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By Martin B. Hudson, Daniel Brescia, Zhangwei Ning

Due to the complexity and sensitivity of surrounding environments, instrumentation and monitoring (I&M) is critical for many urban deep excavations. The objects to be monitored include shoring bulkheads, retained embankments, adjacent buildings and roads as well as underground utilities. However, there are also plenty of constraints on the implementation of I&M such as: congested site space, difficult access to instruments, coordination among multiple contractors, and installation permits for private or public properties. Because of these constraints, sometimes the implementation of the initially planned I&M is delayed, its scope is reduced, and/or the continuity of monitoring is interrupted. For these reasons, it is important to implement the I&M with robust and redundant capabilities while providing minimal interference to the project construction and schedule. This paper describes state-of-the-art I&M technologies including automatic motorized total station (AMTS) with camera and automatic leveling device, reflectorless AMTS and IoT- based wireless sensors based on a case study of an on-going deep excavation project. INTRODUCTION In urban environments, deep excavations requiring the construction of temporary shoring bulkheads are becoming increasingly common, with the associated need to provide protection of the surrounding built environment during construction. Protection of the surrounding environment requires planning, engineering, construction, monitoring, and excessive shoring movement mitigation. The I&M is a vital component of the deep shoring implementation. In public projects, geotechnical I&M is often placed within the general contractor’s scope, whereas the majority of deep excavations are privately undertaken. For those private developments, sometimes the developer contracts the geotechnical I&M directly with the project geotechnical engineer or by a geotechnical I&M specialist hired by the project geotechnical engineer. In either the public project or private development case, the effective deployment of the I&M system relies heavily on coordination and collaboration with the project contractor.

Jan 1, 2018

By Murad Y. Abu-Farsakh

This paper presents the analyses of load-transfer (t-z) behavior of twelve prestressed concrete (PSC) instrumented test piles that were driven in different locations of Louisiana. The load transfer method is an efficient and practical tool for the analysis of single driven pile to predict the ultimate load. The test piles were instrumented with vibrating wire strain gauges in order to calculate the shear transfer for different soil layers during the static load test. The static load test was performed on all the test piles after 10 to 14 days of end of driving. Empirical load-transfer models were proposed previously by different researchers (Fleming 1992, Hirayama 1990, Krasinski 2012, Bohn et al. 2017) after analyzing the instrumented test pile results. For this study, load transfer of each soil layer was measured and compared with the previously developed existing model. The stiffness parameter (M) for the hyperbolic equation was calibrated in order to best match the measurements. The good agreement of the proposed curves was then confirmed by applying them to assess the overall load-settlement curve of other pile load test results available in the literature. INTRODUCTION The load transfer mechanism (stress-strain relationship) for an axially loaded pile usually comprises of three loading mechanisms: axial deformation in the pile (z), soil skin friction along the shaft (qs), and soil end-bearing (qb). The development of soil skin friction with axial deformation is referred as the t-z curve, and the development of soil end-bearing with axial deformation is referred as the q-z curve. Figure 1 presents the load transfer mechanisms in an axially loaded pile and the corresponding spring mass models for t-z and q-z curves (API, 2002). In order to construct the load transfer curve in clay under vertical load, the axial load transfer (t-z) curve and end-bearing load transfer (q-z) for that particular soil should be assessed separately. The axial load transfer (t-z) method is probably the most widely used technique to study the problem of single axially loaded piles. Therefore, the load transfer through the shaft of the pile and are getting more and more important compared to the only the pile capacity analyses. The load transferred from shaft to the surrounding clay soil is a function of the width of the pile and the surface roughness of the pile and clay properties. The development of a representative procedure allows the assessment of the t-z curve in soil (sand and/or clay) that leads to the prediction of a nonlinear vertical load-settlement response at the pile head.

