Search Documents

By D. W. Leyshon

The fluidized solids technique for the calcination of phosphate rock has been well established for over 10 years. This paper is intended to review the recent performance of many of the Dorr-Oliver FluoSolids* calciners. In addition, design features of these three compartment refrac¬tory construction reactors will be described and a comparison made with fuel requirements for single compartment calcination. Also presented will be certain, aspects of the use of the rock including a discussion of non sulfate sulfur in the rock. A system is described for producing a blended mixture of calcined and uncalcined rock.

Jan 1, 1972

By Earle Faig

Earle Faig Along with other transportation modes, the barge industry will be greatly affected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country's energy program. Perhaps even more significantly, a series of events has caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of its long experience in moving large quantities of coal, the barging industry is in an excellent position to capitalize on coal's increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to that industry. Barge companies operate on a river system that is over 40 Mm (25,000 miles) long. It includes the East and West Coasts and the Mississippi River System comprised by the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior-Tombigbee, and Mobile Rivers, and some smaller tributaries. The Gulf Intracoastal Waterway stretching along the Gulf Coast from Brownsville, TX, to Apalachicola, FL, also is considered part of the inland waterway system. Approximately 1,800 companies operate on the inland river system and have a combined fleet of about 4,400 towboats and 28,000 barges. The fleet of towboats represents 4.8 GW (6.4 million hp) of power. The towboats comprising this fleet vary in size from a small harbor boat to a large line haul boat with 7.5 MW (10,000 hp) of power. The choice of size and power of the boat depends on a number of factors, including the size of the river and operational constraints, such as lock size, river-current rate, and water level. The choice also depends on the tow size. A single tow on a river capable of locking through 15 barges at a time handles up to almost 20 kt (22,000 st), whereas a tow on the lower Mississippi, which has no locks, can accommodate up to 41 kt (45,000 st) of cargo. Because the quality of coal is not typically damaged by exposure to the elements, it is usually moved in open hopper barges, although covered barges are used occasionally. The most frequently used size is the jumbo barge that measures 59 m (195 ft) long by 11 m (35 ft) wide by 4 m (12 ft) deep and can handle up to 1.4 kt (1,500 st) of coal. Advantages of Barge Transportation Barging offers several inherent advantages in transportation of bulk commodities like coal. First, barges can carry large quantities of product. A single jumbo hopper barge can handle 1.4 kt (1,500 st) of cargo while it takes 15 91-t (100-st) capacity rail cars or 57 trucks hauling 24 t (26 st) each to move an equivalent amount of cargo. Thus, barges can move more tonnage with less equipment than competing forms of transportation. Second, barging offers the most fuel efficient means of transportation. Less energy is required to push a load over water than to pull a similar load over land. The amount of pollution attributable to barge traffic is minimal because barges consume less fuel. Third, barging is an inexpensive form of transportation. The inland waterway industry transports about 12% of the nation's freight for about 2% of the total freight bill. This can be attributed to competition between the large number of companies on the river system and competition with other transportation modes. Fourth, barging is an environmentally safe method of transportation. Inland river routes expose fewer urban areas to hazardous substances than rail or truck. And barge spills occur less frequently than rail or truck spills. The industry does pose some disadvantages. The waterway system is constrained by the natural river network, so barges cannot travel on the most direct straight-line route. This means that barging is usually an incomplete form of transportation requiring interface with truck or rail. The industry's market is limited to those geographical areas that are located on or near the rivers. In addition, it is a time-consuming transportation mode, making it impractical for many types of commodities.

Jan 10, 1982

By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By Jim Britton

Sustained elevated metal and coal prices in 2011 continued to drive mining projects across British Columbia. The province is the top producer of copper, exporter of coal and the only producer of molybdenum in Canada. The province also produces significant amounts of gold, silver, lead and zinc and more than 30 industrial minerals. The total 2011 value of solid metal production is an estimated $8.6 billion and the outlook for 2012 is positive. British Columbia is poised to bring several new mines onstream in the next few years. Construction continues at the New Afton and Mt Milligan copper-gold projects that are anticipated to be open in 2012 and 2013, respectively. The provincial Environmental Assessment Office indicates there are 26 mine proposals in process with three currently under review and 23 in the preapplication stage. The following text briefly describes 2011 metal and coal mining activities in the five regions reported on by the provinces? regional geologists (Fig. 1).

