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By Gary Almeraris, Vincent Jr Tirolo

Traditionally, “Means and Methods” were the sole responsibility of Contractors. However, because of a number of litigious projects in the 1970s, Owners and their Engineers began including Suggested Methods of Construction (SMC) in Contract Drawings. By the late 1990s these SMCs were becoming baseline “Means and Methods” with Contractor recommended changes often considered as Value Engineering proposals. By 2004, the word “Suggested” was sometimes changed to “Prescriptive.” Owners are also purchasing TBMs and other mining equipment for Contractors prior to bid. Is limiting the contracting community’s innovation in developing their own “Means and Methods” and selecting their own equipment in the best interests of the Owner? Does it reduce the Owner’s, Engineer’s or the Contractor’s risk? Are claims reduced and finally what is the impact on the bid? A questionnaire was sent to more than fifty senior engineering field and management personnel representing more than 30 heavy construction companies to ask their opinion on these questions.

Jan 1, 2005

By Chris Bennett, Drupad Desai, Kirit Mevawala

INTRODUCTION The design/build (D/B) philosophy of contract delivery is neither new nor unusual when it comes to at-grade, elevated or high-rise structures. But when it comes to constructing underground facilities, there were no examples to be followed in early 90sin the continental United States or its territories. When DMJM+HARRIS was selected as general architectural and engineering consultant for the Tren Urbano (TU) project in Puerto Rico, one of the requirements of the Federal Transit Administration (FTA) for funding commitment was to use TU as a demonstration project utilizing design/build contract delivery method. Now fifteen years later, New York City Transit (NYCT) has instituted a similar requirement for their first Tunnel Boring Machine (TBM) contract for the Second Avenue Subway. As with most construction mega-projects, lots of things have happened and there were several lessons learned from the TU experience that are now being applied to Second Avenue. Both of these projects require building tunnels and underground transit facilities in heavily traveled corridors of an urban city, in the vicinity of active business and commercial enterprises. To enhance the challenge, there are noise and vibration sensitive and historic urban receptors either over or along both the transit corridors. Column free Tren Urbano station caverns over18 m (60 ft.) wide were built in soft ground conditions within 3.6 m (12 ft.) of the surface under an aging heavy utility corridor, while NYCT tunnels with station structures stretching the limits of rock caverns to 34.8 m (100 ft.), were planned in rocky geology with the presence of shear and fault zones and some mixed face conditions. BACKGROUND During the early period of design/build experimentation, the speed with which the contract procurement packages could be put together enabled the owners to take advantage of the major efforts underway to rebuild the infrastructure that was suffering from post-World War II neglect. Use of design/build for new starts was unheard of and most of the projects were smaller in nature in order to allow the methodology to be tested. Development of functional design packages with the understanding that the D/B

Jan 1, 2005

By S. M. Jasinski

Peat is a natural organic material of botanical origin. Peatlands are situated predominately in shallow wetland areas of the Northern Hemisphere. Commercial deposits are formed from the gradual decomposition of plant matter under anaerobic conditions for about 5,000-years. In 2004, peat was harvested in 16 states. Florida, Michigan and Minnesota accounted for more than 80 percent of the U.S. production. Reed-sedge was the dominant variety of peat harvested in the United States, comprising almost 80 percent of the output. This was followed by humus, hypnum moss and sphagnum moss.

Jan 1, 2005

By F. Habashi

Asbestos, an extremely useful natural resource, has been studied extensively mineralogically and for industrial application. Its extraction from ores has been greatly improved with respect to safety in the work place. In spite of that, there is a decisive effort in many countries to ban its use on the grounds that it is a toxic substance. This action resulting in drastic decrease in production and the possibility of destroying the industry. The chelation of asbestos with organic dyes seems to be a promising way to abate its toxicity. Dyeing can be done when the fibers are slurred in water at ambient conditions in the same way as textile fibers.

