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By Michael E. Ameel

The vibrated beam method of installing a vertical barrier wall is one of the least applied techniques, yet given certain site conditions and constraints, it is a cost-effective and proven method of controlling lateral groundwater flows. A recent full-scale application of this technique demonstrated its usefulness at an active manufacturing facility located in Northern Wisconsin. At this site, a 3,233 foot long cutoff wall was keyed into an underlying bedrock, which was located an average of 40 feet below the ground surface. Using a slag cement-clay based slurry, a 1E-7 cm/sec or less, nominal 4-inch wide cut-off wall was constructed using the vibrated beam method. Challenges included working around an active manufacturing facility with minimal access to the work area; installing the wall through a very dense glacial till; minimizing soil excavation volumes of potentially impacted soil; and, working around and adjacent to numerous active utility lines without impacting the facility operations. At utility locations, the vibrated beam wall was supplemented with a jet grout panel wall, without the need to bypass or otherwise interrupt any of the plant?s utilities. Quality control consisted of the monitoring and measuring of slurry parameters, survey control, and real-time monitoring and documentation of all critical barrier wall installation parameters. A vibration monitoring plan was also implemented to measure vibrations at utilities and adjacent facility structures. Proper equipment selection, significant up-front planning and close coordination with the facility resulted in a safe and successful project. The work was completed ahead of schedule during the 2009 construction season.

Jan 1, 2010

By R Price

"Technology has the potential to revolutionise industries, work functions or businesses. One such technology in the mining industry is the deployment of automation in a modern autonomous haulage system (AHS). This paper examines a theoretical application of an AHS in a medium scale mine site. The cost-benefit commercial argument is particularly compelling, and the paper outlines metrics and future issues for consideration.Citation:Price, R, 2016. Autonomous Haulage Systems - the Business Case, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 11–17 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2013 draws upon information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration for the year 2013: 1) budgetary statistics expressed in U.S. nominal dollars provided by SNL Metals & Mining (SNL) of Halifax, NS, Canada (formerly Metals Economics Group (MEG); 2) regional and site-specific exploration activities that took place in 2013 as compiled by the USGS; and 3) regional events that affected exploration activities, including economic, social and political conditions, that were derived from published sources and unpublished discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources are used to develop commodity and regional compilations, reported statistics may vary depending on the source and type of data that are being reported. The SNL data summarize planned company budgets for worldwide exploration activities in 2013 for 20 nonfuel mineral commodities based on surveys returned by companies primarily focused on precious metals (gold, platinum-group metals and silver), base metals (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (coal, iron ore, phosphate and potash), and specialty commodities (diamond, lithium, niobium, rare-earth elements, tantalum and uranium). Information on uranium exploration activities was included in the MEG overview for the first time in 2007. MEG included data on the commodities lithium, niobium, phosphate, potash, rare-earth elements and tantalum for the first time in 2010 because of the increased topical significance of these commodities. Since 1999, companies with exploration budgets of $100,000 and greater were included in the MEG and SNL compilations. SNL budget estimates exclude aluminum, coal, and oil and gas. Budget estimates for iron ore have been compiled since 2011 but reported separately. The post-1999 budget surveys by MEG and SNL cover at least 90 percent of world?s reported nonferrous, nonfuel mineral exploration budgets; the 2013 survey is reported by SNL to cover an estimated 95 percent of these budgets. The 5 percent that is not covered is accounted for by companies that chose not to participate in the SNL survey, private companies that do not publish their budget data, and government-funded exploration activities.

By Frederic Souche, Andrew R. Klaetsch, Brian Hann, Nick Goodenow

This paper describes support of excavation (SOE) design and construction for three large diameter shafts excavated through glacial soil and controlled blasting in complex sedimentary rock formations. SOE in soil consists of unreinforced secant pile rings designed to resist lateral pressure in circumferential compression, eliminating costly steel core beam reinforcing. Controlled blasting at the shafts, adits, and tunnels in densely populated neighborhoods requires managing risks to the public, buildings, and utilities. Controlled blasting approaches limited adverse impacts to receptors nearby while achieving adequate production and fragmentation. A site-specific observational approach was used to adjust blasting parameters, limiting the impact on local stakeholders while maintaining daily progress and managing overbreak.

