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By James McKelvey, Larry Drolet, Jason Swartz

INTRODUCTION When divers discovered that sections of a tunnel housing the pipeline that conveys wastewater from the Charleston Peninsula to the Plum Island Wastewater Treatment Facility had caved in, the Charleston Commissioners of Public Works(CPW) moved quickly to determine a long term solution for the city’s collection system, immediately focusing on the Ashley River sewer tunnel along the western boundary of the peninsula. Working with the Charleston community, as well as federal, state, and local officials, CPW developed a fast track yet long life design that can be used as a model for underground construction of tunnels in urban areas. The paper that follows summarizes key aspects of the Ashley River sewer tunnel project. HISTORICAL CHARLESTON Charleston, South Carolina is a culturally significant and historic city that was originally settled in 1670. There are over 100 buildings on the National Register of Historic Places within the Charleston area. Additionally, the first shots of the American Civil War were fired at Fort Sumter in the Charleston Harbor in 1861. As one can imagine, tourism generates significant business for the area with over 1.5 million people visiting Charleston each year. No project, especially one that requires digging, is done within the old city on the Charleston peninsula without careful planning. Many precautions are necessary to prevent damage or disruption to the historical properties. The Ashley River sewer tunnel project is exclusively in the old city. A lot of work was done during the design phase to minimize the impact to historical properties. Some of this work included: an archeological study (where pre-digs were monitored at all shaft sites by an archeologist); a building/structure assessment study (where structures near a shaft site were completely surveyed and cataloged); and an environmental study.

Jan 1, 2005

By Jens Gutzmer, Helmut Mischo, George Barakos

"It has been nearly eight years since rare-earth elements (REE) became the subject of frontpage headlines. It was when the controversial Chinese export policy for these critical commodities was epitomized in a maritime border dispute with Japan in September 2010 that resulted in the big REE crisis and price spike of 2011 (Barakos et al., 2016c; Mancheri, 2015).The world was dismayed, especially in REE-importing countries such as the United States that was, and still is, totally dependent on Chinese production and exports (Barakos et al, 2016c; Kennedy, 2015). The short-lived alarm initiated a treasure hunt by way of exploration for REE deposits all over the world. The continuously growing demand on the one hand, and the Chinese sovereignty of the REEmarket on the other, led the rest of the world to explore their own REE resources. In just a few years, more than 400 projects were initiated to explore REE deposits outside of China (ERECON, 2015; Goodenough, 2016).The prices of REE, however, dropped rapidly in late 2017 and were in six-year lows, before the 2011 crisis (Barakos, 2017). The viability of even major established producers is being challenged, not to mention the development prospects of potential REEmarket entrants (Barakos et al., 2016b; Rollat et al., 2016). Production cutbacks and industry consolidation in China have impelled REE market experts to forecast that prices have already reached their lowest point and have nowhere to go but up (Adamas, 2015; Roskill 2015). Yet, expectations for increased REE prices are limited and drastic changes are unlikely to happen in the near future, as there is still excess supply in the overall REE market (Barakos, 2017). Nevertheless, the low prices of rare earths are not the only reason that potential producers are struggling to enter the global REE market. Among other parameters, the separation process of the individual elements seems to be the most important factor, as it is technically challenging and expensive to build and to operate."

Jan 8, 2018

By A. G. Spencer, A. D. Taylor

This paper discusses some of the advantages and problems associated with the selection of large unit equipment for a metallurgical plant. A given flowsheet and material balance for an iron ore concentrator is assumed. Then two plant designs are developed, one utilizing a number of smaller-size equipment units and one utilizing the largest available equipment units. The mechanical and electrical problems are discussed and a comparison of capital costs is made. Finally, brief consideration is given to a plant de-sign using units larger than those which are currently available.