Jan 1, 2018

By Arash Khosravifar, Matt Steffan

An expansion of the City of Klamath Falls Wastewater Treatment plant required geotechnical seismic hazard evaluations and deep foundation design. The site is located on the shore of Lake Ewauna and is underlain by diatom rich lake deposits. Diatomaceous soils exhibit unique engineering properties that are not well understood. Cyclic Direct Simple Shear (CDSS) testing was performed on three undisturbed samples to evaluate cyclic and post-cyclic properties of the diatomaceous soils. Results from the CDSS testing indicated that the soils would not liquefy in the classical sense, though cyclic softening behavior was observed. The CDSS results were used to develop a Cyclic Resistance Ratio curve for the diatomaceous soil to compare with clean sand liquefaction curves. Seismic lateral pile capacities were developed using two approaches. One approach used conventional p-multipliers for liquefied soil and modified them to reflect expected excess pore pressure ratios. The other approach applied residual strength and fifty percent strain values from post-cyclic monotonic shear testing. A lateral spread hazard zone was identified along the Lake shoreline and reduced, seismic lateral pile capacities were recommended. The objective of this paper is to report the seismic design considerations for this project in a unique geologic and seismic setting. INTRODUCTION The engineering properties of diatomaceous soils have rarely been studied and the cyclic behavior under seismic loading is generally unknown. Some of the critical geotechnical uncertainties of diatomaceous behavior include potential for large consolidation settlement, influence of irrecoverable strains due to diatom particle crushing, shear strength (peak and residual), and cyclic properties. This paper presents results of cyclic shear testing, seismic evaluations and seismic lateral pile design in diatomaceous soils performed for the expansion of a waste water treatment plant in the city of Klamath Falls, Oregon, site of the largest recorded earthquake in Oregon’s history. The expansion consisted of adding six new facilities at the existing Plant including influent pump station (IPS) and headworks, aeration basin, tertiary treatment, and other buildings. The IPS/headworks and aeration basin will be founded approximately 15 feet below ground. The other buildings will be founded at grade. The existing facilities are supported by timber piles that penetrate the surficial diatomaceous soils and terminate on a hard underlying deposit. Figure 1 shows the site plan and proposed additions.

Jan 1, 2018

By Teele Tuuna, Voglers Eesti OÜ

Blasting operations are a strong and important part in any kind of building and mining industry, a shot-firer profession is one of the oldest professions in the civilized world. It still serves an important and ongoing purpose in the modern economy all over the world. Europe, nowadays, values strongly the mobility of workers, the movement of know-how and labor force between different countries inside Europe. There are no borders for most of the everyday professions.

Jan 1, 2018

By Sam Yao, Ali Naeem, Sara Barrett

Brooklyn Basin Project is a multi-billion-dollar development of the former Port of Oakland 9th Avenue Terminal located along the Oakland Estuary of California. A centerpiece of the development is the 10-acre shoreline park which will be built on a 1,200 ft long by 225 ft wide historic wharf. The wharf was built in the 1930’s on concrete and timber piles with a flat concrete slab. Prior to constructing the wharf, a rock dike was placed to protect the shoreline. The presence of the rock dike increased the hazards from lateral spreading of the underlying bay mud and non-ductile shear failure of piles driven through the dike. To open the park to the public, the wharf required a seismic retrofit in compliance with the California Building Code. The paper presents the results and conclusions of the following topics: • Structural condition assessment and repair strategies for the existing wharf deck, piles and jackets • Application of the California Building Code (CBC Ch31F) for the performance-based seismic evaluation of existing piers and wharves • Nonlinear pushover analysis of the wharf including the combination of inertial and kinematic effects • Impact of rock dike on lateral spreading and kinematic effects and the significance of existing piles in stabilizing the lateral spreading of the rock dike • Retrofit strategies for the wharf to meet the required seismic performance requirements per the California Building Code and reduce the demands on existing piles which were driven through the rock dike INTRODUCTION The 65-acre Brooklyn Basin Development project is located in Oakland, California. The project consists of 3,100 housing units, 200,000 sq. ft of retail and commercial space, along with various parks and public access improvements along the Oakland Estuary. A centerpiece of the development is the 10-acre Shoreline Park which will be built on a 1,200 ft long by 225 ft wide historic wharf. The wharf was built in the 1930’s on concrete and timber piles with a flat concrete slab. As shown in Figure 1, the wharf deck and piles support the 9th Avenue Terminal Building.

