vary constantly, should be adjusted automatically to adapt it to the needs arising. The manufacturers of such conveyors are now offering a possibility of equipping a conveyor with a drive with a telescopic trough enabling stepless change of the scraper chain contour by shifting the drive frame. The work presents the outcomes of computer investigations performed using an own mathematical model of an armoured face conveyor with a main and auxiliary drive equipped with a telescopic trough and an automatic initial chain tension adjustment system with the ASTEN algorithm. The ASTEN algorithm is responding to changes in scraper chain elongation caused by changes to conveyor configuration and also by a varying mined coal load resulting from interworking with a mining machine.