Jan 1, 2009

Based on X-ray phase analysis and exploratory experiments, a new technology was developed to recycle multiple valuable elements in spent Al2O3-based catalyst. The experimental results showed that after roasting at 750°C for 30 minutes at an Na2O:Al2O3 mol ratio of 1.2, the leaching recoveries of alumina, vanadium and molybdenum from the spent catalyst were 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by barium hydroxide and barium aluminate. The precipitation recovery of vanadium and molybdenum was 94.8% and 92.6%, respectively. Al(OH)3 is prepared from sodium aluminate solution using the carbonation decomposition process. The purity of Al2O3 is 99.9% after calcinations, and the recovery of alumina can reach 90.6% in the whole process. The Ni-Co concentrate was leached with sulfuric acid, and a nickel recovery of 98.2% and a cobalt recovery of more than 98.5% were obtained under the experimental condition of 30% (w/w) H2SO4, 80°C, a liquid: solid ratio of 8:1 (by weight), a reaction time of 4 hours and a stirring rate of 800 rpm.

Jan 1, 2007

By Christian Maguire

The presence of hydrogen sulphide in sewerage systems leads to severe concrete corrosion. Acid causes breakdown of the concrete matrix, and attacks reinforcement. Older sewer systems under acid attack are often found to be acutely corroded, sometimes after short operational periods. Consequently secondary liners are now almost always used. Polymer concrete is extremely acid resistant and if used in segmental linings can forgo the need for a secondary lining. Combined with fibers and/or GFRP rebar Polymer Concrete can produce a very strong acid resistant lining, saving considerable time in the installation of additional liners. This paper explains the problems and advantages of using Polymer concrete in segmentaly lined wastewater tunnels, addressing areas of design, cost, and programming.

Jan 1, 2008

By S. Hamilton

Borates are essential to life, and to many products that are essential to an acceptable standard of living. They occur naturally in seawater at an average concentration of five milligrams of boron per liter. Fresh water lakes, rivers, streams and ground water generally have concentrations of about one milligram boron per liter. Borates are also present in soil at concentrations ranging from 0.1 to three milligrams of boron per kilogram. Because most of that boron is locked into insoluble minerals, clay or organic matter, boron deficiency is more widespread than boron enrichment. Borates evaporate into the atmosphere from seawater, rain, snow and hot springs. In rain and snow, natural boron concentrations range from 0.002 and 0.1 milligrams boron per liter. All told, boron moves through the atmosphere at a rate of 5 Mt to 7 Mt/a (5.5 million to 7.7 million stpy).

Jan 1, 2005

By P. Conrad

Experience has shown that, since the passage of the Surface Mining Control and Reclamation Act, over-compaction of spoil during the reclamation process has severely limited tree growth on reclaimed land. Researchers at the University of Kentucky have conducted a ten-year investigation at a surface mine in eastern Kentucky that monitored the changes in selected spoil physical characteristics for various reclamation and compaction alleviation methods. More specifically, research plots were developed for reforestation that employed three different levels of compaction and two different methods of ripping for overly compacted spoil. Each year measurements were made in the field of dry bulk density, using a nuclear density gage, and maximum penetration depth, using a recording cone penetrometer. In addition to good correlation between tree growth and selected spoil characteristics, the data demonstrated a gradual convergence of the measured spoil characteristic data over the study period.

Jan 1, 2008

By Rodrigo Jerez

Advances in inexpensive computer automation led to the development and use of a computerized ore control system at the Cyprus Copperstone Gold Mine near Parker, AZ. These new ore control practices improved accuracy, performance and productivity of the ore control effort. An automated system for data collection, including bar coding of blasthole samples, laboratory analysis, data management, grade estimation, cut delineation and ore zone stake out, plays a major role in ore control practices. This is of particular interest because of the large amount of blasthole information being processed, analyzed and reported daily. Copperstone Gold management has been progressive toward new, efficient methods regarding ore reserve estimation, long-term mine planning, short-term mine planning, ore control and surveying. Technological advances, including powerful personal computers, applicable mine planning software and surveying instrumentation, have become readily available and affordable. The computerized ore control procedures used at Copperstone include sample data collection, laboratory automation and computerized data management. These have reduced the time to complete ore control on a blast pattern by 50% to 75%. The final product - ore control - is generated in a more timely and accurate manner.

