Search Documents

By William R. Yernberg

The Fifth International Conference on acid rock drainage (ICARD 2000) was held May 21-24, 2000, in Denver, CO. The three-day conference consisted of about 150 oral presentations and poster sessions that described the state-of-the-art of acid-rock-drainage (ARD) science and technology. The conference also featured a trade show. It included representatives from consulting companies and government agencies with interests in ARD, as well as other environmental issues related to mining. The conference also included field trips to ARD treatment sites and short courses on acid rock drainage issues. ICARD 2000 was planned and promoted by the ICARD 2000 Organizing Committee and the Society for Mining, Metallurgy, and Exploration, Inc. (SME). Financial support was provided by Barrick Gold, BHP Copper, Homestake Mining, Noranda, Phelps Dodge, PlacerDome, the US Bureau of Land Management, the USEnvironmental Protection Agency and the US Geological Survey. Since the original ICARD was held in Roros, Norway, in 1988, knowledge has improved of the behavior of mine wastes as have methods of environmental mitigation. The ICARD 2000 presented the latest advancements in the field of acid drainage.

Jan 1, 2000

By J. Drelich, C. L. White, Ch. Zhou, W. M. Cross, E. T. Zellers, E. M. Nadorny

A laser-based particle deposition (LBPD) technique has recently been developed at Michigan Technological University for patterning mesostructures made of nanoparticles and their clusters. The LBPD technique makes use of laser induced optical forces to transport and pattern nanoparticles on a variety of conductive and non-conductive substrates from nanoparticle-in-liquid suspension. A weakly focused laser beam is used to confine and propel particles along the laser beam. Confinement is accomplished by forces due to optical field gradients that act on polarizable particles and tend to move them to axis of the laser beam. The force propelling the particles along the direction of the laser beam arise from momentum conservation of photons scattered from the particles. In this paper, this novel LBPD technology is briefly reviewed, and several examples of patterning are presented. The size and morphology of mesostrips produced from gold and polystyrene nanoparticles, under a range of deposition conditions, have been characterized by optical microscopy, atomic force microscopy, and scanning electron microscopy. The results presented here demonstrate that gold and polystyrene nanoparticles deposited by LBPD can form clusters of particles. When deposited at an appropriate rate, such clusters can form multilayer mesostrips of high particle density. One goal of research on such systems is to fabricate arrays of parallel lines made up of colloidal particles having a range of surface functionalities. Such arrays have potential for application as novel microsensors for environmental sensors.

Jan 1, 2003

By Vinícius Resende Domingues, André Pacheco de Assis, Bernardo Cascão Pires e Albuquerque

"The increasing demand for underground works in urban centers, and in particular the need to build undercrossing tunnels, requires constant evolution in building techniques in order to achieve success and safety. In the case of Brasilia, capital of Brazil, in order to preserve an important avenue (Eixo Monumental), where are located many historical monuments, the construction of a tunnel was envisioned as an option to interconnect the National Stadium (on one side of the avenue) to the Convention Center Ulysses Guimarães (on the other side). The excavation design is comprised of a coverage smaller than one diameter, height of 7.5 m, width of 9.0 m and length of 25 m. In order to enable a negligible influence on the avenue’s usage, the structure is designed as a portico system composed of pipe canopy. In this context, this study presents the portico analytical solution computed with the aid of the software Mathematica and a numerical solution using the software ABAQUS. INTRODUCTION Undercrossing tunnels are increasingly common in urban centers as alternative roads or as access to underground works of large dimensions (stations and parking lots). The geomechanical conditions of the soil mass, not always favorable, and the low distance between tunnel’s ceiling and the surface require intense treatment of the soil massif and execution of a rigid support system. The importance of the road just above the undercrossing tunnel emphasizes the need for a highly competent monitoring system because existing structures require minimum allowable displacement and do not allow the interruption of traffic. The soils that are excavated for the construction of undercrossing tunnels are composed, in most cases, of layers of fill and / or soft soil or weak rock, showing stability problems when subjected to tunneling operations. The combination of low coverage and week ground is solved by soil improvement techniques and strengthening of the excavated cross-section with further advance with the so-called New Austrian Tunneling Method (NATM). Another option is to build structural frames that support the surface. In this research, and based on the context of a case study, we propose the study of the construction technique comprising a portico structure composed of pipe canopy. For this paper, the technical standards used are the Brazilian ones as the case study refers to this country."

