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Design of a Co-disposal Facility for Thickened Tailings and Potentially Acid-generating Waste Rock

Co-disposal was selected as the preferred waste management strategy for the Alacrán Cu-Au-Ag Mine Project after multiple investigations. This waste management strategy will create a low-permeability waste deposit, reduce foundation seepage, and centralize the storage of all mining and processing waste. Co-disposal, in places where suitable, may reduce environmental risks and impacts, improve public perception, and lower costs and timelines for mining projects.

Compaction Sensitivity in Tailings Stack Infiltration Modeling: Unsaturated Properties Uncertainty Analysis

This study utilized tailings properties from a Brazilian mine, along with site climatic data, and employed a Bayesian approach to address calibration uncertainties. A hypothetical two-dimensional (2D) section of a test pad was considered for the study, and a software that simulates the movement of water and solutes in variably saturated media, for obtaining infiltration rates by solving the Richards Equation, was employed.

Volumes of Dam Material Mobilized by Erosion During Tailings Dam Failure Events

Two empirical equations for calculating the eroded dam volume and the dam erosion rate are presented in this paper. Multiple linear regression equations were developed for a combination of historical erosional breach events of water and tailings dams, which use the breach height and the breach outflow volume as inputs. Also presented is a method to estimate whether the supernatant pond volume is sufficiently large for an erosional breach to progress to the foundation based on these equations.

Estudio de rotura de una presa de jales en la zona centro-norte de México

El análisis y modelado de rotura de presas de jales se utiliza en la industria minera para evaluar las consecuencias potenciales ante la ocurrencia de una falla hipotética en un bordo. La aplicación de este análisis se toma como guía para el desarrollo de planes de emergencia y la clasificación de las estructuras, basada en la evaluación de daños potenciales.

Septiembre 2024

Influence of Pre-Existing Mobilized Zones on B3 Cave Propagation and Initial Subsidence at the New Afton Mine

This paper summarizes observed B3 cave propagation and initial subsidence manifestation, using examples from the available instrumentation and monitoring techniques. Application of each monitoring technique to observation-based interpretation of the conceptual B3 block cave (i.e., seismogenic, yielded, and caved zones) and subsidence zone (i.e., crater, fractured, and continuous zones) subcomponents is also presented.

Septiembre 2024

Importance of Indigenous Community Engagement related to ARD/ML and Long-Term Water Quality

Understanding the long-term consequences of ARD and ML is key for Batchewana First Nation and the protection of the water resources within their traditional lands. Engagement is critical so that the importance of water to the First Nation is understood by the mining industry, both on a time scale that is short-term as well as long-term, and multi-generational.

Septiembre 2024

Effective Assessment of ARD/ML Potential for Non-Mining Infrastructure Projects

This discussion focuses on tailoring existing ARD/ML characterization frameworks to effectively characterize the geochemistry of materials from infrastructure projects. Successful ARD/ML prediction at the conceptual phase will minimize the potential for environmental impacts and escalated project costs associated with unexpected or improperly characterized ARD/ML materials.

CESA Aon Engineering Excellence Awards 2024: Kikagati Hydropower Plant

The Kikagati Hydropower Project (KHPP) is a newly constructed 16 MW run-of-river hydropower station on the Kagera River, which serves as a border between Uganda and Tanzania. This project replaces a former mini hydropower station destroyed in 1979 during the war that ousted Idi Amin from power in Uganda.

Interview: Mario Lazo Emparanza, Regional Manager, Knight Piésold Chile

Companies have become more concerned about their corporate image, which has forced them to follow the global standard. Much of Knight Piesold’s current work is aimed at helping the mining industry standardize its tailings deposits.

Visionary Leadership: Driving Engineering Excellence in Africa with Vishal Haripersad

In the realm of engineering and project management consultancy, few leaders embody the blend of technical expertise, visionary leadership, and deep commitment to social impact as vividly as Vishal Haripersad. As the Regional Manager of Knight Piésold Southern Africa, Vishal’s journey is a testament to resilience, innovation, and a profound dedication to the development of Africa and its people.

Concept Feasibility and Predicted Behavior of Mining a Rock Tower with Drill-and-Blast Undermining Using Dynamic Three-Dimensional Discontinuum Numerical Models

The safety and efficacy of a proposed novel mining method - felling a mineralized rock tower away from an adjacent river and towards an existing open pit using a wedge-shaped “key-cut” blast pattern and post-split hinge – was analyzed by integrating site-specific and site-adjacent data to develop a into a dynamic three-dimensional discrete element method numerical model.

Estimating Shear Stress within a Clay Foundation Using the Burgers-Creep Model

Slope inclinometers were installed at multiple locations along the embankment once construction neared the final crest elevation and during subsequent periodic site investigations. These inclinometers are currently showing constant-rate creep deformations within the Lower Clay. This abstract describes the construction of the FLAC model and calibration of the Burgers model viscous properties.

Laboratory Study of Manganese Mining Overburden Mixed with Lime as a Paving Subbase Layer

This paper presents the results of a laboratory investigation comprising geotechnical characterization, CBR, and resilient modulus tests carried out on a manganese overburden, in the natural state and mixed with 3% and 4% lime, to evaluate the suitability of the materials for road construction.

Knight Piésold: Ensuring African Excellence in the DRC

Backed by more than a century’s experience in the African mining sector, Knight Piésold Southern Africa continues to grow its footprint in the Democratic Republic of Congo (DRC). Since it first entered the country in 2008, it has not only ensured sustainable mining, but it is also creating opportunities for local employment. Knight Piésold DRC’s General Manager, Denis Ngoy explains how this holistic approach is driving African Excellence in key mining regions.

Wild Coast N2 Highway Project Taking Shape

The Wild Coast N2 Highway Project includes the construction of a 17.3 km greenfields portion of the new N2 highway. This portion of the new N2, known as Package 5, is located near Flagstaff in the Ingquza Hill Local Municipality in the Eastern Cape Province. It is being constructed in the form of a single carriageway road between the two new major bridges – Msikaba Bridge and Mtentu Bridge – which are both also currently under construction.

Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú

We conducted geotechnical research in Yanacocha and evaluated a tailings deposit within a leach pad. Introducing the Nuclear Magnetic Resonance (NMR) equipment to gather detailed information on mineral characteristics was a groundbreaking initiative, marking a first in the country.

Risk Mitigation through Design Optimization Utilizing Seasonal Effects under Arctic Conditions at the Amaruq Mine

Agnico Eagle Mines is currently operating the Amaruq Mine located in the Canadian Arctic. Since the beginning of the open pit operations, a series of bench-scale failures and rockfalls have occurred during the freshet and summer months. This paper presents the geological and geotechnical site characterization, emphasizing the challenging komatiite conditions including the impact of the high-strain structures.

Synthetic Rock Mass Modeling of Progressive Unravelling and Overall Slope Stability Using the Discrete Element Method

This study utilizes the synthetic rock mass (SRM) approach by combining the Generalized Hoek-Brown and Mohr-Coulomb Strain Softening constitutive models available in Itasca’s Universal Distinct Element Code (UDEC) to represent intact material and discontinuities, respectively.

Operational Slope Stability Risk Management for Large Open Pits at the Mount Milligan Mine – A Case Study

Mount Milligan Mine presents a good example of risk management for large open pits with limited geomechanical data at the onset of pit operations, where confidence in mine safety was gained over time through ongoing data gathering and interpretation, slope monitoring, targeted slope remediation, and slope optimization to achieve economic success throughout operations.

Risk and Informed Approach to TSF Design and Operation

With the introduction of the Global Industry Standard for Tailings Management (GISTM), the standards for tailings storage facility (TSF) design, construction, monitoring and closure have increased, particularly the requirements related to stability. While the GISTM does not prescribe factors of safety (FoS) for stability, it does require a robust design that considers credible failure modes.

Empoderamiento y Resiliencia

En el ámbito de la ingeniería geotécnica, un campo dominado tradicionalmente por hombres, Nadia Mendoza se ha abierto camino con determinación y habilidad. Ingeniera Civil de la Universidad Autónoma Metropolitana de la Ciudad de México, Nadia lleva 12 años forjando una carrera llena de retos y éxitos, especializándose en la geotecnia y contribuyendo significativamente al sector minero.

Balancing Act: Water Usage Management Vital for a Sustainable Future

The United Nations Sustainable Development Goal 6 calls for safe access to water for all. Many parts of Africa are water-scarce nations and this is why there is strong demand for mines to effectively manage their water usage. How do they get this right? GERARD PETER finds out more from AMELIA BRIEL, Environmental Section Manager and AMANDA CASSA, Senior Civil Engineer at Knight Piésold.

A Difficult Balance Between Engineering, Environmental, Social and Economic Aspects

TSFs must be designed for closure. This is easier said than done. It requires a balance between engineering from the starter works, through the operational phase and into final rehabilitation that is aimed at an acceptable and sustainable post-closure land-use.

Knight Piésold Commences with the ESIA for Haib Copper

Knight Piésold Namibia was appointed by Koryx Copper Inc (formerly Deep-South Resources), trading as Haib Minerals (Pty) Ltd, to develop the environmental and social impact assessment (ESIA) towards applying for the necessary authorisations for proposed Haib Copper mining operations.

Insights from the Compilation and Critical Assessment of Breach and Runout Characteristics from Historical Tailings Dam Failures: Implications for Numerical Modelling

This paper describes the research and development of a database of 12 tailings dam breach events with a specific focus on observations that are needed for numerical modelling, in conjunction with an assessment of existing dam breach conventions to improve consistency in reporting. The characteristics relevant to modelling include outflow volumes, breach processes, breach geometries, and runout observations local to the downstream area. This study and the new database shed light on the diversity of outflow materials, facility arrangements, breach processes, and downstream environments that affect the breach development and tailings runout.

Earthquake-induced Deformation Analysis of a TSF Undergoing Tailings Reprocessing

This study discusses advanced, effective stress analyses conducted to assess the seismic performance of a tailings storage facility (TSF) undergoing re-handling and reprocessing of tailings. The seismic stability of the TSF is of interest as it is situated in a high seismicity area in the South American Andes, where subduction earthquakes are known to occur.

Case Study: Approach to Determining the Risk Mitigation Priority of a Historic TSF in North America

This case study focuses on the risk mitigation prioritization of a series of historic upstream tailings dams located in North America. These dams were constructed in a relatively flat basin as a series of approximately 15 cells.

Data Management and Insights for Effective Tailings Storage Facility Management

Collecting and processing data play a pivotal role in the efficient management of a Tailings Storage Facility (TSF). This paper presents a framework and methodology for effectively collecting, processing, and utilizing data to gain valuable insights into the performance of the facility.

The Role of Sensitivity Analysis in Selecting Dam Breach Parameters

This paper focuses on conducting sensitivity analysis to guide the selection of breach parameters for both water retaining and tailings dams. Sensitivity analysis on breach parameters could be undertaken using multiple empirical equations or through probability analysis (e.g., Monte Carlo simulations), which requires that a range and a statistical distribution are defined for each parameter.

