Civil and Geotechnical Engineering

Transcription

1 Imagine the result Imagine the result Civil and Geotechnical Engineering for the Mining Industry

2 Innovative, Sustainable and Grounded Solutions At ARCADIS, we understand the environment and how to engineer it safely and smartly to improve the quality of life. Our engineers consider all environmental factors when developing civil and geotechnical solutions for our mining clients to ensure that all structures and operations are implemented safely, economically, and environmentally-sound. For more than 55 years, ARCADIS has provided innovative engineering solutions to civil and geotechnical challenges in mining. We use a multidisciplinary team of technical experts to approach these challenges so as to achieve operational and environmental objectives while minimizing the total cost of ownership. At ARCADIS, our teams can see beyond the immediate challenge to anticipate how the solution may help solve future challenges associated with the mine life cycle. We can put this expertise to work for your engineering needs from exploration through operations and ultimate restoration of your mine. ARCADIS HAS SERVED THE MINING INDUSTRY FOR OVER 55 YEARS Our Services ARCADIS delivers comprehensive services that incorporate scientific and technical knowledge to provide sustainable solutions for design, construction, and maintenance for the built and natural environment. Our services include: Hydraulic Structure Design Plant and Building Foundations Tunneling Ground Support Static and Dynamic Stability Analyses Deformation Analysis Landslide Stabilization Geotechnical Characterization and Analysis Dynamic Stability Analysis Seepage Control, Landfills, and Cut-offs Grouting Seismic Risk Modeling and Assessment Cover System Evaluation, Design, and Implementation Design, Construction, and Management of Tailing Ponds, Embankments, Waste Rock Piles, Water Storage Dams, Dikes, and Heap and Leach Facilities Expertise Open Pit Mining Underground Mining Waste Rock Placement Heap Leaching Metallurgical Processing Tailings Management Mine Infrastructure, Surface Runoff Control, and Access Roads Mine Closure and Rehabilitation Compliance

3 Our Experience ARCADIS has experience evaluating the stability, strength, and long-term performance of soft soils/sediments/ tailings, containment facilities and soil, waste rock, and rock slopes. We use the most current analytical and computer techniuques (e.g. Slope/W, FLAC, Plaxis) to address the bearing capacity, slope stability, compressibility, seismic response and liquefaction potential. We also employ a variety of effective geotechnical construction techniques to address geotechnical shortcomings of soft soil/ tailings sites including densification techniques, solidification/ stabilization, wide range of use of geosynthetics, and other innovative techniques such as electro-kinetics and biological soil stabilization. This rigorous, integrated approach has been consolidated in our service-package MakeLand ( Project Highlights Collaborative Design Accelerates Closure of Tailings Impoundment Idaho The Lucky Friday Mine is an operating underground silver, lead, and zinc mine located in the Coeur d Alene Mining District in northern Idaho. A tailings dam built over the last 60 years is being closed within the framework of a Consent Decree reached with USEPA. Because the dam was built using upstream construction, there is a 10-acre, 100-foot-high tailings impoundment adjacent to the South Fork of the Coeur d Alene River, resulting in the need to collect and divert precipitation and surface run-on to prevent pore pressure build-up in the tailings, and to deliver collected surface water to the river. In addition, the toe of the dam wall encroaches on the floodplain of the South Fork of the Coeur d Alene River, necessitating flood protection at the toe. The successful completion of this project is the result of close collaboration with all stakeholders to design a work plan that created efficiencies and minimized obstacles. ARCADIS worked with the client and regulator to re-use prior design documents to streamline the design and regulatory submittal process, thereby realizing cost savings and reducing the time of the permitting. By also including the client s contractor in the design process, ARCADIS developed the closure plan to be implemented in a staged manner with mass grading, using materials readily available at the mine. This has allowed acceleration of the project schedule and additional costsavings. ARCADIS is currently overseeing final grading, the installation of stormwater collection and delivery structures, the vegetation of finished surfaces, and project closeout. Leading Edge Design and Construction Avoids Unsafe Build-up of Pore-Pressure Washington ARCADIS personnel managed the design and construction of the upstream raise of a tailings impoundment serving a gold mine and milling operation. In order to understand the tailings bearing capacity and compression characteristics, extensive geotechnical investigations were required. Accordingly, a test pad was designed and constructed and then evaluated using complex laboratory testing including cyclic tri-axial tests to determine the seismic response of the tailings and seismic stability analyses of the dam wall. The design also included a complex double-lined barrier system to connect upstream liners to downstream liners. The design and construction documents were prepared and permits were acquired through the Dam Safety Section of Washington Department of Ecology. After assisting with bidding/bid evaluation, a comprehensive monitoring program was prepared for construction including settlement and pore-pressure instrumentation to assess construction rate to avoid unsafe build-up of pore- pressure. The construction was managed under strict quality control/quality assurance services so that the contractor used a safe construction rate and proper liner installation testing. Once construction was completed, certification documents were prepared and presented to the Washington State Department of Ecology who in turn approved and issued the permit to operate. The unique innovative design and construction of this project was presented at the Association of State Dam Safety Officials annual conference..innovative and Holistic Approach Brings Former Mine to Successful Closure Canada The former Farley copper and nickel mine site contains approximately 24 million tons of sulfide mineral-bearing tailings deposited over 620 acres, extending within 100 yards of the Lynn River. A system of six dikes is used to contain mine tailings from historical mining operations. The goal of the project was to improve water quality in the Lynn River by treating existing acid rock drainage and installing an engineered cover to impede the creation of additional acid rock drainage. Due to the projects immense scale, remote location and limited availability of local personnel, equipment, and infrastructure resources, ARCADIS used a holistic approach to design and implement a comprehensive rehabilitation plan to minimize the use of imported products and create job opportunities for the local community and Marcel Colomb First Nation. ARCADIS developed a comprehensive site conceptual model to create a phased work plan to mobilize quickly to accomplish winter-only work, followed by an adaptive design process to consolidate and cover waste rock and tailings, manage site runoff, and ensure long-term geotechnical stability. As a measure toward improving the long-term condition of the site, ARCADIS reinforced the site dikes, planned for specific site revegetation, and rehabilitated site buildings. The remedy includes consolidation of more than 1.2 million cubic meters of waste rock and tailings, installation of a 1.8 million square meter engineered cover, and treatment of 600 million gallons of water. As a result of ARCADIS innovative and holistic approach that combined water management, lake restoration, and local economic stimulus, years of project study were brought to an end and a clear path forward was provided for closure.