Jan 1, 2016

By William Brundan

INTRODUCTION The Srisailam Left Bank Canal (SLBC) Tunnel Scheme is part of the Alimineti Madhava Reddy Project in Andhra Pradesh, South India. This scheme has been planned since 1983 and will provide irrigation facilities to drought-ridden areas in Andhra Pradesh. Water will be transferred from the Srisailam Reservoir during the monsoon months to 0.3 million acres of farmland and will also provide drinking water to villages en-route. The paper will address the design and onsite assembly of the Robbins Double Shield TBMs for Tunnel-1 of the SLBC tunnel scheme from planning to start-up of the machines. Also, it will provide a current status of the project and describe the advantages of a site assembly. Problems encountered to date and the solutions adopted will also be described. The project comprises over 50 km of tunnels and involves construction of the world?s longest tunnel without intermediate access. The TBM tunnels at 43.9 km in length and 10.0 m diameter will cross the Amrabad plateau, containing a wild life sanctuary and India?s largest tiger reserve, the Rajiv Gandhi. Jaiprakash elected to excavate the tunnel using two tunnel boring machines, rather than by drill and blast, in order to alleviate surface disturbances to environment and the tiger reserve, wild life sanctuary, and protected forestry areas. The Project was awarded to the Main Contractor Jaiprakash Associates Ltd with The Robbins Company as the Tunnel Boring Machine (TBM) supplier in August 2005. The Robbins Company supplied the TBMs along with two continuous conveyor systems and all spares and consumables to complete the tunnel excavation.

By Larry F. Drolet

Charleston, SC is anything but boring. The city was founded in 1670 and has played a significant role throughout the history of the United States. Located along the coast of the Atlantic Ocean in the southeastern United States, Charleston was a vital city in America?s early existence. Charleston?s coastal location has helped the city become the fourth largest cargo port in the United States and earn the 2011 designation as the number one travel destination in the United States by the Conde Nast Traveler Magazine. Part of Charleston?s charm and beauty can be attributed to its historic structures and churches that line nearly every sidewalk, roadways that were laid out based on the width of horse carriages, great weather, southern hospitality and coastal living. Now imagine the challenges of installing new, or re-placing aging infrastructure, in this setting. Every shovel full of dirt, every stick of pipe and every roadway sub-surface has its own historic story to tell. For engineering minded individuals, Charleston?s infrastructure has almost as fascinating a history as its more visible surface structures. Charleston was among one of the first American cities to construct separate sanitary and storm water drainage infrastructure. This concept has roots dating back to the city?s founding and is a credit to the foresight of its founding fathers who understood the basic health differences between sanitary and storm water.

Jan 1, 2013

By J. H. Rowland

The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) amended the Federal Mine Safety and Health Act of 1977 to improve the safety of mines. The MINER Act established a Technical Study Panel (the Panel) to provide independent scientific and engineering review and recommendations with respect to the utilization of belt air and the composition and fire retardant materials in underground coal mining (1). Because frictional heating is a common cause of belt fires, the Panel recommended that the Mine Safety and Health Administration (MSHA) evaluate the drum friction test to determine if such a test would contribute to conveyor belt safety beyond that provided by the Belt Evaluation Laboratory Test (BELT). This paper compares the results of the drum friction test to results from the BELT and large-scale tests for six different conveyor belts. The results are used to evaluate the drum friction test as a method to determine the fire resistance of conveyor belts.

Jan 1, 2011

By M. Perolo, A. Contini, E. Ramelli, G. Borgonovo, L. Locatelli

This paper presents the ground settlement monitoring system used during the construction of two tunnels bored by two EPB TBMs, beneath the existing and active railway embankment in Bologna (Italy). The tunnels run close to large buildings and beneath bridges and other infrastructure. Data are collected from remote total stations and from electro levels installed directly on the railway tracks. The automated monitoring system acquires and analyses data then sounds an alarm in the event that there is a problem. Alarms are sent out in case of excessive tilt or settlement. Data is provided through a dedicated web application for multiple-party access, to gather, manage and store monitoring data.