Jan 1, 2018

"Mining used to be a business primarily focused on the technical aspects of getting valuable ore out of the ground and extracting the minerals efficiently. Without denying the importance of these skills, a narrow focus on technical issues is no longer enough to guarantee success when it comes to exploiting rare earth element (REE) deposits. Molycorp failed to enter the global REE market in a successful manner, while none of the many REE exploration projects has turned into an active mine so far and none is expected to commence operations in the near future. Accordingly, the world of REE is far more complex compared to other commodities. This paper looks into the REE industry to identify the factors that can connect potential U.S. REE mines to the market. The ability to break free from past thinking and become future-focused is a key driver. Mining of REE is pointless without a corresponding value-adding chain, while developing a value chain without first establishing an uninterruptible source of REE is also senseless. The mining sector must be based on the REE value chain and vice versa, along with the establishment of a market channel for the REE products that come out of the mine. INTRODUCTION It has been seven years since rare earth elements became the subjects of front-page headlines. It was when the controversial Chinese export policy for these critical commodities was epitomised in a maritime border dispute with Japan in September 2010 that resulted in the big REE crisis and price spike of 2011 (Barakos et al, 2016c; Mancheri, 2015). The world was dismayed, especially in REE-importing countries, such as the United States that was and is still totally dependent on Chinese production and exports (Barakos et al, 2016c; Kennedy, 2015). The short-lived alarm initiated a treasure hunt by way of exploration for REE deposits all over the world. The continuously growing demand on the one hand and the Chinese sovereignty of the REE-market on the other, led the rest of the world to explore their own REE resources. In just a few years, more than 400 projects were initiated to explore REE deposits outside of China (ERECON, 2015; Goodenough, 2016). The prices of REE, however, dropped rapidly and at the moment of writing this paper are in 6-year lows, at the level of the price average before the 2011 crisis (Barakos, 2017). The viability of even major established producers is being challenged, not to mention the development prospects of potential REE-market entrants (Barakos et al, 2016b; Rollat et al, 2016). Production cutbacks and industry consolidation in China impel REE market experts to forecast that prices have already reached their lowest point and have nowhere to go but up (Adamas, 2015; Roskill 2015). Yet, expectations for increased REE prices are limited and drastic changes are unlikely to happen in the near future, as there is still excess supply in the overall REE market (Barakos, 2017). Nevertheless, the low prices of rare earths are not the only reason that potential producers are struggling to enter the global REE market. Among other parameters, the separation of the individual elements seems to be the most important factor, as it is technically challenging and expensive to build and to operate."

Jan 1, 2018

By Matt Slezak, Tristan Worsey, Nathan Rouse, Kyle Hall

As everyone knows, blasters are required to file blast reports of every blast for regulatory purposes. To this day, the authors see many handwritten blast reports. Handwritten blast reports are notorious for containing errors or omissions. This is not because the blaster intends to misreport information. It is because blasters have many tasks to complete in a day, are sometimes in a rush, and could accidentally miscalculate data, omit items, or record incorrect data. In most cases, blasters do not suffer consequences to these errors because blast reports are seldom reviewed in detail. In some cases, such as when a blasting operation undergoes some sort of litigation process, the reports are reviewed in detail and the blaster is ultimately held responsible. If the reports contain errors, the blaster can be fined, have his/her license revoked, or worse. Electronic blast reporting and centralized data management can help reduce or eliminate the potential for accidental blast reporting errors to occur. This paper presents many ways that electronic blast reporting can reduce or eliminate blast reporting errors, decrease time and extra costs spent reporting, and improve efficiencies in the field and the office.