Influence of Increased Confining Stress on Undrained Behavior of Tailings: A Case History at the Candelaria Mine

This paper presents an overview of this effect based on published laboratory data on a wide range of soils and outlines a framework to apply this to design. The suggested framework is then compared to data from a case history. The case history involved a thick deposit of loose tailings at the Candelaria Mine where cone penetration testing (CPT) and associated laboratory testing were carried out.

The Re-use of Existing Bituminous Stabilised Materials for the Rehabilitation of National Route 7 - Case Study

This paper will focus on the materials investigation undertaken on the rehabilitation of the N7 that led to the design proposal, design process followed at the time, pavement life cycle evaluation and relook at the design post publication of the TG 2, 2020 BSM transfer function.

Septiembre 2023

Transición energética para gerentes de mina

El almacenamiento por bombeo ha cobrado mayor impulso en base a los requisitos globales de acelerar la transición energética, y en la posibilidad de aprovechar los tajos como reservorios de almacenamiento, así como la infraestructura minera ya construida (accesos, subestaciones, etc.) durante la operación y cierre de la mina, dejando un legado para futuras generaciones.

Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú

Hemos trabajado en un proyecto de reminado en una mina donde realizamos una investigación extensiva y diversos modelamientos geotécnicos avanzados para garantizar la seguridad durante el proceso de explotación. El proyecto fue un éxito y generó beneficios económicos importantes para la mina de forma segura.

Selection of Soil Shear Strength Parameters Based on Integrated In Situ Tests, Lab Tests and Numerical Calibration Approach

Both in situ and laboratory tests have their inherent benefits and limitations. By conducting both types of tests, it is possible to calibrate the in situ tests and identify any improperly conducted laboratory tests. This study has illustrated that (1) numerical modelling can be used to calibrate undrained shear strengths and residual soil yield stresses and (2) it is possible to simulate soil behaviour under complex loading conditions using advanced soil constitutive models.

Determining the Optimum Capacities for the Maguga Expansion and the Lower Maguga Hydropower Scheme

The purpose of this Options Study is to provide a high-level technical, financial, and economic assessment of the various scheme layouts and capacities for the Lower Maguga Hydro Power Scheme and for the expansion of the existing Maguga Hydro Power Station to determine an optimal layout and size based on the available water and associated head for hydropower generation potential. The optimal scheme layout and size will be investigated in more detail during the next phase of the feasibility study.

Leveraging Knowledge and Experience of a Well-Formed Independent Tailings Review Board to Enhance Tailings Facility Safety

This paper draws on the experiences and lessons learned and discusses key features of successfully implementing ITRBs to support resilient designs and operational excellence. The paper focuses on the interaction between the Operator’s team, the Engineer of Record (EoR), and the ITRB. It also discusses the need for a range of experiences, expertise, traits, and skills in forming effective ITRBs are described and the expectations of all involved parties to achieve an effective team with a shared purpose.

Is the Implementation of Dry Stacking for Tailings Storage Increasing? A Southern African Perspective

The paper evaluates the outcomes of a number of such trade-off studies mostly in Southern Africa or arid regions of Africa. It also looks at two mines where filtered tailings has been implemented, their overall TSF operating and stability performance, as well as opportunities and challenges of the technology. No names of the mines are included, as the focus is on whether there is an increased move towards dry stacking, and what obstacles are being experienced.

Canadian Consulting Engineer's Lifetime Achievement Awards: Jeremy Haile

Looking back today, Haile’s 50-year career—one of the longest tenures of anyone currently working at Knight Piésold anywhere in the world—has combined technical expertise in civil and geotechnical engineering, mentorship of his fellow engineers and contributions to industry associations.

Geotechnical Characterization of Collapsible Salty Sands Subjected to Monotonic and Cyclic Loadings – A Case Study for Areas with High Seismicity

This paper presents a geotechnical characterization of collapsible salty sands in the highly seismic southern coast of Peru, which makes the characterization of their dynamic properties and expected response to earthquake-induced demands (e.g., liquefaction) of primary importance.

Methodology proposals for the monitoring of activation levels and response plans for tailings deposits in Mexico

This article presents a methodology proposed by Knight Piésold for the preparation of trigger action response plans or TARPs and is intended to serve as a technical guide for the global mining industry. A TARP provides a set of predefined indicators of failure of a tailings dam, which can be monitored through geotechnical instrumentation, each indicator triggers a set of actions that must be taken into account to prevent the failure or mitigate its impacts.

Evaluación geotécnica del uso de material de banco para la construcción del recrecimiento en un depósito de jales

En este artículo se presenta la factibilidad, evaluación y configuración de un material meteorizado proveniente de banco, para el uso de los recrecimientos de los bordos en un depósito de jales. El principal objetivo de este estudio mediante pruebas de campo parte de la evaluación geotécnica mediante el uso de terraplenes de prueba con la finalidad de establecer un comportamiento mecánico del relleno de los bordos de manera práctica y asequible.

Correlación de valores de densidad con densímetro nuclear y cono de arena en un depósito con residuos mineros tratados con cal

En este artículo se aborda una comparación entre los valores de densidad obtenidos con medición directa en campo mediante cono de arena, respecto a la medición indirecta dada por un densímetro nuclear. Se revisan los procedimientos de medición de densidad con ambas técnicas y se expone la influencia que tiene la composición geoquímica y el tratamiento con cal del residuo minero sobre la desviación en las mediciones con la radiación nuclear.

Application of the 3D Limit Equilibrium Method in Tailings Dam Breach Analysis

This paper describes a case study of a TSF undergoing closure activities, where three-dimensional limit equilibrium analysis was used to estimate breach geometry, breach location, and potential outflow volumes. It highlights the importance of integrating soil mechanics concepts with dam breach analysis methodologies to provide a more meaningful approach for evaluating potential runout impacts of a slump-type failure mode.

Evaluation of Tailings Behaviour for Dam Breach Assessment

This paper provides some insight into the links between simple index tests and rheological measurements for evaluating the potentials for a tailings mass to flow or slump. Simplified methods are suggested to predict the volume of material that may become mobilized in a dam breach event. Finally, practical mitigation measures to reduce the tailings flowability, enhance the impoundment stability and reduce the risk and consequences of a tailings dam breach are briefly discussed.

Tailings Improvement by Stress-Densification from Waste Rock Capping

This paper summarizes the results of field and laboratory testing of the tailings stored in the decommissioned Candelaria tailings storage facility (TSF), showing improvements in the tailings residual shear strength characteristics as a result of increasing the tailings stress state. The results of the field and laboratory program support the use of stress densification as an effective tailings improvement method at the site.

Transforming Tailings Management Systems toward Alignment with the GISTM: A Case History

This paper outlines a case history of developing the first phase of a tailings management system. This process is significant in the context of a dynamic industry that is pushing for a culture of change towards zero harm, while also balancing the established technical aspects that govern tailings dam safety.

Managing Excessive Pit Wall Deformation of Weak Rock Mass

Rapid acceleration of a large-scale creeping instability occurred in an open pit operation in Nevada. This paper summarizes a case history where excessive deformation of a pit wall exposed in weak rock mass was successfully managed.

State-of-the-art Method for Estimating Long-term Hydroclimatic Conditions for Tailing Dam Water Management and Dam Safety Planning

This paper presents a case study of the use of a reanalysis product (ERA5) and a probability-based BC method to develop long-term climate values for a mine site with short-term climate records. The use of this state-of-the-art approach can facilitate mine water management planning and increase dam safety by improving estimates of historical hydroclimatic variability.

Observed Subsidence Progression at New Afton Mine in Response to Lift 1 Mining

This paper presents a case study of the observed subsidence progression in response to block cave mining, from initial breakthrough to the end of the Lift 1 production, using examples from the various instrumentation and monitoring techniques used at the New Afton Mine.

Interview: Guillermo Barreda, Gerente General, Knight Piésold Perú

El año pasado celebramos nuestro 100 aniversario globalmente. Esto es un hito extremadamente importante, que muestra que estamos haciendo algo de manera distinta para haber logrado una vida tan larga en sectores tan competitivos y desafiantes.

Hydrometric Monitoring and Effluent Discharge Mixing in Challenging Natural Conditions

River systems prone to backwatering present difficult conditions for collecting reliable hydrometric monitoring data. Furthermore, passive discharge of treated effluent in low velocity receiving environments may not achieve full mixing without additional measures to promote dilution. Knight Piésold designed a hydrometric monitoring network and a treated effluent discharge system for the Rainy River Mine in Northwest Ontario that had both these conditions.

Inundation Modelling of Non-Newtonian Tailings Dam Breach Outflows

This paper describes recent experiences with modelling the flood wave propagation of non-Newtonian tailings dam breach outflows using hydrodynamic modelling tools. Challenges encountered and lessons learned from various case studies are discussed, including availability and quality of input data and selection of appropriate models for the given conditions. All these factors have profound impacts on the results.

Video: Tailings Management Compliancy Picks Up Momentum

Join Laura Cornish, Editor-In-Chief of Mining Review Africa as she catches up with Andrew Copeland, Knight Piésold Consulting Technical Director for Mining, to talk about the next step in tailings management delivery and the pressure around meeting implemented deadlines.

A Catch up with...Richard Elmer

Knight Piésold’s decision to re-establish a London office in 2013 after a 10 year absence seems prescient in view of the global move towards de-carbonisation, the shift in business ethos to embrace Environmental, Social and Governance (ESG) standards, and the current re-focus in manufacturing to obtain critical metals from ethical sources.

Engineer of Record Services for Tailings Facilities

There remains significant uncertainty about what an EOR is and how to implement the concept on tailings projects. Knight Piésold has prepared this guide for implementation of the EOR concept for the projects and Owners we support. This paper addresses only the case of an external EOR, which is one of the two primary models recognized by the Global Standard.

Knight Piésold's Projects Commended at Prestigious Awards

Consulting engineering firm Knight Piésold’s engineering excellence was recognised through two of its projects, which received high commendations in the consulting engineer category at the Construction World 2021 Best Projects Awards. The projects were the Emoyeni Reservoir in KwaZulu-Natal, in South Africa, and the Neckartal Dam in Namibia.

Advances in Ensuring Tailings Dam Safety

The GISTM provides a framework for safe management of Tailings Dams while allowing operators flexibility in how to achieve this goal. The ICOLD Sub-Committee L (Tailings Dams and Waste Lagoons) has prepared a new Bulletin which will be submitted to the ICOLD Central Committee in November 2021 to provide Technical Guidelines in support of the GISTM’s Management Principles.

