Technical gazette, Vol. 21 No. 3, 2014.
Original scientific paper
Calculation analysis of bulldozer's productivity in gravitational transport on open pits
Mario Klanfar
orcid.org/0000-0003-1629-873X
; University of Zagreb, Faculty of mining, geology and petroleum engineering, Pierottijeva 6, 10000 Zagreb, Croatia
Trpimir Kujundžić
orcid.org/0000-0003-0320-5338
; University of Zagreb, Faculty of mining, geology and petroleum engineering, Pierottijeva 6, 10000 Zagreb, Croatia
Darko Vrkljan
; University of Zagreb, Faculty of mining, geology and petroleum engineering, Pierottijeva 6, 10000 Zagreb, Croatia
Abstract
Analysis of accuracy and calculation applicability of bulldozer's productivity in gravitational transport on open pits has been conducted by comparing computational values obtained by theoretical formulas and results of field measuring. The magnitude of the volume of blade load and the speed of bulldozer's motion, which are the main factors for assessment of machine productivity, have been measured and compared at the same length of transport. Significant deviation of computational specified bulldozer's productivity has been noticed with regard to the ones measured in real conditions. Calculation improvements have been suggested in order to better approximate real exploitation effects by introducing new formulas for the volume of blade load and the speed of bulldozer's motion. The curvature of bulldozer's blade has a substantial effect on the volume of pile in front of blade, and it is not negligible in the calculation. By comparing computational values of different authors, deviations between 3 % and 40 % from measured values have been obtained. The new proposed formula with a 3 % deviation has been proved to be the most accurate. Theoretically calculated maximum speed of bulldozer's motion by means of engine power significantly deviates from the actual measured speed (>49 %). The speed of bulldozer's motion according to the rimpull diagram and the adjusted formula that represents a universal rimpull characteristic of the bulldozer, is applicable in transport where the influence of blade load pushing resistance is prevalent to the bulldozer's speed (deviation <16 %). Bulldozer's speed of motion backwards is more reliable to determine by experience because deviation of computational value (>160 %) introduces a significant error in the productivity assessment.
Keywords
bulldozer; exploitation of mineral raw materials; gravitational transport; machines' productivity; mining
Hrčak ID:
123316
URI
Publication date:
24.6.2014.
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