Jun 13, 2023

By Raja V. Ramani

The recognition that surface mining need not be viewed as a permanent dedication of the land but rather as a temporary non-renewable use in a series of land uses has caused greater emphasis on the re-use of surface-mined lands. In an effort to develop a procedure for evaluating postmining land use potentials, specific mines in various regions of the U.S. have been studied to determine the extent of current mined-land planning and to discover characteristics that are regional in nature. As part of this investigation, the Indian Head Mine, which is located in Mercer County, North Dakota, has been studied. The Indian Head Mine is presently operated by The North American Coal Corporation -Western Division and has been in operation since 1917 under various ownership. The status of current reclamation and postmining land use planning was reviewed. In addition, the relationship between mine planning and public planning in an area impacted by energy development was investigated. Finally, key factors affecting site potential realization for western surface mines have been identified.

Jan 1, 1983

By L. B. Rothfeld

In anticipation of RCRA reauthorization and subsequent rulemakings, the Bureau of Mines is studying potential economic impacts of RCRA on mining. For U.S. copper heap and dump leaching operations in a variety of terrains, the cost of liners and closure caps to comply with RCRA Subtitle D ranges from $55 million to $158 million per site, or about $500,000 per hectare ($200,000 per acre). If RCRA technology requirements and financial assurance had been required on current operations, 27 to 100% of production from heap and dump leaching would have been non-competitive at market prices between $2,310 and $1,650 per metric ton ($1.047 and $0.75 per pound) copper. This result is based on an analysis that considers return on capital, corporate overhead, marketing, and freight costs as well as operating and maintenance costs at the mine. Over the same price range, economic analysis using the IMPLAN input-output model on one-or two-county regions indicates potential net job losses of about 570 to 2,700 jobs. Total economic output of those counties could be reduced by about $180 million to $360 million.

Jan 1, 1994

By Mark L. Chatman

The U.S. Bureau of Mines studied mineral resources of the Dragoon Mountains Unit, Coronado National Forest (54,264 ac), Cochise County, AZ. This study involves literature and field investigations with a focus on mine and prospect sites, which were inventoried and mapped; maps are contained in this report. Rock-chip samples were taken from mineralized zones and from some mine dumps; assays of the 477 samples are in appendixes. Mineral deposits are genetically and spatially related to Tertiary-age granitic intrusive activity. Most metallic mineral deposits are also strongly fault-controlled. Colored marble resources (270,000 st) are valued at approximately $6.5 million, if all were to be developed and sold as landscaping material in the form of-marble chips. However, with current demand, it is unlikely that regional markets could absorb all this material. Economic modeling of copper-zinc-silver skarns suggests none would be profitable to mine and capitalize at early 1993 commodity prices, mainly due to the small estimated size of the deposits (30,000 st to 40,000 st maximum). In the entire Unit, 140,000 st of inferred subeconomic skarn resources were estimated by USBM on five different skarn trends; measured subeconomic resources are negligible. Exploration by industry, 1992, was small-scale (on 2 skarn trends and 1 auriferous fault zone).

