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By L. Hales

Process control systems have evolved from single loop control to distributed control with computer based expert control strategies. The next step is to add adaptive control to the expert control strategies. An object-oriented adaptive optimization approach is defined and simulated results are presented for a plant.

Jan 1, 1996

By Mark C. Williams, Shunsuke Managi, Noriko Hikosaka Behling

Particle processing is a key to using solid particles in fuel cell applications. Selectivity with regard to reactivity, impurities, etc. is an important feature and the treatment of particle surfaces could greatly impact the performance of direct carbon fuel cells. Solid fuel particles will become increasingly important in the future. Present energy conversion systems for solid fuels are too inefficient. New energy conversion systems for solid fuels with higher energy conversion efficiencies are possible. Fuel cell technology is a key technology in these new conversion systems. The direct carbon fuel cell (DCFC) operates on carbon particles obtained from a variety of solid fuel feedstocks. The DCFC is the only fuel cell designed to directly oxidize carbon particles in a special anode chamber. The particles are generally graphite structure with high purity. The electrolyte used is the high temperature solid oxide, molten carbonate, or hydroxide electrolyte. Since a pure stream of CO2 is produced, the stream can easily be sequestered and disposed. Pure carbon dioxide produced as a by-product would also have a market in many industries. A well-defined technology roadmap identifying key research and development (R&D) issues is necessary to provide a framework for the development of these systems and to prevent entrenchment in inherently inefficient technologies. This review paper describes the direct carbon fuel cell and its system, how it works, the developmental status, the characteristics of the carbon particles needed, and the research and development issues for the technology

By Raymond A. Bradbury

Martin County Coal Corporation operates three underground mines and two surface mines on Wolf Creek in Martin County near Inez, Ky. The original underground development was begun in March of 1970. The property being developed is leased from Pocahontas Land Corporation. The A. T. Massey Coal Company, whose offices are located in Richmond, Virginia, is the parent company and sales agent for Martin County Coal. Duke Power Company is the customer who will take all the production from the mines which ultimately are scheduled to produce 2,500,000 tons annually. The Norfolk and Western Railway Company built a 24-mile railroad into this huge reserve of low-sulfur steam coal. Four coal seams, all above drainage, are included in the lease. The Middle Coalburg and Stockton seams are being deep-mined now and it is in three mines that the diesel haulage equipment is used. Those of you who attended the AIME meeting in Birmingham last October or the Diesel Symposium in Pittsburgh in January of this year are familiar with the introduction of trackless diesel-powered haulage equipment into our Martin County mines. I made a presentation at each of those meetings which dealt with our first experience with Wagner Mining Equipment haulage units. These machines are sold exclusively by Lake Shore, Inc. whose offices are in Iron Mountain, Michigan.

Jan 1, 1973

By Ben DiFiore, Richard DePew, Nate Long, Adrian Naranjo-Castillo, Chris Petta, Robert Auber

The Walworth Run stream was brick-culverted in the 1800s, converting it to a 16-ft diameter sewer. This Cuyahoga River tributary contributed to the infamous burning river that became the catalyst for USA’s environmental movement. The NEORSD has been working hard to reduce CSOs here, most recently by diverting Walworth Run’s 882 MGD of flow to the new Westerly Tunnel. This had to consider structure age/size, alluvial/glaciolacustrine deposits (requiring several ground support systems, groundwater control), and maintenance of massive flows. This paper examines challenges identified during design that supported the contractor in development of a risk-mitigating plan, culminating to successful implementation.

Dec 1, 2022

By B. E. MacNab

During the past several years, Raymond Kaiser Engineers has prepared numerous studies concerning the technical and economic feasibility of coal exporting facilities in the western United States. Perhaps the most striking conclusion to be drawn from these efforts is that many people underestimate the complexity of the highly competitive, dynamic coal marketing system which includes coal loading terminals as an essential but relatively low-cost link in the energy production and delivery chain. The title of this paper, "The Status of Western United States Coal Ports - An Economic Assessment," should not delude anyone into thinking that the future of western U.S. coal- exporting ports has now congealed into a well- defined economic plan. As this paper will demonstrate, the situation is complex and more dynamic than ever and promises to remain so into the late 1980's.

