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By Gary English

"Tunnel safety is evolving as science, engineering and technology make advances. Applicable safety codes and standards simply do not cover all the potentials of design, construction and operation. This paper reviews a series of tunnel projects code gaps in Seattle USA that were uncovered during the design and construction of a new highway tunnel, conversion of bus tunnels to combined road and rail tunnels, new rail tunnels using TBM and NATM, conversion of a road tunnel to light rail, and retrofit of an existing road tunnel to add lanes and improve safety systems. The perspectives of the ‘fire code official’ (Authority Having Jurisdiction) on methods to identify and resolve gaps in safety code and standard regulations, while garnering the consensus of the owner, designer, and contractors are presented. Additionally, the emergency responder command perspective on safe tunnel design, tunnel rescue during construction and operational safety is explained TUNNEL SAFETY EVOLUTION The underground has become nearly the only option to provide essential transportation corridors to continue our economic growth in key global areas. Tunnels are not built on a whim. Often significant portion of a regions wealth are invested to meet current, and hopefully future transportation demands. There are more transportation tunnels being built now than at any time in the planets history. The location of these tunnels is often selected for us based upon regional demand. Most commonly under densely populated urban centers and between populations’ centers to bypass geologic conditions like mountains and water bodies. Tunnels are being built in unforgiving soils, between tectonic plates, in extremes environmental conditions and often, under the very heart of the highest density population centers on the planet. All of these locations can bring with it conditions that challenge our common assumptions about safety. These extraordinary locations and soils create risks for both those constructing the tunnel, and in design engineering to meet the ‘minimum’ requirements at the lowest costs. There is lengthy history of above ground safety. Most countries and major local jurisdictions have adopted, or created safety requirements for the construction of above ground buildings. Through decades of use, these safety requirements have evolved, changed and been expanded to cover a wide gamut of actual and potential safety risks. However, the use of the underground for tunnel transportation corridors has grown exponentially with limited attention to safety requirements."

Jan 1, 2016

By S. Sener

In this investigation, the changes in the grindability of both ulexite and colemanite related with the different structural modifications created by the heat treatment were examined with respect to work index (Wi). The effects of the heat treatment temperature and time on grindability index were also investigated. It was observed that, heat treatment significantly affected on the grindability of ulexite. The work index of original ulexite was found 7.11 kWh/shton and decreased to 3.5 kWh/shton level within 200-480°C for 60 minutes. On the other hand, the work index of original colemanite was found as 6.48 kWh/shton and no appreciable change was observed when heated up to 320°C. Thermally assisted comminution can be used to improve the grindability characteristics of ulexite. Besides, the different behaviour of ulexite and colemanite under heat treatment can be used for their separation. The artificial mixture of ulexite and colemanite could be separated with over 90% recovery by utilizing their different grindability characteristics by thermal treatment, semi-autogeneous grinding and screening.

Jan 1, 1999

By H. Ankara

Determining the identicalness levels of the same model trucks working in open pit mine transportation system by means of statistical analysis methods is very significant in terms of availability analysis. In this study, the identicalness levels of two trucks picked randomly from the 170-short-tonne truck fleet working in open pit coal mine over one-year period were examined through a non-parametric test, Mann-Whitney U test for two samples. Time to failures (TTFs) and Time to Repairs (TTRs) of the trucks were analyzed with this test technique and then whether they were identical or not was determined. In order to determine whether the trucks identified to be identical at the end of this test displayed the same mining performances within the same open pit transportation system, the availability analysis of the identical trucks was carried out. As a result of the availability analysis, it was observed that the trucks had availability values that were very close to each other. It was also determined that Mann-Whitney U test could be employed together with availability analysis. Finally, it was observed that Mann-Whitney U test for two samples could yield rapid results in the performance analysis of complex systems like open pit mines.