Jan 1, 2007

By Michael J. Lehnen

Slurry diaphragm walls are commonly used as both temporary excavation support walls, and permanent structural walls, for circular shafts and long rectangular structures (such as underground subway stations); however, they are not commonly used for more compact rectangular or square shafts. In these instances, a second wall is typically cast inside the slurry walls to form the permanent structure. This paper discusses the approach used on the Silicon Valley Rapid Transit Project in California to analyze these compact rectangular types of structures for static and seismic loading, and to determine whether or not slurry walls can be confidently used as both the temporary and permanent walls for two tunnel ventilation shafts.

By Todd Grounds, William R. Reed, VASU GANGRADE, Michael Shahan, Garron Ross, Kunal Singh

Roof bolter canopy air curtains (CACs) are gaining acceptance as a respirable dust control device that can provide roof bolter operators with protection from overexposure to respirable coal mine dust. Both lab and field studies on the effectiveness of roof bolter CACs have been published. Field studies have shown the effectiveness to be variable. However, in all previous field studies, none has been conducted when the roof bolting machine operates downwind of the continuous miner (CM)—a scenario for which the CAC was designed to provide respirable dust control. This study, performed by researchers from the National Institute for Occupational Safety and Health (NIOSH), was conducted to test a CAC on a roof bolter machine operating downwind of the CM. The results of testing demonstrated that the roof bolter CAC can effectively provide respirable dust protection for roof bolter operators with dust control efficiencies ranging from 11 to 40%.

Oct 14, 2020

By D. Olsen, S. Cole, J. Strid, G. Colzani

This paper focuses on the underground tunnel work at the Hollywood Water Quality Improvement Project (HWQIP) in Los Angeles, CA. The HWQIP is being constructed to provide a water distribution system to bypass the existing Hollywood Reservoir System, which supplies drinking water for 500,000 people. The major project features include, a 2.9-meter diameter 1,829 meter long bypass tunnel, a 1.8-meterdiameter 366 meter long utility tunnel, 3 jack and bore tunnels, two 136 million liters underground circumferentially wrapped pre-stressed concrete water storage tanks, associated piping, and mechanical facilities. The physical project location coupled with strong community involvement and stringent environmental concerns was a considerable driving force for this project located in the Cahuenga Pass area of the Hollywood Hills north of Los Angeles, CA.

Jan 1, 2001

By W. Hustrulid

In the mid-to-late 1800’s the U.S. mining industry was on the threshold of nearly a century of golden times. Nearly every state had a prosperous and growing mining sector. The importance of the industry was reflected in the creation of the state school of mines. Today, with the depletion of readily available mineral reserves, much of the U.S. metals mining industry is considered to be in a sunset phase. The same is true with the mining schools that serve the industry. However, the United States is still a major consumer of the world’s minerals and requires a dependable supply of both minerals and minerals professionals. In his 2002 Jackling Lecture “You Can’t Make a Silk Purse Out of a Sow’s Ear” the author presented a list of concerns, propositions and recommendations. In this follow-up paper, the author further explores the subject through the presentation of a detailed case example focusing on the iron mining industry of Minnesota and minerals education at the University of Minnesota.

Jan 1, 2004

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

With the dawning of a new century came the beginning of a new era in the coal industry. Instead of the traditional practice of only buying and selling produced coal in the United States, a coal futures market was established. The New York Mercantile Exchange began trading coal futures in July 2001. But, even in this new era, many of the old is-sues that have beset the coal industry still remain, as was evident in2001. Coal production increased to are cord level during 2001, according to preliminary data from the US Energy Information Administration(EIA). Production in 2001 rose by4% to 1.01 Gt (1.12 billion st), compared with 2000 (Table 1). This barely surpassed the previous record level of 1 Gt (1.11 billion st)set in 1998. Coal consumption remained unchanged. The additional production was used to replenish the depleted stockpiles that had resulted after two years of declining coal production and increasing coal consumption.