Gearing Up for Growth in Zambia

Patrick Kampengele, Managing Director for Knight Piésold Zambia, says the firm’s ongoing relationship with Mopani Copper Mines illustrates the confidence the client has in the quality of work being produced. In recent years, Knight Piésold’s Zambia office has expanded its range of sub-consultants and sub-contractors, as well as recruited additional staff as it positions itself to meet the country’s growing demand for engineering and environmental services.

Climate Change Effects on Rainfall Extremes and Implications for Highway Drainage Structures

Research was carried out to assess changes in extreme rainfall properties over time for the area surrounding the National Route 1 Section 29 (N1-29), located in Limpopo, South Africa. The study examined the changes in return levels for 1920-1970 and 1969-2019.

Knight Piésold, aliado de la minería sustentable

La minería es una de las industrias más comprometidas con el desarrollo sustentable en México. Sin embargo, tiene claro que, para lograrlo, debe procurar el cuidado al medio ambiente, alineándose a estándares internacionales. Knight Piésold cuenta con una vasta experiencia en proyectos relacionados al sector minero. Sus diseños, soluciones y servicios cumplen con las normas más exigentes de la industria.

Septiembre 2021

Knight Piésold Chile enfoque personalizado e integral de trabajo al estilo boutique

La empresa ha crecido en Chile y el mundo gracias a la búsqueda constante de la innovación. Sus especialistas cuentan con una amplia experiencia en los rubros de ingeniería y sustentabilidad. Especialistas de experiencia, comprometidos y con una mirada sustentable sobre cada proyecto, conforman el equipo humano de Knight Piésold Chile, que examina la complejidad y aspectos críticos de cada proyecto, con especial énfasis en ingeniería geotécnica, hidráulica, civil, y mecánica y cañerías.

Septiembre 2021

Engineering the Future: The Profile of the Modern Engineer

The COVID-19 pandemic has highlighted the need to be adaptable in order to thrive in the face of constant change. In an ever-changing global environment, it is important for engineers to continue to increase their range of skills to remain relevant and progress further. Whilst the most recognised profile of an engineer focuses on technical and analytical skills, there are several other skills required for effective performance in workplace and project environments.

Septiembre 2021

Company Uses Innovative Ideas in Municipal Project

Consulting engineers Knight Piésold completed the design and construction supervision of the 25 ML rectangular reinforced concrete reservoir at the Emoyeni site for the eThekwini municipality Water and Sanitation Unit in February 2021. Knight Piésold lead engineer Kendall Slater explains that the project represents creative design elements that exceeded the expectations of both the client and the community.

South Africa Must Focus on STEM Skills to Enable Development

South Africa needs to improve awareness of science, technology, engineering and mathematics (STEM) skills among primary and secondary school learners. These skills should also be taught by appropriately qualified specialist teachers, to develop skilled and experienced engineers necessary for South Africa's infrastructure development, says consulting engineering multinational Knight Piésold South Africa human resources director Mevashnee Naidoo.

Business Success Stories: Knight Piésold

This year marks a historic milestone for Knight Piésold, whose roots go back 100 years in South Africa. Knight Piésold began operations on April 1, 1921, when founder Dr FE Kanthack established a private practice as a consulting engineer, and to date, the firm remains a truly uniquely South African firm that is committed to service excellence with a footprint across the world and in different sectors.

Holistic Approach to Mine and Industrial Water Management

This year marks consulting engineering firm Knight Piésold’s 100th year of existence. The practice was started by a water engineer and now offers a broad range of expertise to assist with industrial effluent and mine water. Kirsten Kelly talks to a few members from the team.

Selection of Undrained Shear Strength Parameters of Residual Soils and their Application in Stability Analysis

Recent updates on tailings dam design guidelines require analysis of undrained (short-term) stability with the application of the SHANSEP model. The SHANSEP model, which was originally developed for alluvial soils, predicates that the Undrained Shear Strength (Su) increases with increasing effective stress. Residual soils by their nature do not necessarily follow this relationship. This paper examines an alternate method to define Su over a range of effective stress conditions for residual soils.

Knight Piésold Focused on Africa's Infrastructure Development

Consulting engineering firm Knight Piésold continues to entrench its footprint in Africa and invest in local skills and expertise to support the growth of infrastructure development in the countries in which it operates. From its humble beginnings in South Africa on 1 April 1921, Knight Piésold has established and grown its local operations within Southern Africa, through its offices in Namibia, Zambia, the Democratic Republic of the Congo, Botswana, Madagascar, Swaziland, Mauritius and South Africa.

Century-old Knight Piésold Remains Committed to Clients and Communities in Phalaborwa

This year marks a historic milestone for Knight Piésold, a consulting engineering firm, whose roots go back 100 years in South Africa. The company’s successful 100-year footprint has a strong history of commitment to communities and clients, including the region of the Limpopo province, where it has had a presence since the early 1960s, explains Le Roux Loubser, Regional Manager in Phalaborwa for Knight Piésold.

Very Few Consulting Firms Reach 100 Years – Knight Piésold Celebrates with Optimism

Local consulting engineers, Knight Piésold, recently celebrated their centenary, reflecting not only on their impressive accomplishments but remaining very optimistic about Namibia’s future despite the slump in engineering contracts. The firm’s flagship project, Neckartal Dam, was completed in 2020.

Knight Piésold Celebrates 100 Years of Excellence in Africa

From its humble beginnings in South Africa on 1 April 1921, Knight Piésold has established and grown its local operations within southern Africa, through its offices in Namibia, Zambia, the Democratic Republic of Congo, Botswana, Madagascar, Swaziland, Mauritius and South Africa. Speaking at the company’s centenary celebrations held in Sandton this week, Vishal Haripersad, regional manager for Knight Pièsold in southern Africa, explained that operations across Africa were staffed by locals in the country, and supported by the collective skills, knowledge, and expertise of both its southern African and global teams.

Video: Knight Piésold Celebrates 100 Years of Engineering Excellence

Knight Piésold is celebrating a milestone achievement – one few companies ever do – turning 100 years old. In the below video, Andrew Copeland, Technical Director at Knight Piésold South Africa reflects on the company’s past, identifies new and emerging trends in the industry and shares how the company is preparing for its next milestone birthday.

Opportunities Abound to Support Africa's Resilient Growth - Knight Pièsold

The median population for Africa is projected to reach 1.68 billion by 2030, which presents significant opportunities for the public and private sectors to help shape the continent for growth across various industries. This is the view expressed by Vishal Haripersad, Regional Manager for Knight Pièsold Africa, during the company’s 100-year anniversary celebration held in South Africa on 1 April. The consulting engineering firm was a founded in Johannesburg on 1 April 1921.

Firm Expands Service Offering

Consulting engineers firm Knight Piésold Southern Africa has added a hydrogeology and groundwater department to its service offering while expanding its mine services offering since the start of the year. “We are providing the full infrastructure spectrum for the mining sector, which includes structural engineering, roads, transportation, geotechnical engineering and environmental engineering,” says Knight Pièsold Southern Africa MD Vishal Haripersad.

Celebrating 100 Years of Engineering Excellence

This year marks a historic milestone for Knight Piésold, a consulting engineering firm whose roots go back 100 years in South Africa. The company was founded in Johannesburg in 1921 and has grown from small beginnings into a global consulting firm operating in 15 countries worldwide. With a staff complement of 850 people, the firm aims to create value for clients at every stage of a project.

Improved Tailings Disposal Could Reduce Water Use

Namibia is a water-scarce country in most areas; therefore, minimising water consumption in ore processing is a focus area, especially for tailings disposal, which can account for over 50% of all water used in processing, states engineering and environmental firm Knight Piésold mining services technical director Andrew Copeland.

Your Community, Your Neighbour

The future of mining projects in Africa no longer rests only on their financial viability but also on their sustainable efficacy, which includes managing and satisfying all stakeholders. This to a large extent includes neighbouring project communities - an important component for the environmental, social and governance (ESG) aspects of a project.

Knight Piésold Turns 100

This year, Level 1 BBBEE, employee-owned Knight Piésold celebrates a milestone achievement few companies ever realise – 100 years in business. Its journey over the decades has resulted in the establishment of a truly global brand, with a very successful South African subsidiary. “Today, we proudly proclaim to be one of the oldest African owned engineering consultancy firms in Africa, with an internationally recognised pedigree of skill sets, committed to serving and uplifting the local markets in which we operate,” MD VISHAL HARIPERSAD tells LAURA CORNISH.

Lepidolite Extraction Solid By-product: Mitigation of Thallium Leaching and Utilization of Radiogenic Strontium Isotopes as a Tracer

The emerging growth of lithium-ion battery usage necessitates the development of unconventional resources for battery grade lithium carbonate. Extraction of lithium from micas such as lepidolite produces several marketable by-products as well as a silt-sized gypsum rich blended residue containing elevated level of thallium (Tl). The goal of this study was to assess the alternative use of the blended residue as fill material for mine reclamation.

Reducing Long Term Risk at the Candelaria Tailings Storage Facility

The Candelaria Tailings Storage Facility (TSF) was deactivated in 2018 and a surface cap is planned for closure of the impoundment. Mining activities will generate approximately 800 Mt of waste rock during ongoing open pit mining operations, and the decommissioned TSF provides an opportunity for TSF closure capping activities to be integrated with long term waste rock disposal.

Dynamic Effective Stress Analysis of a Centerline Tailings Dam – Case Study

This study presents the results for the dynamic effective stress analysis performed to evaluate the seismic performance of a center-line tailings dam in the South American Andes. To characterize the seismic demand at the project site, a probabilistic seismic hazard analysis (PSHA) was performed, producing deterministic-based and probabilistic-based seismic design criteria.

Consolidation Modeling for Design of Complex In-pit Tailings Storage Facility

Suitable locations for safe and economic disposal of mine tailings that pose low long-term liability are limited at many mine sites. In recent years, backfilling of existing mine pits with tailings has garnered attention as one viable alternative. The case presented herein, despite having some fundamental resemblance to typical in-pit filling practices, is unique due to the hydrogeology of the area and envisioned complexities of the tailings deposit development within the open pit over the life cycle of the facility.

High Demand for Tailings Consulting Exceeds Local Capacity

Engineering consultant Knight Piésold is focused on providing technical advice for many local tailings dam facilities, says Knight Piésold technical director for mining services Africa Andrew Copeland. This increase in demand for tailings dam-related consulting can be attributed to several tailings dam failures, most notably the Brumadinho dam disaster that occurred in Brazil in January last year. Copeland argues that such incidents have resulted in a heightened focus from miners on improving tailings dam operations.

Septiembre 2020

Interview: Ama Nketiah, Regional Manager, Knight Piésold Ghana

The mining sector in Ghana and the West African sub region is seeing a boost in activity. This is mainly due to the rising gold price which has encouraged exploration and commissioning of capital projects. The sociopolitical climate is also conducive towards investments in the sector.

