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By S. Bentley

"Everyone has a general idea what mixing means, but describing the mixing process is not so simple. The objective of any mixing process is to distribute and blend the materials with different characteristics, different quantities as evenly as possible resulting in a homogenous mixture. Introducing proportional movement with the optimal intensity into the materials achieves effective homogeneous mixing results. A simple one directional movement with inadequate acceleration of the materials would obviously not achieve the same mixing results. This would be more like stirring than mixing. The amount of relative movement that is introduced is a decisive factor. Circumstances for successful mixing involve distribution of all materials, and achieving the highest probability that all recipe particles located in a specific position at the beginning can be found at any random location in the mixing chamber at the end of the process. This is the only way to ensure that a consistent result is achieved every time mixing is repeated.THREE-PART CYCLE The mixing cycle occurs in three phases; charging the mixer, the mixing process, and discharging. The sequence in which the individual materials to be mixed are filled into the mixer can have a huge impact on the efficiency of the mixing cycle. The mixing cycle overlaps the charging process and the discharge cycle follows the mixing cycle. To achieve optimum results, effective discharging methods should be taken into consideration to avoid risks of segregation. Costs for energy and wear should be as low as possible and finally, it is very important that the mixing cycle takes place as quickly as possible. In concrete or paste backfill production, selecting the best mixing technology is crucial for both the quality of the final product to be blended and the efficiency of the production process. The optimum mixing system is one that rapidly disperses all ingredients evenly throughout the mixing trough and completely surrounds all the course or fine aggregate particles with the slurry cement particles. Specific for paste production it’s the mixers job to also break-down unconditioned tailings to achieve consistent paste viscosity or measured spread. Many paste and concrete formulas also involve small quantities of chemical additives which also must be evenly distributed effectively. The time required per mixing cycle as well as the costs of energy, wear and maintenance will determine the economy of the concrete production."

Jan 1, 2015

By I. Demers

Doyon mine, Quebec, Canada evaluates the possibility of desulphurizing their tailings to produce material to be used in as cover over the acid generating tailings disposal site. Laboratory tests were conducted and showed that a single-layer cover made of desulphurized tailings placed over reactive tailings can prevent the generation of acid mine drainage. Modelling with the software Vadose/W was undertaken to optimize the design parameters, namely cover thickness, water table position, and residual sulphide content of desulphurized tailings following laboratory work. It was found that the optimal configuration includes a 1 m desulphurized tailings cover containing 0.8%S, with the water table kept at the interface between the reactive tailings and the cover. To maintain the cover performance to reduce oxygen flux towards acid-generating tailings even in the event of a long dry period, a sand layer is suggested to protect the cover from excessive evaporation. It is possible to reach the environmental objective chosen for Doyon mine (10 mol/m2/year) with the protective sand layer, even in extremely dry conditions.

Jan 1, 2008

By Samuel M. Bryant

The purpose of this study was to develop procedures to measure Bingham flow properties for mine tailings and to use these to predict the possible consequences of a hypothetical tailings flow failure at the Tenmile Tailings Pond at Climax, Colorado. The consequences of such a failure were found to be minimal, and the failure itself highly; unlikely. Values of Ty (Bingham yield shear strength) and np (plastic viscosity) were measured for 10 materials using results obtained from vaned coaxial viscometer tests and triaxial tests.

Jan 1, 1983

Tailings embankments can develop a high phreatic surface if the original design for the embankment does not include drainage facilities or if existing drainage facilities become ineffective. Subsequent raises can develop a seepage surface due to a high phreatic surface that can lead to stability problems. The U. S. Bureau of Mines amended contract J0100013 to initiate this study of horizontal drains in tailings embankments. This study developed a technique for determining the length of and spacing between parallel drains through the use of the finite element model UNSAT2. The analysis is based on the combined output of a vertical planar mesh and a horizontal planar mesh. The slot opening in the drain pipe and the length of the perforated section are determined from an analogy to water well design. The pipe diameter and gradient can be determined from Manning's equation. To the authors' knowledge, this is the first attempt at horizontal drain design using a finite element model. Additional research is recommended in this area.

