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By B. Jones, W. Zhang, Q. Li

Rare earth elements (REEs) are critical materials to the United States due to the imbalance between their supply and demand. Considerable research and development efforts have been devoted on REE recovery from coal refuse using inorganic acids as lixiviants, however, the cost of inorganic acids is normally high, and the environmental friendliness is low. As alternatives to inorganic acids, organic acids of small molecules such as lactic acid and succinic acid have been used as efficient and green lixiviants for metal extraction. In addition to the supply risk of REEs, food waste generation and disposal is another emerging and critical issue since nearly one-third of the edible food is lost or wasted each year. In this research, organic acids were microbially converted from food waste and used as lixiviants to leach REEs from density fractions of an Illinois Basin coal. Experimental results indicate that REE recovery increases of up to 15 absolute percentage points were obtained using organic acids relative to inorganic acids. The conversion of food waste into value-added, renewable, and environment-friendly chemicals promotes the economic viability of REE recovery from coal refuse.

Mar 2, 2022

By Vladimir Jindrich

This paper presents a history of a successful three year effort in locating a large, economic deposit of high purity limestone. The exploration program has been carried out by Ernest K. Lehmann & Associates, Inc., geological consultants, for Dravo Corporation, owner of the limestone property which is now under development. The permission of Mr. L. P. Struble, Jr, President of Dravo Lime Company, and Mr. M. W. Robinson, Director of Research and Development, to present this paper is gratefully acknowledged. The limestone property is on the Ohio River near Maysville in northern Kentucky, 60 miles east of Cincinnati (Fig. 1). The area lies at the eastern flank of the Cincinnati Arch, a regional structure where the Lower Paleozoic strata crop out below the adjacent younger sedimentary rocks of the Illinois and Apallachian basins. In general, the limestone formations of the Middle Ordovician High Bridge group offer the best potential for industrial limestone in Kentucky and adjacent parts of Ohio and Indiana. These formations are exposed along the axis of the Cincinnati Arch in central Kentucky. Toward the west, east and north, strata of the High Bridge group are progressively deeper, concealed beneath a succession of interbedded fossiliferous limestone and shale. The High Bridge group limestone formations are shallow-marine deposits largely of tidal flat, shallow lagoon and related environments. Principal lithologies include cryptocrystalline micritic limestone and crystalline dolomitic limestone to dolomite. Shale and bioclastic limestone are subordinate but the proportion of shale increases in the basal formations. Characteristic, is the occurrence of several thin beds of bentonite that serve as regional stratigraphic key horizons.

Jan 1, 1975

By Enrique Fernandez

The success of the excavation of a sewage tunnel in a very extreme geological conditions, from river deposits and sandy layers to hard dolomite, and several meters below the estuary under the sea water influence, shows that the choice of a right equipment together with the use of chemical products like foam and polymers enable to dig tunnels in unexpected areas and give solution to the environmental problems. The paper describes the excavation and support process as well as the adopted solutions in every material and during the cross through the intermediate shafts, also under sea influence.

Jan 1, 2003

By J. Engesser

This paper discusses the effect that water chemistry, and water treatment have on pre-fired pellet quality and bentonite-binding effectiveness. A discussion concerning the effect that water temperature, water chemistry, water treatment, and surface area have on disc filter productivity and filter cake moisture is also included. This report is a summary of the data that were presented in five previous research reports, which are listed as references in this paper.

Jan 1, 2003

By Daniel McConvey

Who is the Investor? -Mainly institutional, including resource funds, other mutual funds and pension funds. -Some hedge funds. -Retail investors. -How important is the reserve disclosure to these investors? -Do these investors know the difference between a reserve and a resource?

Jan 1, 2003

By David K. Ingram

The objective of this U.S. Bureau of Mines investigation was to characterize overburden response due to longwall mining. Subsurface strata and surface deformations were monitored during the mining of two adjacent, 900 ft wide longwall panels in southeastern Ohio. The panels were separated by a five entry, four pillar system (about 350 ft wide). The overburden thickness in the study area ranged from 214 to 280 ft, and the extraction thickness averaged 70 in. To delineate the geology of the overburden, six coreholes were drilled along a profile line extending across the two longwall panels. Multi-point borehole extensometers (MPBX) with eight-anchors were installed in six boreholes to measure subsurface displacements. The MPBX units were continuously monitored using a data logger. During the mining of the first panel, displacement occurred in a radiating pattern beginning just above the extracted area in the center of the panel and extending upward and outward towards the surface and margins of the panel. Overburden deformation did not project over the gate road entries. During the mining of the second panel, the MPBX's showed almost simultaneous displacement, indicating that the overburden began to move as a whole unit. Again, overburden deformation was confined to the immediate panel area. At both panels, overburden movement began when the longwall face was approximately 55 ft beyond the line of MPBX boreholes. Moreover, all ground movement was complete when the longwall face was approximately 200 ft beyond the line of MPBX boreholes. This paper discusses the results of the study and identifies the characteristics of overburden deformation.

