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By C. Asgaard

Asset availability has been a longstanding objective in mining and mineral processing plants around the world. Enormous resources in both dollars and manpower are invested in improvement efforts to achieve higher asset availability. One dimension of asset availability is the time equipment is out of service for large scale planned maintenance activity: grinding mills, kilns, furnaces, mobile equipment, shovels and draglines are all regularly taken out of service for extended repairs and service. The speed, cost and quality of these planned outages provide an opportunity to increase asset availability. Equipment shutdowns are projects that are executed in a compressed time period. This paper will describe how the overall time and cost of equipment shutdowns were significantly reduced at Cliffs Natural Resources Michigan Operations (CNRMO) through the introduction of the Critical Chain Project Management techniques.

Jan 1, 2009

By Verya Nasri, Heather M. Ivory, Kevin Clarke, Eric Cole

Development of the New York City Water Supply System The New York City water supply system serves a population of almost nine million, including residents in neighboring counties. Peak day demands on the system are currently running at about 70 m3/sec (about 1,600 mgd), which is significantly lower than in the 1990s. This trend of reducing demands over the past 25 years, which has been experienced in other major urban centers in the US, is mainly the result of conservation measures and increased cost consciousness on the part of water users. In the long term, demands are expected to once again follow an increasing trend with population growth, so that by the end of the planning horizon of these studies, the year2045, the peak day demand is expected to increase to about 85 m3/sec (2,000 mgd).The system is served largely by surface water sources, regulated by a system of 19reservoirs and three controlled lakes, which are connected to the City by a series of aqueducts, the longest of which is about 87 km (54 miles). The total storage in the sys-tem amounts to about 560 billion gallons, providing a system firm yield of about1300 mgd. The Delaware system provides about 50% of the City’s water, the Catskill about 40%, with the remaining 10% provided by the Croton. The system as a whole, which is shown on Figure 1, has been built up over the past 150 years, and is truly a marvel of engineering. The Catskill and Delaware aqueducts both discharge into Kensico Reservoir, which is a daily balancing reservoir located in Westchester County about 24 km(15 miles) north of the New York City line. The two aqueducts extend south for a further 14 miles to combine again at Hillview Reservoir in the Bronx, which provides hourly balancing storage for New York City system. The Croton aqueduct runs nearby as shown on Figure 2, but does not connect into the two reservoirs. From Hillview Reservoir the water is supplied to the city via three main distribution tunnels, known as City Tunnels 1, 2, and 3. City Tunnel No.1 was developed in the 1920s as part of the Catskill system. City Tunnel No. 2 followed in the 1960s as part of the Delaware system. City Tunnel No. 3 (CT3) is partly under construction and partly in operation, and is being implemented to permit the other distribution tunnels to be taken out of operation for the first time for inspection and maintenance. Presently CT3 is supplied with water from Hillview Reservoir via a large underground valve chamber, the Van

Jan 1, 2007

By James F. Kvitkovich, George V. Weisdack

Editor’s note: This is the second part of a two-part series on longwall mining in the United States. Part one was published in the December 2005 issue of ME (pp. 21-26). It provided a history of longwall coal mining in the United States. It also discussed the technology involved in the productivity gains and operational improvements. Boyd anticipates that U.S. coal production will increase by 61 Mt (67 million st) (6 percent) from 2004 to 2010. A combination of higher surface and underground mine production will be required to meet the projected market demand. Boyd’s projections of coal production by major mining methods are shown in Table 1.

Jan 1, 2006

By W. Chae

The influence of solution ionic strength (IS) and electrolyte valence on the flotation behavior of malachite has been investigated. The microflotation tests were conducted over a range of solution IS (1?300 mM) at a constant speed (340 rpm), pH (9.5), flotation time (10 min), and sodium oleate dosage (5.3×10-7 moles/g). The size of malachite ranged from 45 to 53 µm, and two different types of electrolytes (NaCl and CaCl2) were employed. Electrophoretic mobility was also measured over the same IS range employed in the microflotation study. Overall, strong coupled effect of solution IS and ion valence was observed. Specifically, the flotability of malachite increased with increasing IS in the presence of monovalent cation (Na+) while the flotability increased up to 30 mM and decreased with increasing IS in the presence of divalent cation (Ca2+). Notably, the flotability of malachite was greater with the presence of Na+ compared with Ca2+ under high IS conditions (IS>30 mM). Consistent trend for Na+ versus Ca2+ was observed from the flotation results with different SO dosages. The characterization and flotation results suggested that the trend was likely attributed to the increased unfavorable interaction between malachite and bubble via the charge reversal of bubbles and malachite at higher IS in the presence of Ca2+.