Jan 1, 1982

By CASSANDRA L. HOEBBEL, Emily J. Haas, MARGARET E. RYAN

Researchers examined datasets from two separate studies that measured common demographic variables but different safety performance outcome variables. Of specific interest was how types of experience might relate to workers’ preparedness to effectively mitigate or respond to both routine and nonroutine risk in the mining industry. The results suggest that individual factors such as length of job, industry, and mine experience are predictive of routine safety performance — as measured by self-reported proactive and compliant safety behaviors — and/or nonroutine safety performance — as measured by perceived competence in self-escape knowledge, skills and abilities (KSAs) — in significant and sometimes unexpected ways.

By Verya Nasri, Behrouz Esmaeilkhanian, Mohammad Motallebi

Réseau Express Métropolitain (REM) is the new Light Rail Transit (LRT) network of Montreal, Canada. This new LRT network uses a century-old Mont Royal Tunnel (MRT) to connect Downtown Montreal to the north side of the Island of Montreal by passing through Mount Royal Mountain. This railway double track horseshoe tunnel is approximately 5 km (3.1 mi.) long, 8.8 m (29 ft.) wide and 5.5 m (18 ft.) high, with a constant 0.6% grade. Due to different geological characteristics of the surrounding ground, varied from hard rock to soft soil, different cross sections and excavation methods were adopted for construction of this tunnel. In order to use MRT in the modern transit system, the tunnel needed to be inspected, rehabilitated and be compliant to the recent safety standards. This paper presents a summary of history and characteristics of the existing tunnel plus the implemented steps to upgrade the tunnel. It includes the details of the structural inspection and rehabilitation methods of the tunnel. Further, this paper summarizes the procedures for the space proong, construction of the separation center wall, and the tunnel enlargement. It also describes parts of complications encountered during the construction and solutions implemented to tackle these issues.

Jun 23, 2024

By Rebecca Mae Summer

Large scale surface mining has a major impact on land use. Without reclamation, abandoned mining sites are usually less productive than before mining. With increasing and completetive land use demands in the United States, it becomes increasingly evident that multiple land use should be considered for all areas that will be mined, with special emphasis on coal, sand, gravel, and stone. The mining of these commodities affects the largest land areas and the latter two are commonly mined near population centers where high land-use pressures justify serious consideration of multiple use. Typically, sequential use will mean restoration of the mined land or at least transformation of the land into a useable state. Determination of land reclamation capability is a viable approach to planning reclamation of surface mined land. The natural resource base--geology, soil, and water--controls the type and intensity of land-use practices which can be sustained following mining. Evaluating physical limitations can eliminate consideration of uses which would severely impair the environment or which are impractical. This approach provides for an environmentally and economically sound land use at very little cost. In addition, it can save or make money for the mining company and landowner. Sand and gravel is an especially significant resource because it is mined throughout the entire country and commonly extracted near cities. Increasing urban growth and industrial activity require increased supplies of sand and gravel. This translates into expanded surface mining and an increase of disrupted land. Oftentimes this land is within an urban area and has potential for real estate or water-based activities. Therefore, if reclamation is planned and carried out concurrently with mining, it is definitely feasible and

Jan 1, 1977

By Daniel F. Meyer, William C. Paschen

INTRODUCTION The problems involved with moving millions of tons of rock are being addressed by nationally recognized tunnel contractors who have converged in Chicago over the past 5 years. This wealth of expertise has been needed to meet the risk and challenge of constructing the world's largest network of underground tunnels which in turn has required a dramatic advance in the art and science of tunneling. These pioneers, through innovation, adaptation, and hard work, have eliminated the one major concern of The Metropolitan Sanitary District of Greater Chicago - how to move 8 million tons of rock. The Metropolitan Sanitary District of Greater Chicago (MSDGC) serves 122 municipalities covering 866 square miles in Cook County, Illinois. Of these cities, towns, and villages, 53 have combined sewer systems. On an average of once every four days, these systems overflow about 4 million gallons of combined sewage and rainwater into the area's rivers and canals. The overflows occur at approximately 640 outfall locations of which 10% are owned by the MSDGC, with the remainder of the points belonging to various other municipal bodies. All those who own these "point" sources of pollution are in violation of Illinois State and Federal regulations. To enable its member municipalities to come into compliance with State and Federal law, the MSDGC is implementing its Tunnel And Reservoir Plan (TARP). TARP is a regional solution to the problem of combined sewer overflow in the metropolitan Chicago area. TARP will greatly reduce the pollution of area waterways by intercepting the combined sewage and rainwater carried in the existing sys-

