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By C. A. Roberts

What are the benefits and limitations of financial analysis software as a decision making tool in the mining industry? Traditionally, the assumptions and simplifications imposed by complex and uncertain information have been viewed as the main obstacle to reaching an optimum decision. Recently, however, phenomena such as corporate culture and power structure have received increasing attention as significant influences on organizational decision making processes. Studies of these phenomena have suggested an alternative way of understanding decision making processes and an alternative view of the role played by computer analysis in such processes. This paper presents these two views of decision making, and examines what each implies about the role of financial analysis software as a decision making tool in the mining industry.

Jan 1, 1992

By Robert F. Goss

OCAW appreciates the opportunity given to us by the sponsors of this Conference to present our position and policies on the issue of radiation hazards in mining. Our principal concern is the health impact that the mining of uranium has on our members. OCAW represents 1,500 underground uranium miners and more than 10,000 underground miners with 3,000 in the Rocky Mountain region. The U.S. Public Health Service has determined through mortality studies that the number one cause of death among uranium miners is lung cancer. It was also determined that exposure to radon daughters and mine dust correlates with the lung cancer experience of uranium miners. Data from the U.S. Mine Safety and Health Administration has also shown that not only uranium underground miners, but all underground miners, are exposed to radon daughters -- especially underground miners in the Rocky Mountain region. It is our position that any OCAW underground miner is at potential lung cancer risk. The dosages of radon daughters that our miners are exposed to are very many times the background levels of radon exposures in the communities where they live. We are also aware that cigarette smoking accelerates the onset of lung cancer; however, it has to be clear that the available scientific evidence shows that alpha radiation does initiate lung cancer and that cigarette smoke, as a recognized co-carcinogen, promotes cancer already initiated by radiation. It is true that cigarette smoke increases the risk of cancer significantly for miners exposed to radon, but nonsmoking miners have experienced lung cancer rates twice as high as the comparable members of the U.S. population. OCAW's position is that the occupational regulatory agencies should concentrate on the exposures that can be controlled; that is, occupational exposures rather than life-style exposures. Our Union has maintained a consistent posture in relation to carcinogens in the workplace -- that is, exposure to cancer-causing agents should be limited to the [lowest feasible level]. OCAW has interpreted lowest feasible level as the lower limit of detection of the collection and analytical method used to detect the carcinogen. Our posture is based on the available scientific information on carcinogenesis. We have asked the scientific community, many times, to provide us with safe levels of exposure to carcinogenic substances, including radon daughters. The answer has been: "We cannot determine levels of exposure low enough to assure that no cancer will occur." In short, there is not a "safe threshold" for any carcinogen. This statement does not come from one of the few so-called "pro-labor scientists," it comes from the National Cancer Institute and the National Institute for Occupational Safety and Health. I don't need to be a scientific sage, then, to conclude that the lowest level of exposure corresponds to the lowest risk of developing cancer. That is, then, our policy on exposure to carcinogens. It seems there has been an attempt to ignore the fact that lung cancer in uranium miners is the principal cause of death. Uranium miners are no exception from workers exposed to carcinogens. Our policy applies to them. Uranium miners should be exposed to the lowest feasible level of radon daughters and any decrease in the permissible exposure level is a decrease in their lung cancer risk. Accordingly, OCAW has petitioned the Department of Labor for a new permissible exposure limit to radon daughters in uranium mining, which lowers the current exposure standard from 4 Working Level Months (WLM) per year to 0.7 Working Level Months per year. We made our demand to the Department of Labor on April 20, 1980. We are still awaiting action from the Federal Government on our petition. OCAW is also very concerned with other important health impacts of uranium mining. We are concerned with a rate of disabling accidents and fatalities which is twice as high as the same rate in other underground mines, excluding coal. We are also concerned with the rate of respiratory disease fatalities among uranium miners which is almost four times the rate among a comparable U.S. population. We have expressed those concerns when the U.S. Senate proposed a Federal Compensation Act for uranium miners. That proposal, by Senator Dominici of New Mexico, found a quiet death in two Congressional sessions. In conclusion, our position on lung cancer induced by radon daughters is the same position we have taken with all other industrial carcinogens: The lower the exposure, the lower the risk. OCAW is demanding a drastic decrease of the permissible exposure limits. OCAW will never accept that a segment of our membership which mines uranium should take the lion's share of the risk while the uranium mining companies take all the benefits.

