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By Stanley O. Reichert

At nuclear facilities, three types of radioactive waste must be managed: (1) high-level liquid waste containing fission products from the chemical separation of irradiated uranium, (2) low-level condensates from the concentration of the high-level waste, and (3) dry solids such as obsolete process equipment, spent ion exchange resins, and irradiated metal scrap. The geological and environmental characteristics of a site are important considerations in planning the waste management program. At the Savannah River Plant, low-level liquids and dry solids are safely and economically placed in the soil where the geologic and hydrologic conditions are favorable. Within the general area where the waste originates, studies are made to locate seepage basins and burial grounds in the most favorable sites: (1) soils should have a high ion exchange capacity and moderate to low permeability, (2) the water table should be deep, and (3) burial sites should be relatively distant from the nearest flowing stream.

Jan 1, 1968

By Harry Perry

The decline in coal production has been slowed somewhat in recent years, mostly because of the industry's own remarkable success in holding the line on costs, and partly as a result of advances achieved through industry and government research. Nevertheless, the decline has continued. This downward trend combined with the increased productivity of labor through mechanization that has been necessary for coal to retain even its present competitive position, has resulted in a serious reduction in the number of miners required and large scale economic dislocations in mining communities. For coal to regain a more favorable position it must either expand existing markets by reducing the cost of the delivered product and thereby compete more effectively with other fuels or develop new uses that will require large tonnages of coal. New markets involving several million tons, which would look extremely attractive to most other United States industries--including the organic chemical industry--would do little to alleviate the coal industry?s depressed economic conditions, While such small new markets would be welcome, an industry producing over 400 million tons per year must look to large tonnage outlets for solutions to its long range economic problems.

Jan 1, 1964

By Girish Roy, Robert Goodfellow, Angel Del Amo, Bingzhi Yang

Designing and constructing tunnels in seismic prone areas present unique challenges to both designers and contractors. The Westside Purple Line Extension Project– Section 3 in Los Angeles requires crossing an active fault that may subject the tunnels to extreme structural demands. In order to ensure that the linings will safely accommodate the fault movement, a revolutionary composite section—steel plate embedded in the intrados of the precast concrete segmental tunnel lining was finally selected. Additionally, continuous expansion steel plates over the circumferential joints will be installed to mitigate the potential opening of the circumferential joints.

Jun 13, 2021

By D. An, J. Withers

A nano-scale investigation has been carried out by applying an AFM (atomic force microscope) to study in situ the adsorption of various collectors, i.e., oleic acid, octanohydroxamic acid (HA), and salicylhydroxamic acid (SHA), on bastnaesite in aqueous solutions. The obtained AFM images show that the surface morphology of bastnaesite changes greatly after it contacts the solutions of the collectors, suggesting that all these collectors can effectively adsorb on bastnaesite. Increasing temperature can help increase the adsorption of oleic acid on bastnaesite. FTIR (Fourier transform infrared) results also show that all these collectors adsorb strongly on bastnaesite with a strong absorbance spectra being detected, which confirms with the results obtained with AFM imaging analysis. In general, hydroxamic acid collector (HA and SHA) adsorbs on bastnaesite mainly in the form of insoluble metal hydroxamate. This specific adsorption mechanism explains that a high selectivity with a moderate collectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite. INTRODUCTION Rare earth metals, which are very important to modern industry, are generally extracted from numerous rare earth minerals. In practice, however, the actual extraction of rare earth is mainly from bastnaesite, monazite and xenotime. The Mountain Pass mine is one of the largest rare earth mine in the world, at which the main rare earth mineral is bastnaesite. In the past years, froth flotation has been applied to the beneficiation of Mountain Pass ore. In practice, the rare earth ore is usually crushed, milled and further separated from calcite, barite and other gangue minerals by froth flotation, in which the rare earth oxide-bearing minerals stick to aerated bubbles in the pulp and float to the surface, leaving the gangue at the bottom of the flotation cell and disposed of as tailings.(Bulatovic, 2010) In spite of the fact that froth flotation has been applied to treat the bastnaesite ore at the Mountain Pass mine, the rare earth oxide (REO) recovery is still low,(Anderson, 2015) especially compared to the one obtained with sulfide flotation. For example, the typical recovery obtained at the Mountain Pass mine was only about 70%. This may be due to the low selectivity of the collector (oleic acid). In addition, to enhance the flotation selectivity, the pulp in the mine circuit has to be heated up to 70 to 90°C and it involves a lot of energy consumption. Last but not the least, a lot of depressants have to be added to improve the selectivity of flotation process. Therefore, it is critical to re-examine the existing flotation process at the Mountain Pass mine and seek any chance of improvement. (Anderson, 2015)