Jan 1, 1981

By N. K. Bohidar

Evaluation of the stability of a structure under given boundary conditions requires accurate knowledge of the state of stress as well as the mechanism of failure at the critical state of stress. This paper represents a part of the research done by N. K. Bohidar during 1965-1968 for his Ph. D. research in Mining Engineering at the University of Utah. It summarizes the determination of internal stress and failure phenomena around cylindrical openings in viscoelastic media subjected to lateral restraint and vertical uniaxial load. The conditions of lateral restraint and viscoelastic nature of the media represent conditions associated with subsurface openings in rocks. The financial assistance provided to the project from the University of Utah Research (Uniform School Fund), W. C. Browning Scholarship Fund, Earth Science Research Fund, and D. C. Jackling Loan and Scholarship Fund is gratefully acknowledged. The authors also acknowledge the assistance of S. Siugh, W. Jones, and K. McCarter during the project.

Jan 1, 1970

By Martin H. Stanczyk

The Organic Act of 1910 established the Bureau of Mines and gave it authority and responsibility for conducting research on separation, recovery, and recycling of waste products and scrap generated by the mineral and metals industries and the consuming public.(1)1 It was apparent to our Nation's leaders even then that mineral resources, once mined, are irreplaceable and that the development of methods for recycling the values contained in wastes would be required to solve the problem of even¬tual scarcity, Estimates of the increase in per capita consumption of mineral resources in this country indicate that the consumption of metals, minerals, and fossil fuels by 1980 will be double that consumed in 1970 (2). The United States can expect to meet its future mineral needs in three basic ways: the first is through increased production of primary raw minerals; second by increasing imports from foreign sources; and third by recycling secondary materials and metals that were formerly discarded as waste. Rather than consider these

Jan 1, 1972

"Twin Creeks is a gold mining complex that is part of Newmont’s Nevada operations. The mining complex is composed of two openpits, Mega and Vista, external ore sources and a set of existing stockpiles, all of which provide ore for an autoclave, an oxide mill and a heap leach. Mega pit provides sulfide ore for the autoclave, whereas Vista pit provides oxide ore for the oxide mill and the heap leach. Both pits operate the same mining equipment and their extraction sequence must, therefore, be optimized simultaneously. Stringent blending requirements are associated with the operation of the autoclave for the sulfide ore. Strategic blending optimization on a large scale has brought significant value to the operation by increasing synergies. This paper presents the implementation of a stochastic optimization framework for the long-term production planning at Twin Creeks that simultaneously optimizes mining, stockpiling, blending and processing decision variables. The uncertainty and variability associated with the different sources of material are incorporated in the optimization model by means of stochastic simulations. The stochastic solution generated shows substantial benefits by increasing forecasted recoverable gold, leading to increased cash flows, while reducing the risk of not achieving forecasts by increasing the probabilities of meeting production and blending targets.IntroductionMine operations consist of multiple components such as mineral deposits, stockpiles, external sources, mills and autoclaves. These components represent a mineral value chain, also known in the literature as a mining complex (Montiel and Dimitrakopoulos 2015; Goodfellow and Dimitrakopoulos 2016). The material extracted from the mines flows through the different components and is transformed into sellable products. This flow of material in a mineral value chain involves complex, nonlinear transformations that render the use of industry-standard optimizers difficult. Furthermore, the optimization of a mining complex can be formulated as a mixed-integer, nonlinear optimization program with millions of integer variables representing mining, blending, stockpiling and processing decisions, prohibiting the use of conventional nonlinear optimization approaches. Previous methods that consider the joint optimization of multiple components of the mineral value chain are available (Hoerger, Seymour and Hoffman, 1999; Chanda, 2005; Stone et al., 2005; Wooller, 2005; Whittle, 2007, 2010; Bodon et al., 2010). Although these methods add value by increasing the synergy between the different components of the mining complex, they rely on simplifying assumptions that constrain their efficacy, while ignoring a most critical aspect. The latter aspect includes the geological uncertainty and actual variability of the materials in the mineral deposits mined and are supplied to the related mineral value chain, similarly to conventional life-of-mine planning methods used for individual mines (Dimitrakopoulos, Farrelly and Godoy, 2002; Godoy and Dimitrakopoulos, 2011; Spleit and Dimitrakopoulos, 2017). Additional simplifying assumptions may include: the consideration of a limited number of components, the combination of different methods, the aggregation of variables, fixed production schedules the definition of policies prior to optimization, such as cutoff- grade definition or destination of mining blocks, the linearization of nonlinear transformation functions and/or the disregard for the uncertainty of several critical parameters (Whittle, 2007). The simultaneous optimization of multiple components of a mining complex was introduced by Newmont. Hoerger, Seymour and Hoffman (1999) implemented a mixed-integer programming formulation to optimize Newmont’s Nevada operations. The model is based on the work of Urbaez and Dagdelen (1999) and simultaneously optimizes the extraction of materials from multiple deposits and the delivery of ore to multiple plants, as well as as"