Jan 1, 1968

By W. A. Selvig

EQUIREMENTS of montan wax for industrial use in the United States before World War II were met by imports, nearly all of which came from Germany. An important industry for extraction and refinement of this wax from certain brown coals had developed in Germany. At the beginning of the war, montan-wax imports were shut oft, and American industry was forced to rely largely on substitutes. Since the war, relatively small amounts have been imported from Czechoslovakia. Because of the shortage of montan wax at the close of the war and the fact that industry in the United States had to rely on foreign sources in the past, this investigation was started in 1945 to determine probable yields of wax from domestic lignite. Results of the investigation and the properties of extracted waxes are described in this report. Also included in the report are discussions of the occurrence and geology of lignite deposits of the United States from which samples were obtained for wax extraction and the petrographic composition of lignites, particularly in respect to those components that contribute to wax yields.

Jan 1, 1950

By G. J. Abbaschian, A. B. Gokhale, M. M. Kunjapur

"A laboratory scale model furnace was constructed for obtaining radially inward oriented columnar grains in disc shaped castings. The furnace consisted of eleven circular, concentric, equispaced resistance heaters on each half of a split graphite mold. Water or air flowing through a copper pipe along the periphery of the disc constituted the heat sink. After filling the mold, the heaters were turned off consecutively in top and bottom pairs from the rim towards the center, causing the temperature gradients to move inward. Equiaxed structure was obtained at the center by turning off the inner coils together when desired. Sn:15%Pb alloy was used to cast integral blade disc castings using the above technique to obtain dual-property discs with a central equiaxed structure and an outer columnar grain structure projecting inwards from the blades to the rim. A numerical technique was used to predict the temperature profile in the disc during solidification, and good correlation was obtained with the experimentally measured temperature profiles. The corresponding heat transfer coefficient values obtained were h = 544 Wm- 2k-1 (0.013 cal/cm2- ° C-sec) for cooling between metal and chill and h' = 71 Wm- 2k-1 (0.0017 cal/cm2- ° C-sec) for the heat input from the hot mold to the liquid metal. BackgroundHigh temperature alloys used in the current generation of gas turbine engines have evolved through two main stages of development: in 1950's, the increase in the efficiency of gas turbines was paced by improvements in alloy design, which led to the development of Ni and Co-based superalloys (1). By mid-1960's, it was realized that improved alloy chemistry alone was inadequate in meeting the increasingly stringent service requirements. The focus of research then shifted from alloy development to process development, and resulted in the introduction of directional solidification (DS) techniques for the production of turbine blades and vanes (1,2).Under typical operating conditions, the blades and vanes are subjected to aerodynamic loading, while the blades are additionally subjected to high centrifugal loading and vibratory stresses. The primary material requirements for blades may be summarized as follows (1,3):•,High creep resistance•,Good high temperature tensile strength (typically in the range of•,275 to 550 MPa at temperatures in excess of 750°C)•,Resistance to both low cycle and high cycle fatigue (LCF and HCF)•,Resistance to erosion, corrosion, and oxidation•,Resistance to thermal fatigue"

Jan 1, 1986

By R Billingham

QueenslandÆs new safety legislation for metalliferous and coal mining (Mining and Quarrying Safety and Health Act 1999 and Coal Mining Safety and Health Act 1999, together with the Regulations) came into effect on 16 March 2001. The legislation places clear obligations on mine owners, operators and workers to have a safe place of work and to manage risks to safety and health. It also places obligations on contractors, designers and providers of services. The legislation is non-prescriptive in that it states what outcomes must be achieved and not what must be done. The key issue is that the risk of injury to people must be at an acceptable level. The legislation creates a Mines Inspectorate with powers of inspection and audit of mines, their safety management systems and the management of risks. Auditing of the risk management process is carried out against standard risk management techniques and directives for corrective action may be issued when audits reveal non-compliance or unacceptable levels of risk.

Jan 1, 2002

By Glasson K. R

The history of Ore Reserve classification and reporting in Australia is largely a history of the Australian mining industry itself. In the late 1800s, when the industry was dominated by small scale, high grade underground mines, Reserves (if estimated) were based on hand sampling and geological inference, and reporting of Reserves was either non-existent or of extremely variable quality. By the mid-20th century, the industry was dominated by large underground base metal and gold mines. Reserve estimation was coming under the control of skilled geologists and mining engineers, however Reserve classification and reporting standards continued to vary in type and quality from mine to mine. Today, large scale, low grade mining operations predominate, and Reserve estimates are generally based on extensive drilling results processed (with geological control) by computer. Through the efforts of a Joint Committee established by The Australasian Institute of Mining and Metallurgy and Australian Mining Industry Council, Reserve and Resource classification and public reporting has been standardised and controlled by adoption of the ""Australasian Code for the Reporting of Identified Mineral Resources and Ore Reserves"" released in 1989. The Code, which will continue to be modified and improved by the Joint Committee, has also been used as a basis for guides to reporting in other countries, and there is now some hope that this difficult and vexing topic may finally become subject to international standards and controls.

