Optimization of bucket wheel excavator cutting parameters at mining of materials with increased strength

[S. Bošković]

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Rudarsko inženjerstvo - Mehanizacija u rudarstvu i energetici / Mining Engineering - Mine and Energy Mechanization

Otkopavanje materijala rotornim bagerom je veoma sloţen fiziĉko-mehaniĉki proces. Pokazatelji efektivnosti tog procesa zavise od velikog broja raznovrsnih ĉinilaca od kojih se posebno mogu istaći: fiziĉko-mehaniĉke karakteristike materijala koji se otkopava, reţim rada bagera i izbor tehnoloških parametara bloka, odreska i reza, geometrije vedrica i zuba itd. Poseban problem se javlja kod otkopavanja materijala povećane ĉvrstoće, što je ĉest sluĉaj na našim površinskim kopovima. Dimenzionisanje specifiĉne sile kopanja bagera prema manjim masama izuzetno ĉvrstog materijala je neracionalno i rešenje treba traţiti ili u otkopavanju ovih masa drugom opremom ili optimizaciji rada rotornog bagera tj. izboru optimalne vrste reza i parametara odreska u cilju smanjenja otpora na kopanje, smanjenja potrošnje energije i smanjenje dinamiĉkih uticaja na konstrukciju rotornog bagera. Dosadašnjim istraţivanjima ove problematike, ustanovljeno je da se izvesna poboljšanja u radu rotornog bagera na otkopavanju materijala sa povećanom ĉvrstoćom mogu postići optimizacijom odreĊenih konstruktivnih i tehnoloških parametara, ĉiji je osnovni cilj praktiĉno povećanje raspoloţive rezne sile bagera i maksimalno iskorišćenje raspoloţivih mogućnosti bagera uz maksimalnu zaštitu bagera od nepovoljnih dinamiĉkih udara tokom rada. Vrsta i parametri reza su osnovni tehnološki parametri ĉijom se optimizacijom moţe uticati na: smanjenje otpora kopanju u materijalima sa povećanom ĉvrstoćom, povećanje kapaciteta rotornog bagera, minimizaciju potrošnje energije i povoljnije dinamiĉko ponašanje konstrukcije bagera. To je ujedno i predmet istraţivanja ove disertacije, a osnovni cilj je da se kroz sprovedena istraţivanja definiše metodologija koja će se koristiti pri izboru i optimalnom korišćenju rotornih bagera na površinskim kopovima u uslovima radne sredine sa povećanim otporom kopanju. Istraţivanja u okviru doktorske disertacije su realizovana na teorijskom i eksperimentalnom nivou. Na taj naĉin je sagledan, otvoren i determinisan problem, sagledana moguća i odabrana optimalna rešenja i izvršena praktiĉna provera dobijenih rezultata u konkretnim uslovima radne sredine. Terenska ispitivanja, analiza dobijenih rezultata i optimizacija parametara reza pri otkopavanju materijala sa povećanom ĉvrstoćom na površinskom kopu Gacko pokazala su da se najbolji efekti rada rotornog bagera postiţu sa vertikalnim rezom debljine 0,20 m, širine 0,30 m, odnosno sa brzinom obrtanja strele rotora od 24 m/min. Dokazano je da je neophodno promeniti postojeću tehnologiju otkopavanja rotornim bagerom, ali i daljim kompleksnim istraţivanjima postaviti metodologiju optimizacije konstrukcije reznih elemenata rotora.

Mining of material by a bucket wheel excavator is a very complex physical physical-mechanical process. Indicators of the effectiveness of this process depends on a number of various factors, of which in particular may be emphasized: physical-mechanical characteristics of the material to be mined, mode of excavator operation and selection of block technological parameters, slice and cut, and the geometry of the buckets and teeth, etc. A particular problem occurs in the excavation of materials with increased strength, which is often the case in our opencast mines. Sizing of excavator specific digging forces towards smaller masses of extremely hard material is irrational and a solution should be sought either in the excavation of these masses by other equipment or by optimization of bucket wheel excavator operation i.e. in the selection of the optimal type of cut and parameters of slices in order to reduce resistance to digging, reducing energy consumption and reducing the dynamic effects on the structure of the bucket wheel excavator. Current research of this issue, it was found that certain improvements in the operation of the bucket wheel excavator on the mining of materials with increased strength can be achieved by optimizing of some structural and technological parameters, whose main goal is virtually increasing the available cutting forces of the excavator and maximum utilization of the available options with maximum protection of the excavator from the adverse impact of dynamic impacts during operation. Type and parameters of cut are the basic technological parameters that contribute to optimizing may affect: reduction of mining resistance in materials with the increasing strength, increasing the capacity of the bucket wheel excavator, minimizing energy consumption and more favorable dynamic behavior of excavator structure. It is also the subject of this thesis, and the primary goal through conducted researches is to define methodology to be used during selection and the optimal use of bucket wheel excavators in opencast mines in the working environment with the increased resistance to mining. Researches within this thesis were implemented at the theoretical and experimental levels. In this way was perceived an open and determined problem, was reviewed possible, selected optimal solutions, and carried out in practice checkups of results obtained in the concrete conditions of the working environment. Field tests, analysis of the obtained results and optimization of cutting parameters during the mining of materials with increased strength in the opencast mine Gacko has shown that the best effects of excavator operation are achieved with vertical cut and thickness of 0.20 m, width 0.30 m, i.e. with the slewing speed of bucket wheel boom of 24 m/min. It has been demonstrated that it is necessary to change the existing mining technology by the bucket wheel excavator, but also with further complex research to set up a methodology of optimizing the structure of the bucket wheel cutting elements.

rotorni bager, parametri reza, otpor na kopanje, dinamika bagera, kapacitet, optimizacija, specifična potrošnja energije

bucket wheel excavator, cutting parameters, resistance to digging, excavator dynamics, capacity, optimization, specific energy consumption

621.879.44:622.271(043.3)

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