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By B. C. Vargas

The Toulon tunnel project is a key component of the Highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960?s. The tunnel project is made of 2 separate tunnels: South and North tunnel. The North tunnel was built between 1992 and 2002 after 10 years of difficult construction (for example, on March 15th, 1996, a collapse of the tunnel in the ?Marchand Area? generated a sink hole in the city Center, causing 20 months delay). The South tunnel alignment runs parallel to the North tunnel at the same depth below Toulon historical downtown (20 to 40m depth with some areas with less than 10m of cover). The Risk management program was studied to be a State of the Art program in urban tunneling construction. The Hydro Geological Context The whole project area is covered with backfills and colluviums of 1 to 4m thick. The Schist, marls and sandstones, randomly distributed along the alignment below the first layer have different characteristics. While the Schist are pretty compact, the marls are fractured. The other layers have very different characteristics, and many faults are located along the alignment, especially in the limestones. The Breccia are heavily decompressed and deformable, as well as the other soils located in the Marchand Area. This 80m long area is where the settlements need to be controlled with an extensive monitoring program. The complete Geological profile is presented in Figure 1. [ ]

Jan 1, 2012

By Kristian E. Waters, Hao Ma, Haibei Wang

Over the past few decades, ELM based separation processes have become an attractive and efficient way to remove toxic metal ions from the various aqueous waste effluent streams. This paper provides a comprehensive review of the generation, characterization, and applications of emulsion liquid membrane (ELM) from the more than 280 papers and books published so far. First, the ELM formation and the transport mechanism are introduced. Then the ELM stability and emulsion splitting methods are discussed in detail, followed by the latest research and findings of the extraction of copper and nickel using the ELM technique during the past few decades, including a thorough discussion of ELM operating parameters that impact ELM stability and extraction. In addition, the kinetics study and industrial application of this technique for the removal of coppers/nickel solutes are also presented and discussed.

Jan 6, 2023

By Mahiyar Nasarwanji, Jonathan K. Hrica, Jonisha P. Pollard, Lydia M. Kocher, Brianna M. Eiter

Within the metal/nonmetal mining sector, fall-related incidents account for a large proportion of fatal and non-fatal injuries. However, the events and contributing factors leading up to these incidents have not been fully investigated. To help provide a clearer picture of these factors, an analysis of imminent danger orders issued by the Mine Safety and Health Administration (MSHA) between 2010 and 2017 at both surface and underground metal/nonmetal mine sites revealed that most orders are associated with fall risks. Of these cases, 84% involved the workers not using fall protection, fall protection not being provided, or the improper use of fall protection. Fall risks for workers most frequently occurred when standing on mobile equipment, performing maintenance and repairs on plant equipment, or working near highwalls. In most cases, a single, basic, corrective action (e.g., using fall protection) would have allowed workers to perform the task safely. Overall, these findings suggest that a systematic approach is needed to identify, eliminate, and prevent imminent danger situations. Furthermore, to protect mineworkers from falls from height, frequently performed tasks requiring fall protection should be redesigned to eliminate the reliance on personal fall protection.

By Brian Fulcher

In April 1997, Kiewit/Parsons Brinckerhoff (K/PB) completed the 7,600-m (25,000-ft) primary access tunnel for the Yucca Mountain, NV proposed high-level nuclear waste site. K/PB then began boring an exploratory east-west cross drift tunnel at the site. The 2,681-m (8,796-linear ft)East-West Cross Drift Tunnel was excavated through volcanic tuffs having zones of incompetent rock using a rebuilt Robbins 5-m (16.4-ft)hard-rock tunnel boring machine(TBM) with a special arrangement of supporting equipment. This portion of the Yucca Mountain project was completed in eight months.

Jan 1, 2000

By Desiree Willis

One of New York City?s largest subway projects is under way 43 m (140 ft) beneath the surface of downtown Manhattan. The East Side Access project, more than 30 years in the making, was halted after a partial excavation in the 1970s due to a lack of funding. The project, once dubbed the ?Tunnel to Nowhere,? has been revitalized into a groundbreaking subway line that includes unique tunnel boring machines (TBM), construction methods and muck removal systems. Project overview The East Side Access project involves construction of a new 6.7-km (4.2-mile) subway line needed to relieve heavy traffic congestion between the boroughs of Queens and Manhattan. The line will serve approximately 160,000 commuters daily between Grand Central and Sunnyside rail stations. Manhattan and Queens will be connected under the East River by the 63rd Street tunnel, a submersed double-decker tube. The submersed tube consists of reinforced concrete sections barged in place on the riverbed. The tube contains operational subway lines on the top deck, while the bottom deck (the ?Tunnel to Nowhere?) will become operational when the East Side Access project is completed in 2013.