Jan 1, 1993

By M C. Evans

"Mine decommissioning is the final phase in a mining project. Planning for decommissioning must commence for a proposed mine even before the government approves it. Queensland mining approvals require proponents to commit to completion (or closure) criteria defining successful rehabilitation. Queensland mining project statutory environmental authorities must also specify how progressive rehabilitation is to occur throughout the mining project. Final landforms with graded banks together with creek and run-off diversions are often required and constructed early in the life of a mining project. At closure, mining projects must demonstrate that future medium-term risks are not significant, or failing this, a residual risk financial payment must be made to the state. CSIRO climate change projections indicate that Queensland is likely to become warmer this century with less rainfall in parts and with extreme rainfall events likely to occur more frequently. This project was undertaken to?determine: if current rehabilitation planning tools assist in determining the environmental risks from mining closure not adequately addressing climate change if these risks are addressed by current rehabilitation outcomes.The north-west Queensland mining region and the central Queensland coalfields were represented in this project by five study sites. Local data sets for temperature, rainfall and rainfall intensity were produced using conservative greenhouse gas emission scenarios representing likely future atmospheres, and using the SimCLIM climate model, Evaporation data sets were also derived from available climate parameters. These projected climate variables supported equations and models used in Queensland to determine mining project rehabilitation completion criteria. Storm intensities and return intervals were directly applied to assess the likelihood of failure of engineered structures such as stormwater diversions and banks. Plant cover change determined by an existing growth model together with rainfall intensity and changes in the R and C factors of the universal soil loss equation (USLE) erosion model enabled estimates of long-term erosion rates. Flood estimates were undertaken using regional rated catchments.The study found that stormwater diversions and banks on recontoured rehabilitated landforms, if constructed to currently accepted completion criteria, would likely fail within 30 years and with the likelihood of failure steadily increasing thereafter. The change in likelihood of failure was able to be estimated and could be applied to the determination of residual environmental risk for approval of a surrender application involving rehabilitation. The USLE model showed that long-term erosion rates increased as a consequence of climate change from north to south across the Queensland mining precincts. Because the growth model did not consider carbon dioxide fertilisation affects, results would likely be worse-case.Likely climate change outcomes have consequential residual environmental risks of mining project rehabilitation failure. This increased risk may result in increased payments to the state from mining projects where high consequences exist. The liability to the state and risk to the environment can be avoided if today’s completion criteria address tomorrow’s climate change impacts.CITATION:Evans, M C, 2014. Queensland mines should consider climate change impacts for decommissioning, in Proceedings Life-of-Mine 2014, pp 535–562 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By K. A. Stanley, N. A. Karl, D. R. Wilburn

"This summary of international mineral exploration activities for the year 2014 draws upon information from industry sources, published literature and specialists in the U.S. Geological Survey (USGS) National Minerals Information Center. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry.Three types of information are reported and analyzed in this annual review of international exploration: 1) budgetary statistics expressed in U.S. current dollars provided by SNL Metals & Mining (SNL) of Charlottesville, VA; 2) regional and site-specific exploration activities that took place in 2014 as compiled by the USGS and 3) regional events that affected exploration activities including economic, social and political conditions, which were derived from published sources and discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources are used to develop these compilations, statistics may differ depending on the source and type of data that are being reported.The SNL data summarize planned company budgets for worldwide exploration activities in 2014 for 19 nonfuel mineral commodities based on company surveys. Research focused on precious metals (gold, platinum-group metals and silver), base metals (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (iron ore, phosphate and potash), and specialty mineral commodities (diamond, lithium, niobium, rare-earth elements, tantalum and uranium). Information on uranium exploration activities was included for the first time in 2007. Data on lithium, niobium, phosphate, potash, rare-earth elements and tantalum were compiled for the first time in 2010 because of their increased significance. Since 1999, companies with exploration budgets of $100,000 and greater were included in the SNL compilations. SNL budget estimates exclude bauxite, coal and oil and gas. Exploration budget estimates for iron ore have been compiled since 2011 but reported separately. The 2014 SNL company survey is reported by SNL to cover an estimated 95 percent of the world’s nonferrous, nonfuel mineral exploration budgets. The 5 percent that is not covered includes companies that chose not to participate in the SNL survey, private companies that do not publish their budget data, and government-funded exploration activities"

Jan 1, 2014

By Dipankar Gorain, A K. Vishwakarma, Vivek K. Himanshu, Murari P. Roy, Shubham Singh, R S. Yadav

The industrial establishments of a power plant consist of many important structures viz. cooling tower, wagon tippler, track hopper, plants and offices. The leveled foundation is the utmost need for erecting these structures. The leveling of the foundation is done by rock excavation, when the establishments have to be setup in hilly/rocky areas. Drilling and blasting is the cheapest and most dominant method of rock excavation. However, this method has associated hazards in terms of blast induced ground vibration, air overpressure, flyrocks etc. The foundation work and erection of the industrial buildings are done in parallel to achieve the faster construction of the establishment. The challenges to reduce the induced hazards in such cases are more. This paper presents a case study on the controlled blasting method devised for the rock excavation for construction of 2 × 660 MW Obra-C thermal power plant. The foundation work for this power plant was made by excavation of Dolomitic rock. The excavation work was performed in the proximity of the existing residence of the local people and Obra market. With the advancement of project, the excavation was also performed in the proximity to the ongoing construction work of various industrial buildings. Accordingly, the controlled blasting pattern was devised suitable to the specific sites. The pattern consisted of variations in blasthole diameter, burden-spacing, maximum explosive charge per delay, total explosive in a blasting round, initiation system and direction of initiation. The suitable muffling arrangements were also used, when the blast was conducted in the close proximity to the structures. The initial blasting pattern was established by analysis of blast vibration wave propagation characteristics. Thereafter, the final pattern was adopted for the safe excavation at the site. The safe excavation for the foundation work of this power plant has been completed successfully based on the devised controlled blasting pattern.