Septiembre 2020

The New Normal in Consulting Engineering: Drone Technology

The emergence of the Covid-19 pandemic has pushed many industries to revisit the way in which they conduct business. This has led to companies, including those in the consulting engineering sector, to consider new technologies with the aim of adapting and innovating to remain relevant in the current climate whilst also ensuring minimal disruption in the project cycle. Drone Technology has been identified as one such technology which has gained popularity in recent years. The use of Drone Technology as a tool for the development of infrastructure is wide reaching and can be applied to several parts of the project cycle.

Harnessing Hydropower in the DRC

Hydroelectric power, whether it be pumped storage or run-of-river, is a low cost, clean form of energy in areas with rivers or dams. The Democratic Republic of Congo (DRC), with its abundant water resources, is ideally placed to support the development of both small and large-scale hydropower schemes. Join Mining Review Africa, ESI Africa, DRC Mining Week, and Knight Piésold as we examine the potential of hydroelectric power in the DRC, for the benefit of the mining industry and the surrounding communities.

Green Energy for the Copperbelt

The expansion of mining in the Zambia-DRC Copperbelt has led to a severe shortage of electricity. With high annual rainfalls and large rivers, it makes sense that countries on the Copperbelt are turning to hydropower to address the additional demand. Hydropower does not consume water but rather the water is used to turn turbines to generate electricity and then released back into the river. Private developers have identified the opportunity and are addressing the power deficit through hydropower projects in the region.

Safe and Sustainable Tailings Management Training

Tailings dams are a critical element in most mine operations and require sustainable management over the life of the mine in line with modern day "risk management" approaches. Very little formal education is included in University/College courses, leaving a knowledge gap around tailings management. This training will provide up-to-date information on to how to plan, implement, operate and sustainably manage tailings dams in a safe and effective manner consistent with various Government and "duty of care" obligations.

Development of a Decision Tool for Selection of Pit Slope Stability Monitoring Instrumentation

This paper presents a Slope Stability Monitoring decision tool that has been developed to consistently and efficiently select instrumentation across a range of pit slope characteristics. The Slope Stability Monitoring decision tool uses typical slope stability evaluation criteria to assess the risk of slope instability and provides instrumentation recommendations based on the calculated level of risk.

Investing in Safe & Sustainable Tailings Management

The controversial issue of Tailings Storage Facilities (TSF) construction and management following a spate of disasters over the last 24 months was unpacked during a breakfast discussion by leading mining services companies Fraser Alexander, Knight Piesold and Webber Wentzel on the sidelines of the annual Investing in Africa Mining Indaba event in Cape Town this week.

Differences in Physical Habitat Simulation System Modelling Results Using Benthic or Pelagic Fish Species as Indicators in Peruvian Andes–Amazon Rivers

The main objective of this study is to compare the use of benthic native species (Astroblepus taczanowskii and Astroblepus vanceae) versus the introduced Oncorhynchus mykiss (rainbow trout) as target indicators for PHABSIM modelling in the Andean–Amazon piedmont rivers.

Mining Magazine Awards

In early 2019, Inmarsat joined forces with Knight Piésold UK with the aim to deliver highly accurate tailings dam monitoring, analysis and real-time management capabilities for the mining industry. Inmarsat’s satellite-enabled IoT solution was combined with Knight Piésold’s industry-leading consultancy to enable smarter decision-making, improved safety standards and support regulatory compliance; offering a new approach to the way tailings dams are currently audited and managed.

Tailings Management: Zero Tolerance for Failure Not Negotiable

Tailings management fell directly into the spotlight in 2019 following a spate of tailings storage facility disasters over the last 24 months. 2019 saw a ground swell of focus around the safety of tailings storage facilities (TSF) in the mining industry – one that has been building over the last five years – following a series of large and devastating failures.

Assessment of Leach Ore Dry Unit Weight and Hydraulic Performance

Proper design of a heap leach facility requires the development of a leach ore loading plan that can accommodate its ultimate capacity. The loading plan and associated capacity assessments will be more representative of actual field performance if they consider the variation in leach ore dry unit weight over time as the heap is loaded and the leach ore compresses under self-weight. That can be accomplished by careful evaluation of results from laboratory testing of representative samples of the leach ore.

Selecting the Optimum Hydropower Scheme Capacity

To select the optimum dam height and plant capacity, a high-level design should be prepared for a range of the dam heights and plant sizes at a potential site. This paper deals with selecting the optimum scheme capacity for a site using the established economic optimisation method of total revenue – total cost approach and marginal analysis, which mitigates the bias in selecting the scheme capacity.

Septiembre 2019

Evaluating the Effectiveness of Sunnyside Gold Corporation's Reclamation, San Juan County, Colorado, USA

The Animas River in the area around Silverton, San Juan County, Colorado has been adversely impacted by high loading of iron, aluminium, cadmium, copper, lead, zinc, arsenic, and nickel. Metals loading in the Animas River has limited aquatic life, including the trout fishery downstream from Silverton. The metals concentrations in the Animas River is due to acid rock drainage formed from a combination of natural weathering of mineralised rocks and residues from over 100 years of historic mining.

Should Upstream Tailings Storage Facilities be Banned?

Upstream constructed tailings storage facilities (TSFs) have been banned in Chile, Peru and Brazil and there are many other jurisdictions where such designs may not be accepted by Authorities, especially in wet climates and in highly seismically active areas.

Dam-break: Effect of Water Content in Tailings vs Run-out Distance

In the case of run-out analyses, we present a sensitivity analysis of the effect of the degree of consolidation at the time of a dam breach on the run-out distance potential. The results show a decrease of up to 16% in the maximum area reached by the outflow due to the increase in the degree of consolidation. The incorporation of the relative effect of densification methods and the resulting change in rheology represents a progress in understanding the critical elements that drive the potential for downstream impact of a dam breach event.

Vancouver: The Global Mining Hub

Days after the all-share merger between Barrick and Randgold became effective in January 2019, Newmont Mining Corporation entered into a definitive agreement with Goldcorp in a stock-for-stock transaction valued at US$10 billion to create Newmont Goldcorp, as Newmont announced it will move its North American regional operations office from Nevada to Vancouver.

Geotechnical Characterization of Collapsible Soils Cemented by Salts - A Case Study

This paper presents a summary of the geotechnical characterization performed on a deposit of collapsible soil at a proposed mine site near the southern coast of Peru, with particular emphasis on the dynamic characteristics. The site is located in a very high seismic area, which makes the dynamic characterization of these materials of primary importance.

CDA Technical Bulletin on Tailings Dam Breach Analyses

The CDA Technical Bulletin for TDBA will provide the key steps that should be undertaken. The differences between water retaining and tailings dams will be addressed. The presence of a supernatant pond and the potential of the tailings to liquefy and flow, are the key parameters influencing the runout potential and outflow volume. The physical processes occurring during a TDBA will be discussed with guidance provided on estimating the volume of released tailings during a breach and predicting where the tailings could flow. The TDBA is planned to be issued in 2019.

Reducing the Long Term Risk and Enhancing the Closure of Tailings Impoundments

This paper provides a case study for the decommissioned Nye Tailings Impoundment at the Stillwater Mine. The closure plan includes capping the loose, saturated tailings with a thick waste rock layer to stabilize the impounded tailings, mitigate potential dusting and provide for water management.

The Application of Rubble Masonry Concrete (RMC) Construction for African Dams and Small Hydropower Projects

This paper and presentation will cover the design methods and standards applied to recent projects that have incorporated RMC weirs and the construction techniques that were successfully implemented. Case studies of RMC Dams constructed for water supply reservoirs and a remote (11 MW) hydroelectric power project will be presented and discussed.

Staged Emergency Spillway Development – Design Considerations

This paper will explore the key considerations for the development of a TSF emergency spillway. The spillway development at the Phu Kham Copper-Gold Operation (operated by Phu Bia Mining Limited) located in the Lao People’s Democratic Republic will be used to illustrate these considerations.

Solving Spillway Geometry for Three-dimensional Flow

A set of VC-Ogee design curves for these parameters, for an asymmetrical approach channel with side contraction of the spillway, is presented in this paper. Further design curves to accommodate symmetrical, contracted and uncontracted approach channels as well as combinations of these conditions, will be made available in future.

Design of Coarse Tailings and Dry Ash Disposal Facilities

The diamond industry has been disposing of its coarse tailings using conveyor and stacker systems for many years. The process plant typically generates two tailings products, a grit fraction (sand) and a coarse fraction (gravel), which are often combined on one dump. In some cases, the dump is stable with a single steep slope angle. However, in other situations a composite slope forms with settlement and intermittent slumping behaviour, this impacts on both design and operation.

Can Hydro Power Mines?

Whether pumped hydroelectric, run-of-river, or small hydropower systems, there is a growing need to use Africa’s vast hydro potential to boost reliability of power in remote areas, and specifically for the mining industry. The potential is there; however, it’s not without its financial, operational and environmental challenges.

Modelling, Design and Construction Monitoring of Neckartal Dam, Namibia

Neckartal is the largest dam in Namibia, with a full supply volume of 853 x 106m3, exceeding the volume of what was previously the largest dam, Hardap, by a factor of three. Projects of this magnitude need innovative construction technology to be implemented successfully. In the case of Neckartal, a special challenge was its isolated location in the arid climate of southern Namibia, with irregular, high peak runoffs. During the design of the dam, two physical models were built. Results from the physical model testing were used to improve the safety of the spillway and reduce potential scour erosion downstream. Throughout the construction of the dam, innovative techniques were used, which are described in this paper.

Neckartal Dam, the Design & Supply of the Hydro Mechanical Equipment

This paper gives a description of the hydro mechanical equipment for the project, the contractual arrangements to procure and install it, some of the important specifications used for the design and manufacture of the equipment and the quality assurance methods used to ensure that the equipment meets the long-term project requirements.

Knight Piésold World-class Expertise Meets Local Legislation

98-year old proudly South African engineering and environmental consulting firm Knight Piésold (SA) has strategically committed to expanding its footprint in Africa on the back of its growing track record across the continent. Because the Democratic Republic of Congo (DRC) in particular remains a strategic region for the company, it has repositioned its local office to comply with the country’s new sub-contracting legislation and is consequently well placed to take advantage of new business opportunities on its doorstep, environmental section manager AMELIA BRIEL tells LAURA CORNISH.

Consultancy Implements Responsible, Sustainable Practices for Tailings Facilities

Multidisciplinary engineering and environmental consultancy Knight Piésold aims to improve project sustainability this year and lower the possible risks that can arise from tailings facilities. This includes regular inspections, geotechnical investigations and necessary slope analysis, says Knight Piésold consulting lead engineer Veronique Daigle.

Building Namibia's Largest Dam

Upon completion, the Neckartal Dam will be the largest dam in Namibia, with a full supply volume of 853 Mm3, exceeding the volume of the existing largest dam, Hardap Dam by a factor of nearly three. Projects of this magnitude need innovative construction technology in order to be executed successfully, Neckartal more so due to its desolate location in the arid climate of southern Namibia.