Jan 1, 2008

By Joseph Gildner, Donald J. Phelps, Jürgen Laubbichler, Christopher Tattersall, David McAllister

The Beacon Hill Station and Tunnels portion of the Sound Transit Central Link Project consists of one mile of twin rapid transit tunnels, an underground station, portals and ancillary works constructed in an urban environment. Presently under construction, the station will set a number of North American firsts including deepest soft ground excavation carried out using the Sequential Excavation Method (SEM).Located in highly variable glacial soil deposits ranging from soft, water bearing sands to stiff, slickensided clays, the station complex and running tunnels proved to be technically challenging during design. Meeting these challenges necessitated an extensive geotechnical investigation, a trial shaft, and state-of-the-art numerical analyses to develop ground conditioning, pre-support, excavation support and structural design. A comprehensive risk identification and mitigation program, and innovative procurement strategy were incorporated into the design and contract bid documents.

Jan 1, 2005

The market for titanium feedstocks (ilmenite, rutile,synthetic rutile and slag) is driven primarily by offtake from the titanium dioxide (TiO2) pigment industry. The pigment sector depends on the performance of the global economy. Titanium sponge is the first stage of titanium metal manufacture. It constitutes a minor component (3 percent) of overall demand for titanium feed-stocks. Production and consumption TiO2 pigment consumption in 2004 was estimated to be 4.63 Mt (5.1 million st), up 7.6 percent from 2003. It was driven by strong demand in most regions. In the United States, apparent TiO2 pigment consumption rebounded by 5.4 percent (highest growth rate since 1997) to an estimated 1.12 Mt (1.23 million st), following the decrease in demand during 2003. Chinese TiO2 pigment consumption continued its strong upward trend, increasing by 10 percent to 598 kt (659,000 st) in 2004.

Jan 1, 2005

By Robert C. Horton

The Getchell Mine is located on the east flank of the Osgood Mountain Range in the Potosi Mining District, Humboldt County, NV. Mining in the area first began in 1883 for copper, lead and silver in skarn-related deposits. Tungsten was discovered in the skarns in 1916 and was mined sporadically until 1957. The first major discovery was made in 1933 when two Winnemucca prospectors, Edward Knight and Emmett Chase, found gold at the present site of the Getchell gold mine. In 1934, after a small amount of preliminary prospecting, the claims were purchased by Noble H. Getchell of Midas, NV. The Getchell Mine Inc. was organized and exploration and development work began on a broad scale. Major funding was provided by George Wingfield and investors he assembled. Laxalt described Wingfield’s immediate history prior to his financing of Getchell as follows.

Jan 1, 1999

By J. MacFadyen

The U.S. cement industry experienced its best year ever during 2004 in terms of production and shipments of cement. Clinker, portland and masonry cements production and shipments were up considerably. Clinker production as reported to the U.S. Geological Survey (USGS) was 87.75 Mt (96.73 million st), an increase of 5.4 percent. Gray and white portland cement production from domestic and imported clinker was estimated to be 91.6 Mt (101 million st), up 5 Mt (5.5 million st) from 2003.

Jan 1, 2005

By Wolfgang Guetter, Wolfgang Weber

The upgrading project for two hydropower plants in Slovenia, Europe, requires two new pressure tunnels: Plave II (5.9 km Flysch) and Doblar II (3.6 km Limestone). It is the worldwide largest application of the Double-Shield TBM technology combined with an extremely thin-walled monoshell honeycomb lining system. The first drive has been completed by end of June 2000 achieving best performances of 50m/d and almost 1,100m/mth. In September 2000 the TBM started the second tunnel without any required adjustments due to geological or other reasons. Another 52m/d have been bored already within one production day of two 8 h shifts achieving a maximum penetration rate of more than 6m/h. The completion of the Doblar drive can be expected by February 2001.