Jan 1, 1982

By Ken Rahal, Chris Braun

As head grades of mines around the world decline, generation of tailings is increasing. Along with the increased tailings generation, reduction in water availability, and recent tailings dame failures, are causing mining companies to look at different disposal methods. One of the methods that is gaining traction is filtered tailings. Filtered Tailings currently provides the greatest water recovery and the smallest footprint among all the tailings disposal methods. This paper will present two case studies that analyze the filter and air compressor costs associated with a change in the final cake moisture target (i.e. a change from 17-wt% to 15-wt% cake moisture), for a base metal mine and gold mine.

Sep 30, 2022

It is now becoming mandatory in Australia to rehabilitate ponded fine grained coal mine tailings, which may well have been deposited initially with no consideration as to how or whether this could be done nor to the costsinvolved. Of prime importance to the rehabilitation of tailings ponds are the bearing capacity and deformation characteristics of the tailings. Since the tailings are fine grained, time effects will govern the self-weightdeformation of the tailings initially deposited as a slurry and the subsequent deformation of the deposit under the weight imposed by rehabilitation fill. The engineering properties of a particular deposit of ponded tailings havebeen investigated and its response to the placement of fill monitored and analysed.

Jan 1, 1987

By Hilario Gorvenia, Eduardo Ku

Los controles predictivos del tipo de mineral, cambios de reología, etc., que ingresará a la Planta, anticipará al área de Operaciones y al área de Gestión de Relaves para realizar las acciones pertinentes en la disposición de relaves para prevenir imprevistos en la producción de la Planta. El presente trabajo propone una metodología de planificación desde la Mina para optimizar el tiempo de vida útil de los depósitos de relaves y maximizar la recuperación de agua desde los relaves.

Sep 29, 2023

By R Blin, R Walde, R Belli, D Inaudi

A fiber optic distributed sensing system allows the monitoring of parameters useful to determine the short- and long-term behaviour of the structure in response to the external actions, including, eg seismic activities as well as long-term phenomena such as seepage, tunneling, sinkholes, and other geo-structural movements. Monitoring of large retaining structures with such a system provides direct strain/deformation and temperature measurements on the broad interior area with an arrangement of several sensing cable lines, enabling early detection, localisation and sizing of subsurface damages. Measurements are provided every meter along the entire sensing cable, this is particularly important in such cases where the location of defects and damages cannot be predicted. Fiber optic distributed sensing cables are generally available for retrofit installation inside the dam structure using trenches on the downstream face or laid during construction below the geomembrane liner within the bedding sand layer. Mapping the cable route enables exact correlation between a linear coordinate on the cable length and a position in the dam. Cable installation is envisaged to be carried out during further raising of the embankment; additional cable sections are plugged to the previously installed cables and measured with the existing measurement system, requiring only an update of the mapping. The measurement system is placed remotely from the sensing area since a section of sensing cable can be used to link to the sensing area at the storage facility several kilometers away. The system is available for on-line, 24/7 real-time operational data management. Such fiber optic distributed sensing systems allow storage facilities to be monitored with long, accurate, continuous and precise data for geotechnical diagnostic purposes. This contribution will introduce the principles, benefits, and limitations of this technology.

Jul 1, 2021

By Victor Avdokhin, Ivan Kovlekov

"Studies of the process of concentration of gold-containing sands and technogenic resources show that the main reason of gold losses is misbalance between size of gold particles and degree of roughness of mineral bed. This results in free circulation of small gold particles in pores with following washing off the particles from the bed by turbulent flows.We elaborated design of magnetic sluice, intended for improving efficiency of recovering fine gold by optimizing magnetic field of a magnetic system on the base of forming catching coat from magnetic mineralsThe magnetic sluice includes trough-shaped body from magnetic-conducting material. On the bottom of the trough, magnets are placed, and opposite poles of the magnets are oriented outwards. Thickness of the bottom is determined to be sufficient for locking magnetic lines of force of the magnets on each other. The magnets of rectangular plate shape are placed on the rough bottom, covering the whole surface or with spare areas; the magnets are placed across the trough with alteration of rows with the same pole orientation.Catching coat is formed of natural magnetic and weak-magnetic placer minerals in field of magnetic system of the sluice. Magnetic minerals, placing along magnetic lines of force, form rough coat of fluffy structure. Size of the magnetic particles is chosen taking into account expected size of gold particles, which are to be fixed on the rough coat or between the magnetic particles. Changing coarseness of particles of mineral bed allows to regulate selectivity of recovering heavy minerals.Forming artificial fleece from magnetic minerals of initial sand, increasing capacity of the bed and relative hydraulic proportionality of mineral particles of the bed provide for the most effective recovery of fine gold."