Jan 1, 2019

By Ayman A. El‑Midany, Hassan E. El‑Shall, Kerri‑Ann A. Hue

Modification of clays is necessary for the zearalenone (ZEN), as long-chain mycotoxins, removal. The organic-cations were usually used to modify the clay hydrophobicity to accommodate the large mycotoxin molecules. In this study, tri capryl methylammonium (TCMA) chloride and common corn oil were used in clay modification. Several characterization techniques such as XRD, FTIR, and TGA were used to identify the d-spacing changes after modification either by TCMA or corn oil. The results of applying the TCMA-corn oil-modified clays in ZEN removal indicated a noticeable improvement where more than 90% of ZEN could be removed in vitro at acidic and neutral pH values. The success of eliminating a high percentage of ZEN molecules is due to the expansion of intergallery spacing as a result of TCMA surfactant intercalation within the clayforming layers. The removal percentage does not depend only on pH but also on the amount of clay used. In addition, the ZEN removal in the presence of corn oil is better at acidic pH and small clay amount where the ZEN can be fully removed.

Sep 27, 2021

By W. H. Jang

Recent research has demonstrated the utility of the FTIRIIRS adsorption density equation for in-situ study of surfactant adsorption phenomena at the surfaces of reactive internal reflection elements (IREs). The FTIR/IRS adsorption density equation is given by (formula) where r is the adsorption density, A/N is the absorbance per reflection, e is the integrated molar absorptivity, 4 is the bulk concentration of the surfactant, d. is the effective thickness, and dP is the depth of penetration. Previously, the validity of the adsorption density equation had been confirmed only from solution depletion measurements with high surface area powders. Now, FTIR/IRS studies of Langmuir-Blodgett (LB) monolayer films of fatty acid transferred to the surface of a calcium fluorite IRE .clearly validate the reliability of the FTIR/IRS adsorption density equation for quantitative analysis of surfactant adsorption. In addition, it was confirmed from the observed absorption band at 1550 cm-1 that the first monolayer of the transferred fatty acid chemisorbs at the surface of fluorite.

Jan 1, 1994

By A. Pomianowski

A spectrophotometric study of xanthate solutions alone and their mixtures with equimolar amounts of alkyl trimethyl ammonium bromide (CnTAB) has established the additivity of ultraviolet spectra (190 - 400 my) for potassium ethyl xanthate (KEtX) and C12TAB. No obvious effect of C12TAB addition on the decomposition rate of KEtX was observed. The kinetics of collector abstraction by copper, nickel and sphalerite powders were studied in 10-5 - 10-3M solutions of KEtX alone and in equimolar mixtures of KEtX and C12TAB. Presence of C12TAB caused a 2 - 3 fold increase in the amounts of xanthate (equivalent to many monolayers) abstracted by copper and, nickel powders but had no effect on the abstraction of xanthate by unactivated sphalerite. The adsorption of C12TAB itself from the mixed solutions was very low, at most ore monolayer only, and was not influenced by the nature of the solid powder used. The results are interpreted in terms of molecular associations and synergistic action of xanthates and quaternary amines.

Jan 1, 1963

By H. Saito

To Japan, which is scarce in natural resources, limestone is the only mineral resource comparatively rich in ore reserves and having broadly recognized outstanding quality. Distribution of the limestone deposits extends from Hokkaido in the north to Kyushu and Okinawa in the south, and the deposits are located in a manner of framework formation of the Islands of Japan. Studies of the geological ages of these ore deposits reveals that almost all of the main ore deposits west of Kanto Area belong to the Carboniferous Period - Permian Period of the Paleozoic Era. Also in the east of Kanto Area, deposits belonging to the Paleozoic Era constitute the main part, although recently there are increasing examples of reclassifying the geological age of the deposits heretofore considered as Paleozoic Era to the Triassic Period of the Mesozoic Era by the recent discoveries of the fossils of conodont, etc. Large ore deposits and main ore deposit groups are given in the Figure 1, which shows that the deposits are roughly found well distributed throughout the country.