Jan 1, 1981

By C. E. Larson

Man's use of 'glass predates recorded history. Although early man had no knowledge of how to form glass, artifacts have been found near naturally occurring glass formations where molten rock had been rapidly cooled. In areas where volcanic activity is evident, primitive people fortunate enough to have lived in that area used the naturally formed glass to make arrow heads, knife blades, tools and ornaments. These glass artifacts have been found all over the world. In fact in todays modern society there are recorded cases of aboriginal tribesmen in Australia fabricating arrowheads from glass bottles. 2. A Brief History of Glass The first evidence of man made glass were beads made around 2500 BC by the Egyptians. The Mesopotamians also made glass beads at about the same time.

Jan 1, 1986

By K. E. Hjelmstad

In the event of fire underground, it is essential that all miners be warned as quickly as possible. With mine air, rapidly depleted of oxygen and contaminated with smoke and toxic fire gases, any delay in the warning signal could have disastrous consequences. Unfortunately, present mine, fire warning systems, such as stench, audible or visual alarms, telephones, and messengers, are often slow, unreliable, and limited in coverage.

Jan 1, 1989

By K. E. Hjelmstad

Solution mining operations often encounter difficulty maintaining adequate leach solution flow into the ore formation because of loss of formation permeability near the injection well. Permeability loss caused by swelling and breakup of clays and fine particle migration can often be the cause of the problem.

Jan 1, 1989

By S. G. Ozkan

Boron minerals of economic importance are primarily colemanite, tincal, and ulexite. Turkey and the United States are the leading producers of boron minerals and compounds. Other production includes datolite in Russia and synthetic colemanite in Chile. This paper will discuss various types of chemical and physical treatments of boron ores to produce the marketable minerals and compounds that are consumed in commercial products.

Jan 1, 1995

By Taehong Kim, Changsoo (Kevin) Moon, Anil Parikh

"This paper presents an overview and performance evaluation for a reconditioned decades aged open type hard rock TBM utilized for the twin running tunnel excavations of the Second Avenue Subway Project in Manhattan, New York. The TBM tunnel lengths are approximately 2,370 m (7,800 ft, east TBM Tunnel) and 2,190 m (7,200 ft, west TBM Tunnel) with a 6.7 m (22 ft) bored diameter. This “senior” TBM mined through metamorphic rocks consisting of schist, granofels, and pegmatite, and encountered various adverse geological structures, including some relatively heavy groundwater inflows. The ground support was generally pattern friction rock bolts, and steel sets were used in poor ground. This paper presents TBM characteristics and the subsequent performance, such as machine utilization, downtime, cutter consumption rate, net penetration rate, and daily advance rate. Machine operating parameters including thrust, torque, gripping force, and cutterhead RPM, are compared with various accompanying ground conditions. The performance changes between the adjacent tunnel sections are also presented. INTRODUCTION Project Overview The Metropolitan Transportation Authority Capital Construction (MTACC)’s Second Avenue Subway (SAS) Program consists of four (4) phases from 125th Street to Manhattan Battery Park along the 2nd Avenue (see Figure 1) in Manhattan New York. As a part of Phase 1, Contract 1 was awarded to S3 JV (Skanska/Schiavone/Shea) to build a TBM launch box and subsequent twin TBM tunnels from 92nd Street to 63rd Street under 2nd Avenue. Contract 1 was one of the key contracts in Phase 1 to pre-excavate through the footprint of the follow-on underground stations (72nd St. Station, 86th St. Station, and 96th St. Station) by hard rock TBM excavation. The project team included Client MTACC, S3 Tunnel Constructors, Designer, Aecom-Arup JV, and Consultant Construction Manager, Parsons Brinckerhoff. The major elements of Contract 1 included construction of TBM Launch Box supported by secant pile and slurry walls and mining of twin TBM tunnels with a combined tunnel length of approximately 4,560 m (15,000 ft). The dimension of the TBM launch box was approximately 247 m (810 ft) long from 92nd Street to 95th Street, 21 m (70 ft) to 24 m (80ft) wide along the 2nd Avenue, and 18 m (60 ft) to 21 m (70 ft) deep from the ground surface. The launch box was later used for the follow-on 96th Street Station."