Jan 1, 2010

By William D. Mayercheck

The introduction of continuous mining machines in the late 1940's prompted the mining industry to reassess shuttle car batch-type haulage. Between place changes, the continuous miner could cut and load coal on a nearly continuous basis, but after loading a shuttle car, the high-capacity machine had to wait until the second shuttle car came inby and spotted itself under the miner tail boom. Thus, the wait-for-shuttle-car delay periods became the new bottleneck for increased coal production from the mine section. Recent studies have shown that nearly 25 pct of the continuous miner cycle time is consumed by delays in the haulage system, usually waiting for shuttle cars. Computer simulations of a face operation indicate that up to a 45 pct increase in coal production may be realized through the use of a continuous haulage system, assuming of course that the outby haulage system can handle this increased capacity. Coincidently, there are recent claims by some mines using continuous face haulage of a production increase of 45 pct compared with shuttle car haulage. These documented production records, computer simulations, and common sense indicate the potential of continuous face haulage in underground coal. The late 1960's and early 1970's saw several mining machinery manufacturers market mobile bridge carrier and piggyback bridge conveyor continuous haulage systems for use in underground coal mines. These systems have shown limited potential in some mines and outstanding success in others. It appears that no one system can be universally applicable to all underground mining conditions; thus, the Bureau of Mines has conducted extensive research over the last few years to investigate different types of continuous haulage systems for use in high and low coal seams that will advance the state of the art.

Jan 1, 1977

By J. J. Gusek

Several final pits in the Seneca No. 1 Surface Coal Mine were abandoned in the 1960's without being reclaimed. In addition, a progressive landslide aggravated by the abandoned mine land conditions was threatening a county road and private property. An AML-funded project to stabilize the landslide and reclaim the final pits was completed in 1986 for the Colorado Division of Mines and Geology (formerly Colorado Mine Land Reclamation Division). The site was visited after ten growing seasons. The land is stable and the vegetation re-establishment is strong. Volunteer native plant species are now invading the reclaimed sites.

Jan 1, 1997

By K. Johnson, B. Schiffer

Demonstrating aquifer restoration is an essential component of regulatory approval needed to mine uranium, copper, and other minerals by in-situ recovery (ISR). A PHREEQC geochemical model provided a useful means of forecasting the time for restoration and predicting future groundwater quality following low pH mining at Strata Energy’s Ross ISR Project in northeast Wyoming. The model simulated groundwater quality at three phases of the process: at the end of mining; during restoration; and post- restoration. The model utilized the one-dimensional reactive transport and dual porosity features of PHREEQC. Mineral surface ion-exchange, dissolution/precipitation reactions, and adsorption processes were simulated to estimate water quality as the pH was shifted from circumneutral to acidic during mining and back to neutral during restoration. The model results showed that cost-effective management of mine water could meet regulatory requirements. Additionally, the model was used to interpret results from a field trial and inform operational decisions. The predictive approach and geochemical understanding developed have application in assessing aquifer restoration for other ISR projects.

Mar 2, 2022

By Robert B. Crookston

Oil from shale has been produced in foreign countries for more than a hundred years; however, except for short-lived, small operations, no commercial quantity of oil shale has yet been produced in the United States. Efforts to develop a viable oil shale process have been underway domestically for many years. At the present time, with the need for energy so urgently upon us, almost a dozen development ventures are underway or planned in Colorado and Utah. Of these several ventures, only Colony Development Operation has completed the development, testing and design of a ready-to-go 50,000 barrel per day com¬mercial project. Colony is a joint venture of the Atlantic Richfield Company, Ashland Oil Company, Shell Oil Company and The Oil Shale Corporation, more commonly known as TOSCO. TOSCO is the exclusive licensor of the TOSCO II retorting process and other oil shale technology, which includes mining, crushing and spent shale disposal techniques. This paper will deal, however, with only the materials handling aspects of the commercial oil shale operation. Oil shale handling for this infant industry is unique in that an understanding of the physical characteristics of the ore and the demands on material handling to the plant must he understood. Colony Development has completed ten years in the research and development of techniques and processes for mining, crushing and retorting raw oil shale and the disposal of spent or processed shale. A great deal has been learned about oil shale, in many cases confirming our intuitive analyses and the work of others, but more specifically we have brought it all together to a point where equipment performance and the specifications have been established and a design for the first commercial plant is now mature.

Jan 1, 1975

By Wallace W. Wilson

It scarcely 1s possible to read a new issue of any of the principal mining trade journals without noting some mention of a major new overseas mining venture with which one or more domestic companies are involved. These projects seem to follow a fairly consistant pattern; most are large open pit mines, with relatively low grade ore bodies but huge reserves; the total price tag will be in nine significant figures and around half or more of the total cost will be for infrastructure. West1 noted that nearly $7 billion is being invested annually for new mining projects and the expansion of existing mining ventures, in the free world. He anticipates that by the year 1975 such investments would reach the $10-11 billion annual figure, and that in the five year period 1972-76 total capital requirements can be expected to aggregate around $45 billion. The proportion of this total investment which will be financed in some manner is difficult to estimate because of the variety of available financing arrangements. West estimated that around 75% of the total capital would come from internally generated funds, with the balance from external sources. Conceivably a substantially higher percentage could be attributable to external financing, especially it the trend of recent mineral development in Canada and Australia is any criterion, and of course, including local sales of equity as a part of the package.

