Skyline tension analysis in yarding operation: case studies in Italy

A great deal of research in Italy has been directed toward field measurement of cable tension in cable yarding systems in order to facilitate initial tensioning of unloaded skylines or to provide means for avoiding overloading. Unfortunately, at present many cableway extraction systems are just based on the operators’ experience and no calculation of the tension in skylines is carried out. This paper describes results of skyline tension analysis carried out in Italy in cable yarding operations or in lines set up in an experimental field. Measures on the skyline tension were recorded using load cells placed between rope and anchors. The data refer to 69 cableways, both single and multi-span. Tension variation was related to: initial tensioning, load, and line geometrical features. Data analysis provided functions to describe the tension variation in skylines and important recommendations for a safer use of the cableway extraction systems.