Jan 1, 2012

By A. W. Czarnowsky

More than ever before, mining projects are besieged from growing regulatory, political, public, and special interest group pressure. Administrative and legal appeals to permits and environmental documents can delay project start-up and add tremendous cost to mineral development. Some mining projects have been canceled given undue external constraints. Successful managers must learn to cope with these constraints. This paper will discuss controversy and present a number of environmental management tips to minimize the potentials for delay and to lessen the impacts from government and anti-mining pressures.

Jan 1, 2001

By J. Best, K. Gallant

This paper explores the age-old concept of mine-mill reconciliation from a new perspective. Advances in reconciliation processes have been slow to materialize because in the quest for “rightness”, engineers, geologists and metallurgists have become entrenched in their viewpoints, dutifully performing to the metrics and expectations imposed upon them by the siloed organization. Moreover, reconciliation has not been viewed as a primary value creator, but an accounting non-value added task. In reality, the knowledge from reconciliation can significantly enhance yields. Critical review of the direct variables (tons, grade, etc.) and other less-obvious variables (incentives, communication, etc.) reveal a complex web of barriers to be cleared by management in order to realize benefits. Also, mineralogical reconciliation methods may offer renewed faith in the process.

Jan 1, 2004

By L. K. Bandyopadhyay, P. K. Mishra, S. K. Chaulya, R. S. Singh, A. Kumar, N. Tripathi, K. Mandal

A comprehensive field study has been carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling has been carried out to envisage dust concentration due to the existing and closed mines in the region. The predicted total PM10 and PM2.5 levels at the selected receptor locations ranged from 86.39 to 194.89 and from 34.82 to 99.55 µg/m³, respectively.

Jan 12, 2022

By D. McSwain-Santos

Soda ash is the trade name for sodium carbonate, a chemical refined from the mineral trona or naturally occurring sodium carbonate-bearing brines (both referred to as natural soda ash) or manufactured from one of several chemical processes (referred to as synthetic soda ash). It is an essential raw material in glass, chemicals, detergents and other important industrial products. Production U.S. soda ash production during 2004 increased to10.9 million Mt (12 million st). Five companies comprised the domestic soda ash industry. Four were in Wyoming operating five plants. One was in California with one plant.

Jan 1, 2005

By R. L. Virta

Six companies mined fire clay in Missouri and Ohio during 2004. Production, based on a preliminary survey of the fire clay industry, was estimated to be 398 kt(438,700 st), valued at $9.81 million. This was slightly less than the production and value figures from 2003. Missouri was the leading producer state. It accounted for more than 70 percent of the U.S. production. Consumption Domestic producers sold or used fire clay primarily for refractory applications. This application accounted for 79 percent of the market. Refractory products made using fire clay include firebrick and block, grogs, high-alumina brick and specialties, refractory mortars and mixes, and saggers.

Jan 1, 2005

By Roger K. McLimans, Venkatramaiah N. Vasudev, Christian Knudsen, Stefan Bernstein, Dirk Frei

Computer Controlled Scanning Electron Microscopy (CCSEM) analyses of sediment samples from coastal regions of Kerala and Tamil Nadu states and the heavy mineral deposits of Chavara, South India, show large lateral differences in the titanium content in ilmenite due to varying degrees of iron leaching. As the depositional environments for the sands with varying degrees of ilmenite alteration are comparable, the cause for the different degree of alteration is due to differences in the primary source of the ilmenite or to differences in the geochemical history of the ilmenite grains during transport from source to deposit. The CCSEM analyses of the heavy mineral fractions show that source of sediments with a high content of titanium-enriched ilmenites, mainly the heavy mineral deposit around Chavara, resides in the khondalite belt of South India (granulite facies metasediments). The less titanium-enriched ilmenites are sourced from other rocks in the area such as the charnokites. Those conclusions are based on the high MgO content in the leached ilmenites, chemical composition of the accompanying garnets (low CaO and high MgO), and the concentration of aluminum-rich minerals in the sands.