Jan 1, 2016

By D. J. Benton, S. Finley, D. T. Orr, A. J. Chambers, M. A. Stepan

"Corrosion of ground support can lead to falls of ground that pose a significant risk to miner safety. To address this problem, the National Institute for Occupational Safety and Health (NIOSH) is investigating corrosion at the Hecla Mining Company’s Greens Creek Mine, located near Juneau, Alaska, USA. Field studies have used photogrammetry surveys to document welded-wire mesh corrosion, and laboratory studies at NIOSH’s Spokane Mining Research Division (SMRD) have investigated the effects of corrosion on ground support integrity. Findings show that (1) corrosion monitoring through photogrammetric methods may be effective for qualitative measurements of welded-wire mesh corrosion, and (2) there is a relationship between loss of load-bearing capacity and the diameter loss due to corrosion in welded-wire mesh. Photogrammetry results thus far have measured an apparent bulking of the corroded welded-wire mesh, and preliminary laboratory tests have investigated the relationship between the larger bulked and effective wire diameter. If this relationship is verified, these results may indicate that photogrammetry, when combined with the models produced in laboratory tests, could offer a means of monitoring corrosion levels, as well as rock rib deformation. INTRODUCTION Reducing the number of rock fall injuries and fatalities is an important part of the mission of the National Institute for Occupational Safety and Health (NIOSH) Spokane Mining Research Division (SMRD). Ground control using support systems to protect miners from rock falls is one of the oldest mining sciences, and considerable research has led to a variety of modern tools and methods in use today. Among these tools are rock bolts and welded-wire mesh, which are made from increasingly higher-strength steel grades to meet the increasingly demanding requirements of underground mines [1]. However, the benefits of these higher-quality support elements may be negated in corrosive mining environments. A better understanding of how corrosion affects the support capacity of ground support systems will assist engineers in determining when an opening is at a greater risk of falls of ground. Accelerated corrosion has been occurring in some areas of the Hecla Mining Company’s Greens Creek Mine near Juneau, Alaska, USA. Corrosion of ground support has resulted in two falls of ground occurring between April 2015 and March 2016. While these falls of ground did not injure any personnel, mine management recognized the high risk to miner safety and responded by actively undertaking a ground support rehabilitation program. Rehabilitation measures include the installation of both galvanized and coated, corrosion-resistant bolts and welded-wire mesh, depending on local conditions."

Jan 1, 2017

By Michael L. Maniocha

Most magnesia (MgO), whether of natural or synthetic origin, is used in the dead-burned or periclase form as refractory linings for the production of steel. Continued research in refractory science, combined with good refractory maintenance and improvements in steel-making processes, have resulted in decreased use of magnesia. To make up for this loss of business, producers of synthetic magnesia have started to manufacture a variety of magnesium-based chemicals that are used in many industries. There are three primary methods of producing MgO. The first involves the calcination of naturally occurring minerals species. Most of the magnesia produced by this method uses the rhombohedra1 carbonate mineral magnesite, MgCO,. To a lesser extent, the mineral brucite, Mg(OH), is calcined to magnesia. Magnesia produced by the calcination of minerals is called natural magnesia. The second production method uses magnesium-rich brines, or sea water reacting with lime or calcined dolomite to produce magnesium hydroxide. The magnesium hydroxide is subsequently calcined to magnesia. Material produced in this way is called synthetic magnesia. The third major method of production uses saline lake brines to produce magnesium chloride. Magnesium chloride brine is sprayed into a reactor where it thermally decomposes into MgO and HCl. The magnesia is purified by slaking to magnesium hydroxide followed by calcination. Magnesia produced in this manner is also know as synthetic magnesia (Duncan and McKracken, 1994). The degree to which the magnesium minerals or the synthetically prepared magnesium hydroxide is calcined governs the physical properties of the resulting MgO. It is the physical properties that dictate the end use for the product. The terms used to describe magnesia vary along with the degree of calcination. Table 1 summarizes the terminology used when discussing the various forms of magnesium oxide.

