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By F. G. Rinker

The world demand for metallized iron continues to increase, keeping pace with steelmaking requirements for lower cost hot metal. Virgin iron ore and in-plant oxide fines can be reduced to direct reduced iron (DRI) and hot briquetted iron (RBI). MR&E has developed an improved coal-based process for cost-effective production of either DRI or HBI. Starting with dry compaction, the process combines the latest technology for material preparation, rotary hearth furnace construction and environmental control. Coarse iron ore fines are blended with pulverized non-metallurgical coal to produce a highly metallized (>90%) product. This paper presents production and installation cost data based on operating and under-construction iron oxide reduction facilities.

Jan 1, 1999

By Christophe Bragard, Rebecca Reeve

The Regional Connector Transit Corridor (RCTC) Project is a 1.9-mile-long metro light-rail extension project that traverses the historical core of downtown Los Angeles, California. This project aims to improve mobility throughout downtown LA with fewer transfers for riders. It is designed to connect two existing rail lines for a more seamless travel. The project consists of twin bore tunnels, three new stations, and is scheduled to be completed in 2022. The design-build contract was awarded to the Regional Connector Constructors (RCC) in 2014, a joint venture of Skanska and Traylor Bros, Inc. with Hatch Mott MacDonald as the designer. One of the challenging aspects of the project was the construction of a crossover cavern in a narrow public right-of-way surrounded by historical structures. RCC used Sequential Excavation Method (SEM) to construct the crossover cavern measuring 287 ft long by 58 ft wide by 36 ft tall. The initial lining of the cavern featured a 12 in. fiber reinforced shotcrete lining. The initial lining was separated from the final lining by a hydrocarbon resistant membrane, as specified by the standard requirements of Metro. The cavern features a cast-in-place final lining with a thickness of 5 ft 9 inches in the invert and 18 inches in the crown and walls. The structure also features a nonload bearing plenum slab and interior walls for ventilation.

Jun 13, 2021

By D. W. Scott

Ontario has a diverse industrial mineral resource base including abundant resources of structural industrial minerals such as sand and gravel, crushed stone, building stone, clay, shale, limestone and dolostone. These resources are used in the production of aggregates, brick, metallurgical stone, fillers, lime, cement and other construction materials. The majority of the operations are in deposits of Paleozoic and Quaternary age in southern Ontario, close to the major markets. Province-wide, there were over 140 million metric tonnes of aggregates produced in 1985, approximately 115 million tonnes of which was produced in southern Ontario with the remainder being largely from Crown land in northern Ontario. The structural industrial minerals account for over 80% of the value of total industrial mineral production, with the remaining 20% of the value king accounted for by the non-structural minerals being led by salt which is produced in southwestern Ontario. A host of other non-structural industrial minerals are known but production is currently restricted to calcite, gypsum, quartz, talc, nepheline syenite and by-product metallurgical sulphur products (Fig. 1). Location and Market Area Major production is in the area closest to the large markets of urbanized southern Ontario and the northeastern and north-central United States. In general, with the abundant variety and widespread resources of industrial minerals and the large population within 400 miles of most deposits, the market offers great potential. Ontario's 9 million population accounts for about 35% of the entire gross domestic product of Canada of $476.361 billion dollars in 1985. This equates to about 113 of the nation's buying power being within a 200 km (125 miles) radius of Toronto. This major concentration of industrial and economic activity has resulted in a well developed industrial minerals industry fulfilling most of the structural industrial minerals demand in Ontario, as well as a subsidiary demand in neighbouring provinces and states.

Jan 1, 1987

By S. C. Howell

The mining of taconite, to provide feed for a processing plant, requires that the flow of material continue uninterrupted. This means first, that the crude must be of a size acceptable to the primary crusher in order to reduce the delays caused by plugging the crusher with chunks. Secondly, elimination of oversize in the pit will reduce costs of all wear parts used in the mining and processing of taconite. Savings in wear parts is readily recognized in dipper teeth, bases, buckets, truck boxes, and crusher parts, both primary and secondary. During the early days of taconite mining, it was soon recognized at reserve mining company's Babbitt operations that experience in mining other ores was not always (or ?necessarily??) Applicable to excavating taconite. This was especially true in drilling and blasting. Blasting of small tonnages in single or double rows simply filled the pit with scattered chunks and provided very shallow banks for shovel loading. It also created problems for the jet piercers, since all drilling had to be performed in fractured areas. Drilling efficiency suffered and costs were extremely high. Shovel and truck efficiencies were also low and again costs were high. A high percentage of secondary breakage was required. This necessitated the use of numerous man hours to jackhammer holes in chunks, preparatory to loading and blasting. After the chunks were reduced, bull- dozer and grader hours were needed to pile the taconite for acceptable shovel loading.