Feb 27, 2013

By H. Walqui, C. Noriega

Southern Copper Corporation (SCC) is one of the world’s largest copper companies and is finishing the modernization of the Ilo copper smelter. A single ISASMELTTM furnace will start smelting 1,200,000 tons per year of concentrate at the end of 2006. Three existing Peirce Smith converters are being upgraded plus a new one for converting the matte to blister copper is being installed. Two new anode furnaces and a twin anode casting wheel have being operating since January 2006. This represents one of the main changes in the process because the final product of the smelter is now anode copper instead of blister copper. A new oxygen plant, acid plant, and others facilities are in the ramp-up stage. This environmental project will ensure that the new smelter will comply with the environmental regulations of Peru by the end of January 2007. This paper summarizes the background to the modernization project, describes the different stages of the project including engineering, procurement and construction, describes the main areas of the new copper smelter and also the pre-operational testing, commissioning and start-up of them. This is a brown field project with a target of reducing as much as possible the production losses of the existing operation. This paper presents the details of the development of the Ilo Smelter Modernization Project and explains the main aspects of the new facilities, the products to be obtained and the associated facilities for their commercialization, including a Marine Trestle for bulk acid exportation.

Jan 1, 2007

By J. Reed

The RockWorks EarthApps represent a free collection of 74 geology-related programs that read data from a built-in datasheet and create diagrams within Google Earth. EarthApps also includes programs that extract data from Google Earth. The programs that create diagrams include: point mapping (e.g. borehole locations), proportionally scaled icons (e.g. geochemistry), and strike & dip symbols. Line mapping utilities include; polylines, parabolas and pipelines. Polygon mapping programs include; thematic mapping (e.g. geology), mining claims, and public land survey sections. Image overlay capabilities include; draping (e.g. geologic maps) and time-based animations. Vertical image display capabilities are centered on either midpoints (e.g. drill-hole logs) or stretched between endpoints (e.g. cross-sections). The Flyover programs create virtual tours for site presentations. The cell-mapping includes a variety of algorithms (e.g. geochemical and geophysical contouring). Survey programs convert and export survey data to Google Earth as points and polygons. Programs that extract data from Google Earth include; points, lineations, polylines, and polygons. The RockWorks/EarthApps collection is developed by RockWare Incorporated based in Golden, Colorado.

Feb 27, 2013

By Thomas J. Kuli, Tim Rape

When a fan or blower breaks down or becomes worn, customers have two choices. They can replace it or they can have it repaired. In the past, replacement was the preferred option, especially when the equipment was severely damaged or worn. Now, however, customers are discovering the benefits of repairing or rebuilding. Even when the cost of repair is more than 60 percent of the cost of a new fan, customers are choosing the repair option. The cost savings can range from 20 percent to 80 percent. In many cases, the quality of the repaired part or component will exceed the quality of the original. This is because repair engineers have an advantage over the original designers. They can see how the existing fan performed — or failed to perform — in a specific application.

Jan 1, 2005

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. As a result of its potential carcinogenic nature, DPM exposure is regulated by the Mine Safety and Health Administration. Currently, diesel emissions in the workplace are monitored by collecting the aerosol onto filters, which are then sent to a laboratory for thermal-optical analysis using the NIOSH method 5040. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of DPM before the problem is identified. Moreover, the delay involved in getting the loaded filter to the lab inevitably means the loss of some of the more volatile organic carbon. To remedy this delay, researchers from the National Institute for Occupational Safety and Health are seeking to develop a field-portable, real-time method for measuring elemental and organic carbons in DPM aerosols. In the current study, the use of mid-infrared spectrometry was investigated. It is believed that mid-infrared spectroscopy is more suitable for use in a real-time field-portable device than thermo-optical analysis methods. This article presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. The method has been successfully applied to laboratory-generated and mine samples.