Jan 1, 1986

By Dennis Molvik, Omar Fulton, Chris D. Breeds, Don Gonzales

The Tolt Pipeline No. 2, West Snoqualmie Valley project, is part of a water supply project linking the Tolt reservoir in East King County to the City of Seattle through a nominal 2.13 m (7-ft) inside diameter conveyance. Receipt of the National, 2002Microtunnel Award provided recognition of the many challenges overcome by this project. Baseline conditions revealed in the Geotechnical Documentation included over-consolidated glacial deposits, landslide and alluvial deposits, artesian water, boulders up to 36-in in diameter, logs, heaving sands, and liquefiable soils beneath the river. Schedule constraints associated with setting the shafts in the floodplain of a salmon bearing river and the fickle performance of the river during those times it was not supposed to flood added to the challenge.

Jan 1, 2003

By Alexander N. Winchell

"Location. The iron formation of the Gogebic district (including the Penokee) comprises a narrow belt south of the western part of Lake Superior extending from Michigan for a considerable distance into Wisconsin. From the mouth of the Montreal River (about twenty-five miles west of Ashland) the iron formation is only about twelve miles distant, but it is about twenty miles south of Ashland. Beginning on the east at a point about eight miles east of Wakefield, Mich., it extends through Sunday Lake, Bessemer and Ironwood in Michigan, and thence south of west through Hurley, Wis., and only a short distance south of Mellen, Wis. About eight miles westward from Mellen, the formation disappears, but six miles further west it is known to reappear and continue thence for about eight miles. The total length of the range is about sixty miles, two-thirds of this distance being in the State of Wisconsin; but nearly all of the ore has been obtained from the eastern third of the district, which is in the State of Michigan.History. This iron range was first noted in 1848 by Dr. Randall, assistant geologist to Dr. David Dale Owen, while following the fourth principal meridian northward. It was also reported by Charles Whittlesey in an account of a survey made in 1849, and published by Owen in 1852. Analyses of the iron ore are given with the following account. ""The bed of magnetic iron ore south of Lac des Anglais is of extraordinary thickness,25 to 60 feet. * * In the wild and deep ravines where the Bad River breaks through the range, there is a cliff of slaty ore * * * probably three hundred feet thick. * * * I estimate more than one-half of this face to be ore, and in places the beds are from ten to twelve feet in thickness, with very little inter-mixture of quartz * * * . The position of the best exposures of ore which I saw is such as to require from eighteen to twenty eight miles of transportation to reach the lake."""

Jan 1, 1920

By Robert H. Carpenter

Downstream dispersion curves for certain trace metals were obtained from two mineralized areas in the southeastern U. S. In Lincoln Co., Georgia, 7 sample sets were collected downstream from the Magruder mine, a polymetallic sulfide deposit (Zn-Cu-Pb-Ag-Au) in metavolcanic rocks. Five sample sets were collected along Joe Mill Creek in Grainger Go., Tennessee, downstream from a zone of zinc mineralization in carbonate rocks (Mississippi Valley-type). In both areas, analyses were made of Fe-Mn oxide coatings on lithic fragments and quartz pebbles, and the -80 mesh fraction of the stream sediment. A comparison of the dispersion curves reveals the following: 1.) the anomaly/background ratio is markedly higher in the Fe-Mn oxide coatings for zinc and copper; 2.) the anomaly/background ratlo is markedly higher in the -80 mesh fraction for lead which is not concentrated in the coatings; and, 3.) the Zn/Mn and Cu/Mn ratios in the coatings are useful in that they enhance downstream derectability of mineralization as well as provide for a simpler analytical procedure. There are several potential advantages of using coatings vs. the conventional -80 mesh fraction in stream sediment surveys. Because soluble metal is brought into the stream mainly in groundwater, deeper anomaly sources may be detectable from the oxide coatings than from clastic fractions of alluvium where much of the metal is derived from erosion of soils. Variability due to sampling may also be reduced, providing better discrimination of anomalies. In areas of glacial or alluvial cover, coating surveys may be particularly applicable.