Jan 1, 2018

By Federico Pagliacci, Marco Chiarabelli, Salvatore Miranda

The paper describes the adopted technologies and performance controls related to a special geotechnical engineering solution provided within the scope of the Galataport Project, in Istanbul, Turkey. The scheme is the one applied to the new quay of Salipazari, which is a combination of retaining structure and ground improvement, formed by a combi-wall, a reinforced concrete diaphragm wall and a soil improvement by deep soil mixing (Turbojet). The paper highlights the importance of employing cutting-edge technologies within the foundation engineering field and state-of-the-art electronic control devices, in parallel with the essential human expertise, in order to obtain the desired results in this high profile Project. The results of the in-situ and laboratory tests carried out on the improved soil are also presented. Main discussed points are: • History of Galataport and main Project details. • Design principle and soil condition for the new quay of Salipazari. • Difficulties encountered during execution of DSM. • Preliminary field trial tests conducted to establish the operational parameters, with relevant in-situ and laboratory tests executed. • Preliminary tests on material used for DSM (seawater and CEM IV SR). • Electronic equipment mounted on the rig, which allows the automatic execution of DSM columns. • Final QA/QC tests conducted to verify the performance of DSM, mainly consisting in: coring with relevant laboratory tests on samples (UCS + Es), seismic refraction tomography and seismic cross hole tomography. Correlations between UCS and Es, and between Es and Edyn are also presented. • A cross section of the executed treatment could be inspected on site during excavation. Photos and considerations are also presented.

Jan 1, 2018

By S. Jeon, N. Hiroyoshi, N. Kitajima, S. Tanaka, M. Ito, R. Pongsumrankul, C. B. Tabelin

"Gold (Au) extraction is inefficient when crushed waste mobile phones (WMPs) are directly leached by ammonium thiosulfate likely because of the cementation/precipitation of dissolved Au in the presence of base metals like copper (Cu), iron (Fe) and/or aluminum (Al). This study applied physical separation techniques to remove base metals as well as plastics and concentrate the Au containing fractions from WMPs prior to leaching. Coarse fraction of crushed WMP (+2-5.6 mm) was pretreated by jig and magnetic separation to remove plastics and base metals like Fe, Cu, and Al, while the fine fraction (-2 mm) was pretreated by flotation, and float and sink separation. The leaching results showed that Au extraction increased in both of the size fractions. In the coarse fraction, Au extraction increased by as much as 2-fold after pretreated (from 4 to 7%). Improvement of Au extraction in the fine fractions after pretreatments were even more dramatic. Au extraction increased from 4 to 61%. These results indicate that physical pretreatment to remove co-existing common metals and plastics is effective to improve Au extraction from WMPs. INTRODUCTION Global sales of mobile phones are expected to increase steadily in the foreseeable future because a lot of people buy newer phones with upgraded and more advanced functions almost every two years, which leads to the higher generation of waste mobile phones (WMPs). WMPs contain a wide variety of materials including plastics, glasses, base metals and precious metals such as gold (Au). Among all the valuable materials in WMPs, Au accounts for over 80% of its total metal price (Park et al., 2017), so recovery of Au from WMPs is needed."

Jan 1, 2018

By Moi Arzamendi, Jose Ramirez, Kenneth Kniss, Sunil Arora, James Gingery

Construction of a new approach embankment for a railroad bridge over a river in Southern California required placing up to 12 ft of fill over soft to medium stiff silts and clays along an approximate 1,500-ft long stretch. The embankment, situated within a narrow railroad right-of-way between an existing live track and existing buildings, would have been susceptible to excessive settlement that could damage existing buildings and numerous underground utilities if regular weight soil fill had been placed over the unimproved ground. To limit total and differential static settlements to tolerable levels, a design was developed using a combination of mechanically stabilized earth wall with lightweight cellular concrete fill and rigid inclusions ground improvement. This paper describes the design of the ground improvement system, construction methods used, and challenges of working next to live railroad traffic. Ground improvement quality control and assurance measures, and verification of performance by settlement monitoring are also addressed. INTRODUCTION AND BACKGROUND The 0.9-mile San Diego River Double Track (SDRDT) project is located on the Los Angeles-San Diego- San Luis Obispo (LOSSAN) Corridor in San Diego, California. The project includes the replacement of the existing 900-ft long single track railroad bridge over the San Diego River with twin double track structures. Construction of the project is phased and closely coordinated with the associated Mid-Coast light rail project (San Diego Trolley Blue Line Extension). The new bridge is a 7-span, twin steel, through girder structure supported by six cast-in-place reinforced concrete pier caps and two abutments. The large diameter cast-in-drilled-hole (CIDH) foundations are up to 9 ft in diameter, with upper portions encased in a 1.5-in.-thick permanent steel casing. The north abutment approach embankment includes a mechanically stabilized earth (MSE) retaining wall up to approximately 10 ft high and 1,520 ft long. This paper focuses on the design and construction of the north approach embankment. The project site is characterized by challenging geotechnical and seismic conditions. The site contains liquefiable soils interbedded with soft cohesive soils, underlain by competent layers of sand/gravel/cobble and other sedimentary formations. Static settlement of the new railroad, crossing utilities and adjacent buildings was a primary design concern for the north approach embankment.