By L. B. McConville

The general term "tar sand" has been used to describe sand containing varying amounts of dense, viscous petroleum. Deposits of tar sands have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, and is located in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 square miles. Current estimates place the contained raw petroleum at about 700 billion barrels, from which as much as 300 billion barrels of synthetic oil may be recoverable under presently developed technology. For comparison, this latter quantity is roughly equivalent to five times the combined total of U.S. and Canadian crude oil reserves. With the ever-widening gap between energy supply and demand, attention is being directed to all possible energy sources - both developed and underdeveloped - and certainly the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. This paper will review some of the more significant developments and attempt to place in perspective the role that this source of energy could possibly be expected to play in the foreseeable future.

Jan 1, 1974

By S. Mischler, J. Noll, G. Schnakenberg, A. Bugarski, M. Crum

Diesel particulate filter (DPF) systems and biodiesel fuels are two of the most promising technologies available to the mining industry to reduce the exposure of underground miners to diesel particulate matter (DPM). A study has been conducted to estimate the potential of DPF systems and biodiesel blends to reduce DPM emissions from production vehicles. Results of testing three DPF systems in an isolated zone showed 88% to 99% reductions in elemental carbon concentrations. The test results also show that biodiesel blends, B20 and B50, reduced the elemental carbon concentrations in the mine air by 26 and 48 percent, respectively.

Jan 1, 2004

By M. J. Raffaldi, K. W. Harris, K. A. Perry

"Highwall miners have been widely used to extract additional coal reserves from existing surface operations, particularly on contour operations in the Appalachian coalfields. Using a continuous miner cutting head, coal may be extracted from significant depths (such as 150 m), leaving behind an array of web and barrier pillars with the purpose of maintaining highwall stability. This method inherently involves elevated risks to both equipment and personnel due to proximity to and increased exposure time near highwalls. As a result, modern operations should actively design web and barrier pillars to maximize extraction while providing adequate stability. The ARMPS-HWM software, an empirical-based program created for the design of web and barrier pillars at highwall mining operations, is one such approach. The calculated stability factor is compared with empirically established guidelines produced from examining case histories.The ARMPS-HWM program is a handy tool for initial design, but understanding the site’s structurally significant geologic features and geomechanical behavior is important and may potentially increase extraction. We created a two-dimensional numerical model using FLAC3D and calibrated it to ensure pillar strength, closely following the Mark- Bieniawski formula for a typical range of pillar geometries and overburden properties. The development of pillar stresses along a highwall panel was then numerically investigated as mining progressed, and the stress distribution between barrier pillars was found to be asymmetric, which can result in an over-design of the closeout web pillars if tributary area loading is assumed. Finally, the importance of adequate barrier pillar stability is highlighted."

Jan 1, 2014

By R. D. Williams

In spite of the increasingly polarized and politicized view of climate science and climate change in the United States, many of the principles behind the ?theory? of Anthropogenic Global Warming (AGW) or Global Climate Change (GCC) are in fact firmly established both in fundamental physics and detailed observations and are widely accepted elsewhere. The discovery of the earth?s ?greenhouse effect? dates back nearly 200 years to the work of French mathematician and physicist Joseph Fourier in 1824 and 1827. In 1872, John Tyndall an English physicist and mountaineer, described the capacity of various gasses to absorb radiant heat. He identified water vapor and carbon dioxide as the principal ?greenhouse? gasses. The work of Fourier and Tyndall was the foundation for the theory that increasing carbon dioxide (CO2) in the atmosphere might be responsible for an increase in global temperatures developed by the brilliant Swedish chemist Svante August Arrhenius in 1896. This was backed up by the additional work of Gilbert Callendar in the 1930s, and Gilbert Plass, Hans Suess and Roger Revelle in the 1950s. There is little scientific dispute about the physics by which this occurs: carbon dioxide in the atmosphere absorbs long wave radiation that would otherwise escape into space, thus warming the lower atmosphere and respective temperatures worldwide. The Intergovernmental Panel on Climate Change (IPCC), approximately 2500 climate scientists from around the world, has concluded that increases in carbon dioxide resulting principally from the burning of fossil fuels are responsible for most of the continuing increases in global temperatures (IPCC, 2007). NASA?s Goddard Institute for Space Studies (GISS) states; ?The ten warmest years all occur within the 12-year period 1997-2008? (GISS, 2009). 2009 was the second warmest year on record and 2010 was tied with 2005 for the warmest year on record (GISS, 2010, 2011). The science is in fact settled; the earth has not cooled since 1998 as some have claimed. It continues to warm as evidenced by not only surface temperature records but also ocean temperature records as well as changes in physical and biological systems (IPCC, 2007).