Jan 1, 1997

By David A. Hedderly-Smith

Sealaska Corporation, the Alaska Native Regional Corporation of Southeastern Alaska, was organized under the laws of the state of Alaska pursuant to the federal Alaska Native Claims Settlement Act of 1971. Large areas of Sealaska's 630,000-acre (250,000 hectare [ha]) fee subsurface holdings are underlain by carbonate, and while much of this material is assumed to be common variety limestone and lesser dolomite, at least two areas in the Silurian Heceta Limestone contain high-quality limestone at tidewater. This limestone has many potential commercial uses. On northern Prince of Wales Island, about 90 miles (144 km) north-northwest of Ketchikan, resource development at Sealaska's Calder deposit has established a reserve of 13 mil- lion short tons (st) (12 million metric tonnes [mt]) of carbon- ate rock containing an average of greater than 98 percent CaC03, approximately 0.5 percent MgO, less than 0.5 per- cent Si02, and approximately 0.15 percent Fe203, with insolubles averaging less than 0.5 percent and an average Hunter Brightness of 92.07 for the -150 mesh grind (with a bright- ness cutoff of 90). The deposit is open at depth and to the south. Ultimate reserves will likely be several times those currently established. In 1998, Sealaska began mining the Calder deposit, with about 100,000 st (90,000 mt) produced, and also completed a marine terminal one half-mile (800 m) from the deposit. The terminal can load ships up to 680 feet (200 m) in length at a rate of 2,000 st (1,800 mt) per hour. 0 m) in length at a rate of 2,000 st (1,800 mt) per hour. On Dall Island at Breezy Bay, about 60 miles (100 km) southwest of Ketchikan, Sealaska has identified a limestone reserve in excess of 150 million st (135 million mt) that (based on 18 surface samples distributed evenly over about a section of land) contains about 98 percent CaC03, and less than 0.5 percent MgO, 0.5 percent Si02, and 0.15 percent Fe203. Brightness of the Breezy Bay carbonate is considerably less than at Calder. Five samples of brighter material from Breezy Bay returned brightness analyses in the high 80s and low 90s; average brightness is probably below the mid- 80s. Sealaska has also identified a deposit containing more than 19 million st (17 million mt) of similar rock near View Cove, a few miles south of Breezy Bay.

Jan 1, 2001

By Christian Heinz, Doug Harding

TBMs can last for decades and be rebuilt project after project with proper maintenance. How successful can rebuilt TBMs be? At the DigIndy Tunnel System in Indianapolis, Indiana, USA, a rebuilt TBM was used to great effect. The 6.2 m diameter Main Beam, originally manufactured in 1980, bored 40+ km of tunnels and set three world records in its size class of 6 to 7 m, including a best month of 1,754 m. In this paper, the authors analyze the TBM rebuild, performance and lessons learned to make recommendations for future projects seeking to use rebuilt TBMs over long distances.

Jun 23, 2024

By E. K. Albert

In 1977, Congress enacted Title IV of the Surface Mining Control and Reclamation Act (SMCRA), providing for an "abandoned ml.ne reclamation fund". This fund, taken from a fee collected from operating coal mines, provides capital for the reclamation process. However, given the number and extent of abandoned mine sites in some states, the question of project selection is important. This paper describes a project in progress to create a Management Information System application for project ranking under multiple objectives. The benefit of this project for the need of new environmental control technologies will be discussed.