Jan 1, 1968

By B. Salopek

The greatest part of crushed stone, gravel and sand production is extracted through open pit operations, whereas gravel and sand are also partially extracted from riverbeds. Its obvious that such a mining activity provokes some changes in the configuration and environmental characteristics of the region, in the temporary or permament disapperance of vegetable or animal species and in the creation of noise, dust and waste water. However, the above-mentioned mining operations shouldn not have only negative effects on the landscape and land potential, but they can discover and predetermine the potential of the exploited areas for various communal purposes after exploitation (eg. sports and recreation centers, campsites, resorts, fish-farms, etc.). In this paper, the production of construction aggregates in plants located in the vicinity of Zagreb, the capital of Croatia is presented. The advantages and disadvantages of aggregates? production in urban areas in the spirit of sustainable development are discussed.

Jan 1, 2003

By Kailash Narayan

Atlantic Richfield Company began operating a commercial uranium solution mining project in April, 1975 in Live Oak County, 10 miles southwest of the town of George West (Figure 1). The operation is designed to produce 250,000 pounds of U303 per year and is jointly owned by Atlantic Richfield Company, Dalco and U. S. Steel. The proprietary process employed in this operation consists of injecting an alkaline leaching solution into the ore-bearing formation through a pattern of injection wells. The uranium-bearing solution is then removed through producing wells using submersible pumps in central production wells. The produced solution is pumped through a pipeline to the plant area where the uranium is extracted. The barren solution is refurbished and returned to the pattern area for reinjection. The injection field and plant site are located in the drainage of Spring Creek, a small intermittent stream tributary to the Nueces River. Land use in the area is primarily agricultural -- cattle ranching and farming -- but several producing gas fields are present in the areas as well.

Jan 1, 1976

By Haydn H. Murray

In 1967 a large kaolin deposit was discovered on the Jari River, a tributary of the Amazon, in the territory of Amapa in Brazil. The kaolin occurs in the Barreiras Series of Pliocene age and is part of the Belterra Clay. The kaolin was drilled and tested, and today a modern processing plant is producing over 150,000 tons per year of high quality paper coating clay. Some of the problems associated with the mine development, processing, personnel, and marketing of this remote kaolin deposit are discussed. The mineralogy and physical properties of the Jari kaolin deposit are also described.

Jan 1, 1981

By Madeline Mello, Michael Low, Nick Karlin, Bryce Scofield

The LA Effluent Outfall Tunnel is the first tunnel in the United States to incorporate post- tensioning into the precast segmental lining. Several unique components were integrated to ensure that the post tensioning could be carried out successfully in the tunnel, even concurrently with the TBM excavation. This also required the development of new processes both in the casting facility and in the TBM to ensure that the almost 3,700 rings could be successfully manufactured, threaded, stressed, and grouted. This paper will discuss the material selection, fabrication, and installation of, as well as lessons learned from, this first in country tunnel lining.

Jun 23, 2024

By Charles E. Weaver

A core from the La Camelia attapulgite mine in north Florida was studied in detail to determine the detailed vertical variability and the relations of the various parameters. The structural, textural, mineralogical and chemical data indicate there are two major depositional cycles represented within the minable interval. The sediments deposited during the two cycle differ in detail but in general are similar. The environments of deposition grade from shallow marine to lagoonal to tidal flat to marsh. The sedimentary structure (lamination, burrows, pebble conglomerate), mineralogy (attapulgite, montmorillonite, sepiolite, dolomite, calcite) chemistry (Al, Mg, Fe) are closely related to each other and their nature is determined by the depositional environments. Most of the clay minerals and carbonate minerals are authigenic and are therefore particularly sensitive to environmental differences. The variability and environmental features seen in this core are characteristic of the sediments in the general attapulgite mining area. A detailed understanding of the relationships discussed should be of value in prospecting, mining and processing.

Jan 1, 1972

By William C. Larson

The number of uranium in situ leach operations has increased significantly since 1975. As of May, 1980, there were a total of 27 active projects, including 16 commercial scale operations (or under construction) and 11 pilot scale operations. The south Texas uranium district and Wyoming have been the most prominent areas in early field experiments as well as in commercial application of this new recovery technique, although in situ leach tests are now being conducted in Colorado and New Mexico. The growing number of commercial-scale operations is accepted as prima facie evidence that in situ mining now offers a third option along with open pit and underground mining for winning uranium from sandstone host rocks. It is estimated that in 1979 about 9 percent of the nation's total uranium production was from in situ mining. However in situ mining of uranium is not without its environmental controls. The primary emphasis of environmental controls falls into two catagories; namely, control of the leach solutions during mining and demonstration of ground water restoration. Finally this paper briefly reviews the Bureau of Mines research program in uranium in situ mining.