Feb 6, 2023

By Paul J. Sabatini, Robert C. Bachus, Terence P. Holman, Panos Andonyadis

A recent landslide comprising approximately 12 acres (4.86 hectare) and a displaced volume of more than 500,000 cy (382,000 m3) caused the shutdown of a four-lane state highway and two high-capacity freight railway lines. After completion of immediate landslide stabilization activities, various long-term slope stabilization measures were implemented that focused primarily on gradual slope unloading in areas near and upslope from the scarp of the landslide. Near the completion of the upslope excavation, an anchored soldier beam and lagging wall was constructed to allow for the temporary unloading of the toe of the main landslide area to facilitate installation of a permanent underdrain. The design of the anchored wall utilized information collected during the rehabilitation construction and included inclinometer data, site survey results, piezometer data, and field construction observations. Using the history of site-specific movements, results of back-analysis calculations from the landslide, and geometry/performance of the post-construction slope configurations, the fully softened and residual shear strengths along two potentially critical sliding surfaces were calculated. Owing to the high confidence in the values of shear strength as afforded by this information, the confidence in local groundwater conditions, and control of the loads, the designers selected a relatively low, calculated short-term factor of safety (FS) (i.e., FS ˜ 1.1 to 1.2) for the most critical unloading step. Long term calculated FS values on the order of 1.2 to 1.3 were anticipated. This paper describes the detailed evaluation of the landslide slope movement data associated with the shallow and deep potentially critical failure surfaces and selection of the associated values of design shear strength for these potentially critical surfaces. A description is presented of the analyses and design of the anchored wall, measures implemented during construction to minimize slope movements, and post-construction monitoring results during the unloading and subsequent installation of the underdrain.

Jan 1, 2017

By R Hargreaves, C Morley

The authors often see problems on mine sites that are due to insufficient feedback between technical discipline silos as the realities on the ground fail to inform the models and plans used to drive resource exploitation. Resource modelling, reserve definition, life-of-mine planning, short-term mine planning and scheduling, mine operations and beneficiation operations are all processes that inform each other, but in many instances feedback between these processes occurs in an ad hoc way and only after problems have come to light.Universal reconciliation uses a multidisciplinary approach across the entire mining value chain to identify both opportunity and loss of value and to maximise operational performance. This paper will look at the operational effectiveness of universal reconciliation and will outline the important elements that make it successful, including how to map out the detail underpinning modelling, planning and execution processes. We do this by documenting the physical processes, logical work practices, organisational roles and responsibilities, data origin and quality, working assumptions and information management practices at an operation. The results quickly show how misinformation and assumption causes suboptimal decisions to be taken, where inefficiencies exist and what the opportunity is to remedy these issues.A universal reconciliation study opens up an opportunity for stakeholders to reassess how the operation should be run and how operational effectiveness should be measured. Clear envelopes for reconciliation become obvious and questions about the practicality and data quality can be addressed.A reconciliation code of practice is a key element of a successful universal reconciliation project and the authors outline the important aspects that will provide an operating model, showing the effectiveness of the resource and reserve modelling, the practicality of the mine planning and scheduling practices, how well the mine operations team are executing these schedules and how effective the processing area is given what it is fed. Most importantly, a system that allows operations time to react before the losses become systemic and that is based on identifying early warnings from hard data when these processes start to wobble is outlined. Finally as a case study, the revenue and cost benefits resulting from universal reconciliation diagnostic projects for nine mine sites is documented.CITATION:Hargreaves, R and Morley, C, 2014. Universal reconciliation – a multidisciplinary approach across the entire mining value chain to identify loss of value and maximise operational performance, in Proceedings Ninth International Mining Geology Conference 2014 , pp 411–420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Kirk Ellison, Eric S. Lindquist, Peter Faust, Stephen M. McLandrich