Jan 1, 1990

By A. Moergeli, Philip Sander, John J. Reilly

"Estimating and managing the costs of complex infrastructure projects – in the planning/design and construction phases, for both owners and contractors – has been a challenge for decades. The more complex and technologically advanced the project, the greater the uncertainty, including potential risks that are important to owners and contractors, such as:• Cost risks to owners – meeting budget and schedule, maintaining public credibility.• Cost risks to contractors – profit, consequences of loss, impacts to reputation/future work.This concern has been addressed in various ways by the underground construction industry for some time (Reilly, 2001). In particular, while significant advances have been made in cost estimating for the planning and design phases (Reilly et al., 2004), that are important to agencies and political decision-makers, it is not apparent that these advances have been widely adopted for construction cost estimates. The reasons for this may relate to lowbid considerations – any method that tends to increase the contractor’s cost estimate, by including risk or likely costs, could lead to an erosion of the contractor’s competitive position – if others are not similarly required to include such costs.Different cost estimating methods produce different levels of information. Specifically, there is a large difference in the character and depth of information if a deterministic (quantities times price plus a contingency) and risk-based cost methods are used. It is this difference in character and depth of information that is the reason that risk-based cost estimating has potential value for owners and contractors. Figure 1 presents hypothetical cost results from deterministic and risk-based methods and illustrates some of these differences.In Fig. 1, the results for deterministic and risk-based cost estimates are given related to the potential profit or loss for a typical project. As is evident in this example, there is significant potential for costs to be realized that are higher than the proposal/bid value estimated using a deterministic approach, with a 15 percent probability of a loss. There is a 30 percent probability that the project will have a reduced profit. There is a 55 percent probability that the project will return a good profit. Using a risk-based approach, it is possible to better recognize this potential outcome in the bid phase and, as a consequence, develop a strategy to:"

Apr 1, 2016

By M. Baumann

Operating and maintaining the heavy equipment used in open-pit mining operations is an ongoing challenge for mines. Typical operations employ a combination of shovels, wheel loaders, and haul trucks to excavate and transport the material for further processing. As this is the first point of contact for the material after blasting, it is often a bottleneck of all downstream processes, thus, equipment uptime and efficiency is crucial. Automated systems for bucket tooth monitoring, payload measurement, proximity detection, and rock fragmentation analysis will be examined. The impact of these systems on operation safety, efficiency, and reliability, in real-world scenarios will be investigated. The process of managing all the above fleet of equipment in a mine can be streamlined by connecting the equipment monitoring systems to a central server. Using the central server, the distribution of this information can be automated to ensure that the right people see the data in a timely manner, improving both proactive and reactive responses to threats to safety and productivity.