Jan 1, 1975

By J. Bowders

A case study describing the expansion of Marion County landfill is presented. The exapansion area is located on a deep mined area. Finite element analyses were used to predict the surface subsidence and associated tensile strains on the landfill liner of the expansion site. A synthetically reinforced liner system is recommended to minimize the impact of the subsurface movements on the integrity of the liner system.

Jan 1, 1986

By C. Manea

During exploration and exploitation of complex ores, waste dumps that contaminate severely the environment and in particular soils, are genetated. The most hazardous pollutants are heavy metals and metalloids (e.g As, Mo, Pb and Cu) as well as radionuclides (e.g U and Ra). Ecological remediation aims, among others, at decontamination of soils by preserving important properties as soil fertility.

Jan 1, 2008

By Joseph T. Matoney, Okley B. Bucklen, Claude A. Goode, Philip G. Meikle

INRTODUCTION Annual coal production rose to over 1.03 billion st (931 Mt) in 1990. At the same time the number of mines producing this increased tonnage has decreased over 60% in a 30-year period, from 9230 mines in 1960.1 The great increase in production made possible through continued mechanization requires greatly improved loading facilities just to get coal away from the mine. Also the trend to combine production from more than one mine and cleaning it in a single preparation plant continues. A recent census of US coal preparation plants indicated that 310 plants were in operation.2 In addition to increased loading capacity, storage and blending facilities are more necessary both at the producer and user end. In this climate of rapidly changing technology, any written account is faced with the possibility of obsolescence before its appearance. Thus, this chapter seeks to define the common and current practice in coal loading and storage facilities with the full knowledge that this practice is an ever-moving target. FUNDAMENTALS OF COAL STORAGE Storage of coal is becoming an increasingly important part of coal handling systems at mines, particularly since the advent of the unit-train concept in transportation. In order to take advantage of reduced transportation rates on trainload shipments of coal offered by unit-train movement, operators have found that storage is an economic necessity. In unit-train practice, large predetermined quantities must be loaded in relatively short periods of time, as opposed to conventional practice where coal is loaded at a speed dependent on the production capacity of the mine and/or the cleaning capacity of the preparation plant. Clean coal storage is generally practiced in order to accomplish one, or a combination, of the following objectives: 1. To load out promptly and economically. 2. To facilitate blending in order to even out chemical and physical inconsistencies and to prepare desired products or to attain maximum product uniformity. 3. To store certain sizes whose prices and market demand fluctuate with seasons and to permit shipping in good weather. Coal storage, then, is necessary and desirable, both from production and utilization standpoints. There are, however, several undesirable aspects attendant to the storage of coal, the most important of which are oxidation and spontaneous combustion, changes in properties which may affect utilization of the coal, degradation of coal due to rehandling, and the added cost of handling and storage facilities.

Jan 1, 1991

By G. J. Lindenburg

The Velvet mine is located in the Big Indian district of the Colorado Plateau. The general area, also known as the Lisbon Valley district, is about 65 kilometers southeast of Moab, Utah and about 120 Kilometers southwest of Grand Junction, Colorado. As shown by the slide, the Velvet area is typical of the high desert of the southwest United States. The elevation at the decline collar is 1,967 meters above sea level. To date, the Velvet has produced 1.5 million kilograms of U308 and 2.1 million kilograms of V205. The current production averages over 4,000 metric tons of ore per month. Access to the Velvet mine is by a 1,160 meter long decline. Fresh air is supplied through the decline and a 152 centimeter cased borehole. Contaminated air is removed by two 152 centimeter cased boreholes. The east side of the mine is mined using a conventional room and pillar method; whereas the west side is mined as combination conventional and random room and pillar,

Jan 1, 1983

By Gonzalo Barrientos

Instrumentation and observation of real mine structures helped define the pressure arch at White Pine, a large copper mine in sedimentary rocks. The pressure arch, which is attributed to inherent horizontal stresses, is used in the design of mine openings.