Jan 1, 1992

By E. H. Jr. Dix

THE use of magnesium as an alloying element in aluminum alloys has been limited, in general, to comparatively small quantities. In duralumin-type, strong-aluminum alloys, magnesium is present to the extent of ½ to ¾ per cent. and various grades of Magnalite and the "Y" alloy of the National Physical Laboratory of England contain up to 1 1/2 per cent. In this country small quantities of aluminum alloy sheet containing 4 per cent. magnesium are produced commercially. All commercial aluminum contains sufficient silicon to convert a portion of the magnesium added to the compound Mg2Si. It is well known that the solubility of both magnesium and magnesium-silicide decrease with decrease in temperature. It is, therefore, impossible to separate the age-hardening effect of the magnesium-silicide from that of magnesium, except by the use of aluminum of such high purity that the silicon content is negligible. The present paper is the fifth1, 2,3,4 of a series from the laboratories of the Aluminum Co. of America reporting the results of investigations of the equilibrium relations in aluminum-rich alloys made from the high purity aluminum manufactured by this company .5

Jan 1, 1929

By E. J. Garrison

A.C. Noble presents a clear and concise summary of the factors pertinent to a competent reserve evaluation of a mineral occurrence. However, I believe that he confuses the difference between a resource and a reserve. By definition, a reserve estimate includes all known economic, legal, mining, metallurgical and environmental factors impacting the recovery of the product(s) found in the deposit. A resource estimate, however, is an estimate of what is there - what is available for exploitation and should not include economic and other considerations. Only after defining the resource, its extent, location, physical and chemical properties, can an intelligent selection process begin of the extraction and processing technologies most appropriate to the circumstances encountered. The early and almost certainly inappropriate application of these often cookbook choices has probably lead many companies to walk away from good properties. (How many mines have been found in others rejects?) An example of the process is the early selection of metallurgical samples, after encouraging values are found in a few holes or surface samples, in an attempt to determine the economics of the prospect. Unfortunately, the sampler does not know how representative of the occurrence the sample is because he does not know what the deposit looks like. As a consequence, the property becomes saddled with a bad metallurgical sample that is often inappropriately used in evaluating the deposit which it does not represent.

Jan 1, 1994

By B. Wasmund, B. Haneman, G. Sheehan

Success in implementing new technology for metallurgical processes is not a foregone conclusion: This paper includes a survey of 23 new technology-based metallurgical plant start-ups, in which the authors have identified 7 successes, 9 difficult start-ups, and 7 failures. Success is defined not only as meeting the schedule and budget to the end of mechanical completion; the key goal is a fast ramp up to the full design production level, with minimum plant and equipment modifications required after start-up. This paper sets out the key factors that underlie achievement of a quick production ramp up curve, as determined from the authors' project experiences and a quantitative analysis of over twenty metallurgical plant start-ups, both pyrometallurgical and hydrometallurgical. Thorough test-work and pilot plants, plus appropriate scale-up to the full commercial plant, are key determinants of success in implementing new technology in metallurgical processes. Another critical factor is the number of new elements and their interactions. Project phasing is also particularly important for new technology projects, with appropriate review after each phase to develop a risk mitigation plan for the subsequent phase. New technology projects need committed champions to advance the project in the face of sceptics, but also require dispassionate and unbiased experts to ask the hard questions. As a project evolves, it is important to periodically question the appropriateness of assumptions, as well as to re-assess the relevance and completeness of data from test-work I pilot plants I industrial analogues. Sufficient human and financial resources are required to complete the often arduous implementation phase. During the ramp-up period, the operation generates little positive cash flow; however, significant expertise and capital are required for the de-bottlenecking projects that are often necessary to reach the plant's design output level.