Jan 1, 2003

The characteristics of mineral resources and tailings resources in China are analyzed. Those tailings, which have double characteristics, can occupy land, pollute environment and even influence human habitat if they are not disposed in time. So pay attention to the comprehensive utilization of the tailing more and more both at home and abroad. The present situation and problems in comprehensive utilization of iron tailings in China are introduced by combine some practice experience, and have looked forward to the comprehensive utilization of iron tailing situation.

Jan 1, 2014

By James A. Brown, Marius Botha, Christopher A. Fleming

"The technical and economic feasibility or re-processing hundreds of millions of tons of tailings in a number of historic gold tailings dams in the Witwatersrand area of South Africa is being investigated. The objective is to recover uranium and residual gold from the tailings, as well as to oxidize the sulphides to eliminate long term environmental liabilities associated with acid mine drainage. The tailings from the re-processing plant will be re-deposited in a new area far from urbanization, allowing for the rehabilitation of the real estate currently occupied by these historic tailings.The first step in the process involves a mild-regrind and mild acid leach of the tailings (pH 2.5 to 3.0) to dissolve up to 40% of the uranium. This uranium is recovered directly from the pulp by resin in pulp (RIP) with a strong base resin. The RIP tails are then treated by flotation to recover a rougher pyrite concentrate, and flotation tailings that are discarded. The rougher concentrate is cleaned to produce a final pyrite concentrate and cleaner scavenger tailings, and the pyrite concentrate is oxidized in an autoclave to leach uranium and generate acid. The autoclave discharge is combined with the cleaner scavenger tails, and the acid and ferric ions generated in the autoclave are used to leach more uranium and oxidize more sulphide in the cleaner tails. The product from the concentrate leach circuit is processed by resin in pulp for uranium recovery, followed by neutralization, cyanidation and carbon in pulp for gold recovery.The rougher float tails may be further treated to recover gold that was not recovered in flotation, but which had been liberated from the old dumps by natural oxidation of some of the pyrite over many decades. The float tails would be neutralized and treated by cyanidation and CIL to recover this liberated gold.All parts of the flowsheet have been extensively tested in the laboratory, and the critical elements of flotation, pressure oxidation and resin in pulp have been demonstrated in pilot plants. The results of the hydrometallurgical investigations are presented here."

Jan 1, 2010

By J. Mark Richardson

Modern mining operations are increasingly affected by complex economic factors. Broad and rapid fluctuations in metal prices, rising operating costs, socio-political trends and the inherent technical difficulties encountered in most operations, all can combine to quickly change once-profitable ventures into money-losing propositions. Accurate knowledge of metal inventories during all phases of an operation has become essential to wise management decision-making. This paper reviews key elements of metallurgical accounting: sampling theory, measurement technology and computerized data adjustment. Application of current technology to the reconciliation of a hypothetical operation is discussed.

Jan 1, 1991

By Leslie F. Sawatsky

Raw water import requirements for oils sands mines depends mainly on factors such as ore processing rate, ore material characteristics, tailings processing technology, tailings storage systems, process water storage operations, the phase of tailings production, and non-recoverable seepage losses from tailings ponds. These factors can be readily quantified to calculate raw water import needs. Nevertheless, mine water balance continues to be misunderstood by some regulators, stakeholders and possibly even mine operators. Confusion over consumptive uses has led to a focus on recycling which is not necessarily applicable to a closed circuit water management system. Some water conservationists focus attention on raw water intake rules instead of the technical decisions that control consumptive uses. Typical oil sands mine water balances for various types of tailings operations, are analyzed to illustrate the effect of controllable and uncontrollable parameters as well as major options that need to be explored for reducing water demand. Uncontrollable parameters including tailings fines content, oil content of ore, connate water, mine depressurization water inflows and surface water hydrology. Controllable parameters include storage operations, advance water supply ahead of mining operations, type of tailings operation, net tailings pond seepage losses, and tailings impoundment operations. Potential reductions of raw water supply rates may be obtained by providing greater on-site storage to attenuate fluctuation in water demand, advance water accumulation prior to mine start up, early commencement of CT operations, thickened tailings disposal and paste technology. Water conservation measures should be focused on reducing on-site process water storage and water content of tailings material.