Jan 1, 1969

By R. H. Moore, B. D. Breitenstein

INTRODUCTION The United States Uranium Registry (USUR) tissue program was funded in 1978 by the United States Department of Energy (DOE) through its Human Health and Assessments Division, and registrant enrollment began in 1980. It is operated by Hanford Environmental Health Foundation (HERF), Richland, Washington, with support provided by Pacific Northwest Laboratory (PNL).** The USUR tissue program is the first systematic effort to contact and gain assistance of workers occupationally exposed to uranium and to seek and study uranium deposition in human tissue. This paper describes the program objectives, populations selected for study, procedures for enrolling workers in the program, types of tissue to be studied, and analytical procedures to be used. PROGRAM OBJECTIVES The objectives of the USUR tissue program are to: 1) Determine the distribution and concentration of uranium, if any, in the tissues of occupationally exposed workers. 2) Compare bioassay measurements of exposed individuals with the results of analyses of tissues obtained at autopsy. 3) Seek evidence of histopathologic changes related to any uranium deposition that may be present. 4) Conduct analyses of whole bodies, when available, to obtain more precise data on the uranium burdens, if any, in the body and organs, and especially the distribution in parts of the body, such as the skeleton, that are not usually accessible for sampling. 5) Develop data that will assist in evaluating a) the accuracy of current in-vivo measurement techniques, b) the propriety of existing regulations, and c) the adequacy of current protection programs. SELECTION OF POPULATIONS FOR STUDY Selection of the populations for the USUR tissue program was based on studies of the United States Uranium Registry described elsewhere (0c81). Potential populations for study were quite varied because of occupational exposure to different chemical forms of uranium, different levels and eras of exposure, varying ability to identify populations exposed in the past, and the general interest and cooperativeness of the populations. Nevertheless, certain identifiable populations emerged that were both willing to participate in the study and likely to provide useful information. Among the targeted populations are individuals who were exposed to uranium prior to the existence of modern exposure standards. These individuals are presently being enrolled by the USUR. The reliability of concentration and distribution data and the demonstration of effects are more likely in such individuals than in those who have received less exposure. However, the targeted groups also include individuals who Have been exposed to permissible levels of uranium, and reference employees in uranium plants who have not worked with uranium. The lesser exposures are of immediate interest because of the rarity of heavy exposures under current standards. The sampling of potentially exposed individuals with negative in-vivo measurement results may serve to check the adequacy of in-vivo measurements in the detection of deposition. [ENROLLMENT PROCEDURE] The enrollment of participants follows three patterns. 1) Presently employed workers are enrolled by the cooperative efforts of USUR staff with the medical, industrial relations, and/or health physics personnel of the uranium facility. Volunteers may be enrolled by medical personnel at the time of their physical examination or by health physics personnel at the time of a bioassay or lung counting procedure. Follow-up after initial contacts with currently employed uranium workers is carried out by on-site personnel, but subsequent follow-up is the responsibility of the Registry. 2) Retired workers are contacted by mail, with a covering letter from their former employer supporting the principles of the study but leaving participation in the program on an entirely voluntary basis. 3) An alternate method of enrollment is to obtain a USUR autopsy consent after death from the next of kin. As part of enrollment in the program, permission is requested for access to the individual's medical and exposure data, and a short occupational history is filled out. The autopsy permission agreement signed by the individual is for an initial period of 5 years; the USUR ordinarily seeks renewal of the agreement upon its expiration. While this agreement provides

Jan 1, 1981

By R. J. Smith

Hornestake's Mclaughlin Mine is the first commercial application of pressure oxidation pretreatment of gold prior to cyanidation. Inherent to the autoclave process are several liquid/solid separations. Flocculant consumption represents a significant portion of the consumable reagent costs at McLaughlan. This paper focuses on the efforts of the Operating, Metallurgy and Engineering groups to improve thickener operation and minimize flocculant consumption. An operating philosophy incorporating feed solids control, increasing flocculant dilution water and minimizing flocculant solution shear has resulted in a reduction in 1986 flocculant costs of $0.054/t ($0.06 st) versus 1985 costs. Additional changes are projected to result in a further cost reduction of $0.20/t ($0.22/.st) in 1987.