Jan 1, 1973

By Thomas P. Meloy

The understanding, quantification and use of locked particles. Specifically discussed is the use of Textural Transforms (Meloy, 1991) for the implementation of the Interfacial Area Conservation hypothesis (Meloy, 1984); the quantification of the locked particles as a function of fragment to inclusion size ratio; and the selection of set points.

Jan 1, 1991

By S. Mason

Many organizations are realizing that continual improvement in health and safety relies on addressing the potential for various forms of human error. Of these, violations are often the most frequent form associated with accidents. These occur when an individual, or individuals, deliberately contravenes established and known safety rules. They have been associated with up to 90% of accidents and incidents in some industries and yet rarely receive the systematic attention they deserve in the promotion of safety. This paper presents underlying motives which cause violations. These can vary significantly from mine to mine and from job to job. Managers need some measure of attitudes to determine the underlying motives behind violations if they are to determine effective strategies for promoting safe behaviour. Questionnaires form the starting point to address attitudes and the motives behind rule violations. The choice of the most suitable questionnaire, however, will vary from organization to organization. Guidelines on the choice of questionnaire are offered.

Jan 1, 1998

By P. Oghazi

It is possible to have traceability in the mining industry, by parameters and signatures like particle mineralogy, mineral association, texture and mineral liberation. The study is on an apatite-iron ore deposit at Malmberget, Sweden, and characterizes an ore body both mineralogically and texturally in a quantitative manner by using analytical methods like optical microscopy, microprobe (EMPA) and an automatic SEM based system, Particle Texture Analysis (PTA). The mineralogy was evaluated by PTA and characterized by modal mineralogy, mineral liberation and mineral associations. Magnetite has a simple outline and straight grain boundaries and the gangue minerals have a finer particle size with a more complicated texture. The PTA analysis also shows that apatite is associated to magnetite as mixed particles, while smaller grains of magnetite are inclusions in feldspar. Result from particle texture analysis shows that there is a connection which link to the mine-to-mill context, and it may be used to create traceability. This link is not the associations of the main ore mineral magnetite, nor the modal mineralogy. Instead, it is the mineral associations of contaminating minerals (apatite and feldspar) that appear to be most promising since they survive from mine to mill. The modal mineralogy may be used to understand how contaminated minerals break into or out of particles size fraction during grinding.

Jan 1, 2010

By Nobuharu Isago, Atsushi Kusaka, Kosuke Kawata

"Rock tunnels suffered severe damage from recent large earthquakes in Japan, despite the empirical knowledge that tunnels tolerate earthquakes better than surface structures. Seismic design for rock tunnels have therefore become a fascinating subject for many tunnel engineers. However, even basic behavior, including deformation mode and loading magnitude for hard-rock TBM tunnels and conventional ones during earthquake, has not been fully understood due to lack of actual seismic data; while EPB and slurry TBM tunnels take account of seismic design in Japan if needed. This study conducted a dynamic measurement in an actual road tunnel constructed in rock. The strongest aftershock of “the 2011 off the Pacific coast of Tohoku Earthquake” (Mw = 7.1) occurred during the measurement, providing precious data to examine deformation mode of the tunnel. Considering the acquired data, numerical analysis was also performed to calculate loading magnitude to cause fatal fracture of tunnel lining during earthquake.INTRODUCTIONLarge earthquakes can pose serious risks even for rock tunnels, as evidenced by large earthquakes in the past. In the large earthquake in Japan in 2004 (Mw = 6.6), some tunnels suffered severe damage including collapse of their permanent lining (Mashimo 2005), even though the tunnels were constructed in ordinary ground conditions except for fault, fracture zone, portal area, etc. To mitigate such risks, mechanical behavior of tunnel lining during earthquake should be clarified; however, even basic mechanical behavior including load-bearing capacity of the tunnel lining against earthquake is not fully understood.Numerous damage modes were actually observed due to various ground conditions (eg. Wang et al. 2001; Mashimo 2005). Among them, major tunnel damage caused by earthquakes can be grouped into three main modes as shown in Figure 1, excluding extremely unusual conditions such as a tunnel located on a stratum boundary where the stratum stiffness varies significantly. TYPE-I shows flexural failure or crack by bending moment at shoulders; TYPE-II indicates compression failure or flexural compression failure at crown; and TYPE-III illustrates compression failure at sidewall, mainly observed on tunnel that was constructed using steel ribs and lagging method. These damage modes, Type-I, II and III, are predominantly caused by shearing, horizontal compressing and vertical compressing deformations of the surrounding ground, respectively (Kusaka et al. 2011; Asakura et al. 2001)."