Feb 23, 2014

By D. Malhotra, K. Purdy, G. Ramadorai

INTRODUCTION Today, flotation is clearly the dominant mineral concentration method. Since it is a relatively selective process, it is used for almost all sulfide minerals. A recent U. S. Bureau of Mines study indicated that approximately 225 million metric tons of sulfide ore was processed in 67 plants in the United States in 1980 (USBM Staff, 1981). There were over 100 plants processing copper ores in the world (Bassarear, 1985). Sulfide ores containing lead, zinc, copper, molybdenum, precious metals, cobalt, nickel, and iron are generally separated and concentrated by flotation. This chapter briefly reviews the plant practice related to the recovery of the above-mentioned sulfide minerals with emphasis on chemical reagents used for the production of marketable-grade products. PROCESSING OF SULFIDE ORES It is beyond the scope of this chapter to review the milling data for operating plants which have been extensively covered in literature (Tveter and McQuiston, 1962; Rausch and Mariacher, 1970; Weiss, 1985; Crozier, 1979). However, the following generalizations can be made regarding the processing of sulfide ores: 1. The primary grind is targeted to produce as coarse a product as necessary to provide an economic degree of liberation. 2. The concentration process, generally flotation, is designed to produce a concentrate consisting predominantly of valuable minerals and a middling fraction which may require further grinding to produce an optimum release of minerals. 3. The chemical reagent suite (collectors, frothers, etc.) for the separation of sulfide minerals from gangue minerals is generally complex. Total reagents used in the flotation process can be as high as six to eight, as is the case for lead and molybdenite separation from complex sulfide ores. 4. Chemical reagents are generally expensive because of the high selectivity for sulfide minerals. The process flowsheet is dependent on several factors, including ore grade and mineralogical composition. Generic process flowsheets for processing different sulfide ores have been developed for discussion in this chapter. However, there appears to be a consistent relationship between the reagent combination choice and the mineralogical composition of the ore (Tveter and McQuiston, 1962). These are covered in detail in the following sections. LEAD AND ZINC Galena (PbS) and sphalerite (ZnS), which commonly occur together, are the only minerals of lead and zinc, respectively, in most primary deposits. Feed ore grades are typically 1 to 5 percent Pb and 1 to 10 percent Zn. Very often economic quantities of copper and precious metals, silver and gold, also occur with these base metals.

Jan 1, 1986

By Peter Amelunxen, Kain Nugent, Brandon Akerstrom, Willem Duyvesteyn, Todd Harvey

In 2024, Capstone Copper Corp commissioned a new sulfide flotation plant at Mantoverde in the Atacama region of Chile to process copper ore at a design rate of 32,000tpd. The pyrite associated with the copper ore body contains cobalt in solid solution, with Co replacing Fe in the pyrite matrix. As per the existing sulfide flotation flowsheet most of the pyrite is depressed and sent to tailings via the cleaner scavenger tail stream. A new project considers the recovery of the pyrite from the cleaner-scavenger tails via froth flotation to produce a cobaltiferous pyrite concentrate, which is then leached via the existing dynamic copper leach pad to oxidize the pyrite and dissolve the cobalt. The cobalt is recovered from the solution by treating a bleed stream of copper SX raffinate through a continuous, counter-current ion exchange (CCIX) facility. This approach to by-production of cobalt confers numerous benefits, including reduced costs compared with alternative cobalt recovery processes, reduced acid consumption in the heap leach, increased copper production, and reduced acid mine drainage potential due to the removal of pyrite from the mill tailings.

Feb 1, 2025

By P. Albert Carpenter, Wallace B. Howe, Michael N. Greeley, E. C. Bingler, Gilbert R. Eakins, Christy Bell, John Callahan, Gary B. Glass, T. J. Crabs

Although gold's market price dropped considerably from 1980's all time high, exploration for the precious metal remained a particularly bright spot last year, especially in the western US. For example, in Nevada-the nation's largest gold producer-further exploratory drilling at Louisiana Land & Explorations Co.'s deposit at Round Mountain and Newmont Mining Corp.'s find near Carlin resulted in sharp boosts in estimated reserves at both sites. Louisiana Land said its deposit is well on the way to being one of the largest gold reserves in the US. Based on further drilling, Newmont said its Gold Quarry property near Carlin could now produce 4.7-6.2 t/a (150,000-200,000 oz/ year). Reserves at Newmont's two properties near Carlin and a third property in southeast California are reportedly at least 218 t (7 million oz), up from the previously announced 128 t (4.1 million oz). Gold exploration activities were brisk in many other states, including a noticeable effort to explore and reopen dormant properties. Although the return on investments didn't appear as favorable last year as they did in 1980, the gold price was apparently sufficient to spur healthy exploration activity. Outside precious metals, market conditions, and subsequent exploration activity, appeared much more bleak. In the molybdenum market, for example, prices continued to slide, and Amax Inc. tightened its exploration budget. (Amax supplies 60% of the domestic market and 45% of the world demand for molybdenum.) The company spent 16% less on exploration during the first six months in 1981, compared to the same period in 1980. Copper and many other base metal producers appeared in similar straits throughout the year. Uranium exploration activities continued to suffer last year also due to depressed market conditions. Among others, Gulf Minerals Resources and Amoco Minerals Co. suspended uranium exploration activities in the West. Despite current unfavorable conditions, some companies continue uranium searches, confident that market conditions will rebound. On a brighter note, interest in exploring for some industrial and strategic minerals appeared on the upswing last year. Minerals used for oil and gas drilling, such as barite and special sands, were especially noteworthy. In geophysical activity, significant developments were achieved for electromagnetic techniques in both frequency-domain and time-domain systems. Geophysical logging activity declined due to decreased uranium exploration, and computer hardware continued to impact the way mining geophysical data are being acquired. Many presentations and papers were given last year to help exploration geochemists develop new techniques to locate concealed ore bodies. Among techniques described were statistical and computer modeling for enhancing anomalies over blind deposits.