Dec 1, 2018

By C. K. Blankenship

The competitive forces now driving the electric utility industry and the constraints of regulation at all levels are changing the way we will all do business now and into the next century. Utilities are using every technological tool at their disposal to find optimum solutions to challenges in every aspect of operations. In fuel planning and procurement, these tools include models that predict which dispatch line-up will comply with environmental regulations at minimum cost. This paper presents how those tools are being used for Duquesne Light Company.

Jan 1, 1995

By H. R. Manouchehri

"Pyrrhotite (Po) is one of the most abundant sulfide minerals in processing industry and must be rejected in most cases. Particularly, Po rejection and its selectivity against pentlandite (Pn) have long been a challenge due to similarities in the mineral composition of the two minerals and the collectorless flotation characteristics of Po. Xanthates have been widely used to promote sulfide mineral flotation; however, in the presence of xanthates, the redox potential established at the mineral/solution interface is most important, determining the flotation performance. In this paper, the importance of electrochemistry in Po and Pn flotation has been demonstrated and a comprehensive study was conducted on two different feed streams (i.e., magnetic concentrate and scavenger cleaner streams, containing magnetic and nonmagnetic forms of Po, respectively), from Vale’s Clarabelle Mill in Sudbury, Ontario, with an objective to determine if improvements in Po rejection and Pn recovery could be achieved by controlling pulp electrochemistry. By conducting a series of flotation tests under different Eh conditions and reagent usage schemes, it was revealed that higher Po content in the magnetic stream may protect Pn from being oxidized, improving Pn recovery. The results indicated that at low oxidizing pulp chemistry, the rest potential for the Pn is still high enough to allow the formation of dixanthogen to promote its flotation. Using a Pt electrode, it was found that by controlling pulp potential at -50<Eh< +50 mV, the Pn recovery and Po depression would be satisfactory. The results, using mineral electrodes (Outotec Chena analyzer), indicated that selective separation can be achieved if low-to-moderate oxidation potentials (0 to 100 mV) or reduction (0 to -100 mV) potentials are monitored using Pn and Po electrodes. Mixing two streams at 50:50 wt % would be possibly beneficial in selective separation.IntroductionPyrrhotite (Po), Fe1-xS, is one of the most abundant sulfide minerals in the processing industry. It is an iron-deficient sulfide that occurs either in monoclinic or hexagonal form. The monoclinic one is richer in sulfur and is ferromagnetic, whereas the hexagonal Po is poorer in sulfur and has no magnetic properties. In general, the ferromagnetic properties of natural Po increase with increasing sulfur content. Although Po holds significant iron content, it is not used as a feedstock for the iron and steel industry due to the difficulty in achieving complete removal of sulfur. The common availability of iron oxide ores makes the iron sulfides irrelevant for the steel industry."

Jan 1, 2015

By M. Govinda Raj, S. Sridhar, M. Aruna

Hand-transmitted vibration (HTV) exposure is associated with various health risks for operators of mobile mining equipment (MME). The case–control research was conducted to determine the musculoskeletal disorder (MSD) risks associated with exposure to HTVs in the exposed (case) and non-exposed (control) groups. HTV readings were measured at the interface between the hand and the steering device using the SV 105B triaxial hand accelerometer connected to the SV106 human vibration analyzer involving 40 MME operators in accordance with ISO 5349:2001 guidelines. A questionnaire survey was also carried out among both the study groups using Cornell Musculoskeletal Discomfort Questionnaire. The European Union's 2002/44/E.C. was used to assess the health risks posed to the MME operators. Twenty-eight out of the 40 MMEs were generating HTVs exceeding the stipulated daily limits of vibration, putting 70% of the operators at increased risk for developing MSDs. The case group was found to have an elevated risk of exposure with odds ratio (OR) 7.56 (95% confidence interval (CI), 1.159, 49.39) and OR 12.80 (95% CI, 2.436, 67.285) times more likely than the control group to suffer discomfort in the left shoulder and left wrist, respectively, indicating increased risk of exposure to HTV. Additionally, cases had elevated risk associated with exposure to tobacco, OR 9.35(95% CI, 1.856, 47.129) compared to those who did not use tobacco. MSDs were more prevalent in the case group compared to the control group. This observation was validated by the field investigations and the responses of MME operators to the questionnaires.