Jan 1, 2016

By V. Svalbonas

When the Trelleborg Divisions of Boliden Allis and MPSI merged, a unique opportunity occurred for two independent mill fabricators to compare various design procedures and the research upon which they were based. This paper documents such a comparison in the structural design area. Several SAG mill analyses are compared using both Boliden Allis and MPSI methods. The differences and similarities are then utilized in a correlation of critical stress definitions and the acceptable design and inspection criteria.

Jan 1, 1992

By H. V. Scotland III

Lafarge Corporation's Texas Quarry, in Baltimore MD, achieved a substantial expansion of pit reserves by removing an inactive underground mine. The day lighting program, designed, and completed in 1997, open pit mined more than 400 meters of room and pillar workings which were originally developed to recover high brightness Calcium Carbonate. The project proved to be a challenge throughout its course as the pit plan was modified and successful daylighting techniques were developed to remove the mine without adversely affecting the safety of the operation, quality of the stone recovered, or negatively impacting the surrounding community. The design parameters and techniques developed and implemented at Texas may prove of interest to other operators as they are faced with daylighting opportunities. This article will detail the challenges we faced and the solutions which made the project a success.

Jan 1, 1999

By D. P. Patil, B. K. Parekh

Water is the mainstay for beneficiation of fine size coal and minerals; however, it is also the least desirable constituent in the final product. The basic concept of the novel process described in this paper is based on the differential surface heat absorption capacity of individual particles, which differs for different species of mineral. When a mixture of fine material is exposed to a radiant energy source, the various solids components present in the mixture will absorb heat energy depending on their composition and there will be difference in the surface temperature of the particles. When this differentially heated solid mixture is placed on a moving belt, which is coated with low temperature melting resin, the hotter component of the mixture will stick to the belt and relatively cooler will stay free on the belt and fall off at the end of the belt run. Experiments were conducted with pyrite, coal and quartz of 6 x18 mesh particle size. The goal of the test program was to find the optimum conditions at which there exists a required temperature difference between minerals and coal particles by controlling the operating and system variables. Preliminary tests results showed that there is a potential for separating mineral matter from coal using the thermo-adhesive separation technique.

Mar 2, 2022

By Allegra Yeley, Ted Klemetti, Gamal Rashed, Tim Miller, Nicole Evanek

In 2015, the Subtropolis Mine in Petersburg, OH, experienced a massive ground collapse that continues to grow over time. Horizontal stress effects have affected the roof at this operation in the past and may have played a large role in this collapse. Horizontal stress can impact the roof and floor stability and endanger the health and safety of underground stone miners. Mines experiencing damaging effects from horizontal stress typically find that the principal stress direction is the same throughout the mine and the region. At the Subtropolis Mine the principal horizontal stress direction appears to change as conditions change and differs from the regional horizontal stress, particularly near the collapse or other roof fall areas. The growth over time of this collapse and other roof falls have been captured and analyzed using geologic mapping, 3D LiDAR scanning, numerical modeling and geographic information systems like ArcGIS. Utilizing these tools to better understand sitespecific conditions can be critical to reducing the potential of massive ground collapses in the underground limestone industry.

Feb 1, 2024

By Matthew Preedy, Anthony Pooley, Mike Wongkaew, Dirk Bakker, Raghu Bhargava

Sound Transit’s ST3 program will add 62 miles of light rail to the Puget Sound area, including connections to the neighborhoods of West Seattle and Ballard. These connections include considerations for both elevated and tunnel alternatives in West Seattle and Ballard, as well as a new tunnel and six underground stations in the densely developed downtown Seattle. This paper describes the conditions and constraints along the corridor, and the latest development in the ongoing process to plan the underground guideways and stations.