Knight Piésold Well Positioned to Soar in 2019

On the back of an “exceptionally good year” in 2018, 97-year old proudly South African engineering and environmental consulting firm Knight Piésold (SA) is looking to build further on its strong achievements in 2019. Thanks to its fully transformed, Level 1 BBBEE, 57% black ownership structure status and growing office footprint in Africa, the company is well positioned to service the entire African continent – using its award-winning technical experts to deliver industry revolutionising solutions for the mining sector, technical director for mining ANDREW COPELAND tells LAURA CORNISH.

Steel Reticulation Design Excels

Serving the growing needs of the City of eThekwini’s industrial and residential sectors is an expanding network of steel pipelines that traverse the hilly terrain common in this region. The challenging topography calls for innovative design and construction methodologies, which had a direct bearing on the pipeline reticulation system adopted.

The Best in Municipal Engineering

The 2018 IMESA/CESA Excellence Awards recognised municipal infrastructure projects that demonstrated significant achievement through innovation, design or construction. Presented at the 82nd IMESA Conference, the 2018 awards recognised outstanding achievements in municipal infrastructure, demonstrating the best of civil engineering as a science and how engineering enhances the lives of local communities

Interview: Ken Embree & Greg Smyth, Managing Principal and President (Effective 2019) & Project Manager, Knight Piésold Canada

Knight Piésold is recognized for technical excellence and dependability. We are nearing our 100-year anniversary and have operated in Canada for 44 years. Our B.C. based clients will continue to play a very important role in our operations and we will continue to partner and integrate with them. We are proud of our track record in sustainable development, both in power and mining projects, and aim to continue to grow and enhance our capabilities moving forward.

Knight Piésold - A Shining Example

MULTI award-winning civil engineering consultancy, Knight Piésold has proved that it is possible to become a truly transformed multi-national organisation that embraces South Africa’s B-BBEE imperatives as responsible corporate citizens. Having recently achieved Level 1 B-BBEE accreditation through the training and development of local staff and shareholders as well as enterprise development and participation in meaningful CSI initiatives, the 97-year old firm is a proudly South African company that invests its profits locally.

A Conceptual Elevation Versus Volume Curve Determination Method for Tailings Dam Breach Studies

Most of the theory used in tailings storage facility breach studies was developed for water dams and are not fully applicable to tailings storage facility failures. This paper describes a conceptual alternative formulation of the elevation versus volume curve of the cone of depression that forms during a tailings dam breach.

A Brief History of the RCC at Neckartal Dam

The construction of Neckartal Dam started in September 2013. The full-scale trial section was done in August 2015 and the first RCC was placed on the dam foundation in October 2015. The RCC placement was completed 32 months later in May 2018. This paper gives a brief history of the RCC through the various project phases.

Tailings Impoundment Closure Enhancement

Many tailings impoundments provide long?term storage for saturated, semi?fluid fine grained materials. Closure of these tailings impoundments represents an ongoing priority and a potential challenge for owners and professionals due to the potentially fluid nature of the impounded tailings in the event of a hypothetical dam breach.

Review of Risk Management and Regulatory Framework of Mine Waste Facilities in Zambia

Fatal and life threatening incidences related to mine waste facilities occurring in the mining sector worldwide are a source of concern to the industry. Despite the implementation of management strategies and enforcement of relevant pieces of legislations, fatalities associated with the operations of mine waste facilities have continued to befall the mining sector.

Design of Zinc Tailings Storage Facility

One of the largest diversified natural resource companies required a tailings storage facility (TSF) as part of the new Zinc mine in the Northern Cape, South Africa. The concept design incorporated a spigot deposition system, but due to footprint and cost limitations, the final design was changed to a centerline and upstream constructed, cyclone deposition method, which provides an acceptably stable outer zone, built from cyclone underflow (coarse tailings) with cyclone overflow (finer tailings) stored in the internal basin. This paper discusses some of the design aspects and challenges faced during the design process.

Construction Supervision of a Zinc Tailings Storage Facility and Return Water Dam

One of the largest diversified natural resource companies required a 110-hectare tailings storage facilities (TSF) as part of the new Zinc mine in the Northern Cape, South Africa. This facility and return water dam (RWD) were required to be covered by 1.5mm HDPE smooth and 1.5mm HDPE double textured geomembrane in specific areas to make up the barrier system. The main objective of the barrier system is to contain the slurry being deposited to ultimately prevent groundwater contamination.

What it Means to be an Engineer of Record

The term Engineer of Record (EoR) is commonly used in North America to define the responsible person for design and construction phases of a project. For tailings storage facilities (TSF’s), an EoR is often appointed as the person technically responsible for seeing that a TSF is built according to the design. The use of this appointment has increased due to recent high profile TSF failures, and has spread to countries outside of North America, especially for mining companies that are based or listed there. Recent updates to national/international TSF guidelines suggest appointing an EoR is good practice.

Selati Tailings Dam New Decant Tower

A failure occurred along the Selati Tailings Dam decant outlet conduit in February 2013. Emergency response procedures ensured the integrity of the facility. Improved engineered remedial measures were then executed. A trade-off study was conducted to find the preferred option for replacement of the decant system. The outcome was that a gravity decant system similar to the existing system is preferred and is to be located on natural ground in the facility basin on the Southern side.

Azambi HPP – Private Hydropower Development in Africa

Throughout the world, there has been an increasing trend toward development of low impact small to medium sized hydropower schemes by Independent Power Producers (IPP’s) and Private Developers. In this paper, the authors present the design and construction of Azambi Hydropower Project, the third HPP developed by the Kibali Gold Mine, located in the remote north-east province of Democratic Republic of Congo, Africa. The mines concession is not serviced by an electricity utility provider but is favourably enveloped by large untapped rivers.

Determining the Optimum Scheme Layout for the Sombwe Hydropower Project

Legislation in the DRC has recently changed to allow Independent Power Producers (IPP) to compete in the local power market. To this end, Kipay Investments appointed Knight Piésold and Ingerop Consulting Engineers to conduct a feasibility study for the proposed Sombwe Hydropower Project in late 2016. The project is located approximately 290 km north of Lubumbashi in the Katanga Province of the DRC.

Challenges in Classifying and Designing Spillway Upgrades for a Small Embankment Dam Upstream of an Urban Population

A 10 m high embankment dam located 4 km upstream of a populated area was assessed during its Dam Safety Review as requiring an upgrade to the spillway capacity to comply the current CDA Dam Safety Guidelines and BC Dam Safety Regulations. At normal operating levels, the Dam stores approximately 31,000 m3 of water. The Dam was completed in 1966 and has been successfully operated by the Dam Owner without incident for over 50 years as a critical part of the water distribution system.

Tailings Impoundment Closure Enhancement

Many tailings impoundments provide long-term storage for saturated, semi-fluid fine grained materials. Closure of these tailings impoundments represents an ongoing priority and a potential challenge for owners and professionals due to the potentially fluid nature of the impounded tailings in the event of a hypothetical dam breach.

Lined Tailings Facilities - Consequential Risks Require Better Understanding

The mining industry in South Africa – which extends back more than a century – is grappling with historical legacies that have been put under the spotlight as the world becomes more environmentally conscious and responsible. Tailings management in particular, an area neglected in the past, is now a priority. While lining have become the preferred option to reduce possible environmental impact of tailings material they pose their own set of risks which urgently need to be monitored and addressed, Knight Piésold technical director for mining Andrew Copeland tells Laura Cornish.

Septiembre 2018

Design of a Centerline Method Tailings Dam using Mine Waste Rockfill in Perú

This paper provides a summary of the design analyses and describes observations made during construction and operation. Site-specific deterministic and probabilistic seismic hazard analyses, seep-age, slope stability, and deformation analyses performed to predict the long-term engineering behavior of the dam and impounded tailings are described.

Septiembre 2018

Benefits of Rotational, Thin Layer, Air Dried Tailing Deposition after 25-Years of Operation of the Juniper Tailing Storage Facility

This paper discusses the design, construction and operation of the facility including a summary of the benefits realized by the type of embankment constructed and the use of rotational, thin layered, air dried deposition. The features discussed could be considered for inclusion in other projects to provide safety and security, reduce costs and provide efficient operations.

Septiembre 2018

Vertical Expansion of a 41-m High Geosynthetic Reinforced Soil Slope

The Pampa Verde waste dump expansion is highly driven by the following constraints: (1) relatively limited options for laterally extending the existing buttress; (2) the need to satisfy both static and seismic stability; (3) the need to properly select high-strength reinforcement products; (4) the importance of conducting material-specific tests to characterize the soil-geosynthetic interaction; and (5) the complex geometry of the overall system, particularly its global stability.

Septiembre 2018

The Assessment of the Overall Probability of Failure of Hard-rock Slopes Using the First Order Reliability Method and the Hunting Equation Method

The overall probability of failure of a hard-rock slope is assessed using a combination of the First Order Reliability Method (FORM) and the Hunting Equation Method. FORM is used to assess the probability for each potential failure mode, which considers the correlation of the variables (e.g. discontinuity friction angle and cohesion). The overall probability of failure of the rock slope is then assessed using the Hunting Equation Method by combining every potential failure mode’s probability of failure.

Remediation Helps Rescue a River

Metals loading adversely impacts the Animas River in the area around Silverton, San Juan County, Colorado. The metals of concern include iron, aluminum, cadmium, copper, lead, zinc, arsenic and nickel. The metals loading in the Animas River is due to acid rock drainage that is created when sulphide minerals are exposed to air and water to produce sulphuric acid. The acidic water can dissolve area minerals and then deposit metals in rivers like the Animas. Metals loading in the Animas River has limited aquatic life, including the trout fishery downstream from Silverton.

A Day in the Life of a Consulting Engineer

The goal of the CESA (Consulting Engineers South Africa) Job Shadowing Initiative, is to expose and entice school learners to the engineering field, but more so into Consulting and Environmental Engineering. By giving them an experience like no other, learners get a chance to imagine, live, work and play Engineering, opening their minds to a world of possibilities and opportunities.

Incorporating Climate Variability into Water Balance Modelling to Help Inform Water Management Design: The Pebble Mine Project

Water plays a key role in the operation of mining projects, and it is essential that water management facilities be designed to manage the inflows and outflows required for proper operations, as well as accommodate any unpredictable runoff resulting from storms events. The amount of water available varies by year, season, and day, so how do you design for this?

Landslide Risk Management for the Construction and Operation of the Upper Lillooet River Hydroelectric Facility Near Pemberton, BC

The Upper Lillooet River Hydroelectric Facility is situated approximately 60 km northwest of Pemberton in southwest British Columbia, Canada. The site is located on the north side of the Mount Meager Volcanic Complex (MMVC), which comprises weak, locally hydrothermally altered rocks and is especially prone to large (>1 Mm3) landslides.