Feb 27, 2013

By W. Dan Hausel

More than 220,000 diamonds have been found in the United States that range from microdiamonds to 40.42 carats in weight (Table 1). Some reports suggest diamonds weighing more than 100 carats have also been found in this country, although these reports have not been verified. The source of most of the diamonds in the United States is a group of kimberlite pipes, dikes and blows in the Colorado-Wyoming State Line district and a group of lamproite pipes in the Murfreesburo, AR area. Other areas where diamonds have been found include the Great Lakes region, the Pacific Coast and the southern Appalachian Mountains. The latter two regions are generally not considered favorable for diamond deposits. This is based on exploration models. They suggest commercial diamond deposits will be restricted to kimberlites emplaced in Archean cratons and to lamproites emplaced in Proterozoic mobile belts accreted to the cratons.

Jan 1, 1995

By K. N. Panigrahi

India bestowed with 6000km of the coastal belt, contains some of the richest and largest placer deposits with a mixture of heavy minerals like ilmenite, rutile, leucoxene, zircon, monazite, sillimanite and garnet. Each of the minerals is having economic value due to its inherent characteristics for industrial use in fields of paints, metallurgy, refractory, abrasive and so on. The reserves of titanium bearing minerals (ilmenite, leucoxene, and rutile) in the country is around 378 million tonnes. More than 90% of the titanium based minerals produced worldwide are utilised for making value added products in the pigment industries. Approximately 8 million tonnes of monazite reserves are available in the country from which several rare earth elements like cerium, neodymium, lanthanum, yttrium etc. can be extracted for use in several industries. The country contains a deposit of about 20 million tonnes of zircon, which is used in foundries, refractories, ceramics and chemicals. India has a reserve of 107 million tonnes of garnet and 131 million tonnes of sillimanite required for the abrasive and refractory industries respectively. Keeping in view the multifarious uses, the beach sand minerals are being exploited to have the economic growth of the nation. Although the process adopted for the separations are simple, the equipment involved are specially designed because of the nature of the material of construction. Starting from the spirals to magnetic separators, all equipments are manufactured outside India, which is not only costly, but the availability also takes much time for fulfilling the import formalities. Unlike open cast mining, beach sand mining is a environment friendly mining because dredging is implemented to cut and pump the loose sand through a slurry pump causing less damage to the surface topography as both mining and backfilling takes place simultaneously. Therefore all out efforts are made to explore the beach sand placer deposits in an economic manner to emerge as a leader in the global mineral industries.

Jan 1, 2005

By R. A. Franks

An evaluation of a nuisance-emissions-discriminating smart mine fire sensor system was made in an operating coal mine. These field evaluations were conducted to determine the sensor system?s ability to discern nuisance emissions, such as diesel exhaust, emissions from flame cutting and welding operations or hydrogen gas from a charging station, from real fires and to compare the number of falsely reported fire alarms generated between the sensor system and a standard carbon monoxide (CO) monitor. The sensor system?s ability to operate successfully in the working environment of an operating coal mine was also evaluated. The smart mine fire sensor system consisted of four sensors whose data outputs were fused with the use of a neural-network-type computer program. Long-term trials were conducted in a haulage way, a belt entry, and a track entry. The system functioned successfully in the belt entry, in accordance with its developmental goals, where the sensor system even discriminated events not anticipated during development. It was not totally effective in the haulage way and track entry, though, due to a combination of significant diurnal air temperature variations, dust, and mechanically induced vibrations. Also, deteriorating rib conditions contributed to operational problems in the haulage way evaluation. In general, the smart mine fire sensor provided nuisance emissions discrimination and was shown to be a viable new approach for mine atmospheric monitoring, enhancing miner safety. This paper describes the in-mine evaluation of the smart mine fire sensor system and discusses recommendations for improving the system. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2008

By Jim Owens

The methodology of quarrying changed significantly in the Indiana limestone industry in the 60 years between Sept. 11, 1941 and Sept. 11, 2001. The former was the date of the Pentagon groundbreaking ceremony, while the latter was when the building was damaged by American Airlines Flight 77. So too, though to a lesser degree, did the machinery and methods used to fabricate the stone. The rededication ceremony on Sept. 11, 2002 marked the end of the Phoenix Project, as the rebuilding effort was named. The story of this remarkable project illustrates what the American construction(and Indiana limestone) industry can accomplish when working toward a common goal.