Jan 1, 2002

By L. H. Michaud

A mining company plans to extend its surface coal-mining operations in central Pennsylvania. Although the proposed site contains pyritic material, the results of the acid-base accountings for the site shows an overall Neutralization Potential to Maximum Potential Acidity Ratio (NP:MPA) of 4.26:1 for the entire site. The pyritic material is, however, associated with the lower of the three seams to be mined. If traditional dragline-mining methods are used, this would result in the acidic material being placed at the top of the spoil piles, exposing it to air and water, and therefore to the formation of acid mine drainage (AMD). Further concerns are associated with the fact that the alkaline material is not distributed evenly over the mine site. To prevent the formation of AMD, the company has proposed to mine the area using truck-shovel mining methods. This technique offers a more flexible alternative for cut sequencing and for the selective placement of waste material. Working with the Department of Mineral Engineering at The Pennsylvania State University, amine plan was developed for this site. This plan results in the layering of the alkaline and acidic spoil to achieve an overall net alkalinity in all spoil areas. Therefore, mining this site should not result in the formation of AMD.

Jan 1, 1996

By Wolfgang Gütter

India is targeting to boost its electrical capacity from 100 GW to 200 GW within the next 10 years. The National Hydroelectric Power Corporation (NHPC) has decided in2001 to take execution of the 800 MW Stage-II of the prestigious 2,051 MW Parbatihydrol electric project in Kulu district of the northern province Himachal Pradesh. Two parallel 30° inclined underground pressure shafts of 1.542m in length each will be excavated in different geological formations and lined with hexagonal concrete segments by a hard rock double shield TBM. That kind of heading will be a novelty to India and an innovative method for inclined pressure shafts. The 4.88m Mitsubishi DSTBM will be assembled underground on a swivelling steel platform especially designed for the launching as well as for the acceptance of the TBM in the upper cavern of each shaft. The hexagonal segmental lining system causes a significant higher job safety than an open TBM with conventional support. Each ring consists of four honeycomb segments with 20 cm thickness. After finalisation of the excavation a steel liner will be installed and concreted. The Joint Venture Jäger-Seli will perform the two pressure shafts as a sub-contractor for the Indian company Gammon India Ltd.

Jan 1, 2005

By M. A. Trevits

Mine seals are used in underground coal mines throughout the United States to isolate abandoned mining areas from the active mine workings. The objective of adding inert gas to a sealed mine area is to quickly reduce the oxygen concentration in the sealed area to a level that will not support combustion. In the US, this process is typically conducted from the ground surface and because surface-to-mine access is constrained by so many variables, it is very difficult to provide a source of inert gas to the place where it is needed underground. To alleviate this problem On Site Gas Systems, under a NIOSH contract, built a nitrogen (N2) generation plant that operates in the underground environment. The purpose of this work was to create a reliable in-mine mobile plant that would extract N2 gas from the mine atmosphere and use the gas to create and maintain a safe sealed mine area. The plant is based on a novel design using pressure swing adsorption technology and is sized to fit on a standard shield car or mine dolly for easy transport in and around an underground coal mine. The plant is capable of producing about 900 scf/min of N2 gas at ambient mine conditions. After an exhaustive series of laboratory tests, the plant was field tested at the NIOSH Safety Research Coal Mine (SRCM) where a portion of the mine was sealed and rendered inert. During the test, the movement of the injected gas was monitored at several underground points to observe the progress and extent of the inerting process. This paper describes the plant design and the results of the field test at the SRCM. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

Newmont Gold's methods for deposit modeling vary, depending on geology, mining and processing methods, economic feasibility and availability of historical information. It is argued that successful modeling requires understanding these factors, knowing the strengths and weaknesses of the various modeling techniques and being flexible in selecting the appropriate methods. Newmont is one of the world's largest gold mining companies, with operations in the United States, Peru, Mexico, Indonesia and Uzbekistan. And it is active in exploration worldwide. At the end of 1996, Newmont declared a total reserve of 1.15 equity kt (37.1 million equity oz) of gold and 2.17 equity Mt (2.39 million st) of copper. The gold deposits managed by Newmont totaled 752 Mt (829 million st) of ore containing 1.28 kt (41.3 million oz) of gold averaging 1.71 g/t (0.05 oz/st). In addition, Newmont is developing a porphyry copper-gold deposit that totals 9.1 Gt (1 billion st) of ore containing 380 t (12.1 million oz) of gold and 4.82 Mt (5.32 million st) of copper. (In May 1997, Newmont Gold Co. merged with Santa Fe Pacific Gold Corp., thus increasing Newmont's reserves to 1.72 kt or 55.2 million oz of gold and 2.17 Mt or 2.39 million st of copper.)