"The 181 Fremont Tower will be an 800-foot high-rise with a 60-foot deep basement located in a dense urban part of downtown San Francisco. The design and construction methods of the subsurface elements navigated a variety of site constraints such as loose fill and soft estuarine soils, shallow groundwater, contaminants, historic obstructions, small work area, proximity of adjacent buildings, and the on-going excavation and build-out of the adjacent Transbay Transit Center (TTC) train box. Design of the approximately 260-foot-deep drilled shafts (some of the deepest foundations ever constructed in San Francisco) was proven by a full-scale load test that provided unique data on the frictional capacity of the deep soil and Franciscan Complex bedrock in the region. Design and construction of the shoring system for the 5-story basement excavation was exceptionally challenging because of the on-going construction for the TTC. To allow for flexibility during construction, hydraulic rams were placed in a transfer waler along the shared TTC shoring wall that could adjust the forces transferred through to the TTC excavation if required. Open and steady communication between the shoring engineer, the geotechnical engineer, and the shoring/foundation contractor was crucial in order to satisfy the complex constraints of this site.INTRODUCTIONThe 181 Fremont Tower is a new build mixed-use tower, currently under construction in the dense urban core of the South of Market District of San Francisco, California. This high-rise will consist of 54 above ground floors with the roof level 700 feet high. Atop the roof will be some architectural features including a spire that will top out at just over 800 feet, which will make it the second tallest building in San Francisco upon completion.The tower is being developed by Jay Paul Company and the architectural design is by Heller Manus. The structural engineer and geotechnical engineer for the project is Arup North America Ltd (Arup). The shoring designer is Brierley Associates (Brierley). The general contractor is Level 10 Construction (Level 10) and the specialty foundation contractor and excavation contractor is Malcolm Drilling Co., Inc (Malcolm)."

Jan 1, 2017

By J Burgess, G Scanlan

In 1993 after over 110 years of mining operations, production ceased at the Broken Hill North Mine. Following the cessation of operations a rehabilitation program was developed to satisfy the requirements of the various government departments. This program has been implemented progressively since mine closure. The paper will discuss: primary aims and objectives of the rehabilitation program, implementation of the program, rationale behind rehabilitation objectives, and problems encountered in implementation of the program. To-date the primary rehabilitation of the mine has involved the capping of redundant tailing dams with inert waste rock to prevent the contamination of the receiving environment. A Water Management Plan has been developed to contain all run-off from the mine area in an extreme storm event. A cultural heritage assessment of the leases has been undertaken to ensure the rehabilitation is consistent with the historical significance of the site and community expectations. All redundant material from the mine has been sold in a æno reserveÆ auction and the workshop area has been relocated to the Southern operations. At present the only active areas on the mine are a maintenance area for equipment for the Potosi open pit, and a primary crusher for Potosi ore which is railed to the Southern operations for further processing. Upon completion of the rehabilitation program, Pasminco Broken Hill Mine intends to relinquish the mining leases to the Department of Mineral Resources.

Jan 1, 1998

By Stephen C. Tadolini

The Bureau of Mines conducted field investigations in two underground mines to determine the actual loads to which bearing plates were subjected when installed in conjunction with full-column resin-grouted bolts and the roof movements generated by the applied loads. Measured loads indicate that the bearing plate is an integral part of the support system. Vertical displacement gauges installed to monitor roof displacements in the test sites show that the highest degrees of loading occur in conjunction with the largest amounts of movement.

Jan 1, 1986

By Peter Waggitt

Northern Australia has been home to uranium mining for over 70 years, more or less continuously. In the early days, post World War 2, there was little effort made to remediate workings at the end of operations. The three “campaigns” of uranium mining (1951-55; 1960-70; and 1979-present) are all now in various stages of remediation. This includes not only the large legacy site at Rum Jungle but also smaller fields like the South Alligator Valley, as well as contemporary works at Nabarlek and the ongoing closure at Ranger– Australia’s longest operating uranium mine. This paper briefly describes some of the past remediation activities before providing an update on the Ranger closure programme and future timetable.