Jan 1, 1982

By P. W. Finck

Detailed mapping, using a large diameter diamond-drill in conjunction with high resolution reflection seismics, has increased known resources of kaolin clay and glass-grade silica sand from scattered deposits generally < 1 km2 to large areas of Cretaceous valley fill up to 130 m thick. Detailed chemical and physical analysis of drill core is presently underway. Silica sand deposits intersected in this study are up to 99.4 % SiO2 without beneficiation. Light grey to white kaolin clays identified by XRD and DT A have concentrations values (without beneficiation) up to 47.28% SiO2, 37.44% Al2O3, 0.45% Fe2O3, 0.49% K2O, 0.07% Nap, 0.07% CaO and 0.39% MgO.

Jan 1, 1996

By Jr. Freed

Basic design features, details of the face ventilation system, roof support and Operator protection system, certified lighting, and in-mine evaluation plans are presented for an Automated Extraction System (AES) that has been designed to fill needs which are present in the Mining Industry. The philosophy of design and proposed operation of the machine, as well as the relationships between these factors, are reviewed. The AES is designed to help overcome production problems resulting from the regulation of roof control, clean-up, ventilation, dust suppression, and operator protection required by the Federal Coal Mine Health and Safety Act of 1969. The design permits more continuous operation and greatly improves operator safety. The machine is a full-face drum-type continuous miner which includes self-advancing, continuous temporary roof support and permanent roof support equipment. Onboard self-advancing face ventilation, dust suppression, and air scrubbing equipment are also included in the design. A further improvement over existing equipment is the incorporation of an automatic programmed cutting cycle control system. All mining functions including movements of the roof support system are handled by this automatic system.

Jan 1, 1978

By David Butts

Solar ponding to crystdlize sodium chloride has been used for thousands of years.1 The systems used were inefficient and usually small compared to the large 25,000 acre pond areas seen today. It has only been in the last 25 years that any real effort has been applied to develop solar ponding technology. Many large solar pond systems have been constructed without much thought to efficient and optimum production rates. The recent high costs of labor, of equipment and of energy have forced producers to take a closer look at their solar pond systems in an attempt to squeeze out the highest possible yields. Other companies such as the Arab Potash Company, the Dead Sea Works, Texas Gulf (Moab, Utah) and San Francisco Salt Companies have no more land area in which to expand and therefore efficient ponds are essential. This paper is written to show how the subdivision of solar ponds can result in production increases of up to 20% and beyond.

Jan 1, 1984

By Sidney V. Gold

Should Gold Producers Hedge Their Positions Through : Sales on Forward Markets? Purchases of Put Options? Sales on Spot Market? Forward Markets Assumptions 1. Producer has a known amount of Gold to sell in year ahead. 2. Effect on price is the same whether sold Forward or Spot Market. 3. None of us have knowledge of Future Price Trend. 4. Contange Market prevails in which Forward price premium is approximately equal to rate of interest.

Jan 1, 1983

By Adrian E. Scheidegger

Recently, a new theory of the subsidence of rock masses has been advanced by Litwiniszyn and coworkers, which is based on the notion that the individual rock particles perform random walks. It is shown in the present paper that the final equations of the random walk theory can be justified from general principles of statistical mechanics in which no specific theoretical model of particle behavior has to be made. The theory appears to account appropriately for subsidence phenomena.

Jan 1, 1966

By M. Tomono

Harima Works is operating as the zinc and lead simultaneous smelter utilizing the imperial Smelting Process. The smelter commenced its operation in 1966 with designed capacities of 3500 t/M of zinc and 1500 t/M of lead. After that, owing to the results of progressive developments and improvements in operating efficiency and equipments, it has doubled its production figure. This report reviews our recent developments carried out from 1983 to 1985. Firstly, the furnace bottom design was modified for the purpose of reducing carbon consumption ratio. As a result, shaft operating condition has been satisfactory and carbon consumption ratio was improved by 2%, in addition, furnace zinc production was increased by about 8%. Secondly, the oxygen enriched operation at sintering machine was tested from July 1984 to June 1985, in order to increase the sinter productivity, and to solve the capacity imbalance between sinter plant and ISF. As the test result, it was found out that sulfur elimination rate was increased by approx 10% with the oxygen enrichment of 500 Nm3/hr.