Jan 1, 2005

By Paul M. Godlewski, Joseph P. Gildner, David S. McAllister

With construction underway on the 22.5 km (14 mile) Initial Segment of the Link Light Rail transit system in Seattle (including the one-mile EPB-driven running tunnels and mined station at Beacon Hill), the Sound Transit Board on May 20, 2004 voted on selection of a preferred route for an approximately eight-mile extension northwards from the central business district to Northgate, and authorized immediate start of advanced conceptual/preliminary engineering and geotechnical exploration programs scheduled to be completed in Spring 2005. The extension includes approximately914 m (30,000) route-feet of bored running tunnels, a mined station with platform level approximately 60 m (200 ft) below grade, three (possibly four) cut-and-cover stations and a cut-and-cover cross-over structure, as well as an aerial terminal station at Northgate and other line-section below-grade and aerial structures. All tunneling will be in glacial soils.

Jan 1, 2005

By Adrian Coombs

The York Durham Sewage System (YDSS) Interceptor Tunnel Project is located in the Town of Richmond Hill, Ontario, Canada, just north of Toronto. Construction commenced in September 2006 and completion is planned for early summer, 2008. The project involved public and agency buy-in of construction technologies and methods that minimized dewatering, design and construction of sealed shafts with jet grout break-in and out blocks in order that Earth Pressure Balance (EPB) mode could be maintained by the Tunnel Boring Machine (TBM) during shaft entry and exit. This paper will discuss the advances that were made possible through the opportunity to apply and test these technologies in order to accommodate the aquifer and artesian conditions present on this project.

Jan 1, 2008

By S. Culp, P. Metcalfe

Web technologies and the Internet have revolutionized the computer industry. The Web browser technologies have also moved to portable devices such as Personal Digital Assistants (PDAs) and mobile phones. This paper looks at how to implement a Web Server solution and addresses some of the inherent advantages in the technology. It will also look at some examples of how plant productivity can be managed with a Web Server approach.

Jan 1, 2002

By Enrique Fernandez

M-30, Madrid’s inner ring, covers 42 sq km of the city centre where one million people reside. It was constructed in several phases during the sixties and the eighties. The design criteria applied to those phases were different and were not always homogeneous with urban roads with lighting regulation as well as speedways. These areas had a heavy concentration of access and exits and there had been made many changes on the number of traffic lanes which has caused heavy traffic congestions and high accident rates. The environmental impact and noise pollution in residential areas are also consequences of M-30. The Madrid Major took a decision at the beginning of the present legislation, based on socio economic and environmental evaluation; rebuild the M-30 with the following sustainable mobility principles: Underground transfer of a considerable portion of the main ring and some of its links replacing some parts of the surface with new green areas in order to reduce the environmental impact. Increase the traffic capacity, improving the traffic continuity and fluidity and eliminating the lighting regulation areas, which is one of the main congestion problems currently. Increase the traffic safety with clear signalling information panels and avoiding difficult maneuvering. Redesign the links with the high capacity radial highways and other connecting lanes of the city. The project is worth 3.7 billion Euros. In 2007, when the construction is completed, it is expected will save 14 million of journey hours that represent 4.5 million Euros saved in fuel consumption per annum, There will be a very significant reduction of 35,000 tons of CO2 in terms of pollution and 400 less car accidents. Those values will increase even more in the following years. The areas beside Manzanares River, running parallel to the M-30 on the western side of Madrid, will be highly enhanced. Better water quality and the recovering of the green areas existing in old times will also return for the citizen’s enjoyment. TUNNEL CROSS SECTION OF CALLE 30 SOUTH BY PASS One of the major challenges of the new Calle 30 is actually not only the related to the main road but also to the link with the A-3, with highway to Valencia. This link is currently the most congested area and has one of the highest traffic densities of Spanish roads, with more than 250,000 vehicles/day. The remodelling of this area is the principle objective of the South by-pass. The tunnel is the only answer for this by-pass as the road alignment will go among buildings. A twin tube design, one for each direction, with three lanes allowing the circulation of both, light cars and heavy trucks, is the solution that has been

Jan 1, 2007