Jan 1, 2005

By M. T. Webster

Views about the proper aim of public policy are, of course, matters of perspective and debate. Regardless of perspective, one would assume some consensus around the view that public policy ought to encourage mine operators to seek independent and critical assessments of worker safety and health at their operations through voluntary auditing. However, a review of the law on this topic shows that there is little to no manifestation of such a policy. Indeed, the balance of this paper, with a couple of exceptions, is devoted to the existing legal pitfalls that should be considered before a safety and health audit is conducted at a mine. While attorneys, particularly litigators like the author, might tend to focus on the potential problems that could arise from any given situation, the fact that most of this paper is devoted to potential legal concerns associated with auditing is a realistic reflection of the current state of the law. Specifically, this paper addresses the interplay between voluntary safety and health audits conducted at mines regulated by the Mine Safety and Health Administration (MSHA), and the administrative and civil legal issues related to such audits. The paper first provides an explanation of how and by whom an audit is conducted. The paper also addresses whether voluntary safety and health audits may be considered privileged and kept confidential in administrative and civil proceedings. Finally, selected legal issues related to such audits that could arise in administrative and civil litigation are discussed.1

Jan 1, 2012

By R. E. Krauss

The McLaughlin Mine is a world class epithermal gold deposit located in the coastal thrust fault of Northern California, U.S.A. Homestake adopted a proactive strategy in the permitting of the Mine. Extensive environmental base line studies were undertaken. Engineering and process alternatives were evaluated for environmental impact along with other factors. A unique pressure oxidation process was selected. Screening studies were conducted as a basis for the selection of waste rock and tailings disposal sites. Project engineering and permitting were fast tracked. Construction required eighteen months and the first gold bar was poured in Parch of 1985, six years after the initial discovery. Project facilities are designed and operated so as to minimize environmental impacts. A comprehensive monitering program demonstrates permit compliance. Reclamation of the site is ongoing throughout the Mine?s twenty year life. Non-mined lands are managed to maximize wildlife habitat value.

Jan 1, 1990

By R. L. Virta

Four companies mined ball clay in four States during2004. They were H.C. Spinks Clay (owned by Franklin Minerals) Kentucky-Tennessee Clay (owned by Imerys),Old Hickory Clay and Unimin. Production was estimated to be 1.46 Mt (1.61 million st) valued at about $56.9 million, based on a preliminary survey of the ball clay industry. In 2003, production was 1.31 Mt (1.44 million st) valued at $56.2 million. Tennessee was the leading producer state with 61 percent of production. It was followed by Texas, Kentucky and Mississippi.

Jan 1, 2005

By A. M. Radigan, W. G. Prast

M.S. Azun The authors' paper did not explain the facts and reasons why state companies are established and what their role is in international industrial mineral trading. Also, I do not agree with the conclusion implying that the main goal for state companies is to capitilize natural resources. Almost all state companies are founded by certain laws and their activities are arranged by state regulations. Their only aim is to operate mineral deposits for their people and to protect the rights of the people. Although some ore deposits, such as nonstrategic or small, may be exploited by privately owned companies, the state has the right to control the operation and production. Activities of state companies may or may not be widened because of the character of the deposits and the importance of the mineral market involved. For some countries, although governments may occasionally change hands, the policy of the mineral trading system is not affected by this change. There is no doubt that any government desires to make more earnings to increase GNP, when it is involved in operating and trading mines. It wants to produce and sell the finished products, instead of unprocessed ones, if possible. When it is known that some mineral deposits are relatively rare, such as Turkish boron deposits, the government can nationalize the mines to control production and affect the market. If there is an abundance of a certain mineral in the market, the government can cut production and set a floor price, such as Canadian potash. Also, when production of a specific mineral is unique, such as Turkish chromite, the price of such mineral may be set by correspondant government. One may add that if some governments with their state companies produce a certain mineral in a larger amount, they may decide to establish a cartel to protect their production and price. These are the facts followed by government-owned state companies and partially government-owned companies. The reason being charge of many deposits by the state companies is always the same: "protect" the mineral rights of the people.