Jan 1, 1991

By S. C. Sun

Pennsylvania has ample reserves of high-alumina clays which are potential sources of alumina, but many of these clays contain large amounts of iron, which makes them unsuitable for treatment by acid processes(1). The purpose of this investigation was to determine the optimum conditions for the selective hydrochloric acid leaching of iron (2-4) prior to the sulfuric acid extraction of alumina from Pennsylvania ferruginous high-alumina clays. This was accomplished by first testing the iron-bearing minerals and the clay minerals most often encountered in Pennsylvania clays to determine their rate of dissolution in hydrochloric acid solutions. The results of individual minerals were then based for leaching Pennsylvania clays with a 19% hydrochloric acid solution at the boiling point of the acid for approximately 30 minutes to achieve as high as 90% iron removal and only 2-5% alumina losses.

Jan 1, 1968

By R. Gunda

Due to the rapidly increasing production rates and deepening of mine working areas, there is a drastic rise in the number of thermal issues to be addressed for maintaining a safe mine environment. As high temperatures and humidity in underground mines could affect the health and performance of workers, and ultimately the production rate, it is necessary to provide a properly controlled safe environment. The backfilling of stopes in metal, non-metal mines results in different thermophysical properties for the hanging, side and foot walls, modeling of which is not provided by any existing mine climate simulation software. This paper presents the modeling of such a single stope using the MULTIFLUX (MF) software, developed at University of Nevada, Reno. A special case is presented in this paper, where a case study from the Homestake mine in the US with a drift and ramp connected to a stope with high Virgin Rock Temperature (VRT) and various spot heat sources is modeled in MULTIFLUX and CLIMSIM, and the results are compared against each other. Another case is presented in which the stope of the previous cases is modeled with walls, each having a different set of thermophysical properties. These results are compared with the former results to analyze the effect of anisotropic properties.

Jan 1, 2011

By A. W. Popp

After forty years of exploration and development, the heavy mineral sand deposits of the Murray Basin are on the eve of substantial exploitation by Iluka Resources Limited, Southern Titanium NL and RZM/Cable/Bemax, whom plan to initiate mining and processing operations in 2005. A trial mining and processing operation was undertaken on the Wemen North strandline deposit in 2001-2003 by Murray Basin Titanium, a joint venture of Sons of Gwalia and RZM/Cable, which brought to light a number of mining and processing problems which have since been the subject of extensive studies and process development work. The mineralogy of these weathered strandline deposits is complex by industry standards due to the variety of the heavy minerals present, coatings on the mineral grains and the extensive weathering and alteration which has taken place during the past 50 million years. This paper provides an overview of the complex mineralogy that, in turn, dictates the processes that can be used to recover the valuable heavy minerals. The Murray Basin encompasses some 300,000 km2 and has been a depositional basin, often land locked, since the start of the Cenezoic Era. The economic heavy minerals include ilmenite, altered ilmenite, leucoxene of highly variable composition, rutile, and zircon. There are also other heavy minerals present such as cassiterite, chromite, and monazite in quantities that pose both problems and opportunities. The clay content and overburden thickness also play a major role in the selection of the deposits to be mined. Project Services Consultants (PSC) has undertaken the preparation of this paper as part of its ongoing participation in the mineral sands industry and in particular the project development activities in the Murray Basin region currently being undertaken by Iluka Resources. PSC has been involved with the mineral sands business for several years with senior staff having in excess of 30 years global industry experience. The company is well placed to provide a range of services to clients like Iluka Resources in the areas of project development, execution and strategic development and industry advice.

Jan 1, 2005

By Robert C. Freas

While on the surface limestone marketing may appear mundane, it has continued to provide a series of challenges beyond the realm normally envisioned with this industry. This paper presents a case history of a mature and well-established quarry company that has attempted to keep pace with an ever-changing economy. It examines the impact of socio- economic and technological factors on the company's marketing efforts, and looks at the role of both short and long range planning. The realities which have had to be faced and how product requirements have been kept in balance with production restrictions are also discussed.