4 Safety First A Real Commitment, A Daily Issue: Safety Tracking to Zero: Integrating Health and Safety into Every Project. Project Highlights Providing a healthy and safe work environment is an integral ARCADIS value and a key element of the solutions we provide. Our clients demand robust programs that involve continuous improvement, strong leadership and employee engagement. We address these concerns through our risk-and behavior-based health and safety management program, proactively identifying and prioritizing risks, developing robust approaches to eliminate or minimize these risks, and keeping health and safety first in everything we do. As a result, ARCADIS work-related injury and illness rates are currently below industry benchmarks. Strategic Pond Consolidation Mitigates Risks during Smelter Site Closure New Mexico After 20 years of operation, this 364-acre smelter transitioned to Care and Maintenance status and now is undergoing closure. ARCADIS developed the closure plan, including basis of design documents and engineered construction drawings, to close four ponds containing approximately 1 million cubic yards of sludge at the site. As the work plan was developed, geotechnical and chemical data gaps were identified and a sampling and analysis plan was implemented to collect the missing data. From the data, ARCADIS determined that onsite disposal in a repository was the most feasible, efficient, protective, and cost-effective response alternative for the long-term closure of the neutralization ponds. ARCADIS submitted the work plan to the New Mexico Environmental Department and successfully negotiated the strategic approach. ARCADIS is providing engineering support and discharge permit compliance assurance during the implementation of the work plan, working closely with the client to address and resolve technical issues resulting from construction activities. Incorporating consolidation of the neutralization ponds into the engineering design, ARCADIS is successfully bringing the site to closure while mitigating potential risks, if any, to human health and the environment and increasing the overall environmental quality of the property. Real Time Modification of Diversion Channel Design Keeps Construction on Schedule Arizona The Carlota Copper Company (CCC) developed a new mine in which the main ore body is bisected by Pinto Creek, an ephemeral stream that flows during the winter and spring months and is a jurisdictional water of the United States. As part of CCC s mining permit, the existing streambed had to be reestablished around the ore body and integrated into the northerly pit slope in a diversion channel designed to withstand 10,000-year flows and incorporates a replacement riparian habitat. ARCADIS characterized the existing streambed, designed the diversion channel, and provided quality control/quality assurance support services to document and facilitate its construction. Special considerations were required in the design configuration to withstand a 100-year storm and to prevent seepage from the channel into the pit slope, which could cause slope instability. The diversion channel is 5,500 feet long and drops 90 feet along this length. The channel accepts flows from the natural stream channel for various storm events, with flows ranging from 200 to 18,000 cubic feet per second (cfs). In the construction phase, ARCADIS identified changes in alternative bench conditions, which led to real-time modification of the design without compromising the integrity or permit requirements of the diversion channel or its completion.

5 About ARCADIS: ARCADIS is a leading international company providing consultancy, design, engineering and management services in infrastructure, water, environment and buildings. We enhance mobility, sustainability and quality of life by creating balance in the built and natural environments. ARCADIS develops, designs, implements, maintains and operates projects for companies and governments. With 22,000 employees and more than $3.3 billion in revenues, the company has an extensive global network supported by strong local market positions. ARCADIS supports UN-HABITAT with knowledge and expertise to improve the quality of life in rapidly growing cities around the world. ARCADIS U.S., Inc. 630 Plaza Drive Highlands Ranch, Colorado Together we can do a world of good V02