Jan 1, 1980

By Ronald T. Cosburn

The Province of Ontario covers an area of some 400 thousand square miles, however the subject I will be talking about today, the licencing of pits and quarries in southern Ontario, refers to about one quarter of this total area but contains better than 93% of the total population of the province or about 8 million people. Southern Ontario had and still has many inviting features to industry. The Great Lakes almost surround us, hydro power has been relatively inexpensive and abundant, but more in line with our topic today are the ample deposits of sand, gravel and limestone, all of which are used directly or indirectly throughout and are the mainstay of our construction industry. I say we are fortunate to have these non-renewable resources in abundance in close proximity to our industrial and metropolitan areas, but like so many of our resources we have taken them for granted for too long. What has happened in our case, as I am sure is common in many of your own similar situations, because of the recent, current popular trend by naturalists and environ- mentalists to preserve our natural heritage at the expense of all else, through parklands and indiscriminate zoning policies, these once abundant reserves have been tremendously eroded.

Jan 1, 1982

By P. A. K. Wilkinson

This paper is concerned with the development of an in situ recovery of boric acid from a deep-seated colemanite deposit in California. The deposit contains 147 million tons of borate ore containing 6.4% boron oxide (B203). It is the largest undeveloped colemanite deposit in the United States and because of its unique occurrence and grade, in situ extraction appears to be the most economic viable process. The paper covers the geological, mineralogical, hydrological, well-field development, and extraction considerations leading to the initial pilot plant and subsequent demonstration plant phases of the project. Market potential aspects and preliminary economics of the project are also covered.

Jan 1, 1987

By M. Kung, D. Schwegler-Berry, V. Castranova, D. Lewis, H. Abrons

Pulmonary responses to coal mine dust exposure were investigated by analysis of bronchoalveolar lavage specimens from non-smoking coal miners (n-12, mean age-43 ± 2 years, mean underground exposure-17 ± 2 years) and from non-smoking normal volunteers (n-18, mean age-43 ± 2 years). Spirometric and diffusion capacity indices were monitored as part of a physical exam. Lavage was performed in a subsegment of the right middle lobe by instillation of 200 ml of warmed saline solution in 50 ml aliquots and recovery by gentle suction. Specimens were centrifuged at 500g for 5 minutes at 2°C. Total and differential cell counts were recorded. Secretion of oxidants measured by chemiluminescence, surface morphology (spreading and ruffling), and lymphocyte parameters were determined. Lavage fluid was analyzed for the presence and quantity of acute phase reactants and immunoglobulins. Pulmonary function measurements as well as recovered lavage volume, total lavagable cells, and differential cell counts were similar in both miners and controls. Both resting and phorbol myristate acetate-stimulated chemiluminescence were also similar in miners and controls. In contrast, particle-stimulated chemiluminescence was significantly decreased in the alveolar macrophages from the miners (48% of control values). Morphometric analysis of scanning electron micrographs indicate that phagocyte surface spreading was similar in miners and controls. However, surface ruffling was 127% greater in the miners compared to controls. Lymphocyte subpopulations were similar in miners and controls. Protein analysis of the lavage fluid revealed lower total protein content in the lavage fluid of miners. However, the concentration of albumin, IgG, and IgA were similar in miners and controls. We conclude that most indices were normal in underground miners working under the current dust standard of 2 mg/m3. The decrease in particlestimulated chemiluminescence and the increase in surface ruffling in miners may suggest the beginnings of particle overload and activation of the macrophages. In addition, a decrease in total protein was noted in lavage fluid from miners.

Jan 1, 1991

By John R. Duble

Through 1980, demand for cement in the Pacific Basin countries still seemed to exceed output. Availability of cement in the industrialized and developing countries of East Asia, Southeast Asia, and Australasia for the 1975 - 1980 period are discussed in this report. Quantitative data includes production, imports, exports, and apparent consumption. An account of new cement plants and plant extensions is provided. Countries and areas covered include: East Asia---Japan, South Korea, North Korea, Taiwan, China, Hong Kong, Philippines; South east Asia---Thailand, Vietnam, Singapore, Malaysia, Indonesia; Oceania (Australasia)---Australia, New Zealand, New Caledonia, Fiji.