Jan 1, 1981

By J. M. Dempsey, R. A. Litle

Asarco Incorporated’s Omaha, Nebraska refinery site and the City of Omaha’s downtown redevelopment projects are the perfect example of the marriage of the Brownfield and Sustainable Development strategies. Nebraska’s largest voluntary site remediation project created a focus point for redevelopment and has spurred over $1 billion in economic investment within a 1-mile radius of the site. Asarco was faced with options of very expensive and uncertain facility upgrades or a shutdown. Local leaders, Asarco, and regulators worked together to convert a controversial and complex site to a park-like redevelopment area with numerous long-term benefits to the City and the environment.

Jan 1, 2004

By Robert J. F. Goodfellow, William A. T. Meakin, Kevin Clarke, Eric Cole

INTRODUCTION New York City Water Supply—Background and History Since the 1840s New York City has been developing the largest, and perhaps, the best urban water supply and distribution system in the world in terms of quality and reliability. One of the engineering marvels of the modern world, the New York City water supply and distribution system serves a population of almost nine million, including residents in nearby Westchester, Putnam, Ulster, and Orange Counties of New York State. The average daily supplies presently are running at almost 60 m3/sec(about 1,350 million gallons per day). The watershed for the New York City water supply system, under the jurisdiction of the New York City Department of Environmental Protection (NYCDEP), consists of19 reservoirs and three controlled lakes, and covers an area of approximately5,000 square kilometers (about 2,000 square miles) north of New York City. The watershed total available storage capacity is about two billion cubic meters (560 billion gallons) and is divided into three reservoir systems: the Catskill and Delaware watersheds located West of the Hudson River; and the Croton watershed, located east of the Hudson River, see Figure 1. The first element of the system, the Croton Aqueduct, started operations in 1842.Through several updates and expansions, the present-day Croton system was in place by 1911, providing a potential maximum supply of about 15 m3/s (about 340 mgd). The system includes ten reservoirs and three controlled lakes. In the late 1800s, with the tremendous growth of the City, New York City water engineers began to look for additional sources. Between 1907 and 1929, the City acquired water rights and constructed a new 148 km (92 miles) Catskill aqueduct to convey water from the Ashokan Reservoir to the City. The Catskill system also included the construction of the Kensico and Hillview Reservoirs just north of the City,

Jan 1, 2005

By Günter Huber, Bruno Mattle, Helmut Westermayr, Daniel Spöndlin, Max John, Nejad Ayaydin

PROJECT DESCRIPTION Alignment The Strenger Tunnel forms part of the S16 four-lane expressway between Landeckand Bludenz. The construction of this important East-West connection started in 1973with the Arlberg Road Tunnel as its key constituent. Beginning in 1992, solutions for the section between Pians and Flirsch were investigated. Efforts to conserve nature and to avoid potential avalanche and landslide areas led to a solution detouring the villages in the Stanz valley. The starting points were predetermind by the intersections at Pians in the East and at Flirsch in the West. As a result of the expected traffic load and the comparatively high gradient of 2.9%, both one-way, two-lane tubes were constructed at once. The north tube is 5.851 m long, the south tube 5.775 m, see Figure 1. Layout of Tunnel Cross-Section The tunnel cross-section was determined by 2 × 3.75 m wide, 4.70 m high roadways, two sidewalks and sufficient space for two fans above the clearance

Jan 1, 2005

By Brian Fulcher

While tunneling in Europe has been a tradition for centuries, many companies and countries have embraced tunnel innovation with considerable vigor and creativity. Indeed, local needs and site conditions have provided the initiative for improved means, methods, materials and equipment to complete progressively more challenging projects. Many recently completed tunnels have expanded tunneling technology and contributed to the development of highly specialized and productive equipment ? such as the mixed-mode tunnel boring ma-chine (TBM) presently in operation at the SOCATOP A- [ ] 86 road tunnel and the high-pressure slurry TBMs for the Westerschelde Tunnel in the Netherlands and Hollandsas near Malmo, Sweden. This paper describes some of the key technologies employed by European tunnel builders and designers including the New Austrian Tunneling Method (NATM), advanced earth pressure-balanced (EPB) machines, pres-sure-faced (slurry) tunneling machines as well as ?hybrid? or mixed-mode TBMs. While these tunneling methods and equipment generally involve significant equipment investment, they may also involve highly trained, experienced and specialized tunneling and support crews as well as materials and tools specifically developed to supplement or complement tunneling performance. For example, mechanized pipe arch placement substantially improves ground support measures and NATM advance and on larger tunnel cross-sections.

