Copy of workshop presentation. Ridlen presents the difference between tailings and water dams and the challenges of both. He then presents his client experiences and an example of a client policy and project.
Estimation of fines and solids content in tailings oil sands deposits is imperative for tailings planning as well as reporting tailings inventory to the regulator. This report reviews the development of a proper procedure for the engineering assessment of uncertainty in reported tailings mass/ volume as a function of data spacing.
Quote from main page: A Guide to the Management of Tailings Facilities (the Tailings Guide) is designed to be applied by MAC members and non-MAC members alike, anywhere in the world. The Tailings Guide, first released in 1998, provides guidance on responsible tailings management, helps companies develop and implement site-specific tailings management systems, and improves consistency of application of engineering and management principles to tailings management.
The Multiple Accounts Analysis (MAA) method presented in this paper provides a sound basis for presenting, discussing and exploring differences of opinion (between stakeholders) in the analysis and decision making for a preferred alternative (e.g. tailings impoundment site) based on an alternatives selection process.
Background page on tailings. From ICMM Page: Tailings is a common by-product of the metals and minerals recovery process. It usually takes the form of a liquid slurry made of fine metal or mineral particles and water – created when mined ore is crushed and finely ground in a milling process.
Tailings dam failures have and continue to cause large-scale devastation and environmental impacts. Historically these impacts have largely been predicted using Newtonian hydrodynamic modelling principles resulting in a general overestimation of potential consequences. However, since about 2014 the collective mining industry began developing complex tools to better predict the likely impacts of these failures. The industry has focused on leveraging the latest in computational flow dynamics modelling software and computational hardware to preform non-Newtonian tailings dam break assessments. However, as our tools become more sophisticated so does the requirement on input data. This paper discusses the past modelling approaches and the development of non-Newtonian tailings dam break models. The sensitivity of the flow behaviour is presented through four case studies, showing how this selection influences the outcomes and how previous approaches assuming Newtonian characteristics may present an overly conservative result. It is noted that additional knowledge and expertise will become available as non-Newtonian tailings dam break studies become the norm. In the interim, the uncertainty of these analysis needs to be analysed.
?To explore the spatial strength distribution of backfill in the stope, a group of experiments in a large similar stope model was designed for simulating the consolidation of cemented tailings backfill (CTB) in a stope. The height of CTB in similar stope model was measured to analyse the flow and sedimentation characteristics. The unconfined compressive strength (UCS) test on specimens cored in the different position of CTB sample in similar stope model was conducted. Moreover, the particle size and cement content of CTB sample were tested to help to explain the mechanism. The results show that during the flow and sedimentation of filling slurry in the model, inconsistency of the particle size and cement content leads to the inconsistency of strength. In the flow direction (horizontal direction), the median particle size of CTB first increases and then decreases, the cement content of CTB decreases slowly and then increases sharply, and the strength of CTB first decreases and then rises. In the sedimentation direction (vertical direction), the cement content of CTB decreases with the increase of depth, while the strength of CTB increases with the increase of depth. The strength is affected by the interaction between particle size and cement content, and the higher cement content of CTB does not translate into higher strength. The results provide a theoretical basis for improving the quality of CTB and optimizing the design.
Report and appendices to the report available on the bottom of this web page. Appendices are relatively technical.
The new Technical Bulletin: Application of Dam Safety Guidelines to Mining Dams, complements the Dam Safety Guidelines re-published by CDA in 2013 by providing additional explanation of how the concepts described in the guidelines apply to mining dams. The Bulletin identifies some specific issues that should be considered during the design and safety evaluation of both tailings dams and water retention dams used in the mining industry. Available in hard copy only.
Since 2005, the ACG has published conference papers across the geotechnical mining spectrum, including: underground and open pit mining, paste and thickened tailings and mine closure. The repository aims to provide the mining geomechanics fraternity with open access, peer-reviewed conference proceedings that may assist readers to maintain and develop their skills, knowledge and capabilities.