Jan 1, 2001

By J. Olsson

Introduction Stainless steel has by tradition been a common construction material for hydrometallurgy processes and the most common grades can be found amongst the ASTM 300-series, i.e. austenitic grades of type 304L, 316L and 317L. However, there are a number of new grades available today, which imply more cost effective solutions for those designing plants where good resistance to acids, containing the desired metal ions, often contaminated with chlorides and other halides, is the key issue. There are austenitic-ferritic or duplex grades having the same or even better corrosion resistance than the austenitic grades and approximately twice the strength, which enables design in thinner gauges, which in turn implies less weight and less cost. They have also excellent engineering properties, enabling fabrication of process equipment, machinery and different types of tanks. On top of that, they contain less nickel and molybdenum than their austenitic counterparts, which implies not only lower cost for alloying elements, but also a more stable price when considering the price fluctuations for these alloying elements during the last years. This paper describes briefly the family of duplex stainless steel and it presents a number of relevant corrosion tests where duplex grades have been compared with austenitic grades. The results have in several cases been verified by in-plant exposures in zinc and copper production plants. It also describes applications and experience of duplex grades within a variety of hydrometallurgy plants. Installations of highly alloyed austenitic grades will be described as well. The corrosion tests and service experience reported cover hydrometallurgical processes based on sulphuric acid.

Jan 1, 2007

By M. Javier

This concept paper is presented in the hope of raising the awareness of mankind on the necessity for its peaceful coexistence with nature. It is a food for thought. It takes compromise and sacrifice of people, who will have to learn to curb their greed and move toward a more organic form of prosperity. A nature-friendly sustainability is first step toward the protection of nature that is critical to the mutual survival of mankind and nature. People need the resources from the finite earth to survive and nature needs the prevention of human destruction in order to continue to regenerate and provide. The contemporary notion of sustainability is self-serving. It serves the interest of industry by camouflaging itself to look like nature?s protector. The ?sustainability? concept presented in this paper aims to extend the longevity of the utilization of the limited natural resources for many generations to come. It is an important, responsible first step in creating a healthy sustainability concept that, when implemented, extends the longevity of mankind by the most efficient use of the finite resources on this limited Planet Earth, all the while taking into consideration the increase in anthropogenic activities due to exponential human population growth. This new definition of ?sustainability? has completely different characteristics than its contemporary versions. Nature has its own destiny, rules and principles. Being a part of nature, human society depends on it for survival and must play by its rules and never the other way round as in its initial pretensions. Society should not try to humanize nature, but rather to respect the rule of the nature in a peaceful way of co-existence. When implemented, this new concept of sustainability aims to affect the designs of engineered structures and revolutionize the recovery methods and processing of natural resources, such as mineral resources in the most efficient manner. Finally, this paper intends to stimulate critical thinking and initiate serious discussions aiming at producing a general consensus for the best definition for human society to not only enrich, but to extend its existence. Thus, the spirit of this new definition is pro future generations and environment. KEYWORDS: Sustainability Definition, Nature, Geomímic, Deproduction.

Feb 27, 2013

By M. Valdebenito, J. Rajala

An OCS Expert control system was implemented by Svedala Cisa at the Minera Maricunga Refugio Crush-Leach Operation near Copiapo, Chile. The purpose of the Expert system was to maximize production through the primary and secondary crushing circuits and help balance crusher usage between each stage to maximize total plant production. Interesting aspects of the control strategies are discussed. Benefits of the control were verified through a randomized On/Off test program. Tonnage increases ranged from 5% to approximately 20% at good confidence intervals. Benefits analysis results are discussed. The crushing plant at Refugio is very remote and is located at approximately 15,500 ft. This poses many challenges. The effect of altitude and remote location on plant operation are discussed.

Jan 1, 2002

Sustainable development is at odds with reality in the minerals industry. Increasing world population and aspirations are leading to increased energy and mineral consumption. Non-renewable fossil fuels are being exploited at a much faster rate than they are being discovered. Mineral reserves are diminishing and of lower grade. Despite recycling, many of the economic reserves of the rarer metals on which technological society has come to depend are being depleted, and many of the bulk metals are being exploited at ever increasing rates. And yet, mining continues, with a long-term downtrend in commodity prices, matched by more efficient mining and processing. Will society turn to a low carbon economy before fossil fuels are depleted? Will prices come to better reflect the full cost of mineral production? Will technology save us, or is it at the root of the problem? The key drivers continue to be an ever increasing aspirational population and the law of supply and demand, rather than sustainability considerations. The paper illustrates this with examples of worldwide and Australian data.

Jan 1, 2011

By Rafael C. Castro, Geoffrey Hughes, Fredrick (Rick) Vincent, Philip H. Albert

Seven pairs of drop and ventilation shafts, between two and nine feet in diameter, will convey combined sewer flow to a 230-foot-deep, 26-foot diameter storage tunnel. This paper will present case histories for each site. Discussion will include functional requirements, program and site access constraints, structural design, geology, the variety of excavation and lining construction methods used, and lessons learned. Noteworthy observations include the importance of assuring competent ground sup-port at the soil-bedrock interface and of achieving tight verticality tolerance using both top-down and raise bore excavation methods.