Jan 1, 1988

By Thomas Schultheis, William Heron, Paul Watson, Colin Warren

This paper describes the geology and geotechnics associated with construction of the Thames Tunnel, part of the UK’s Channel Tunnel Rail Link (CTRL). The 2.5km long twin tunnels run beneath the river Thames at depths of up to 40m and are currently under construction. They pass through varying geology comprising alluvium, terrace gravels and chalk with flints and are currently being bored using Herrenknecht mixshield slurry tunnel boring machines (TBM’s). This paper outlines the lithology and engineering properties of each geological formation and describes the geotechnical processes, potential hazards and difficulties experienced in the works. A summary is given into the extent of the investigative work in terms of route selection, tunnel design, TBM optimisation and further details are provided on the geotechnical aspects associated with the construction of the tunnel approach structures and the tunnels.

Jan 1, 2003

By W. M. Ma, W. L. Zhong, Syd S. Peng

In a longwall section that consisted of 7 longwall panels, there were two high pressure gas transmission pipelines across the panels burying from 3 to 10 ft. below the surface. One pipeline was 20 in. in diameter while the other was 24 in. in diameter. In order to investigate the stress conditions sustained by the pipelines during underground longwall mining, strain gages were mounted on the pipelines above panel #3, #4, and #5. Survey monuments were also installed along but near the pipelines. This paper presents a subsidence prediction method and the preliminary results of the pipelines' stress conditions as affected by underground longwall mining.

Jan 1, 1986

By Zbigniew Hladysz

INTRODUCTION In the Polish coal mining industry, the Upper Silesian coal basin has an important position. It contributes over 98% of the total coal production of Poland which reached 193 mt in the year 1979. In view of the significant urbanized area in this region as well as the industrial potential, it is important to protect the surface by stowing the mined out underground workings. Approximately 18% of the total production is mined from longwall faces with stowing. However, caved longwall faces are most popular. In the upper Silesian coalfield, approximately 337 highly mechanized longwall faces are in operation. Out of these 337 faces, 301 longwall faces are caved. One of the main requirements for effective and safe coal extraction is a suitable method for strata control. We can divide the complex process of strata control into four steps: 1. Strata investigations 2. Selection of supports for roadways 3. Selection of supports for longwall 4. Rock bursts and other hazards protection STRATA INVESTIGATIONS Estimation of the structure and physico-mechanical properties of the rock mass surrounding the workings is an important constituent of strata control. These factors definitely influence the rock stability, support load, working conditions as well as the mining technology. Complex methods of strata investigations involve a set of indicators enabling the estimation of the stability of the roof rock, strength of the coal seam and load bearing capacity of the floor. The basis for the evaluation of roof stability for a coal seam is the classification according to the resistance to bed separation (1). The bed separation resistance is equal to the strength of the rock in tension perpendicular to the bedding plane. In order to properly classify a rock, it is indispensable to make continuous profiles of the bed separation resistance from the immediate roof up to a distance of three times the thickness of the coal seam. The profiles are developed by utilizing mine roof investigations with the hydraulic borehole penetrometer. (Fig. 1) The penetration resistance is determined by the critical pressure required to cause crushing of the rock by the penetrometer indentor (2). The classification of roof rocks and their ability to cave spontaneously during longwall mining is shown in [Fig. 2]. The measurement of the critical pressure also allows for the determination of the compressive strength of the rock, the index of workability and roof fissuration.

Jan 1, 1982

By Karen Bolm, Floyd Gray, Ailiang Gu, Kerry Caruthers, Carlos Velez, Laurie Wirt, Douglas M. Hirschberg

Understanding sources of dissolved metals and transport characteristics of acid drainage is needed to assist land-use strategies in mineralized regions, particularly in the semi-arid southwestern United States. Water- quality samples were collected from mined and un-mined parts of the Patagonia and southern Santa Rita Mountains of southern Arizona from streams, springs, seeps, adits, alluvial wells, and bedrock wells. Water quality during base-flow conditions was compared with that *of runoff samples from infrequent winter and summer storms. The largest fraction of annual discharge in these ephemeral streams consists of storm runoff, although springs provide a steady source of low discharge base flow to numerous intermittent perennial reaches. Several abandoned mines in the northern Patagonia Mountains contribute acid and heavy metals to streams. During base-flow conditions in mineralized areas, natural springs and intermittent stream reaches produce acidity but the volume is typically low and acidity is often diluted or neutralized down gradient. Overland runoff contains low concentrations of dissolved metals and moderate acidity, however, stream waters were strongly acidified and metal-laden from contact with abundant pyrite-bearing stream sediments derived from erosion of waste-rock material in and along the sides of the stream channel.

Jan 1, 2000