Jan 1, 2018

By Peter Faust, Jeremy Zorne, Timothy Siegel, Diane Fiorelli

Professional sport venue construction follows a very simple rule. Once the decision has been made to move the team to a new place, construction shall begin immediately, so that not more than one or two seasons pass by stuck in the old home. Such tight construction schedules require a different approach than traditional design-bid-build contracts. Design is mostly done on the fly, the construction schedule becomes a main risk factor and an early contractor involvement is desired. As specialty contractors become more and more sophisticated, owners, their construction managers or the general contractor have realized the value of ideas and modern technology they can bring to the table for a successful and fast project completion. Local knowledge and experience in a variety of solutions play a key role in the specialty contractor’s ability to provide added value to the project. This is also true for the specialty foundation contractor, who needs to understand the complexity of such modern structures from its integrate foundation, over the delicate concrete structure to a potentially fancy movable stadium roof. Not to mention all the modern high tech equipment which shall make such a place a great customer experience. His expertise shall enable him to propose the most suitable foundation element for the given ground condition and application. Rather to build what others have designed, his strength is to propose alternate concepts which will be faster and (hopefully) more cost effective. This paper highlights different value engineering (VE) input a specialty foundation contractor had on 3 major sports arena projects in California. Together with the entire team from owner to GC, including the Geotechnical (GEOR) and the Structural Engineer of Record (SEOR), the most efficient and best performing foundation solution can be found every time. But such an approach also requires the open mind of the owner to entertain last minute changes when the permit drawing set has already been submitted for approval.

Jan 1, 2018

By Mauricio Terceros, Martin Achmus, Freddy Lopez

The massive use of deep foundations had a remarkable influence in the building industry in the 20th century. Piles and micropiles made possible to erect thousands of civil structures around the world, changing quintessentially the urban and rural landscapes. Especially in urban areas, the ongoing development requires not only new infrastructure, but also to increase the capacity and/or to extend the serviceability of existing structures (buildings, bridges, etc.). Factors such as the change of use of existing facilities or the requirement to comply with updated building regulations confront Civil Engineers with the question, whether to tear down and build new structures, or to reinforce the existing structures from their foundations. Micropiling has enabled designers to come up with technical feasible solutions to retrofit the existing deep foundations, making the structural reinforcement a real option, even under considerable changes in the loading conditions. The following article presents an overview of an intervention project, where micropiles were designed to reinforce the original pile foundation of an existing building, enabling it to be reused with a different structural function. This paper will focus mainly on the analysis of the interaction between the existing piles and the reinforcing micropiles, especially in terms of settlements’ compatibility. Finally, the adopted solution, with its correspondent design considerations and execution process will be presented.

Jan 1, 2018

By Scott Rosenthal, Logan Connolly

Butte, Montana holds a prestigious place in the history of mining, deemed “The Richest Hill on Earth,” containing a plethora of underground mines. The Orphan Boy/Orphan Girl underground mines, on the western side of Butte, operated from 1895-1956 producing zinc, lead, silver, and manganese. Today, the Orphan Boy mine is part of Montana Tech’s Underground Mine Education Center (UMEC) and the Orphan Girl mine houses the World Museum of Mining. Underground development in the Orphan Boy mine continues to progress as students from Montana Tech receive hands-on underground training; in addition, the UMEC is a multi-disciplinary research facility. Repeated underground blasting occurs in close proximity to old mine workings (wood supports installed circa 1950 or earlier). Research began to determine the impact of underground blasts on nearby pre-existing structures. Using the ISEE Field Practice Guidelines for Blasting Seismographs, one seismograph monitors the predominately-wooden structures to measure their response during each underground blast and one seismograph positioned on the surface to monitor surface structure response to the blast. This paper presents the findings of the research conducted to date for the project. The paper includes analysis of the research data, and conclusions determined from the research. Recommendations for the future work are included as well.