Jun 13, 2023

By David E. Sims

Asarco has been using computer-aided open-pit mine design since 1966. The in-house developed program package includes drill-hole analysis programs, interpolation routines, and three-dimensional open-pit design programs. The financial analysis step after pit design required that a reasonably accurate schedule be produced so that a good cash flow model could assess the feasibility of a project. The manual method of scheduling was too time-consuming for feasibility work, so a computerized scheduler was required. Since no computerized mine scheduling programs existed, we requested proposals from consulting firms to develop such a program. The selection of a consulting firm, the formulation of the contract and design specifications required about three years to accomplish. The consulting firm, Systems Control Inc. (SCI), of Palo Alto, spent over one year doing the programming and testing alone. The details of the program development were reported in "Computerized Year-by-Year Open-Pit Mine Scheduling," SME-AIME Transactions, December 1974. In June of 1973 the program, which SCI dubbed Optimum Resource Extraction or ORE, was installed. Version 1 of ORE was utilized successfully on three separate properties over a period of two years. During this time it became obvious that some of the original design specifications were restrictive, and certain modifications were required. The ORE program was submitted for modification, and after one year version 2 was operational in May of 1976. The program now consists of approximately 20,000 lines of FORTRAN source statements grouped into 190 subprograms, and runs in a 450K region of Asarco's 370/148 in Cranford, NJ. The Tucson com¬puter (370/115) is tied to the Cranford computer via a 9600 baud leased T.P. line, for running mine scheduling and other large mine planning programs.

Jan 1, 1979

By Siegfried Zell

INTRODUCTION Denmark is a small country with a population of about 5.5 million in the north of Europe. A substantial part of Denmark consists of islands, and the Danes have been familiar with ferry links between their islands for ages. However, their wish for fixed links has resulted in the con¬struction of bridges between most of Denmark's islands in this century. (Fig. 1) A fixed link across the Store Belt or Great Belt, Denmark's most important waterway bet¬ween the island of Fyn and main island of Sjaelland, on which the capital of Copenhagen is situated, has remained to be constructed hitherto. In 1987, the Danish government decided that the Great Belt should be crossed by a fixed link, incorporating a two-track railway line and four-lane motorway. The Storebaelt Forbindelsen AS, a joint stock company in the sole ownership of the Dan¬ish state, has been established for the purpose of planning, constructing and operating the Great Belt Link. The company will refinance the construction project by charging toll to the motorway users and fees to the state railway. Here it should be mentioned that Denmark and Sweden are about to jointly realize the fixed rail and road link across the Øresund or The Sound between Denmark and Sweden on the basis of the realization model of the Great Belt link. At present, the project is at the com¬petitive tendering or contract awarding stage. In the near future, also the third fixed link of comparable extent, that is the crossing of the Fehmarn Belt between Denmark and Germany, will go into the decisive projecting stage prob¬ably in conformity with the aforementioned pattern. Going back to the Great Belt, it should be noted that this fixed link involves three exten¬sive sections and has been under construction since December 1988.

Jan 1, 1995

By M. L. Mellish

In 1989, for the third consecutive year, both the production and consumption of coal in the United States reached record levels. Domestic coal consumption totaled 806.5 Mt (889 million st) in 1989, a 5.4 Mt (6 million st) increase from the year before (Table 1). US coal exporters also had a banner year. For the first time since 1982, exports ex¬ceeded 91 Mt (100 million st). US coal production in 1989 rose by a surprising 27.3 Mt (30 million st), reaching 889 Mt (980 million st) for the year. To a certain extent, the sizable difference between production and demand growth was due to smaller consumer stock withdrawals. Coal consumers withdrew only 12.7 Mt (14 million st) of coal from their stocks in 1989, com¬pared to 22.7 Mt (25 million st) in 1988. Despite strengthening coal consumption, exports, and production, coal prices to all domestic sectors declined slightly during the year. That essentially continued the trend of the past several years. On the labor front, the United Mine Workers of America struck the Pittston Coal Group in 1989. It was a bitter work stoppage that was not settled until February of 1990. This was the first major coal strike since 1985. The strike also precipitated a series of wildcat outages by UMWA members in June and July. At their peak, more than 40,000 UMWA members participated in the wildcat strikes. Except at Pittston, however, most miners were back to work by August. It is estimated that perhaps 4.5 to 9.1 Mt (5 to 10 million st) of coal production was lost due to the Pittston and associated wildcat strikes. However, some of this production may have been recouped by other coal companies not affected by the wildcat strikes, and by the affected companies after the strikes ended.

Jan 1, 1990