Jan 1, 1982

By A. C. Kunkie, C. J. Marshall

Highly delaminated muscovite mica products (WG-1 and WG-2) have been developed by J.M. Huber Corp. The micas are characterized as a 325-mesh product having high brightness and very narrow particle size distribution. At 40% loading in polypropylene, WG-1 mica provides substantial improvement in tensile modulus and equal tensile strength to unfilled polymer; in high-density poly- ethylene (HDPE), WG-1 provides four times the tensile modulus and a 50% increase in tensile strength over unfilled polymer. Surface modification of the water-ground mica (SM ™) provides substantial improvement in tensile strength over untreated mica at greater than 20% loading in polypropylene; in HDPE, tensile strength is twice that of unfilled polymer.

Jan 1, 1988

By Ole Bernt Lile

The well-known method of C. Schlumberger, Mise a la masse, has become a popular method again in ore exploration in Norway after many years of dominance by EM methods. The principle of the method is to place a current electrode within a conducting ore body and remove the other electrode to a great distance. (Figure 1). Often it is convenient to place a return electrode on each side of the area explored. The method is best suited for ores that have a conductivity contrast, relative to the host rock, of several orders of magnitude. The potential drop within the ore itself may then be neglected and the ore contact against the rock may be regarded as an equipotential surface. One may say that the ore body is electrically charged. Therefore, in Norway the method is now most often called the Charged Potential Method (abbreviated CP). The most usual way to present data obtained by CP, is to draw equipotential lines based on potential values measured in profiles on the surface. Such a potential map gives an immediate picture of the outcrop of the ore and also indicates disturbing conductors in the neighborhood. It may also be useful to look at the potential profile and its horizontal gradient along the strike axis of the potential map. These profiles may give information about the strike length of the conductor. Figure 2 shows the theoretical profiles of potential and gradient along the axis of the potential picture on the surface over a charged line plunging 15 degrees. It may be seen that the maximum of the gradient curve clearly indicates the lower end of the conductor. Figure 3 shows the corresponding pro- files over a charged line plunging 45 degrees. In this case, it is not possible to see an indication on the curve of the lower end. Only curve fitting could help interpretation in this case.

Jan 1, 1975

By John D. Morgan

The United States is the world's most productive nation and its citizens enjoy one of the highest material standards of living of any people in the world. Materials and energy are the lifeblood of any industrialized economy. Annually the United States uses over 4 billion tons of mineral materials and fuels, or 40,000 pounds per person as detailed in Figure 1. Domestic processed materials of mineral origin and energy are valued at more than $150 billion annually, and they are derived largely from domestic sources, supplemented by imports, as detailed in Figure 2. In recent years the superior productivity of the United States has also enabled it to give food and manufactured articles to many other less fortunate nations and peoples of the earth. What then is our concern with materials at this time? Seeing the burgeoning increases in our mineral demand: from 2 billion tons in 1950, to over 4 billion tons today, and projected to 11 billion tons by 2000 - we are getting questions concerning our ability to continue to increase production sufficiently for the future.

Jan 1, 1974

By R. J. Puchala, B. M. Hawrylewicz

High voltage electrical discharge in water causes instantaneous release of accumulated energy into water. The experiment described in this paper regards the utilization of the electric discharge phenomenon in rock splitting. The pressure in the shock waves created by the discharge inside a small volume of water enclosed in solid rock causes stresses which can result in breakage of rock. Holes drilled in tested samples were notched in order to weaken the tensile strength of the rock and achieve a uniformly directed split. The influence of the notches was theoretically analysed and compared with experimental data. Results of the tests have been statistically elaborated in order to correlate the newly-created surface to the energy supplied.

Jan 1, 1986

By R. J. Beckman

This paper traces the history of mica mining in Alabama from 1870-1970. The decline of sheet mica production is noted and emphasis is placed on the more recent activity of scrap mica production and the development of the U. S. Gypsum Co. mica properties in Randolph County, Prospecting for weathered pegmatites of sufficient size to warrant development is a continuing challenge since most deposits are too small and all exhibit varying characteristics as to size, shape, and weathering. Quantity and quality of muscovite mica in the pegmatites is of utmost importance and its recovery during processing of the ore is described.

Jan 1, 1970

By J. M. Dean, R. L. Grayson, R. D. Begley, G. L. Winn

Evidence has accumulated indicating that cultural change toward safer workplace behaviors is beginning to occur systematically in the coal industry. Through a range of programmatic mining company successes, enforcement and litigative actions, economic responses to competition and integrated efforts by federal and state agencies, a broader participation of safety and training professionals is being achieved to address prioritized workplace problems at mines. Small steps in workplace-related improvements have been realized already, but the trends in industry safety statistics, coupled with focused programmatic initiatives, indicate that more definitive and systematic steps are occurring to improve safe behavior in the workplace routinely.

Jan 1, 1998