Jan 1, 2018

By Haijian Shi, Drew Pizzo

This article focuses on the appropriate application of subsurface investigation methods for transmission structures, which are typically designed to resist lateral rather than vertical loads. Currently, the three methods used most often for the subsurface investigation of transmission structures in the field are the Standard Penetration Test (SPT), the Cone Penetration Test (CPT), and the Flat Dilatometer Test (DMT). Each of these methods has advantages and disadvantages, and each is more applicable to some scenarios than to others. To gain a better understanding of these test methods and the implications of using them for various kinds of applications, a comparison study was conducted in the field in Maryland, for three boring locations. Each boring location was explored using each of the three tests as stated. The results of the tests and lessons learned are presented and compared, and these comparisons show that the three test methods agree on the majority of the findings. The results from each test method were also used to derive key parameters such as the soil friction angle for given foundation designs considered in order to establish a clear basis for comparison. Recommendations for performing transmission structure subsurface investigations are made in order to optimize the use of each method and thereby optimizing subsequent foundation designs. INTRODUCTION For overhead transmission structures, the most important structural requirement for determining the foundation design differs from the requirement for other structures such as buildings and bridges in accord with the conditions the transmission structures will need to withstand. In addition to the ability to bear a given vertical load consistent with its use, the foundation must bear lateral loads arising from wind and other weather conditions. The foundation types used most often for overhead transmission monopole structures include concrete drilled pier, vibratory caisson, and direct embedment. In order to determine an appropriate and even an optimum foundation design for any given set of conditions, an appropriate subsurface investigation method or approach is needed. Currently, the standard penetration test (SPT), the cone penetration test (CPT), and the flat dilatometer test (DMT) are the three most commonly used subsurface investigation methods.

Jan 1, 2018

By Scott A. Walker, Roberto A. Lopez, Lori A. Simpson, David A. Shook

500 Folsom Street is part of the new Transbay neighborhood in San Francisco, which is being redeveloped after the 1989 Loma Prieta Earthquake damaged a freeway viaduct; removal of the viaduct created parcels of land available for development. The development consists of a 42-story residential tower with a six-level basement. The slender, core-only structure was designed using performance-based seismic design. Subsurface conditions include undocumented fill, Dune sand, marsh deposits, sand, and clay, all overlying sloping bedrock of the Franciscan Formation. The building is supported on a 10-foot-thick mat foundation approximately 62 to 72 feet below street grades; clay, sand, and bedrock are all present at mat subgrade. Under a portion of the mat, sand susceptible to liquefaction was present. The variable subgrade conditions and potential for ground failure, along with the depth of mat subgrade below street grade, created a challenge for the design and construction team to solve. The ground below mat subgrade needed to be improved to mitigate the liquefaction potential and provide more uniform support. The areal extent and depth of ground improvement necessary to support the mat with an acceptable amount of deformation was determined. Settlement was analyzed and subgrade moduli were provided for design of the mat, with multiple iterations performed to converge between the geotechnical and structural models. Based on the project schedule and logistics, it was beneficial to work from street grade to improve the ground. In order to target the depths below the mat and minimize wasted effort and materials within the depth of excavation, grids of jet grouting were determined to be the most economical ground improvement method; however, it was challenging to install the columns from 65 feet above the top of the target zone. During installation, QA/QC was performed to check that the jet-grouted columns were installed to the design depth and diameter and developed the design strength.