Aug 2, 2022

By George Vranesh

Synfuels development in the upper Colorado River basin and the population growth attendant with such development demand sizeable quantities of water. Unfortunately, the water supply in the basin is limited and such limitation may impose a significant constraint on the development of the West&apos;s abundant energy resources. Although the water for the synfuels development will be governed by the law of prior appropriation adopted in the upper basin states, the authors point out that an apparently senior water right .my not deliver a firm supply of water. The federal and Indian Reserved Water Rights Doctrine, the Colorado River Compacts the Doctrine of Equitable Apportionment, and the federal and state environmental laws can all severely diminish the value of any given water right and the synfuels industry should take care to evaluate these factors in acquiring its water.

Jan 1, 1981

Bigger is indeed better in today&apos;s surface mining operations. That is especially true regarding haul trucks. Building larger, "supersize" trucks, however, means designing more powerful engines and drive systems that are also more efficient and environmentally friendly. And miners are demanding that these trucks have longer service lives with minimum maintenance. So truck makers are teaming with engine manufacturers and mining customers to design these larger trucks that will ultimately lead to reduced mining costs. About 180 of those truck makers, engine designers and miners gathered in Tucson, AZ in September to discuss the state of haul trucks in today&apos;s mining environment. Haulage 2000 was sponsored by World Mining Equipment and attracted attendees from around the world. Manufacturers described the latest in haul truck advancements. These included the design of more powerful engines, improvements to mechanical and ac and dc drive systems and suggestions on how to reduce maintenance spending. Technology improvements in tires for larger struck was discussed as was the cost efficiency of new, lighter-weight bed liners. The following is a summary of a handful of the presentations.

Jan 1, 1997

By Y. Luo

In designing and operating underground room-and-pillar coal mines, it is always difficult to achieve a good balance between preventing surface subsidence and achieving high recovery ratio. In this paper, a design methodology applying the pressure arch theory is proposed, and the principles and mathematical models involved are detailed. A computer program was developed to carry out the design optimization process and was applied to the examination of a documented case in which a massive cascading pillar failure had occurred over a large area in a shallow coal mine. The results indicate that the proposed design method can be applied to prevent subsidence while achieving reasonably high recovery ratio for roomand- pillar mining operations.

Jan 1, 2014

By R. Mattos, E. Calcina, G. Quispe, S. S. Kanchibotla

During blasting, rock breaks and moves but standard grade control practices do not adjust ore waste boundaries to cater for blast movement. Rock movement resulting from blasts can result in mischaracterization of grade boundaries resulting in ore loss and dilution. Ore loss takes place when ore is mischaracterized as waste and sent to waste dumps, and dilution occurs when waste is mischaracterized as ore and sent for processing. Las Bambas operations of MMG Peru, realized the economic impact of blast movement on ore loss and dilution and adjust ore boundaries using limited blast movement measurements. This is a step in the right direction but has limitations for everyday application. This paper discusses the advantages of disadvantages of current blast monitoring techniques and introduces an operational tool to estimate polygon movements for different blast designs and confinement conditions. Blast movement estimates from this new tool have been compared against the estimates from the current tools for several production blasts and the results were quite promising.

Mar 2, 2022

By Don Phelps, Christopher Tattersall, David McAllister

Located south of downtown Seattle, the Beacon Hill Station & Tunnels is the key section of the southern segment of Sound Transit’s proposed new LINK light rail system. This paper presents an overview of the design, which includes 4,300 ft of segmentally-lined bore twin tunnels and a deep mined station. With platforms located156 feet below grade, the station itself is only the second large-scale mined station in soil the US. Its complex geometry combined with variable soil conditions—sands, silt sand clays with slickensides—challenged the designer’s to come up with a SEM-based design that addresses the owner’s risk, cost and schedule concerns.

Jan 1, 2003