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By Timothy P. Smirnoff, Anthony Stirbys, Amanda Elioff

The construction of the continuing expansion of the Los Angeles Metro System has required the construction of eight new station structures. One contractor proposed, as a construction alternative for the support of excavation of the Hollywood/Vine Station, the use of soil-mix walls instead of the conventional soldier piles and wood lagging. Soldier piles and shotcrete or wood lagging support systems had been generally used on the other sub-way station excavations constructed to date throughout the system. Immediately east of that station and in almost exactly the same geology, the Hollywood/Western Station was being excavated at the same time using a conventional support system. This paper com-pares the performance of these two support systems in the alluvial soils of the Los Angeles Basin.

Jan 1, 1997

By Harry R. Price, Behrooz Tahmasbi, Charles J. Roarty

The 2,408 meter (7,900-foot) long Middle Rouge Parkway Interceptor Extension varies in size from 1.52-meter (5-foot) to 2.36 meter (7-foot 9-inch) inside diameter. Most of the sewer was constructed in tunnel through fine sands and silts. Piping of these soils through the concrete liner eventually resulted in a loss of soil support, settlement and/or severe distress of the sewer, and the formation of several sinkholes. The repair and restoration was generally performed in the sewer and included cast-in-place concrete, shotcrete, cured in place pipe, soil stabilization, cement grouting, dewatering, and chemical grouting. As a part of the work, temporary pump stations and flow diversions were required to perform the work while minimizing discharges to the adjacent Rouge River.

Jan 1, 2007

By C. Özgen Karacan

The formation of the gas emission zone in longwall mining and the potential amount of gas in this zone are factors of local geology and spatial variability within this geology. Therefore, geostatistical methods can be used for modeling and prediction of gas amounts and for assessing its uncertainty in the gas emission zone of longwall mines. This study used core data obtained from 64 exploration boreholes drilled from the surface to the bottom of the Pittsburgh coal seam in a mining district in the Northern Appalachian basin. After identifying important coal layers for the gas emission zone, semivariogram modeling was conducted for different coal seams to define the distribution and continuity of various attributes. Sequential simulations were performed for stochastic assessment of these attributes to calculate gas-in-place (GIP) in each coal seam. GIP calculations for coals of various gas emissions zones were combined and ranked for their cumulative distribution function to find GIP in the caved zone and in the fractured zone at the 5%, 50%, and 95% quantiles. Fifty percent quantile results were later used to isolate a panel from the whole area and create a mosaic representation corresponding to the daily advance rate of the longwall face. This approach helped to estimate the daily emissions of this panel from the caved zone and from the fractured zone. Results showed that gas-in-place in the Pittsburgh coal seam, in the caved zone, and in the fractured zone showed spatial correlations that could be modeled and estimated using geostatistical methods. This study showed that gas-in- place volumes in the study area may be as high as 12.3 Bscf and as much as 3.5 MMscf per acre of mining.

Jan 1, 2012

In September 2003, a test was conducted to see if a115-mm- (4.5-in.-) diam Mocap Vari-Stem blasthole plug could improve the pattern of explosives using different top stemming material. The test took place at the J.S. Faulkroad and Sonsstone quarry in McCalisterville, PA. The test consisted of a production stone blast. Half of the holes were stemmed with standard crushed stone. Two-thirds of the remaining half were stemmed with Vari-Stem plugs and crushed stone. And the remaining one-third of the second 50 percent was stemmed with Vari-Stem plugs and only drill cuttings.

Jan 1, 2004

By Gui DeReamer

Located on the Wabash River in the central portion of the state, the city of Lafayette, IN is relatively small compared to most cit-ies that incorporate tunnels into their combined sewer overflow (CSO) systems. The original CSO plan for the city was to replace two aging lift stations that were built in the 1950s. The original con-cept was to build a new sewer using conventional cut-and-cover construction to eliminate one of the lift stations ? the Parking Lot Lift Station ? and build a new regionalized one at the location of the Pearl River Lift Station. The initial sewer design was sized just to handle the flow that would eliminate the Parking Lot Lift Station. The planning for this project was being developed as part of the city?s CSO long-term control plan (LTCP) that focused on reducing the overflows from the city?s 14 overflow points. However, during the development of the CSO LTCP, a major industrial user indicated it would be increasing its flows to the system, which required additional conveyance capacity to meet the city?s CSO LTCP. After reviewing the design concepts with city representatives during the planning phase of the project, the mayor indicated that he wanted to minimize impacts to downtown businesses; therefore, trenchless alternatives were considered. The last piece of the puzzle that drove the project away from a small diameter pipeline was discovered during a flow monitoring program to collect flow data for the CSO LTCP project. This study revealed a major restriction in the 100-year-old Pearl River Trunk Sewer, located beneath four active railroad tracks. To eliminate this flow restriction, provide more overflow storage and reduce the impact to local businesses, a new 2.7- to 3.6-m- (9- to 12-ft-) diameter tunnel sewer became the most viable solution.