Jan 1, 2020

By A M. Sardo, D E. Sinnett

This study uses the Q Method to examine how those living in former metal mining landscapes value this heritage and their preferences for the long-term management of mine waste. Such sites are often perceived as derelict or degraded, and of very little value. It is therefore assumed that their reuse, for example for development or recovery of metals, is likely to be beneficial. There are around 5,000 former metal mines in England and Wales, many of which are protected for their ecological, geological or cultural value. The Q Method is particularly suitable for issues where there is no consensus of opinion. We asked 38 residents of six mining areas in England and Wales to ‘sort’ a series of statements based on their resonance with the resident’s perspective; this is the Q sort. The statements covered a range of opinions of the mining legacy, its value and options for its management with a particular focus on the potential for metal recovery from the wastes. Analysis of the Q sorts revealed five perspectives on the mining heritage. All placed a high value on the cultural and ecological value of this heritage, however, they differed in their priorities for long-term management. For example, emphasis was placed on either nature conservation, cultural heritage, water quality or the opportunity for job creation through reworking the mines. Cutting across these themes there were also differing perspectives on the role of experts and local people in shaping the future management of the wastes. This research suggests that the views of local people are nuanced; they value their mining heritage but opinion is split on the most effective way to manage these sites especially where there is an impact on water quality.CITATION:Sinnett, D E and Sardo, A M, 2018. Former metal mining areas in England and Wales – local residents’ preferences for the management of wastes, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 126–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By S. Vongpaisal, T. R. Yu

"A set of new blast damage criteria has been developed, with special reference to blasthole mining operations, for assessing damage by incorporating the vibration level, rock properties, site characteristics and the effects of ground support systems. The main objective of this work was to provide a database with reasonable accuracy for use in optimizing blast design, numerical analysis and ground control expert system module development.The new damage criteria allow one to estimate the degree of damage to rock structures in terms of a dimensionless parameter defined as Blast Damage Index (BDI). This allows for the description of blast damage in a unified form, and facilitates the development of codes for numerical modelling to express the degree of blast damage universally. A number of field investigations from several stope production and slot opening blasts at a large underground base metal mine were carried out to verify the developed index. The results show a good correlation between the observed damage and the type of damage predicted from the BDI values.Practical measures are also provided for minimizing blast damage in large underground blasthole mining operations"

Jan 1, 1996

By Charles W. Kenney

Mercury contamination of soil at an old chemical plant surrounded by a residential community and adjacent to a river has provided unique challenges for the current owner. Inorganic and organic mercury compounds had accumulated over the past 50 years to levels that require remediation. Hazen Research, Inc. conducted a multi-phased program to characterize contaminants and their occurrences, evaluate various treatment technologies, and demonstrate the selected technology at bench and pilot scales. A combined physical cleaning and chemical treatment was demonstrated to meet treatment goals for the site. This paper discusses the methods of process selection and results of the bench-and pilot-scale testing.

Jan 1, 2003

By Scott A. Walker, Gabriel J. Alcantar, Brian Zuckerman, Ramin Golesorkhi

"The new San Francisco 49ers Levi’s Stadium is part of the next generation of sporting facilities. Constructed in Santa Clara, Calif., the new structure has 68,500 open-air bowl seats and includes a 7- story tower housing more than 150 suites. The overall project includes the stadium structure, elevated open pedestrian walkways, commercial community space, three new pedestrian bridges and improvements to the adjacent light rail station. Sustainable design for the project includes a green roof, photovoltaic panel and a ground source geothermal system. Stadium-wide next-generation Wi-Fi capability is another feature. The design-build project team included HNTB (project architect), Magnusson Klemencic Associates (MKA, structural designer) and a joint venture of Turner Construction and Devcon Construction (TDJV, general contractor).During preconstruction, the 49ers’ original design team and the design-build team formed later worked together to facilitate communication and provide continuity. This helped to meet the project’s aggressive schedule. Working directly for the 49ers, with the design-build team, Treadwell & Rollo (T&R) served as the geotechnical engineer of record for the project from preliminary to final design and through construction. Although not contracted directly to TDJV, the stadium ownership encouraged direct interaction between T&R and TDJV and improved responsiveness to geotechnical issues during design and construction.Subsurface ConditionsThe new stadium lies within the Santa Clara Valley, a deep alluviumfilled basin resulting from historic movement on the active and potentially active strike-slip and thrust faults that bind the valley. The valley is filled with Holocene age (approximately 11,000 years old to present) alluvium, consisting of levee and basin deposits, with bedrock more than 750 ft (229 m) beneath existing ground surface. The stadium site is between two of the highly-active faults in California, the Hayward Fault 6.8 mi (11 km) northeast, and the San Andreas Fault about 11.8 mi (19 km) southwest."

Jan 1, 2014