Jan 1, 2007

By J. W. Wilson, P. C. Graham

SUMMARY The Witwatersrand quartzites in which South African gold mining operations are moat exclusively conducted, are notoriously difficult and costly to drill. Despite this situation, however, with the high cost of developing new mines and extending existing mines, together with the rising cost of labour and mining problems resulting from the ever-increasing depths of workings, the demand for raise-boring in these formations is increasing rapidly. Not only is the demand for raises and shafts increasing, but also the length and size of these excavations. Raise-boring studies carried out in South African gold mines have indicated that increased penetration rates and possibly reduced costs could be obtained if higher thrusts were available at the reaming head. Until fairly recently there has been no raise-boring machine suitable for underground use that possessed the thrust and torque characteristics necessary to achieve high penetration rates in hard abrasive quartzite formations and the cutters available were not really developed for high loading. In response to these requirements a raise-borer, the Robbins 83R was designed and built in Seattle, U.S.A. for the Anglo American Corporation. This machine is operating in South African gold mines and is currently being used at a depth of 12 000 ft below surface in one of the. Group's mines. The initial raises bored have substantiated that increased penetration is attainable at high thrust and it is now apparent that the machine is sufficiently versatile to drill raises of up to 12 ft in diameter in quartzite formation over a length of 2 000 ft.

Jan 1, 1974

This study was conducted to establish the effects of a diesel particulate filter (DPF) system with sintered metal substrate on the concentrations and size distributions of nano and ultrafine aerosols and concentrations of nitric oxides in underground mine air. The study focused on the formation and transformation of nucleation mode particles in mine air under prevailing test conditions. Experimental work was conducted in the NIOSH Diesel Laboratory at the Lake Lynn Laboratory experimental mine, a facility developed to allow evaluation of control technologies directly in underground conditions. The DPF system was examined for four repeatable steady-state engine modes using a naturally aspirated mechanically controlled Isuzu C240 diesel engine fueled with ultralow sulfur fuel. The engine coupled to an eddy-current dynamometer was operated in the underground drift with tightly controlled ventilation. Measurements upwind and downwind of the exhaust system discharge were used to quantify the effects of the DPF system on the mine air. A baseline was established using a standard muffler. The study showed that sintered metal DPF systems reduced the total mass of aerosols in the mine air by more than ten-fold when compared to a muffler. The nucleation mode aerosols (50dem<40 nm) in mine air were found to be strongly influenced by engine operating mode. The concentration of nucleation mode aerosols was found to be significantly higher for high-load modes than for low-load modes. The muffler and DPF system resulted in comparable total nitrogen oxides (NOx) concentrations. However, the nitrogen dioxide (NO2) fraction of the total NOx was found to be substantially higher for both systems for low-load modes than for high-load modes.

Jan 1, 2009

It is crucial to reestablish a domestic rare earths minerals production industry to help secure the Nation&apos;s clean energy future, reduce the U.S. vulnerability to material shortages related to national defense, and to maintain our global technical and economic competitiveness. Given that the Chinese dominance of the rare earths market has adversely impacted supply stability and endangers the United States and its allies&apos; assured access to key materials, rare earths should qualify as materials either strategic or critical to national security. Further, the U.S. government should facilitate the reintroduction of a globally competitive rare earth industry in the U.S. Realization of this objective requires: ? Developing domestic processing capability so that the U.S. is not primarily dependent on China as a source of rare earth ore, and almost exclusively dependent of China for processing of the ores. ? Providing a mechanism where access to Federal lands for rare earth exploration and extraction is possible, and ? Training engineers to design and operate rare earth ore processing facilities

Jan 1, 2011