Jan 1, 2011

By I. A. Kunasz

This paper is not intended to review and re-state general information on lithium, but rather to analyze the paradigm that has caused such a rapid rise in lithium production and the development of new lithium producing centers. Details on pegmatites, brines, concentrate and chemicals are amply covered in a number of publications ? SME?s Industrial Minerals and Rocks, Industrial Minerals, Roskill and a host of other publications. There is no question that the latest interest in lithium has been driven by the potential development of the electric car. This stimulus prompts one to recall two symposia: 1. ?Lithium Resources and Requirements be the year 2000?, organized in 1976 by the U.S.G.S. in Denver (1) and the sequel 2. ?Lithium ? Needs and Resources? at Corning, N.Y. (2).

Jan 1, 2011

By Onur Golbası, Berk Gokce

Investment decisions in the mining industry are complicated by sector-specific uncertainties. This study presents a multi-submodule system dynamics model to capture the dynamic complexities of decision-making across mineral property development stages. The model includes five interconnected subsystems: valuation, production, growth strategy, demand, and finance. Developed through system decomposition, expert input, and literature, the model is tested on a hypothetical copper mine with 850 ktpa capacity and 1% cu grade. Simulated over five years with quarterly steps, it estimates an enterprise value of $78.9 million and a target growth rate of 11.2%. Results highlight the significant effects of operating costs, capital policies, and inflation on free cash flow, and the critical role of mineral reserves in sustaining growth. This model supports strategic investment analysis across different minerals and development phases, offering mining investors a robust tool for optimizing decisions.

Feb 22, 2026

By Michael F. Kitto

The production of sulphuric acid at base metals smelters is predominantly an involuntary activity and now comprises approximately 17% of all-forms sulphur supply in world terms. The majority of elemental sulphur is also produced involuntarily in response to environmental regulations regarding emissions from hydrocarbon processing plants. The paper examines the points of similarity and difference in the sulphur and smelter acid markets, and reviews their interactions. The reasons for the merchant acid market collapse of 1993 are analyzed, and the prospects of a recurrence are considered.

Jan 1, 1996

By Ronald B. Stone

This paper describes a proposed solution to the problem of mining a 315 foot diameter unsupported sphere at a depth of 2700 feet in a salt dome by conventional mining methods. The proposed solution utilizes many of the varied technologies available to the mining engineer for solving mining and underground construction problems. The following are reviewed in the paper: A. The location of the sphere within the dome as required by construction criteria. B. The relation of the location of the access shafts to the sphere. C. The rock mechanics theory in relation to the salt dome and large size of the excavation. D. The proposed "honeycomb" method of mining which will be a partial answer to rock mechanics stability requirements. E. The equipment which it is recommended be utilized to accomplish the construction. F. The rock mechanics measuring instruments proposed. G. The methods of disposal of the mined salt. Conclusions and areas of further study are outlined in the final statement.

Jan 1, 1968

By Thomas S. Lovering

Hot springs, geysers, steam-emanating fumaroles- these creatures of nature were until recently little more than geological curiosities, but today they are exciting the interest of engineers around the world for it has been shown that such hyperthermal areas can be profitably harnessed by man to provide heat and power for his communities. Although water from hot springs was used centuries ago to heat some Korean dwellings, is being used today by one-third of Iceland's population for similar purposes, and is finding industrial applications in New Zealand and elsewhere, the most dramatic use of geothermal energy has been its conversion into electricity. The largest installation at the present time is that at Larderello, Italy, where the Count of Larderello began to experiment in the production of electricity from geothermal steam in 1904. Eight years later after a quarrel with the local power company, the Count installed his first steam turbine, a unit of 250 kw capacity.