Jan 1, 2007

By Greg Partington, Darryl Thorburn, Charlene Wildman, Elisa Puccioni, Connie Payne, Campbell McKenzie

"Mineral prospectivity modelling of polymetallic nodule deposits has been completed over the Cook Islands Exclusive Economic Zone (CIEEZ) using the GIS based Weights of Evidence modelling technique. Polymetallic nodules, also known as manganese nodules, have been explored as a possible resource for a number of metals including cobalt since the early 1970s. Recent data on the nodule composition and abundance in the CIEEZ has led to a renewed interest in the prospectivity for manganese nodules in the region. The predictive modelling has used the most recently accepted mineral model for polymetallic deep-sea nodule deposition to identify factors that are most likely to map the presence of this type of mineralisation in the CIEEZ.Manganese nodules form on the deep seafloor as concretions formed by concentric layering of iron and manganese hydroxides around a core and they grow at a very slow rate, on the order of millimeters per million years. The available data for the CIEEZ indicates a greater abundance in the area of nodules formed by hydrogenetic processes, which are the result of slow precipitation of metallic components from seawater. The environment in which the nodules are most abundant is at depths between 4,000 m and 6,000 m in areas of low sedimentation rate. Hydrogenous nodules commonly grow on siliceous and pelagic clay sediment, they are less common on other types of sediment."

Sep 1, 2014

By Brett Campbell

The San Vicente to 2nd Aqueduct Pipeline?Tunnel project is a raw water conveyance tunnel linking the San Vicente Reservoir (SVR) to the 2nd Aqueduct Pipeline via Rancho Penasquitos Pressure Control Facility (RPPCF). This 58,230 lf long tunnel will be 8.5? final ID, and has four points of construction access. The job is classified into 6 Reaches of tunnel, identified by the dominant geology within the reach. This paper will focus on Reach 3, specifically the measures necessary to drill and blast a 550 lineal foot section of granitic rock tunnel immediately in front of an open face digger shield.

Jan 1, 2008

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001

By Patrick J. Doig

The contract for the construction of the Inline Pump Station for the Milwaukee Metropolitan Sewerage District involves the sinking of three shafts and the excavation of a pump chamber. The shafts are being sunk to a depth of 104 meters and pass through 52m of sediments before encountering dolomitic bedrock. The pump chamber is constructed in dolomite. The sediments are alluvial, estuarine and lacustrine in origin, with some ice margin deposits. They comprise loosely consolidated fine to coarse grained sand, silts, clays and gravels, and they are heavily saturated with a water content often above 60%. The water table is at a depth of 3m. The dolomite is silurian, generally dense, with some clay-filled vugs and shale partings. Until 1983, underground construction in the Milwaukee area had been limited to depths of 26m in the sediments and 20m in the dolomites. Water control methods had included caissons, compressed air, extensive internal and external dewatering, and grouting. Flows of 20 liters per second were commonplace with as much as 80 liters per second being encountered in the rock. However, in 1984 work was commenced on the deep sections of the Milwaukee sewerage scheme with the letting of three major contracts including the Inline Pump Station. With excavation taking place at greater depths, it become obvious that previous methods of water control would be inappropriate. To protect against major inrushes of high pressure water in the rock, an extensive program of pre-grouting from the surface was specified. Water control in the sediments was left to the discretion of the contractor and in each case freezing was choosen. This paper describes in detail the grouting and freezing procedures.

Jan 1, 1985

By Timothy P. Smirnoff

Sustaining the region?s mobility needs, achieving projected economic growth, and maintain Midtown Manhattan as a center of regional, national and global importance has led to continued investment in commuter rail and transit infrastructure in New York City and resulted in design and construction of large underground caverns. The current plans for stations in Manhattan include New York Penn Station Expansion (NYPSE) caverns for Trans Hudson Express (THE) Tunnel Project for New Jersey Transit (NJ Transit) and the Port Authority of New York and New Jersey (PANYNJ), Metropolitan Transportation Authority Capital Construction Long Island Railroad (MTACC/LIRR) twin caverns for East Side Access (ESA) Project, and station caverns of the No. 7 Line Subway Extension Project and Second Avenue Subway Project for Metropolitan Transportation Authority Capital Construction/New York City Transit (MTACC/NYCT). This paper provides a general overview of these large caverns now in design or construction in Manhattan, the area?s geologic setting, the geotechnical factors considered and approaches commonly applied for cavern design.