Jan 1, 2011

Editor’s note: As usual, the June issue features an industrial minerals review. And some thanks are in order. Thank you to the industrial minerals annual-review editor, to the technical committees chair and vice chairs and to the authors of the individual commodity profiles. Jim Norman of GeoTrans Inc. is the industrial minerals annual-review editor. William Langer, U.S. Geological Survey, is the chair of the SME industrial minerals technical committees and the vice chair of the technical committee for construction materials. Other technical committee vice chairs include: •Lucy McCartan, U.S. Geological Survey, agricultural minerals. •Steve Herron, Oglebay Norton Performance Minerals, ceramics and refractory materials. •Srinivas Veeramasuneni, U.S. Gypsum, chemical raw materials. •Ismail Yildirim, Imerys, fillers and pigments. •Charles Landis, BPM Minerals, sorbents, filters and process aids. •Ray Harris, Wyoming Geological Survey, specialty minerals. Their help makes possible this June industrial minerals issue. On behalf of the readers, the editors thank them

Jan 1, 2004

By A. Johnson

When are SMART transmitters the smartest choice? To answer this question requires a closer look at SMART transmitter technology. It is necessary to understand this technology in order to recognize how it can best be utilized to give the greatest value for the application. And, once the decision to buy transmitters has been made, it becomes a question of whose SMART transmitter to buy. For, although the under-lying technology is similar, the differences that exist in how the technology has been implemented can make a dramatic difference in the end result. What prudent users of SMART technology do is to analyze their needs by application before making their buying decision.

Jan 1, 1988

By Nick Barton

A recent analysis of 145 TBM tunnels of more than 1000km total length has helped to quantify the time dependence of utilization (U). In fact U = Tm, where T is time in hours and m is a negative gradient of deceleration. In poor quality ground, gradient m has a strong dependence on rock mass quality Q, for example m ˜ -0.5when Q = 0.1. Good investigation is critical for ensuring faster TBM tunneling then drill-and-blasting, which tends not to slow down (in m/hr) as the tunnel length increases. Anew design model called QTBM allows more reliable prognoses be made, and occasionally will disqualify the TBM solution.

Jan 1, 2001

By E. Krist

The newest addition to the Anamax Mining Company's Twin Buttes copper producing complex is a by-product uranium extraction plant which was placed into service in February 1980. The plant is unusual in that it is placed internal to the copper countercurrent decantation, solvent extraction, and electrowinning plant. The plant reached full production within a month and, to date, has produced continually above design rates.

Jan 1, 1981

By William H. Eatock

The Saskatchewan ore zone strikes slightly south of East, from the Alberta border to Manitoba; and dips to the South. The conventional mines are located along a broad strike line from Saskatoon to Esterhazy-Rocanville. Nine conventional mines have developed ore bodies at a nominal depth of 915 metres (3000 ft.). One mine had developed an ore body at 1525 metres (5000 ft.) by solution mining. Mining reserves of 100 years are not unusual in this vast ore body. Most of the mines were brought on stream during the 1960s. All the conventional mines were influenced by practices developed at Carlsbad, N.M. By 1970, the industry was faced with serious over-capacity resulting in the cancellation of some projects and the introduction, by the provincial government, of the Potash Pro-rationing Regulations designed to share the available market amongst all the producers. This resulted in production rates as low as 40% of capacity. As a result, the 1970s were characterized by attempts to reduce cost, rather than improve production or processing techniques. In recent years, the plants have all been brought to full capacity, and are currently involved in a massive program of expansion, which promises a period of advancing technology.