Jan 9, 1965

By Pedram Sahba

In today?s emerging economy, pooling resources is a growing trend to reduce overall system costs. Two important resources of every maintenance department are repair shops and spare parts. In this work, we consider a system consisting of mine drills at multiple areas in a mine. In each area, a number of identical drills are operational. When a failure occurs, the defective component should be repaired in a designated repair shop. The failed component can be replaced immediately if a spare part is available. Otherwise, the drill is down until a component is repaired and put back into service. In this paper, the effect of pooling resources is examined, and the conditions under which it is beneficial to pool the resources are investigated. In addition, determining the optimal number of stand-by units, equipment or spare parts, in each case is of interest.

May 1, 2013

By Kenneth S. Johnson

Large reserves of high-purity Permian gypsum crop out and are at shallow depth in three regions of western Oklahoma, Gypsum beds in the Blaine Formation are 10 to 30 feet thick and are generally 95 to 99 percent pure, whereas the massive Cloud Chief Gypsum is 20 to 100 feet thick and is 92 to 97 percent pure. Reserves are estimated at 48 billion short tons. Eight companies in the State currently mine about 1 million tons of gypsum each year for wall- board, for plaster, as a retarder in portland cement, and as a soil conditioner. Future uses, under more favorable market conditions, may be in the chemical industries, largely because of gypsum's potential as a source of sulfur. Three thick sequences of Permian rock salt underlie most of western Oklahoma at depths of 30 to 3,000 feet. Individual salt beds 5 to 30 feet thick are interbedded with thinner layers of shale and anhydrite. Five large salt plains, fed by natural springs of saturated brine constitute additional resources of salt. Reserves, estimated at 20 trillion short tons, are virtually untapped, and, ironically, about 90 percent of the salt used in Oklahoma is imported. Chemical data on the rock salt are lacking, but evaporated salt produced from brines is generally 97 to 99 percent pure. Current production from three solar-evaporation plants is used mainly for stockfeed, recharging water softeners, and deicing roads. Potential uses are in the chemical industries, where salt or brine is a necessary raw material.

Jan 1, 1973

By Malcolm Mudge

"One of the oldest mining areas in the World exist in Africa and the Middle East. This area is being exploited by foreign and local mining entities. Several large plants, both foreign and local as well as small operators, conduct their mining business on a scale which would be could be prohibited in any other part of the world. Relatively recent European disaster with tailing disposal and breakout has highlighted the problem.More important to the author is that the presence of foreign entities in zones which have not remedied the situation but has heightened the concern due to those entities using similar outrageous methods in treatment of waste. The abject misuse of technology cannot be permitted to continue and the lack of any metallurgical knowledge in the treatment of gold ores is considered deplorable for the majority of third world countries.The destruction of cyanide is simple and straightforward and requires no special skills. In South America, we developed a system that is modular, compact and can be operated in batch mode to cater for several clients, as required. Larger installations would require a separate module, as treatmentwould be on a continuous basis."

Jan 1, 2003

By L. Xinguang

Shandong MinMetals Corporation, a state-owned import and export organization located in the city of Qingdao, Shandong Province, China, was opened in 1954, with the mission of marketing metal products and industrial raw material in oversea areas for hard currency to support the modernization project of the country as well as the province. The management officers are appointed by the provincial government, and report to the Foreign Trade Department of Shandong Province. Meanwhile, the company also receives guidance from MinMetals head office in Beijing, the capital city of China. The head office does not own and control any provincial MinMetals organizations, but merely coordinate business among provinces.

Jan 1, 1990

By H. Lawson

The Mine Safety and Health Administration (MSHA) issued Program Information Bulletin P09-03in April of 2008, providing formal guidance on using programs that model the redistribution of stress during underground mining of coal. A key part of this guidance is visual observation and mapping of ground conditions. If a correlation between ground conditions and model output can be established, the model is considered to be verified, and can be used to guide mine design in similar ground. A simple scale is recommended for ranking observed roof, rib, and floor conditions. This paper discusses optimization and implementation of a ground condition rating scheme in the gateroads of a deep underground longwall coal mine. Roughly 80% of each gateroad length deteriorated in a fairly uniform manner. However, this manner varied between gateroads, as did pillar size. The implementation of a ground condition mapping program, similar to that recommended in PIB 09-03, was successful in characterizing the ground response to mining in gateroads of a longwall coal mine.

Jan 1, 2012