Jan 1, 1998

From Sept. 22-24, the Las Vegas Convention Center will be home to MinExpo 2008, the world?s largest mining equipment show that comes along once every four years. Sponsored by the National Mining Association (NMA), this year?s show is on pace to be the largest ever. Nearly 1,300 exhibitors have purchased nearly 55,700 hm2 (600,000 sq ft) of booth space. At the center of it all will be some of the most impressive mining equipment that the industry has to offer. And in the shadows of the massive haul trucks, drill rigs and bulldozers, attendees will be able to see the latest and greatest products including hand tools; the latest in automation and robotics; safety and communications equipment; longwall mining equipment; engines and parts; materials handling and processing equipment and services; pollution control equipment; reclamation equipment and services; computer applications; consulting and financial services and more. While many companies will be on hand to display the tried and true, there will also be plenty of new things to see. ?We anticipate that a whole range of new products will be introduced at the show,? the NMA said of the show that has been called the world?s richest deposit of mining technology, services and products. In addition to the show that will take place in Center Hall and North Hall of the Las Vegas Convention Center, MinExpo 2008 includes a conference program with 20 educational sessions that will tackle the most timely and pressing issues affecting the mining industry. Many of the industry?s top professionals will lead the discussions.

Jan 1, 2008

By O. Noirot, H. C. Owens, P. D. Rao, D. E. Walsh, J. R. Mokka

Over a period of seven years (1989-1996) the Mineral Industry Research Laboratory (MIRL) University of Alaska Fairbanks, has investigated the effects of temperature, residence time, and particle size on the degree of low-rank coal (LRC) upgrading for a non-evaporative, hydrothermal drying process, also known as hot water drying (HWD). Three Alaskan LRCs were used in this study: Usibelli coal (Seam No. 4) from the Nenana Coal Field, Little Tonzona coal from near McGrath, and Beluga coal from the Beluga-Yentna field on the west side of Cook Inlet. Replicated, factorial tests were conducted. Experimental results indicate that most of the low-rank coal upgrading via HWD occurs rapidly within the first 10-20 minutes of residence time. Thereafter, the upgrading process slows down and over 100 minutes of additional residence time are required to produce similar percentage increases in coal properties to those achieved in the first 10- 20 minutes. The properties of the hot water dried products were very sensitive to process temperature. Calorific value, carbon and oxygen contents, equilibrium moisture levels and Hardgrove gindabilities all appear to change linearly with temperature within the 275°C to 325°C range.

Feb 24, 1997

By S. Roy

Soft laminated iron ore (SLO) having a higher hematite content and Martite goethite iron ore (MGO) having a higher goethite content were subjected to detailed characterization and beneficiation. The present research was designed to investigate if these abundant, low-grade ores can be enriched adequately using standard industry techniques. No significant enrichment of the ores using jigging operation on the coarse (-3,200 +595 mm) size fraction could be achieved. Good liberation was only attained in the 150 to 300 mm particle size range in both cases. Desliming enriches the ground ores significantly. The effect of the feed size on the separation efficiencies of the ground ores were studied using flowing-film concentration on a Wilfley table. Better enrichment is obtained in the case of 150-mm sized feed by tabling. The grade of SLO is improved from 56.14% to 66.51% Fe, while the Fe content of MGO is enriched from 55.16% to 65.83%. Substantial rejection of alumina and silica is also achieved. Due to the friable nature of MGO and the higher goethite content in it, the loss of Fe in the form of ultrafines is greater in this case compared to that of SLO.

Jan 1, 2009