Jan 1, 1980

By F. Calizaya

The Western Mining Training and Translation Center is a consortium of four universities devoted to developing educational and training projects to reduce the incidence/accident rates in the mining industry. The center consists of Missouri University of Science and Technology, Montana Tech, the Colorado School of Mines and the University of Utah. It is fully funded by the National Institute for Occupational Safety and Health (NIOSH). The center manages 15 educational projects and one translation project. Hazard Identification and Risk Assessment (HIRA) for Small Mines is an educational project managed by the University of Utah. The objectives of this project are to identify critical mine hazards, assess risks; outline procedures to reduce accident/incident rates in small mines in the western United States and to train mine workers and super-visors on HIRA in each participating mine. To accomplish these objectives, the HIRA personnel visited 15 small mines in Utah, Colorado, Nevada and California. At these mines, most operators were employing independent contractors to perform several tasks ranging from drilling, blasting and mucking of rock at the work site to hauling ore to a processing plant. The operation of diesel-powered equipment was one of the major tasks performed by the contractors. This article presents three case studies in which contract workers performed a number of tasks with no reportable incidents but did so unsafely. It also highlights the training received by most contractors, the constraints imposed upon them and the safety hazards to which they are exposed most frequently.

Jan 1, 2008

Even though the economy of the United States remains in recession ? or not, depending on which economist you listen to ? muicipalities still need improved transportation, water and wastewater transit systems. And they are willing to spend the necessary funds on those systems, provided they are affordable, environ-mentally friendly and sustainable. From June 20-23, professionals in the tunneling and underground construction industry from around the world gathered in Portland, OR to learn new ways of providing those systems using the latest technology available. The North American Tunneling (NAT) conference attracted 803 attendees and 108 exhibiting suppliers of equipment and services.

Jan 1, 2010

By Christopher J. Bambridge, Lee Seng Hoor

The Stormwater Management and Road Tunnel (SMART) Tunnel is a world first in the use of tunnel space transmitting both road and water through the same spatial envelope. The unique aspect of the SMART project is that the highway decks are used periodically for the conveyance of water. This aspect of the project has posed its own technical challenges that have been overcome in the design stage of the work allowing the project to be taken forward to construction with confidence in the systems to be Installed in the tunnel.

Jan 1, 2005

By Edward A. Nowatzki

The purpose of this paper is to present an example of the application of a theoretically derived mathematical model for track-soil interaction to the evaluation of the mobility of large-scale mining equipment used in open pit operations. The model described by Karafiath and Nowatzki (1978) and presented in detail by Karafiath (1978) was used to predict the performance characteristics of four different bucket wheel excavators (BWEs) on rwo types of copper mill tailings at various moisture conditions. The BWEs considered In the analyses are two-and three-tracked continuous excavators. Most have boom-mounted rotating buckets and swinging side- or rear-discharge conveyors. The analyses were performed at the request of Dames and Moore for the Kennecott Corporation's proposed remining of selected tailings deposits at the McGill, Nevada, concentrator. The objectives of the analyses were to determine whether BWEs would have sufficient mobility In the tailings deposit to achieve satisfactory production rates, and TO compare the predicted performance of the various BWEs evaluated. Good qualitative agreement was obtained between the results of the theoretical analyses performed for the McGil1 operation and the actual performance of BWEs in two South African gold mine tailings impoundments.

Jan 1, 1980

By Marco Sonnenschein

As time is costly, engineering companies have developed methods, procedures and mechanical equipment to tunnel faster. But the best excavation method will not be able to cope with the time pressure if there is not a reliable backup system. Therefore, the application of belt conveyors for tunnel boring machine (TBM) drives as well as for drill-and-blast driven tunnels assure a quick and smooth removal of excavated soil in order to enhance the efficiency of the tunneling equipment. During the last 10 years, belt conveyor systems have achieved ?state-of-the-art? levels and have become the first choice for muck removal systems in both TBM and drill-and-blast driven tunnels. Because time has become such a key criterion in tunneling projects, it is essential that all equipment is operated so as to derive optimum efficiency and minimize costs. Efficiency also means to think about new tasks for existing technologies.

Jan 1, 2012

By J. G. Pippenger

Rio Tinto Coal Australia (RTCA) developed the Meandu Mine in Queensland, Australia in 1983 to supply thermal coal to the adjacent and newly constructed Tarong Power Station (TPS). In designing the mine, RTCA selected Meandu?s best economic reserves for a 27-year life based on station owner Tarong Energy Corp.?s (TECs) estimated life for TPS. That 27-year plan changed dramatically in the early 2000s when TEC approved life extensions to TPS?s four existing units plus construction of a fifth unit. After reviewing Meandu?s remaining reserves, RTCA decided the nearby Kunioon reserve offered the more economic option for maintaining deliveries beyond 2010. Those plans changed again in 2007 when TEC chose to purchase the Meandu Mine and nearby reserves. TEC then selected Thiess Pty Ltd. (Thiess) to continue operating Meandu until the new mine at Kunioon could be developed. After assuming operation of the mine in 2008, Thiess began a review of Meandu?s remaining reserves and found considerable coal available with economic potential. Working jointly with TEC, Thiess performed several analyses on Meandu and subsequently the Kunioon coal reserves. The results changed TEC?s decision from expediting Kunioon?s construction to instead continuing Meandu?s operation for up to 15 additional years.