Jan 1, 2018

By Larry Stearns, Lori Tiefenthaler

Remediation of contaminated soil represents a significant market for application of Deep Soil Mixing (DSM). Eighty-one percent of U.S. Environmental Protection Agency (EPA) Superfund Program’s site remedies have involved contaminated soil. Contaminated soil is frequently treated by In-situ Solidification/Stabilization (ISS). ISS treatment of contaminated soil involves mixing binding agents into soil using DSM techniques. DSM is a core business for many DFI members. Members may improve and broaden their services to clients by learning about the recent ISS treatment of contaminated soil at a Superfund site. ISS treatment is part of the EPA-selected remedy for a Superfund Site in the metro New York City area. The property has seen heavy industrial use for more than a century. Soil at the site is contaminated with a variety of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) including coal tars and heavy metals, principally arsenic and lead. Beginning in 2017 and continuing through 2018, approximately 150,000 cubic yards (115,000 cubic meters) of soil will be treated by ISS at the case study site. Portland cement and slag cement are mixed into the soil by DSM techniques using GPS guided excavators to immobilize the hazardous constituents within the treated soil. ISS treatment by DSM will contribute to redevelopment of this valuable property. This paper will describe ISS constructability and performance, case study grout mix design with geotechnical results for strength and permeability, and deep soil mixing techniques. INTRODUCTION In-situ solidification and stabilization (ISS) is a deep soil mixing (DSM) technique applied in the environmental remediation field to physically encapsulate, or chemically bind, contaminates of concern such that the impacts to human health and the environment are mitigated. Common remediation applications of ISS include mixing cementitious reagents into contaminated soils to form a monolithic mass with desired performance characteristics, and the installation of vertical subsurface walls designed to control groundwater movement. A key characteristic of ISS is that the contaminated soils are treated in their existing location at the project site and then are left in place after treatment. Typical performance characteristics of the ISS treated soils include improved unconfined compressive strength (UCS), reduced hydraulic conductivity (HC), and reduced leaching potential of soil contaminants. Increased shear resistance of the treated soil may also be a performance requirement where seismic loading is a concern.

Jan 1, 2018

By Ron J. Elliott, Dylan Wedgewood

A series of five signature holes were blasted at the Highvale Mine and the resultant seismic data was analyzed to make recommendations on how best to address neighbour complaints regarding blast vibrations. From an analysis of peak vibration levels measured at the closest neighbour for blasting during 2016, it was determined that the blast vibration intensity varied between 1.4 to 4.3 mm/sec (0.06-0.17 ins./sec.), well below the level of concern for the onset of minor damage to residential structures, however, the frequency of the blast vibrations was between 2.2 and 9.7 Hz, which is within the range of the natural resonant frequency for a single story home. This was determined to be the cause of the neighbour complaints, as the home would be responding to the blast vibrations.

Jan 1, 2018

By Thi Hien Tran, Ngoc Anh Tran, Thi Thu Hien-Dinh, Duy Anh Dao

"Natural graphite exists mainly in three types of amorphous graphite, flakes graphite and lump graphite. Graphite from Bao Ha mine, Lao Cai province is with 11.8 carbon-graphite %, forms in flakes and dense crystals. The paper presents the comparison among enrichment of Bao Ha’s graphite by two types of froth flotation with 90 g/t kerosene oil as collector, 50 g/t montanol 800 as frother, in natural pH, and at 20 wt.% of solid. The differences among three flow charts indicated that using middling flotation and re-middling flotation for the cleaning tails and the scavenger concentrates, the final concentrate was improved and containing up to 94 carbon-graphite % of flakes graphite, up to 82 carbon-graphite % of fine graphite with 93.48 % total recovery, moreover, carbon-graphite in the final tail is 0.86 % with 6.52 % recovery. However, a refining mill and a classification stage were applied before doing the middling flotation stages.1. INTRODUCTIONGraphite (black lead or plumbago) is used in many industrial applications due to its high electrical and thermal conductivity, lubricity, and chemical inertness. High quality graphite can be used in metallurgy, molding, brake linings, batteries, and fuel cells. Graphite, composed exclusively of the element Carbon, is rather common mineral, but fine crystals are rare. Graphite is soft (hardness: 0.5-1 Mohs scale); has a layered, planar structure; occurs in platy or acicular (occasionally) morphology (Minerals.net; Pierson, 1993).USGS (2017) reported, global consumption of natural graphite continuing increase in the period of 2012-2016. In 2016, China used up 35% while produced 66% of the world’s graphite. Graphite mining are being developed in Madagascar, Mozambique, Namibia and Tanzania, but production reduced in Canada from 2015. Based on the statistic of Statista.com shows from 2011 to 2014 and a forecast to 2020, the global graphite demand is mostly in refractories, batteries, others, lubricant/crucible, foundry and pencil, and that is increase every year.Graphite Vietnam lies on the fault of the Red river from Yen Bai to Lao Cai, the reserves is estimated around 29.3 million ton and mostly in Lao Cai province where has Nam Thi graphite mine and Bao Ha graphite mine (MOIT, 2008). Vietnamese graphite products could reached to ~92% graphite carbon (Cg) (Tran Thi Hien et al., 2008). Studied samples was collected in Bao Ha graphite mine, is located in Lao Cai province. Graphite Bao Ha exists in two types as graphite flakes and amorphous (Hoang Thi Minh Thao et al., 2017)."