Jan 1, 1986

By James F. Archibald, Ferri Hassani, Jacques Nantel, David O. DeGagné

Operators depend upon the success of backfilling programs to ensure that mine activities run continuously (Archibald et al, 1993) where backfilling is an integral part of the mining cycle. In order to ensure that the backfill is prepared and delivered to the stope possessing the required engineering properties, as designed, and that the backfilling process is safe, mine operators at all stages of the backfilling system must be adequately trained for their tasks and be aware of how their work affects other backfilling stages, both up- and down-stream of their station. Mine operator training is primarily based on learning on-the-job from experienced supervisors or training personnel. Classroom training and the availability of reference manuals are less common. While in use by many industries for some time now, computer-based training (CBT) is becoming more readily accepted by the mining industry for a wide variety of training. It is not intended to replace on-the-job training, but to augment it. CBT offers many advantages to enhance operator learning by utilizing multimedia presentations, interactions and on-line testing to teach complex concepts and relationships. Discussions with many operations revealed that there is an industry need for a backfill guide for frontline operator training and as a reference manual for operators and mine engineers. Sponsored by the mining industry and the CIM, "Mine Backfill, An Operator&apos;s Guide" has been developed by the Departments of Mining Engineering at Queen&apos;s University and McGill University to fulfil this need. "Mine Backfill, An Operator&apos;s Guide" is an interactive multimedia package that incorporates high quality colour images, animations, sound, and video with text to review the main backfill methods employed in Canada, including hydraulic/slurry, paste and rock fill. The Guide is divided into training and reference primer sections. When in training mode, the operator is guided through a presentation of common mining and backfill practices and technologies so that he/she may become more familiar with different aspects of backfill processes. To ensure that key concepts have been learned during training, the operator will be tested after each section using a series of multiple choice and true/false questions. When in reference mode, alternatively, the operator may browse through the information in a more detailed and independent fashion through a series of interactive menus. The Guide focuses on the following main topics: resources, surface preparation, distribution, stope activities, health and safety, and quality control. Special features included in the Operator&apos;s Guide are a Buyer&apos;s Guide, a Trouble Shooting Guide, and an interactive glossary of backfill and mining terms. Concepts in interactive and computer-based learning are also reviewed in this paper.

Jan 1, 2001

By David T. Kao

The energy situation the world faced during the decade of the Seventies resulted in actions throughout the free world to reduce its dependence on OPEC oil. Many nations heeded the indicators early in that decade and commenced efforts to reduce their oil requirements. Those nations which did not heed these warnings had the message brought to them more emphatically in the last portion of the decade with the further rapid and continuing rise in prices of OPEC oil. Furthermore, the demonstrated unstable nature of large oil-producing countries has made it clear to all free world nations that their energy demands of the future must be provided for by some more stable and assured supply. Now, early in the decade of the Eighties, we see the need for expanded use of coal as an energy supply to be essential. The result in 1980 and 1981 has been a great increase in demand for steam coal worldwide. In essence, a new business for the United States has developed in steam coal export. In the United States, the large growth in foreign demand for our steam coal is now well recognized and documented. A major impediment in meeting this growing demand became abundantly clear in 1980. This impediment is the congestion existing at U.S. coal export ports. With the recognition of this constraint, a plethora of activity has been observed in announcements for alleviating the problem by improving and expanding current export port facilities. In addition to improvement and expansion, an abundance of totally new facilities has been announced in an effort to find ways to meet this large demand in the new business of steam coal export. This is needed; and hopefully, many of these plans will be translated into action. While total implementation of all stated plans is not expected, much of the implementation depends upon large- scale dredging, large waterside ground storage sites, and improved handling equipments in the conventional type of export ports. The time and capital required for implementation is great, and environmental problems associated with dredging are substantial. Host significantly, and unfortunately, implementation that does include dredging our ports will still not permit use of the truly large colliers of 140,000 DWT and greater, which are evolving as the "state of the art" in long-distance sea transport.