Jan 5, 1982

By Luisa Alfieri, Giorgio Fantauzzi, Sergio Notarianni, Spencer Cavagnet, Alessandro Damiani

"The new tunnels of the Copenhagen ""Cityringen"" will be excavated, at Kongens Nytorv square, crossing over the existing M1 and M2 metro lines. After the crossing, the tunnels will underpass the historical building of the Magasin du Nord and adjacent masonry buildings, with a minimum tunnel cover of about 4.5 m. The tunnels have an internal diameter of 4.9m and are being excavated through earth pressure balanced Tunnel Boring Machines in mixed face.The Magasin du Nord estate is characterized by a very complex structure, with different blocks built in different times. An assessment of the condition of the building and its sensitivity to tunnellinginduced ground movements has been conducted through a fully coupled soil-structure interaction analysis; based on the results of this analysis, mitigation measures have been designed.INTRODUCTIONThe Copenhagen Metro Cityringen is expected to be running in July 2019 and will consist of two single tracks in a twin tunnels, each approximately 16 km in length, for transporting up to 243,000 passengers on an average work day. The Cityringen includes 17 underground stations with island platforms, 4 crossover facilities and 3 construction and ventilation shafts. The tunnels is being excavated using earth pressure balanced Tunnel Boring Machines and have an internal diameter of 4.90 m.The intersection with the existing M1 and M2 metro-line will take place at Kongens Nytorv and at Frederiksberg. According to the design alignment, in Kongens Nytorv the new tunnels will pass over the existing M1 and M2 ones; as a result of this, the tunnels will underpass the historical building of the Magasin du Nord and the adjacent masonry building hosting a Mc Donald’s with a minimum cover of about 4.5m.In the framework of Risk Assessment for sensitive buildings, the effects of tunneling-induced ground movements on the Estates ØS0437 (McDonald’s building), ØS0428 (Magasin du Nord) and ØS0004 (Hviids Vinstue) were evaluated. To achieve this goal a fully coupled soil-structure interaction has been considered and the entire excavation process has been reproduced in a 3D model where the abovementioned buildings have been modeled. In this way, a risk assessment analysis was performed evaluating directly the effects of the excavation in terms of settlements and variations of the internal forces as far as the excavation process proceeds. In figure 1, a picture of the construction of Kongens Nytorv station, with Magasin du Nord and Mc Donald’s building on the background, is presented."