Jan 1, 2018

By Wayne Rogers, Kell Monro, Arthur Pacunana

The Phu Kham Copper-Gold Operation (PKM) is a large-scale open pit mine located in northern Laos. It was developed and is operated by Phu Bia Mining Limited (PBM) a Lao-registered subsidiary company of Australian incorporated, PanAust Limited. Production commenced at Phu Kham in 2008. Since the second half of 2016, there has been a significant increase in ore hardness and this has negatively impacted the PKM concentrator and resulted in lower SAG mill throughput rates. Over the remaining life of mine, the changing ore body and increase in ore hardness is forecast to continue as the pit deepens and the availability of softer blending ores reduce. To manage this risk, PKM initiated a Hard Ores Management Program to determine the most effective way to improve the mill throughput of harder ores. This involved conducting a number of innovative and process control driven blasting trials to optimize run-of-mine (ROM) fragmentation and other blasting outcomes. From 2016 to 2017, the performance of high powder factor blasting, electronic detonators and fast timing, high velocity of detonation (VOD) explosives, double-priming, and deck blasting, were individually and systematically assessed. The success of each blasting trial was then based on a ‘value for money’ criteria. This criteria is a cost / benefit analysis that weighed-up the additional cost to implement the trial against the measured improvement in mill throughput. Electronic and high VOD 90:10 emulsion:ANFO blasts were determined to have the best value for money, achieving an increase in mill throughput of 54% compared to baseline. This paper discusses how the implementation of an innovative and process control driven blasting trial methodology was able to successfully manage the hard ore challenges at PKM. In addition, this success was achieved without any major cost implications, safety incidents or process plant set-backs.

Jan 1, 2018

By M. E. Taranenko, V. A. Krivonosov, S. A. Nemykin

"In concentrating production energy-consuming power installations are wide used, the most powerful of them are the wet autogenous grinding mill operating in closed circuit with a spiral classifier. The analysis of the current state of the automation of the grinding process shows that the reserves for maximizing productivity and minimizing electricity consumption have not yet been exhausted on the existing process equipment. Usage of the achievements of the modern management theory reveals an opportunity for further optimizing of the grinding process. The purpose of the research is to develop an automated control system of complex ""the mill-classifier"" to conduct the grinding process in the most operating efficiency, ensuring the maximization of productivity and minimization of specific electricity consumption. The main idea of this work is to study the specific features of the ore grinding process and creation on this basis of automated control system complex ""mill-classifier"" which allows to find and to maintain the optimal mode of grinding based on identification of the current object parameters, observance and regulating of the object state coordinates. Research methods. We used the methods of system analysis, mathematical statistics, modern automated control theory, theory of systems identification, optimal control, modelling of dynamic processes. Developed scientific provisions: - identification algorithm of the loading sub-system management object of complex ""mill - classifier"" allowing to obtain the unbiased estimators of its parameters according to the data of normal object exploitation; - observing device, which differs from the classic version of the observer Luenberger with possibility of estimating not only the state coordinates of the control object, but also the low-frequency perturbation component; - automated system stabilizing the active power of the grinding mode on the basis of a states controller with Luenberger observer; - structure of the software and hardware that implements the developed models, algorithms, methods of control, management and optimization in the framework of the automation of grinding."

Jan 1, 2018