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United States Department of Agriculture

Agricultural Research Service

Research Project: Technologies for Managing Water and Sediment Movement in Agricultural Watersheds

Location: Watershed Physical Processes Research Unit

Title: Velocity field measurements in tailings dam failure experiments using a combined PIV-PTV approach

Authors
item Alexio, Rui -
item Ozeren, Yavuz -
item Altinakar, Mustafa -
item Wren, Daniel

Submitted to: International Association of Hydraulic Research International Symposium
Publication Type: Proceedings
Publication Acceptance Date: February 4, 2014
Publication Date: N/A

Interpretive Summary: Tailings dams are built to impound mining waste, also called tailings, which consists of a mixture of fine-sized sediments and water contaminated with some hazardous chemicals used for extracting the ore by leaching. Flow with water and particles mixed follows different physical laws from water flow, and there is a need for research into this phenomenon. Dam break experiments happen very quickly, so specialized methods of data collection and analysis are needed. Here, high speed cameras and laser particle tracking are used to study the behavior of water a particles released suddenly from a tank by the removal of a gate. Several fractions of water/sediment mixture were tested. The main focus of this paper is on the techniques used to collect the data.

Technical Abstract: Tailings dams are built to impound mining waste, also called tailings, which consists of a mixture of fine-sized sediments and water contaminated with some hazardous chemicals used for extracting the ore by leaching. Non-Newtonian flow of sediment-water mixture resulting from a failure of tailings dam is a highly complex transient flow phenomenon, which is not yet fully understood. Detailed experimental studies in the laboratory are needed to understand the fundamentals of the physics of these types of flows and to collect data that will be used to validate mathematical and numerical models. Given the highly transient nature of tailings flows, application of image processing techniques applied to video and digital photography taken during carefully constructed laboratory experiments, such as those described in this paper, is the suitable approach for better understanding the physics of these complex flows of sediment-water mixtures. The laboratory experiments were performed for different conditions of water and sediment levels in a channelized reservoir, ranging from the case of only sediments (no water) to the case of only water (no sediments). High-speed cameras were used to capture the whole flow field. Simultaneous measurements of the velocity field of sediments layers inside the upstream channel and wave front progression velocity on the downstream floodplain were obtained. A combined approach PIV-PTV was used to measure the velocity field upstream of the dam’s reservoir, and the wave front was captured with an interface tracking technique. This paper presents the application of measurement techniques based on digital video analysis to the case of a tailings dam-break flow.

Last Modified: 12/22/2014
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