Application of the First Order Reliability Method to Planar-Type Failure in a Hard-Rock Slope to Assess the Probability of Failure

The First Order Reliability Method (FORM) is a semi-probabilistic reliability analysis method devised to evaluate the reliability of a system. The stability of the system must be a function of two or more probabilistic variables that have a mean, and standard deviation. The correlation between the probabilistic variables must be determined, which can be difficult, as will be show, independent variables can be functions of independent variables.

Environmental Legislation Development - Mining Sector, Take Note

In order to keep up with the moving target of environmental legislation, the South African mining industry needs to keep its pencils sharp. Not only is environmental compliance a confusing business given the rapidly changing legislation imposed by different environmental authorities, but it is also becoming an ever more risky business with legislation becoming more stringent, more prescriptive and better enforced.

Sustainable Strategy Engenders Results

Consulting firm Knight Piésold’s sustainable, quality process ethos across the board, from executing projects to implementing transformation, has enabled the company to maintain its competitive advantage amid a currently turbulent consulting engineering industry.

SGC Mining and Reclamation Activities and Metals Loading in the Animas River

Metals loading adversely impacts the Animas River in the area around Silverton, San Juan County, Colorado. (Church, et al., 2007). The metals of concern include iron, aluminum, cadmium, copper, lead, zinc, arsenic, and nickel. (U.S. Geological Survey, 2007 at 7). The metals loading in the Animas River is due to acid rock drainage. (Yager and Bove, 2007). Acid rock drainage refers to acidic water that is created when sulfide minerals are exposed to air and water to produce sulphuric acid.

Mining and Environmental Consulting Pioneers

Environment consulting specialist Knight Piésold is today recognised as the ‘consultant of choice’ in the mining sector – thanks largely to the skills sets and experience it has built up over almost a century (96 years to be exact). This has positioned the firm as a leader is its fields of expertise and enabled it to stay fully in tune with the changing needs of the countries and landscapes it operates in. This is highly pertinent to the mining industry and explains the company’s on-going success, despite the lingering economically challenging environment.

The Construction Supervision of Your First Category III Dam - Aspects All Young Engineers Should Know - The Neckartal Dam, Namibia

Young engineers are well equipped with knowledge regarding the design, engineering, and construction of Category III dams, but require in-field experience to develop both their project and program management skills for such an undertaking. The figures and statistics of these large scale projects can be overwhelming and it can often take months for young engineers to find their feet during the construction phase of such a project.

What Does it Mean to be the Engineer of Record (EoR) for a Tailings Storage Facility (TSF)?

One would think the term “Engineer of Record (EoR)” is an easy concept to grasp. For most public infrastructure projects (e.g., roads, bridges, buildings, water dams, etc.), the Design Engineer and the EoR are one and the same. This concept has also been applied, to some degree and in a similar manner, to tailings storage facilities (TSFs). However, TSFs do not apply a “conventional” construction process, nor do they adhere to a typical construction schedule.

Characterization of Unsaturated Tailings & its Effects on Liquefaction

In the mining industry, it is becoming relatively common for filtered mine tailings to be stacked to a significant height (>100m) with little to no compaction. The resulting deposit can be loose and potentially unsaturated. Characterization of these filtered tailings facilities for slope stability and deformation under earthquake loading conditions can be complex due to the potentially unsaturated state. This paper presents a summary of test results from the assessment of a filtered tailings facility which is located in Latin America.

Characterizing and Stabilizing a Historical Tailings Facility: The Rheology to Soil Mechanics Continuum

This paper presents a case study of the investigations and testing relating to the design and pro-gressive implementation of remedial stabilization measures for the historical tailings facility at the New Afton Mine located in British Columbia, Canada. It was necessary to evaluate both the geotechnical conditions (soil characteristics) of the tailings mass, as well as the potential rheo-logical behaviour (fluid flow characteristics) of loose saturated zones that could be susceptible to liquefaction and migration into the cave zone or underground workings.

Box Canyon Hydroelectric Project

The 16 MW Box Canyon Hydroelectric project may have the most hydraulically complex design of any run-of-river hydroelectric project in North America, if not the world. It has nine intake structures on different creeks and tributaries, all feeding into a single, high-pressure penstock that directs water to the powerhouse containing a six-jet vertical axis Pelton turbine generating unit.

Novel Application of Proven Best Available Technologies to Stabilize a Historical Tailings Impoundment

This paper presents a case study for the New Afton Mine located in British Columbia, Canada. The opportunities to use best available technologies to reduce the risks associated with operating and closed tailings facilities are presented and discussed. The emphasis is on novel application of simple and proven technologies to efficiently and effectively stabilize the tailings to achieve the ultimate objectives for dam and mine safety.

Septiembre 2017

Making Small Hydro Development Affordable and Acceptable

Recent small low-head hydropower development in the U.S. has occurred at non-powered dams and irrigation canals, a significant break from historical development at sites without existing hydraulic and dam structures. The latter is termed greenfield development or new stream-reach development (NSD). These sites are the bulk of the existing technical hydropower resource potential in the country. The financial viability and feasibility of NSD is influenced by: development risk and uncertainty associated with the cost and duration of the licensing process, the cost of site-specific design and customization of equipment and structures, and evolving environmental constraints on design and operation.

Design of the Box Canyon Scheme

The 16 MW Box Canyon hydroelectric project ranks among the most hydraulically complex of any run-of-river hydro project in North America, if not the world. The project, which is located in the McNab Creek watershed, 40 km northwest of Vancouver, British Columbia, has nine intake structures on different creeks and tributaries. All nine feed into a single, high-pressure penstock that directs water to the powerhouse containing a single six-jet vertical axis Pelton generating unit.

Unpacking TSF Challenges and Solutions

Water management is and will remain one of the primary challenges on any mine. As legislation grows increasingly stringent and corporate standards constantly improve, it is becoming more and more difficult and costly to adequately manage water within tailings storage facility (TSF) circuits. ANDRIES STRAUSS, sector manager: mining for Level 2 BBBEE environment consulting specialist Knight Piésold, discusses some of these challenges and demonstrates some of its expert solutions offerings through a number of recent projects.

A Passion for the Community

At Knight Piésold Consulting, one of the founding principles of the firm’s success over the past 96 years has been its focus on human resource development across its global workforce. This focus includes promoting diversity in terms of culture, leadership style, ethnicity and the way opportunities are developed for engineers. Academics are a baseline entry requirement, but from there, the playing fields are levelled when it comes to mentoring and growing pure engineering talent.

Effects of Stress State on the Cyclic Response of Mine Tailings and its Impact on Expanding a Tailings Impoundment

The current paper focuses on the characterization of the two primary tailings deposits. This includes the cyclic response over a range of stress conditions, the compressibility and its implications for liquefaction potential after construction of the dike, and the likely settlements to be expected after shaking. The laboratory program performed includes undrained cyclic simple shear testing under both the current and projected stress conditions after expansion, consolidation testing under conventional and post-cyclic conditions, and assessment of the steady state relationship of these materials. These results are complemented by cone penetration tests and borings from the field.

Estimate of Settlement of a Tailings Dam Founded on Collapsible Soils: Case Study

Collapsible soils are common in arid regions near the southern coast of Peru and often have a loose, metastable and brittle structure. They are usually of an eolian or alluvial origin with very low moisture content, negative pore pressures, and interparticle contacts that are partially cemented by salts. Thus, making them prone to sudden and substantial settlements and loss of shear strength by quenching of the negative pore pressures and dissolution of the salts if the moisture content is increased.

Tailings Impoundment Stabilization to Mitigate Mudrush Risk

Historical tailings impoundments may contain saturated semi-fluid materials at depth, long after tailings deposition has ceased and after surface reclamation has been completed. These saturated materials can liquefy and flow if the impoundment is breached. A historical tailings pile can represent a risk to an underground mine development if there is potential for the mine development to generate a propagating zone of cracking and/or surface subsidence that ultimately interacts with the historical tailings impoundment.

Site C Hydroelectric Project: Predicted Changes in Peace River Morphology and Sediment Transport

The 1100 MW Site C Hydroelectric Project involves the construction of a large dam on the Peace River in British Columbia, Canada. The Environmental Impact Statement (EIS) for the project considered technical, socio-economic and environmental aspects and described the predicted effects in the context of previous hydroelectric development and future climate change. Studies were based on long-term field observations and comprehensive modeling.

Challenges with Conducting Tailings Dam Breach Assessments

Following the recent tailings dam breaches at Mount Polley, Canada, and Samarco, Brazil, the mining industry and regulatory agencies worldwide increased the demand for tailings dam breach analyses and flood inundation mapping. The results of such studies are used to determine the hazard classification of a dam through the assessment of dam failure consequences, to support emergency preparedness and response planning, and to inform environmental assessments.

Precast, Modular Construction for Water Impoundment Infrastructure

Physical civil construction is the largest single component of new hydropower development cost, from 40%-90% of total capital cost depending on the project size (HRF/ORNL, 2014). Risk associated with civil-related schedule and corresponding budget overruns for new projects are significant, and can be due to weather and river flood events, contracting delays, major equipment lead-times, and other factors caused by the lengthy civil and equipment installation construction periods.

Design Considerations for the Capilano Energy Recovery Facility and Break Head Tank

Metro Vancouver (MV) is a public works organization that serves 18 municipalities (over 2 million people) in the greater Vancouver region of British Columbia, Canada. Amongst numerous other functions including waste collection and disposal, one of its primary tasks is to reliably provide clean, potable drinking water (over 1.1 million m3 per day average) to the residents of the cities served through a system of reservoirs, treatment facilities, pump stations and piping networks.

Operation of the Multi-Intake Box Canyon Run-of-River Hydroelectric Project to Meet Environmental Commitments

The Box Canyon Hydroelectric Project is a 16 MW run-of-river facility located in the McNab Creek watershed on the north side of Howe Sound, British Columbia, Canada. The Project includes intake structures on three of the tributaries to McNab Creek (Box Canyon, Marty and Cascara Creeks) as well as six minor tributary diversions, all of which feed into a single high pressure penstock to direct water to the powerhouse.

Characterization of Unsaturated Mine Waste: A Case History

It is becoming increasingly common in the mining industry for either crushed ore or filtered mine waste to be stacked to a significant height (>100 m) in a moist state with little compaction, resulting in deposits that can be potentially loose and unsaturated. This paper presents a case history describing the characterization of stacked filtered tailings at a mine site in South America.

The 'One Team' Approach

Adaptability, professionalism, excellence, sustainability, and teamwork are all core values that define the way Knight Piésold engages and grows its presence in the engineering and environmental sectors. These values also form the basis for the company’s talent acquisition strategy, as well as its training and development programmes at all levels, with a major focus in South Africa on selecting, mentoring and growing young engineers through to professional registration. “It’s an exciting journey for our young candidates and we have structured programmes in place to get the best results,” explains Mevashnee Naidoo, human resources director, Knight Piésold.