Jan 1, 2016

By Art Hamid, Manfred Wong, Carlos Jaramillo, Greg Raines, John Caulfield

"The Central Bayside System Improvement Project (CBSIP) is a critical element of the Sewer System Im-provement Program (SSIP), a 20-year, $6.9-billion investment by the San Francisco Public Utilities Commis-sion (SFPUC) to upgrade San Francisco’s 100+ years old seismically vulnerable combined sewer system. The CBSIP’s centerpiece, a proposed 10,000-foot-long (3,048-meter-long) Channel Tunnel, will provide reliable and redundant gravity conveyance and storage of combined wastewater flows from the northern and central parts of San Francisco to the Southeast Water Pollution Control Plant (SEP) while ensuring compliance with regulatory requirements for combined sewer discharges to the Bay. A tunnel with a diameter of 23 to 30 feet (7 to 9 meter) is being planned using pressurized-face tunnel boring machine technology. Project challenges include tunneling through Franciscan Bedrock, mixed ground conditions in close proximity to the Bay, connector tunnels and shafts, construction in congested urban environment, and challenging real estate issues for shaft access. BACKGROUND AND NEED FOR TUNNEL The City of San Francisco is one of the most beautiful cities in the world. About 850,000 people live in the city and many more come to work, for tourism, and for attending conferences. The SFPUC is a department of the City and County of San Francisco that provides energy, drinking water and wastewater services to San Francisco, wholesale water to three Bay Area counties, and green hydro-electrical and solar power to San Francisco municipal departments. The SFPUC wastewater system includes tunnels, large storage/transport boxes, 1000 miles of collection sewers, 28 pump stations, and three wastewater treatment plants. San Francisco’s combined sewer system collects both wastewater and stormwater in the same sewers, which is then pumped, treated to stringent state standards and discharged into the San Francisco Bay and Pacific Ocean. After decades of service, much of the sewer system is nearing end of its working life. During the 1989 Loma Prieta earthquake, damage to SFPUC water and wastewater infrastructure was extensive. The 11,200-foot-long (3,400-meter-long), 66-inch-diameter (1,676-mm-diameter) Channel Force Main, built in 1976, and a critical component of the SF wastewater system was also damaged. This force main carries 70 percent of the bayside dry weather sewage flow from the northern and central part of the city to the SEP. The force main is at the end of its life and was not constructed to the current seismic code; in addition it has no redundancy. Figure 1 shows the project background and the force main that will be provided redundancy by the new gravity tunnel."

Jan 1, 2016

By J. Sidhom, W. Fourie

"As the mining industry continues to face difficult challenges the need to persistently focus on productivity and utilization of labor and equipment costs will intensify. With these challenges in mind, Joy Global is helping to bring mining performance and analytics to the next level. By evaluating underground haulage, a significant component of the Room and Pillar mining value stream, variables have been identified and sensitivities have been performed to show opportunities to balance and streamline throughput. As a result of applying operational excellence tools to the mining environment, Joy Global is seeking to optimize mining performances by limiting waste, simplifying the process, increasing productivity and machine utilization, as well as removing workers from harm’s way. These days it’s not enough to work harder; mines have to work smarter. Improving efficiency, reducing costs, increasing safety: these are no longer ‘nice to haves’, they are ‘must haves’. Starting with the best products and the right people is a first step, but then what? How do mines take their operations from just OK to being a top performer? By using operational excellence principles aimed at eliminating waste, simplifying processes, automating where possible and removing people from harm’s way. The fundamentals of operational excellence (OpEx) are based upon the DMAIC process, which stands for define, measure, analyze, improve and control. DMAIC is an improvement cycle that helps with, for example, haulage optimization by: defining the issues and problems in the process as well as the areas of improvement; measuring and collecting mining operational data by time study and equipment monitoring system; analyzing through sensitivities and production modelling to determine root causes; then improving the performance and controlling the operation. Joy Global uses Joy OpEx or ‘lean’ principles inside its organization to drive efficiency, but it also helps its customers employ them to achieve new levels of productivity and safety. These same principles can be applied in most situations to streamline processes, improve operations and deliver value. As applied to mining, OpEx is seen as moving the needle on value creation by first identifying the value stream, then analyzing the areas that are not optimized. Once defined, these areas are ‘designed out’ of operational processes to create an automated operational flow. At a US coal mine, Joy Global was brought in to apply Joy OpEx principles to optimize mining and haulage to improve productivity and reduce costs. This multi-phase process started by defining the existing systems challenges to start finding areas for improvement."

Jan 1, 2017