May 1, 2004

By Scott Donald, Barry Esford

Cameco Corp. operates uranium mills and tailings management facilities at its Key Lake and Rabbit Lake operations in Northern Saskatchewan, Canada. Development at both mine sites began in the 1970s, with initial tailings deposition occurring within above-ground impoundments, which was common for these facilities at the time. As open pits became available at each site, and mining continued at other orebodies in the area, tailings management shifted to in-pit facilities to meet stakeholder expectations and improve the long-term security and environmental performance of tailings management at these facilities. The in-pit facility at Rabbit Lake (receiving tailings since 1984; Fig. 1), was one of the first (if not the first) engineered in-pit tailings facilities in the world and adopted a full pervious surround design concept with subaerial deposition. Under this concept, permeable sand and coarse rock are placed at the base of the pit, around its perimeter, as well as overlying the tailings at closure to promote regional groundwater flow bypassing the lower-permeability tailings. In contrast, at Key Lake, the in-pit facility (receiving tailings since 1996) adopted a partial pervious surround design concept. Under this concept, permeable materials were again placed at the base of the pit, and partway up the side walls; although for the upper portion of the tailings, the material is placed directly against the natural geologic materials. In the Key Lake case, the natural geologic environment provided the required bypassing of the tailings deposit to achieve the desired environmental performance while the base drain again facilitated pumping during operations to achieve consolidation objectives (Fig. 2). In both the initial design of the facilities, and through more than several decades of operation, it is clear that although in-pit tailings facilities provide common benefits with respect to long-term geotechnical stability, it is critical that their design approach take into consideration site-specific conditions

Jul 1, 2025

By E. G. Joe

Introduction Uranium mining has been actively carried on in Canada for over twenty-five years mainly in Ontario at Elliot Lake in Bancroft, and in Northern Saskatchewan at the operations of Eldorado Nuclear Ltd. During this period, approximately one hundred million tons of mill tailings have been created and lie mainly on the surface close to the mining and milling installations. If all of the present reserves of uranium ores in Canada are mined, a further eight hundred million tons of mine tailings could be created in Ontario, Saskatchewan, the Northwest Territories, Labrador and British Columbia. The present control of effluents from existing tailings is managed by the operating mines under the regulations of both federal and provincial control agencies. It is the long-term effect of these tailings on the environment that has not been clearly defined or measured. Several years ago, the Canada Centre for Mineral and Energy Technology of the Department of Energy, Mines and Resources, embarked upon a program of research directed at the long-term effects of uranium mine tailings. Much of the research to date has been on tailings in the Elliot Lake, Ontario area where some tailings piles have existed for over twenty years. The program consists of two projects, one to address the problem of existing tailings and the other to examine alternatives in the management of current and future tailings. TAILINGS CHARACTERISTICS Uranium tailings are generally the result of sulphuric acid leaching in which the uranium and alkaline minerals such as carbonates and chlorites are leached out. If the ore contains sulphides, these minerals potentially present an additional hazard of acid generation over time and could increase the mobility of heavy metals and some radionuclides such as thorium-230. Except for the extracted uranium, most of the radionuclides from the ore remain in the tailings pile. Uranium ores in Canada span a wide variety of mineralization and associated gangue composition. Uranium minerals include pitchblende, uraninite, uranothorite, brannerite and the phosphate uranium minerals autunite and saleeite. Gangue minerals vary from acid consuming carbonates, and chlorites to acid producing sulphides and inert silicates. With such a wide variety in ore composition, the characteristics of the resultant tailings in Canada are in many cases site specific and the solutions to the long-term effects of these tailings may also be site specific.