Deterministic Lake and Stream Temperature Modelling: Maintaining Optimal Water Temperatures for Kokanee and Rainbow Trout through Informed Design

Stream temperature is an important indicator of habitat quality for fish of all life stages. However, stream temperature is often overlooked when designing mitigation systems, with the focus being on the effects of development on stream flow, depth and velocity. A number of simple deterministic water temperature models exist for lakes, channels, and pipelines that can be utilized to optimize key design parameters for mitigation systems.

Mount Polley Tailings Dam Failure - More Lessons to Learn

The Mount Polley Tailings Facility was first constructed in 1996 at a time when three new mines were under development in BC, Canada (Mount Polley, Huckleberry and Kemess South). The design, review and regulatory oversight of these three projects were influenced by tailings facility failures that had occurred at that time (Merriespruit, South Africa (1994), Omai, Guyana (1995)).

Von Bach Dam Receives Major Facelift

The Sartorius Von Bach Dam (Von Bach Dam), situated east of Okahandja in Otjozondjupa Region, has recently received a new bituminous seal layer after approximately 50 years of service. The previous asphalt seal had become brittle, due to loss of volatiles from the bitumen, which typically leads to cracking on the surface of the asphalt.

Building for the Future

The first principle of problem solving is to look to history as someone, somewhere, has, in all probability, solved your problem already. While this is true, one still needs to implement the solution. Herein lies the crux of the matter. Without the right people, possessing the necessary skills and experience, no solution, no matter how brilliant, will work. This is particularly true of water supply infrastructure. Fortunately, in South Africa, we don’t have to look very far to find these people. We have a home-grown, problem-solving, solution implementing civil engineering company right here in eThekwini.

Mapping Water Reuse Strategies

Water engineering has always been a key focus for Knight Piésold Consulting since its inception in 1921 – an area of expertise which runs in parallel with many other multidisciplinary fields that have evolved within the group over the past 96 years. These often complement or interconnect at some point and include dams, hydro-electric schemes, mining, roads and transportation, environmental services, geotechnical engineering, pipelines and pump stations. Knight Piésold is one of the few wholly owned South African consulting engineering firms operating worldwide.

Applying the Rational Quantitative Optimal Risk Approach to Optimize Rehabilitation for a Portfolio of Dams

The Rational Quantitative Optimal (RQO) approach to risk based dam safety produces a definitive result for an assessment of the reduction of risk from the overtopping of embankment dams. The model is applied to 3 embankment dams in Namibia.

The Design and Construction of Neckartal Dam

Neckartal Dam is located on the Fish River, a tributary of the Orange River. The project will supply bulk water to a new irrigation scheme located 40km south-west of Keetmanshoop in Namibia. Keetmanshoop has a desert climate. The daytime temperature often rises well above 30°C during the summer and the mean annual precipitation is less than 150mm.

State of the Art Thermal Analysis for Neckartal Dam

The Neckartal Dam Project is currently under construction on the Fish River near Keetmanshoop in Namibia. The main purpose of the dam is to form an impoundment of 857 million m3 that will supply irrigation water to 5000 ha of agricultural development in the Karas Region. The outlet works at the dam is also equipped with a mini hydropower facility (3MW), which generates from the ecological releases made.

Assessment of the Curvature and Slope for the VC-Ogee Relationship Allowing for 3D Flow

The van Vuuren and Coetzee (VC) Ogee relationship was introduced at ICOLD 2016 (van Vuuren & Coetzee, 2016) and is the only Ogee profile relationship that compensates for the effects of 3-dimensional flow that results from the upstream approach channel. This VC-Ogee relationship is distinguishable due to its derivation from both physical and numerical modelling of prominent 3-dimensional flow in the approach channel.

96 Years of Design Execution

Knight Piésold is a multidisciplinary consulting firm that has a long history in water delivery projects across all the integrated engineering fields, and was one of Africa’s foremost pioneers in hydroelectric power, which remains a core focus area to this day. Born in 1921, Knight Piésold is the oldest consulting engineering firm in South Africa, and probably Africa, and built its reputation in the mining sector, where the firm remains a design innovation leader, alongside its other multifaceted specialisations within the world of infrastructure.

Valuing the Environment

Level 2 BBBEE environment consulting specialist Knight Piésold is looking to consolidate its business in order to continue growing in 2017–with a strategic focus on its geotechnical capability, says mining technical director Andrew Copeland. "This will entail expanding into pit slope stability and rock mechanics, a service that is offered by our overseas offices, but not locally. Our name is synonymous within the water fraternity for the design of large dams and hydro-power schemes..."

Experience Counts

Knight Piésold has been involved with numerous large-scale projects, many of which have been for the South African Roads Agency Limited (Sanral). In fact, Sanral projects account for about 70% of the work the company has done. With a focus predominantly in the northern parts of the country, the company has completed several projects for the provincial governments of Mpumalanga, Gauteng and Limpopo.

Knight Piésold Builds a Sustainable Future for the Next 95 Years

2016 represented a major milestone achievement for Level 2 BBBEE environment consulting specialist Knight Piésold having celebrated 95 years in business–making it the oldest consulting engineering company in South Africa. With almost a decade of experience behind its name, the company has retained its strong reputation in the mining, water and hydropower sectors in southern Africa and has further built a strong and growing transportation and pipeline capability as well.

Presenting a Case for Two Closure Approaches

This articles makes a case for two closures approaches: (1) a plan developed pre-mining; or (2) a plan developed during late operations or post?mining. A pre-mining closure plan that dovetails with a tailored operating plan can achieve goals with modest and low-volatility post-mining capital expenditure. A post-mining closure plan can capitalize on practical yet innovative techniques to yield best-achievable results with the resources available

Repairing Von Bach Dam Wall

The Von Bach Dam, situated outside Okahandja in Otjozondjupa Region, was built in 1970. Unlike Avis Dam in Windhoek, which is a concrete-faced rockfill dam (CFRD), the dam at Okahandja is an asphalt-faced rockfill dam (AFRD), a design that provides a more flexible sealing membrane. Other AFRDs are the Hardap Dam in Namibia and five similar dams found elsewhere in Africa. Over the past 10 years, three large CFRD dams have failed — one in Lesotho and two in Brazil — due to compressive forces in the rigid concrete membrane; an AFRD construction would likely have been able to absorb these forces without failing.

Capilano Break Head Tank and Energy Recovery Facility

Knight Piésold designed and commissioned the BHT & ERF, which dissipates excess energy in the water flowing from the Seymour-Capilano filtration plant and recovers that energy to generate electricity. The facility has one of the largest energy recovery turbines in a municipal treated potable water system in North America.

Tailing Storage Within a Heap Leach Facility - An Update on the Success at Yanacocha

The Yanacocha Operation is an open pit gold mine located in mountainous terrain in Northern Peru. The Operation includes one tailing storage facility (TSF) and four heap leach facilities (HLFs). Given constraints imposed by topography and permitted boundaries, the efficient use of space is a priority.

Seismic and Structural Stability Analysis for Increased Ground Motions at the Corra Linn Dam in British Columbia, Canada

Canada’s extensive and aging dam infrastructure in combination with the updated and revised Dam Safety regulations often require re?examining previously satisfactory analysis and developing a greater understanding of the cumulative and independent effects of a series of common design assumptions. Knight Piésold Ltd. recently completed a seismic and structural stability analysis on the Corra Linn Dam and Spillway located on the Kootenay River, approximately 15 km downstream of the city of Nelson, British Columbia.

Geotechnical Characterization of Old Tailings for Use as Sand Stacking Foundation

This paper presents the results of a geotechnical site investigation program of piezocone penetration tests (CPTu) and standard penetration tests (SPT) that was carried out in an old tailings facility to evaluate its feasibility as a foundation material. The old tailings (approximately 20 to 30 years old) need to be geotechnically characterized to assess how they will behave after being loaded by the fresh tailings.

Seismic Analysis of an Existing Earth and Rockfill Dam Subjected to the MCE by FLAC

This paper presents the 2D dynamic analysis of an earth and rockfill dam subjected to the maximum credible earthquake (MCE) using the software Fast Lagrangian Analysis of Continua (FLAC) and the UBCSAND constitutive model for the characterization of the tailings. The main purposes of the analysis were to predict a satisfactory behavior of the dam crest, to estimate the global permanent displacements and to assess the influence of the tailings liquefaction in the seismic performance of the dam.

Advice for Design Professionals at the Beginning of Their Careers

The authors of this paper represent people at a broad range of experience in their careers, anywhere from less than one year of professional employment to a few decades. The intent of gathering this diverse group was to capture people at various stages in their career and to ask them what advice they wish they had received early in their employment. The first activity of the authors was to brainstorm through a list of topics that would form the basis of the advice.

95 Years and Still Going Strong

2016 represents South African engineering and environment consulting specialist Knight Piésold’s 95th year in business—a milestone achievement which officially makes it the oldest South African engineering and consulting company. Having evolved over the decades to meet changing industry needs, it is well positioned and prepared to extend its successful legacy for another 95 years, writes Laura Cornish.

Septiembre 2016

Geotechnical Characterization of a Heterogeneous Unsuitable Stockpile

Typically, stockpiled unsuitable soils from construction activities are classified as saturated soft fine soils. Nevertheless, because of some projects particularities, unsuitable materials could also present coarse soils resulting in a heterogeneous stockpile. This paper presents the geotechnical characterization of a heterogeneous stockpile in Peru in order to verify the physical stability of the disposal pile and to optimize the closure configuration.

Septiembre 2016

Don't Underestimate the Impact

It is widely understood today that the viability of a new mining operation—specifically in remote regions—is to a large extent dependent on supporting infrastructure, primarily access roads to site. Despite this, few companies take cognisance of the associated environmental impacts or take into account that such access corridors leave a lasting legacy well beyond a mine’s active lifespan, Knight Piésold environmental section manager Amelia Briel tells Laura Cornish.

Septiembre 2016

95 Years of Consulting

Almost 10 decades have passed since Knight Piésold Consulting was founded on 21 April 1921, and the legend continues. It’s proud history of excellence began in its home base of South Africa, which has subsequently expanded over the years to cover most of the developed and developing world, through the establishment of a series of global offices.

The Development of the VC-Ogee Relationship Which Incorporates Upstream 3-Dimensional Flow Conditions

The widely used Ogee relationship is one of the most studied hydraulic relationships in the world (Savage & Johnson, 2001). Various attempts were made to accurately describe the shape of the lower nappe of water flowing over a sharp-crested weir, known as the Ogee profile. The current Ogee profile relationship was formulated from 2-dimensional hydraulic assessments.

Surveillance of Bedford and Bramhoek Dams

Bramhoek and Bedford Dams are the two reservoirs for the Ingula Pumped Storage Scheme. Bedford Dam is the upper storage dam which is a 41m concrete faced rockfill dam. Bramhoek Dam is the lower storage dam which is a 32m high roller compacted concrete dam. Both Bedford and Bramhoek Dams have been provided with a wide range of instrumentation to measure their performance.