Jan 2, 1984

By B. S. Pierce

The National Coal Resource Assessment – 2000 project was a multi-year effort by the U.S. Geological Survey to identify, characterize, and assess the coal resources that will supply a major part of the Nation’s energy needs during the 21st century. The purpose of the USGS National Coal Resource Assessment (NCRA) was to (1) digitally assess selected coal beds and zones that will be the most important in the next few decades, (2) create publically available stratigraphic, geochemical, and geographic information system (GIS) databases to answer a variety of questions of importance to government, industry and public decision makers, and (3) provide interpretive geologic and geochemical information for the primary coal resources of the Nation. Five priority regions were assessed: the Appalachian Basin, Illinois Basin, Gulf Coast, Illinois Basin, and Northern Rocky Mountains and Great Plains. The NCRA was a cooperative effort between the USGS and a number of State geological surveys in these coal-bearing regions. A study of coal resources on Federal lands was also conducted. Adequate energy supplies and the efficient use of those supplies are critical to the economic well being of a country. Affordable and reliable coal supplies are essential to the interests of our national and local policymakers. Policy makers require a range of information on the energy supply, as well as the economic and environmental issues associated with that energy source and its use. Formulation of an effective national energy policy and development of energy resources requires that we understand the geology, distribution, quality, and size of the national energy endowment.

Jan 1, 2001

By M. V. T. Da Silva, J. C. Harrison

Eldorado Gold Corporation of Vancouver, B.C. owns and operates three gold mines. The São Bento underground gold mine in Minas Gerais State, Brazil produced 105,907 ounces in1997. The La Colorada and La Trinidad open pit, heap leach mines in Mexico produced over 83,000ounces in 1997. With a deteriorating gold market plaguing the industry throughout 1997 Eldorado had to take critical measures at each mine to enhance gold production while lowering cash operating costs. Each mine had its own unique problems to confront. This case study will discuss three distinct courses of action taken at the three mine sites.

Jan 1, 1999

By R. L. Virta

Common clay is a natural, fine-grained material composed of hydrous aluminum silicates. Shale is a laminated sedimentary rock that is formed by the consolidation of clay, mud or silt. Production About 160 companies produced common clay and shale in 41 states. In states not reporting production, common clay and shale probably was mined and sold for construction applications by companies not participating in the U.S. Geological Survey’s canvass of producers.

Jan 1, 2005

Commercialisation of outcomes from research projects is a process often poorly understood and managed, but has the potential to achieve significant benefits for the industry and community as a whole. JKTech Pty Ltd was established in 1986 to transfer viable research outcomes from the Julius Kruttschnitt Mineral Research Centre (JKMRC) at The University of Queensland, Australia. This paper describes successful and unsuccessful examples of commercialisation by JKTech over the years, and draws some conclusions as to the factors that contribute to success and failure in technology transfer.

Jan 1, 2012

By A. Karami

It is well established that an ordered sequencing of charge initiations in a blast pattern is an important design consideration that affects blasting performance. Delay times must be chosen such that damage to the rock mass is controlled. The accuracy of delay detonators is also of major concern. A large scatter could lead to an incorrect blast sequencing that would lead to damage to the rock mass causing increased over-break, degraded fragmentation, increased fly-rock and poor vibration control. In this study, the effect of using accurate delay detonators on the explosive energy generated is investigated. For this purpose, power spectral density of the blast vibration for delayed shots are calculated and compared with the case where holes are shot at the same time (no delay). At the end the results are presented and discussed.

Jan 1, 2000

By R. C. Milici

The primary factors that determine the marketability of coal from various supply centers in the U.S. are coal quality and supply; i.e. low sulfur, moderate- to high- Btu coals have large market areas when compared to less expensive but poorer quality coals. Price is the major factor in the competitive marketing of similar coal products. Good quality, (moderate- to high- Btu, low sulfur) coals from the Powder River and central Appalachian basins are marketed over large areas of the country, and central Appalachian coal is widely distributed in foreign markets, primarily as coking coal. In contrast, poorer quality bituminous coal (low calorific value and/or high sulfur) from the Illinois Basin, northern Appalachian Basin, and lignite from the Gulf Coast is marketed in or near the States in which it was mined even though the price at the mines may be lower than mine prices for central Appalachian coal. Widespread distribution of sub-bituminous Powder River Basin coal is enhanced by its exceptionally low mining costs, which offsets transportation costs to distant markets.

Jan 1, 2001