Jan 1, 1980

By L. Avramovic, B. Han, R. Jonovic, Z. Stevanovic, K. Haga, S. Dimitrijevic, A. Shibayama, L. Godirilwe, Y. Takasaki

Pyrite (FeS2) and chalcopyrite (CuFeS2) which could not be recovered, are present in mine tailings discharged from Bor copper mine. About 0.3% of copper (Cu) is contained in these tailings, therefore it can be considered as a useful copper resource. At the same time, pyrite is known to promote acid mine drainage, therefore it is necessary to detoxify the tailings. An efficient method has been proposed to recover copper and reduce the environmental impacts of tailings by a combined hydrometallurgical process of high pressure leaching (HPL), solvent extraction (SX) and electrowinning (EW) process. HPL process yielded high copper leaching rate (>95%) when water (H2O) was used as a leaching media. On the other hand, pyrite contained in the tailings was converted to iron oxide by high pressure leaching. Stability evaluation of the residue obtained from high pressure leaching, confirmed almost no elution of metal ions. The percentage of copper extracted and stripped from the Cu-loaded organic phase reached 97.4%. Moreover, it was confirmed that a low iron concentration in the electrolyte of copper electrowinning, resulted in the improvement of current efficiency of copper electrodeposition. INTRODUCTION Mine tailings are a by-product obtained from the flotation process and there are billions of tons of already existing tailings all over the world. Moreover, several billion tons of additional copper tailings will inevitably be produced in the coming years (Onuaguluchi & Eren, 2012). With the declining average copper ore grade, alternative sources of copper are highly sought, mine tailings have a comparable copper grade to that of low-grade ores (0.2–0.3%) therefore, it can be said that copper mine tailings present a very important source of secondary raw material for copper production (Antonijevi´c et. al., 2008). Consequently, it is necessary to confirm the possibility of the valuable metals (such as copper) recovery from mine tailing in which copper content is about 0.2–0.3%. Our group investigates the flotation and high pressure leaching processes for recovering of copper from mine tailings. Previous work on related samples include copper and nickel flotation tailings from Botswana, and a low–grade copper ore sample from Chile. Impurities, which are associated metals in mine tailing such as iron (Fe) and aluminum (Al) co-dissolve into the solution during the HPL treatment process. Therefore, separation of copper from impurities is necessary for selective extraction of copper from mine tailings and upgrading the copper concentration in the leachate to enable further purifying of Cu by electrowinning. Thus, it is important to investigate the possibility of applying solvent extraction for concentration of copper from leachate solutions of mine tailings (Onuaguluchi & Eren, 2012; Antonijevi´c et. al., 2008). In this study, LIX-84I was used as an extractant of copper from the leachate of high pressure leaching of mine tailing. As a fundamental solvent extraction investigation, the extraction behavior of copper was studied using a simulated solution of the leachate from the high-pressure oxidative leaching of mine tailing. The effects of; solution pH, extraction time, extractant concentration and phase ratio on copper extraction and sulfuric acid (H2SO4) concentration on stripping were investigated.

Jan 1, 2019

By Briony C. Ruse, David V. Boger, Fiona Sofra1

"The sustainability of the mining industry must be addressed through improving tailings management. The use of thickened tailings and pastes stems from a paradigm shift towards designing tailings disposal sites to suit their surrounding environment, rather than manipulating the environment to accommodate the tailings. Thickened tailings and pastes usually exhibit non-Newtonian behaviour, so a thorough understanding of the rheological characteristics of the material is required in order to determine the disposal plant operating conditions.As environmental factors translate into economic issues, minimising waste production using dry disposal methods is gaining popularity. The use of rheological information is of high importance in evaluating the spreading characteristics, the transportation and the dewatering of thickened mineral tailings. The principles outlined may be applied to many industries encompassing a wide range of waste materials. The main obstacle to the widespread implementation of dry disposal methods has been the high initial capital cost of the methods due to the dewatering step, and the high cost of pumping thick suspensions across any great distance. Proper and thorough costing of tailings disposal activities combined with an accounting approach that shows closure and post-closure care costs on a per tonne basis of tailings disposed throughout the life of the tailings facility will show that dry disposal methods are more favourable than they might seem on initial appraisal."