Key Steps for Conducting Tailings Dam Breach Studies

Engineering practitioners currently use a combination of guidance documents, published papers, and professional experience to support tailings dam breach and inundation studies. There is considerable knowledge and information available in this relatively new field of practice, but standardised and comprehensive guidelines specific to tailings dams are not available.

Run of River Hydro - Latest Innovations in Diversion Dams and Sediment Exclusion

The exclusion of sediment for hydropower intakes and the flushing of sediment from reservoirs in order to maintain live storage are critical to the long- term viability and sustainability of hydroelectric projects around the World. This paper presents several design innovations and case studies of run-of-river diversion dams and intakes incorporating inflatable rubber dams, vortex de-sanders and Coanda screen intakes for sediment exclusion and flood passage. It presents the findings of physical and CFD model tests, case studies of operating facilities and lessons learned.

95 Years of Engineering Excellence

Established in April 1921, Knight Piésold (Pty) Ltd is a valued, trusted and uniquely South African company that has remained at the forefront of infrastructure development in South Africa, on the African continent and around the world. As South Africa’s longest-standing consulting engineering company, it is justifiably proud of being viable, profitable and South Africanowned. It has sustained operation through world wars, periods of major economic upheaval and depression and periods of great political change.

Innovating Excellence for the Mining Sector

Knight Piésold was established in 1921 when Dr. Francis Edgar Kanthack set up shop in Johannesburg, South Africa as an engineering consultant. Over the years, the company has developed into a major global consulting firm for the mining, power, water, transportation and construction sectors by delivering high quality specialty services with respect to social, environmental and economic responsibilities.

Engineering Excellent Design: Innovative Designs Awarded at Kokish River Power Project

Knight Piésold recently received an award for engineering excellence from the Association of Canadian Consulting Engineers for the detailed design and construction supervision of the Kokish River hydroelectric project. The award was in recognition of the project’s unique solutions and innovative designs that cater to the sensitive environmental attributes of the site, primarily on the presence of steelhead trout and salmon throughout the diversion reach.

Award of Excellence: Kokish River Hydroelectric Project

The Kokish River Hydroelectric Project is a 45 MW run-of-river facility 15 km east of Port McNeill, on the north of Vancouver Island, B.C. Every step during the development process took into consideration the diversity of fish habitats in Kokish River. The project has unique and innovative details throughout the diversion reach designed to cater to this sensitive environment, and in particular the presence of steelhead trout and salmon.

Renewable Energy for Mines

Mining operations require a secure energy sources(s) to maintain their operation and many around the world typically resort to expensive diesel generated power, with fuel operating costs alone varying from $300/MWh in West Africa to over $800/MWh in the Canadian Arctic. Renewable energy solutions such as small hydro, wind and solar offer significant cost saving opportunities for these mines, and in addition help the miners attain their “Social License” to operate.

Tailings Mobilization Estimates for Dam Breach Studies

Quantitative assessment of potential consequences caused by a flood from a dam breach of a tailings facility requires an estimate of the volume of water and tailings released during the breach. A methodology for estimating the volume of tailings mobilized by the free water stored in the pond and the resulting initial flood wave following a dam breach is presented.

Combined Tailings and Mine Waste

The benefits of combining tailings and mine waste in a relatively homogenous manner, in which tailings just fill the voids between the waste rock particles while the waste rock maintains particle-to-particle contact, has been the subject of study over the course of several years. Such a combination of materials could be used for a closure cover or as a singular large-scale facility to store both mine waste products.

Challenges with Conducting Tailings Dam Breach Studies

Engineering practitioners currently use a combination of guidance documents, published papers, and professional experience to support tailings dam breach and inundation studies. There is considerable knowledge and information available in this relatively new field of practice, but standardized and comprehensive guidelines specific to tailings dams are not available.

Assessing Credible Modes of Failure: Afton TSF Dam Breach Study

The Afton Tailings Storage Facility is located in the semi-arid Interior Region of British Columbia and has been in care and maintenance since 1997, after approximately 20 years of operation. In response to the British Columbia Chief Mine Inspector’s orders issued in August 2014, following a dam breach incident at the Mount Polley Mine, dam breach analysis and inundation studies for the Afton Tailings Storage Facility were conducted.

Septiembre 2015

Selati Tailings Dam Decant Failure and Remedial Actions

On 27th February 2014 solids were noted to be discharging into the Return Water Dam below the Selati Tailings Dam at Foskor in Phalaborwa, indicating a decant failure. All parties involved reacted quickly to curb the discharge of solids and minimize the risk of catastrophic failure of the facility. Within days, a temporary filter was constructed on the outlet, followed by the design and construction of a medium term filter, while a solution is being sought for the permanent sealing of the decant outlet.

Predicted Changes in Peace River Channel Morphology and Sediment Transport Related to the Site C Clean Energy Project

The Site C Clean Energy Project is a third dam and 1100 MW hydroelectric generating station on the Peace River in northeastern British Columbia, Canada. BC Hydro plans to start construction in the summer of 2015. This paper presents the predicted changes in channel morphology and suspended sediment dynamics during Project operations that were described in the Environmental Impact Statement (EIS) for the Project.

Hydrodynamic Modelling of Intakes for Run-of-River Hydroelectric Projects

Run-of-river, diversion-type hydroelectric projects on steep mountainous streams create changes in environmental conditions, including modified hydraulic and sediment transport conditions in the headpond upstream of the flow diversion intake and in the diversion section of the stream between the intake and the tailrace. These types of changes can lead to environmental and operational challenges that require careful consideration at the project design stage in order to achieve a successful, sustainable project.

Procuring Construction Contracts for Affordability and Risk Sharing

Getting hydroelectric projects off the ground is increasingly challenging in terms of affordability (the sites are now generally more remote and in more challenging topography); the ever-tightening social and environmental restrictions (during construction and operation); and the availability of finance. This has led to the exploration of different methods for the procurement of construction in an attempt to reduce costs whilst still managing risks and providing a fair deal to all the parties concerned. This paper provides case studies of four different strategies employed recently by international consulting engineers Knight Piésold (KP), in Africa and Canada, for the development of hydroelectric projects.

Northern Mineral Development: We All Need to Have Skin in the Game

All stakeholders involved in northern mineral development have a role to play in positively advancing an industry that represents an opportunity for socio-economic development. Mining has the potential to bring self-sufficiency to the North; empower people with education, training, and employment; increase territorial revenues; and support infrastructure development.

Heap Leach Pads - The Importance of Proper Testing, Interpretation, and Analysis of Soil Liner Geomembrane Interfaces

The design of heap leach pads involves a variety of components. One of the main components for these structures is the leach pad liner system, where a low-permeability soil is normally used in combination with a geomembrane to reduce seepage losses. Although this combination of materials has been shown to effectively reduce rates of infiltration, the soil liner-geomembrane interface presents a challenge to designers since it incorporates a “weak layer” into the system.

A Practical Method for Extrapolating Ambient Pore Pressures from Incomplete Pore Pressure Dissipation Tests Conducted in Fine Grained Soils

The estimation of ambient pore water pressures in an existing soil stratum for use in developing appropriate pore pressure distributions for input to various geotechnical engineering analyses often presents the engineer with challenges in locations devoid of sufficient piezometer coverage.

Casino Project: Interactive Design of A Large Tailings Dam to Achieve Mine Waste Mangement Objectives

The Casino Project is a proposed copper-gold-molybdenum mine in the southwest Yukon. The deposit will be mined using open pit methods with a nominal mill throughput of approximately 125,000 tonnes per day of ore over a 22 year operating life. The climate at the project site is characterised by long, cold, dry winters and short, warm, wet summers. Permafrost is discontinuous over the Tailings Management Facility embankment area.

Interview with Sam Mottram, Managing Principal, Power Services

Under the Integrated Resource Plan (IRP), BC Hydro is planning to spend $1.7 billion per annum over the next 10 years. What are the principal opportunities for Knight Piésold in British Columbia given this plan? We have bid on a number of upcoming refurbishment projects, including the 130-megawatt (MW) John Hart Hydroelectric Redevelopment Project, and teamed up with a number of contractors and developers to help realize these projects. BC Hydro has aging facilities that need a lot of work. Under the IRP, BC Hydro now has a program to upgrade all of these, many of which are 60 to 70 years old on both the hydro generation facilities side and the transmission and distribution side.

Investigation of Sediment Transport Through a Run-of-River Hydroelectric Project

A 25 MW run-of-river hydroelectric project is proposed in coastal British Columbia, Canada. Baseline studies identified that the bedload sediment transport rate in the project area is relatively low, and consequently, interruption of bed material replenishment in the reaches downstream of the intake represents an environmental concern.

Design and Construction of the 45 MW Kokish River Hydroelectric Project in British Columbia, Canada

This presentation will cover the design innovations and lessons learned from the detailed design and construction of the Kokish River Hydroelectric Project recently constructed in the northern part of Vancouver Island located in British Columbia, Canada. This hydroelectric facility is a private sector development by Kwagis Power, a limited partnership of Brookfield Renewable Energy Group and the ‘Namgis First Nation that was awarded an energy purchase agreement by BC Hydro in an open call for clean energy.

Can Modular Pumped Storage Hydro (PSH) be Economically Feasible in the United Sates?

To date, the vast majority of global and domestic Pumped Storage Hydro (PSH) development has focused on the construction of large (generally greater than 300MW), site-customized plants. The viability of alternative design paradigms for PSH technologies has been actively discussed in industry and the research community, but no reliable determinations on the viability of these concepts have been made. Of particular interest is the development of smaller, distributed PSH systems incorporating elements of modular design to drive down cost and increase the ease of implementation.

Integrating Engineering & Environmental Concepts for Mine Development

Designers of modern-day mines must consider and incorporate nearly endless aspects of a project so that it is technically, economically, environmentally and socially balanced. Technical and economic feasibility continue to be the key drivers behind development decisions. However, environmental and social considerations are growing in their influence on both the design and ultimately the decision to move a project past concept and into construction and operation.

Hydropower the Key to Northern Development

One thing everyone can agree on is the need for a reliable source of energy for any form of existence in the Canadian north. With the extreme cold and shortage of sunlight hours throughout the winter, energy for heating and light is of paramount importance. This becomes even more important for any form of mining venture where there are large power requirements to run the mine.

Elko Roundtable Discussions

Knight Piésold USA has been hosting the Elko Rountable since 2005, with an aim in creating an environment to discuss current practices, challenges, and accomplishments associated with the need for, and the advancement of, innovation. The roundtable forum encourages an exchange of ideas and information pertaining to broad topics revolving around the subject of innovations in heap leaching and mine waste management. Compared to traditional conferences and symposia, the forum provides a much less inhibited format for discussion.