Jan 1, 2011

By T. Hudaverdi

Control of the particle size distribution of a muckpile after blasting is always an important subject for mining industry. Blasting has a significant impact on downstream processes such as loading, crushing and grinding. Improvement of blasting results provides increase in loader and excavator productivity due to increased diggability capacity, and increased bucket and truck fill factors. Suitable and uniform particle size distribution results increase in crusher and mill throughput and decrease in energy consumption in size reduction process. Digital image analysis technique has been used for many years in mining industry in order to determine blast fragmentation. The images of muckpile surface can be used to determine the mean fragment size (x50). The source of digital images can also be haul truck, leach pile, waste dump, stockpile, and conveyor belt. The screening that is conventional method to measure blast fragmentation is time consuming and expensive. Digital image analysis is a cost effective and faster method (1).

Jan 1, 2012

The National Institute for Occupational Safety and Health (NIOSH) conducted a study to determine the effectiveness of a filtered air delivery system to reduce respirable dust exposure to roof bolter operators in underground coal mines. When performing roof bolting operations, roof bolter operators may experience exposure to high levels of respirable dust during a working shift, especially when working downwind of the continuous mining machine. While drilling and installing roof bolts, this filtered air system supplies a clean curtain of air over the roof bolter operator by means of a plenum mounted beneath the canopy. This experimentally designed air curtain, adapted for roof bolting machines used in this study, is based upon previous design prototypes, computational fluid dynamics (CFD) simulations, and trial-and-error testing. Both prototype and final designs were tested in the full-scale mining galleries at the Office of Mine Safety and Health Research (OMSHR) in Pittsburgh before being taken underground for field testing. Test results of the system in both laboratory and field studies show reductions in operator exposure to respirable dust when the operator is positioned directly under the protected zone of the canopy.

Jan 1, 2012

By D. Kozelj

Introduction The porphyry copper deposit “Borska Reka” is the biggest undeveloped deposit in the Timok Magmatic Complex (TMC). Total reserve calculated manually is 611 Mt (cut-off grade 0.3% Cu) of 0.62% Cu, 0.21 g/t Au and 1.81 g/t Ag and 869 Mt of 0.58% Cu, 0.14 g/t Au and 1.11 g/t Ag using software. But since several deep drill holes are suspended in high grade (0.7% Cu) porphyry, total reserves could exceed 1Gt. The massive sulfide is also detected in the central (12 m at 4% Cu) and the bottom of porphyry style. Deposit was discovered during geologic exploration of deeper part of the Bor copper and gold deposit, i.e. area of high sulfidation with dominant massive sulfides. During exploitation of massive sulfide, constant explorations were carried out aimed at the expansion of reserve and discovery of new ore bodies. In that way, porphyry copper mineralization was discovered without knowing in the beginning that it was different mineralization type in regard to the ones that had been already identified and exploited. Vertical extension of porphyry is 0 m up to -1000 m sea level and not contoured along plunge. In the very beginning (1976), the exploration was focused on the shallow part of porphyry. That is because block caving method of massive underground mining was not developed at that time. Up to 1999, most of activity was related to underground exploration up to level -395 m. Geographic position The Bor deposit is located close to the industrial and University town Bor, which has over 50,000 inhabitants (census made in the year 2002). Apart from the Bor Mines, industrial complex of Mining & Smelting Basin Bor (RTB) comprises also a copper smelter (installed capacity up to 160,000 tons of blister copper) and tank house, copper wire factory, copper tube factory etc. Currently, RTB Bor is under privatization process that is going to be completed by the end of 2006. Up to date, over 20 companies have bought tender documentation.

Jan 1, 2007

By Martin Stone

Industrialized countries, particularly the United States and the United Kingdom, remain at the forefront of international efforts to control the potential disruption from computer malfunctions caused by the date change from1999 to 2000 — widely known as the millennium bug or Y2K. Disruption is least likely in the developed world, including the United States, Canada, western Europe, Japan and Australasia. However, the picture is potentially different in developing countries where many mining companies operate. The less developed the country, the greater the chance of some form of Y2K-linked disruption.

Jan 1, 1999