Jan 1, 2003

By C N. Hatton, K Ward

Tailings operations are inherently reactive as operations personnel continuously contend with a concentrator reject feed (tailings) transient in physical and engineering properties, which places a constant constraint on capital and operational spending. It requires a unique skill set to manage the prescribed distribution of tailings under unenviable conditions. Enter the tailings operator, an oftenundervalued commodity and untapped resource that can provide benefits beyond the rigors of dayto- day operational support. Experience consistently demonstrates that skilled and committed operators can serve a vital function in the safe construction of a tailings storage facility. It takes a village to raise a tailings dam. An important part of this process is establishing a culture of operational accountability and ownership. Operator development training is nothing new. However, we find that many of the intrinsic operator skills are left unexploited, and an operator's experiential knowledge base and creativity are commonly overlooked and underutilized. With proper training and guidance, these skills can be harnessed, contributing to safe dam operations. Operator engagement, when properly facilitated, provides tangible benefits ranging from improved tailings engineering properties to reduced closure costs. One important benefit is helping transitioning tailings management from reactive to proactive. There are many processes involved in the reactive to proactive transition process. One element of that process includes engaging operators in the tailings management process and facilitating legacy ownership. The core of operational legacy ownership is measured and described using five-stage operator engagement rubrics. Levels of operator engagement are presented with a description of the incremental benefits of each stage. An important part of legacy engagement is providing the tools to operators necessary for managing the tailings. Therefore, the approach identifies specific methods used by operations personnel to control tailings distribution and in-place properties. The end goal of leveraging operator engagement is to facilitate committed ownership and transition tailings management from an inefficient, reactive process to an improved, cost-effective, proactive practice.

Jul 1, 2021

By W. G. Miller, J. D. Scott, D. C. Sego

ABSTRACT: As part of an overall study of properties and processes influencing consolidation of oil sands fine tailings resulting from different extraction processes, self-weight consolidation tests were per-formed. Fourteen 2 m and 1 m high standpipe tests were instrumented to monitor the rate and magnitude of consolidation of seven fine tailings materials. Tests provided valuable information about the variation of consolidation related to differences in fine tailings material properties that result from a change in bitu-men extraction process (caustic versus non-caustic). In addition, the effect of adding a coagulant to caustic fine tailings was measured. Test results are presented and discussed in terms of consolidation rate long-term volume decrease, compressibility, and downward drainage. Non-caustic fine tailings had fasterinitial consolidation, which is important in tailings ponds for reducing storage capacity and returning decant water at a faster rate to the extraction plant. Similar results were obtained for caustic fine tailings with a coagulant addition. However, long-term settlement of the different fine tailings appears to con-verge to a similar value over time because it is then governed by effective stress.

Jan 1, 2011

By P E. H Gregg, D Horne, R B. Stewart, N Bolan

The Tui mine site is situated on the NW flank of Mt. Te Aroha, at approximately 400 m altitude. During underground mining operations two lead-copper-zinc ore bodies were exploited and processed on site. The legacy of the mining operation is a barren dam containing over 100 000 mm of sulphide-rich tailings. The Tui mine site is arguably the worst case of environmental degradation resulting from past mining activity inNew Zealand. Although the impacted area (approximately 4 ha) is extremely small by international standards, acid mine drainage (AMD) emanating from the abandoned tailings dam and mine adits has severely contaminated local streams and prevented natural plant recolonisation of the site for more than 20 years.   The suitability of the tailings as a potential plant growth medium was assessed with the end view of revegetating the tailings dam and alleviating AMD. This paper outlines characterisation work conducted on the tailings and summarises preliminary results from plant growth trials. The tailings contain up to 5% Fe, 1.15 % Pb, and 0.45% Cu in the form of sulphide minerals. The distribution of heavy metals, sulphate and total sulphur with depth indicates that the top 200 - 300 mm of the tailings have been extensively weathered since their deposition. The oxidation of sulphide minerals, particularly pyrite (FeS2 ) has reduced the pH of the tailings to nearly 2 in places. Below 300 mm the sulphide minerals are largely unweathered and the theoretical acid generating potential of the tailings exceeds 170 Mg CaCO3/1000 Mg tailings at certain depths. Plant growth trials were conducted to study the effects of lime and organic matter addition on the establishment of vegetation on the Tui mine tailings. Several plant species were assessed including some cultivars bred for their tolerance of heavy metals.

Jan 1, 1995