Analysis of dragline cycle time components

Abstract

This paper focuses on the breakdown of dragline cycle time. A 15-year old dragline deployed for casting the interburden and extracting the coal seam immediately beneath is monitored for a period of 45 days. The following operational modes are sampled: key-cutting, main-cutting, chopping and coal extraction. Data are handled regarding the parameters which have influence on particular stages of a cycle. It has been revealed that bucket loading is influenced by dimensions and geometry of the excavation face, material diggability, spatial position of ground penetration point and operator preference. Dumping phase appears to be affected by bucket fill factor and operator preference. Loaded and empty swing times are positively correlated with associated swing angles. Angular velocity of draglines is low at swing angles of up to 60 degrees. Loaded swing phases appear to be operator-dependent. Bucket repositioning phase is affected by geometry of the excavation area and the position of bucket penetration point. It is independent from the operator preferences.