Jan 1, 1981

By T. V. Subrahmanyam

Unlike coarse particles (40-50 µm), the fines (<10 µm) have low collision efficiencies with gas bubbles in flotation process. Among the alternative methods for recovering the fines are their aggregation with coarse particles (carrier flotation) and flocculation of the fines alone (shear-flocculation), prior to flotation. In any case, hydrophobic aggregation is the mechanism involved though the technique is known by different names in literature. This paper deals with theory and state-of-the-art of particle aggregation. To illustrate the dependence of aggregation on particle hydrophobicity, charge and, in turn, the sheer force, the results of quartz-DDACI and galena-xanthate systems are considered. In the flotation of complex ores selectivity is achieved by chemical control and aggregation of particles of the same species is analogous to that; however, more work is necessary on ores for a better understanding of the pulp chemical aspects from the view point of selectivity in aggregation. For a few ores, the results of earlier workers confirm improved recoveries of fines by aggregation prior to flotation.

Jan 1, 1997

By Herbert P. Haschke

I. Changes made by the Economic Recovery Tax Act of 1981 (ERTA) which have an effect on investing in tax shelter investments A. Maximum ordinary income tax rate on individuals is now 50%. B. Maximum tax rate on long-term capital gains for individuals is now 20%. C. Maximum tax rate on alternative minimum taxable income for individuals is now 20%. D. Although not changed, the "add-on" 15% minimum tax on tax preference items and the possibility of paying the alternative minimum tax cause individual U.S. income tax planning to continue to be very complex. II. Real Estate A. The new Accelerated Cost Recovery System of depreciation (ACRS). 1. Mandatory for assets placed in service after 1980. ACRS will eliminate most if not all controversies with the IRS over depreciation. 2. Real property now depreciated over 15 years. Component depreciation is not available. 3. Accelerated depreciation is available - a 175% declining balance method with an automatic shift to straight line method at the optimum point in the asset&apos;s life. Alternatively, a taxpayer can elect to use the straight line method.

Jan 1, 1982

By R. L. Eppley

The Blacklick Creek Watershed Association was awarded a $158,000 Growing Greener grant from the Pennsylvania Department of Environmental Protection in 2002 for the design and construction of a sulfate reducing bioreactor (SRBR) cell to treat acidic discharge from the Judy 14 abandoned underground coal mine near Indiana, PA. The vertical flow SRBR was designed to treat 38 liters per minute of MIW containing elevated concentrations of aluminum and iron. Other treatment systems at this site plugged due to aluminum precipitates; this problem did not occur in the SRBR. The bioreactor has been periodically overloaded with flows up to six times the design rate. To date, the only maintenance performed on the unit has been the addition of hay to the surface of the unit in response to less than expected performance. The periodic hay additions appear to have restored the SRBR to nearly post-construction levels. Since construction, the SRBR has treated about 136,000 cubic meters (36 million US gallons) of MIW.

Jan 1, 2010

By Steven J. Schatzel, Kayode M. Ajayi, Zoheir Khademian

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine creating safety concerns. To provide recommendations for developing guidelines that ensure a safe co-existence of longwall mining and unconventional shale gas production, this study evaluates the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach using a discrete fracture network (DFN) model. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations is within values validated with field measurements. The results show that a decrease in fracture aperture (potentially due to longwall-induced stress in the likely vicinity of the breach location) reduces the potential gas flow to the mine by a significantly higher proportion. A 50% decrease in the aperture of the fracture that directly transports the gas from the casing breach location reduces the gas flow to the mine by over 70%. Similarly, changes in the fracture water saturation level significantly affect the gas flow. In all cases, the potential gas flow to the mine is higher if the casing breach occurs at an increased gas well pressure. These findings provide critical information regarding the impact of each of the parameters associated with gas flow in the event of a shale gas casing breach near a longwall mine and could help towards the development of guidelines to ensure a safe coexistence of both industries.

Sep 28, 2022