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By D. R. Gibbons

This morning I would like to speak to you about an area of chemistry that is enjoying a revival-organometallic compounds. This renewed interest, principally stimulated by defense needs, has already created new markets for the products of the mineral industry. Although the consumption of metals in these new products is modest at oresent, several hold promise of importance. Because this is a new and growing market, I am sure the Council of Economics is aware of many of its facets and is interested in new developments. Of course, the chemical industry has been a significant consumer of minerals for many years. I estimate that in 1957 the chemical-industry purchased a total of $1175 million worth of minerals as raw materials (not including fuels). This estimate can be broken down as follows: [Metals and metallic minerals $375 million Nonmetallic minerals (excluding hydrocarbons ) 330 million Hydrocarbons 470 million $1175 million]

Jan 1, 1958

The response of 174 domestic water supplies to longwall mining of the Pittsburgh coal seam was compared to various physical parameters. Sixty-four percent of domestic water supplies returned to service without the need for intervention, while thirty six percent required intervention to reestablish a suitable water supply. Domestic well response is strongly correlated with the topographic setting. Valley wells showed the least effect while hilltop wells showed the greatest effect. Well response was also found to be correlated to the location of the well above the mining with greater effects observed in zones of surface tension and compression, and fewer effects in zones which are stress neutral. Ground water supplies remained unaffected or were re¬established at 149 of 150 sites, indicating that ground water resources remain available to domestic wells after mining. Results of this study support the stress-relief model of ground water flow in the Northern Appalachian Basin. Longwall mining's effect on this system is to locally increase fracture connectivity in the near surface zone. This may shift the zones of saturated fractures to greater depths beneath hilltops and hillsides, and increase recharge and storage in valleys. General trends in well response are predict¬able utilizing the stress relief conceptual model, the topographic setting of the water sources, and their location over the mine.

Jan 1, 1986

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 Vittorio Manassero, Antonello de Risi, Filippo Cavuoto

"This paper deals with an innovative mechanized method to bore and simultaneously line circular shafts, adopted in the Naples Metro project for the installation of 10 vertical shafts for ventilation purposes. With this method, excavation of shafts is carried out under a positive head of stabilizing fluid by a milling machine, temporarily set at the bottom of a permanent lining made of precast reinforced concrete segment rings. The debris is evacuated by inverse fluid circulation. The shafts in Naples are 4.5 m I.D., from 34 to 44 m deep and they are all located downtown in a highly urbanized area. They were bored and installed into volcanic soils under a hydrostatic head of up to 30 m. Displacements and groundwater level were constantly monitored to keep control of the effects on the surrounding buildings and utilities. INTRODUCTIONThe extension of Metro Line 1 in Naples (Italy) from the previous terminal of Piazza Dante to Piazza Garibaldi is also called the “low stretch”. Most of it runs along the coastline, encompassing the historical city center, the Greek-Roman Neapolis. The Metro Line crosses under densely urbanized areas for the whole way (Figure 1). It runs beneath Via Toledo, which follows the layout of the ancient Aragonese walls. The first station (Toledo) is located halfway along this street. Then, after a wide bend, the line reaches Piazza Municipio, where the second station is located. From there, the line moves along the axis of Via Depretis and Corso Umberto I, where the stations Università and Duomo are situated. The fifth station is in Piazza Garibaldi and the end of the stretch is located at the Naples Business Center. The twin single track tunnels were bored into volcanic tuff by TBM. This design choice simplified by far the construction of the tunnels and reduced to practically zero the interactions between tunnelling and surface buildings and utilities. Nevertheless, this choice entailed that the line had to be located at depths to the order of 35-45m below ground level and 30-35m below the water table. At each tunnel segment between stations, a pair of ventilation chambers were constructed (10 in total). Each ventilation chamber is connected to one TBM tunnel by a vertical shaft and a horizontal drift at the base of the shaft. The shafts, in addition to tunnel ventilation, provide a safety access/escape."

Jan 1, 2016

By Gerald P. Kelton

Over the past quarter of a century, the success of the hydrocyclone as a classifier in closed circuit grinding installations has permitted the introduction of the cyclone into virtually all fields of wet industrial processing. Research and experience gained in these applications have established the optimum cyclone sizes and designs necessary to provide the required performance. Although cyclones are used in widely diverse liquid-solid applications, their use for ultrafine separation clearly demonstrates the importance of a familiarity with previous case studies. Krebs Engineers is firmly dedicated to serving the process industry and has acquired the unsurpassed knowledge and experience to handle all types of separations and classification problems. Cyclones have been used for a number of applications to make what might be considered fine separations. A typical example is in an iron ore grinding circuit where a 381 mm diameter cyclone will classify an overflow product to 85% -44 micron. There is no question that this is a fine separation, but still finer separations are possible, and these are known as ultrafine separations.

Jan 1, 1983

By L. Whitby-Costescu

The Shebandowan mine and concentrator, with a capacity of 9072 t/week (10,000 st per week), was opened in 1972 after several years of environmental study and planning. The mine is located in a popular vacation cottage .area about 96 km (60 miles) west of Thunder Bay, Ontario. Undertaken before environmental assessment procedures had become an established requirement, Shebandowan is one of the first Canadian examples of effectively integrating environmental work into overall planning. Although it is an underground mine, many of the environmental considerations are common to open-pit operations, and hence, it provides a case history for the use of all mine planners. Computers can play a part in such studies by simulating the annual production of mine wastes, by on-line polling of environmental sensors and by processing sensor data. Early attention was focused on establishing base-line conditions in a two-year water quality monitoring program. Since production began, water quality monitoring has shown that mining has not caused any significant changes. However, mine drainage disposal arrangements had to be modified in the light of operating experience. There is no townsite associated with the mine, and workers commute from established municipalities. Harmonious relations have been achieved with local cottage residents after their initial fears were dispelled. Plans are ready to begin revegetating the tailings when a sufficient area of dry elevated tailings has been accumulated. Rehabilitation of the land disturbed during development was begun before start-up and was completed during initial operations.

Jan 1, 1979

By Alfred A. Roetzer

In several sections of the country new demands are being brought bar cement users. Among these the demand' for truck shipments; and palletized loads present new problems that do not lend themselves to sample solution. In fact these demands have far-reaching effect in the way bagged cement might be marketed. Early solutions of palletized truck loads filled from existing packing and loading facilities have resulted in' slowdown in packing, additional labor and space for palletizing, considerable experimentation in type and construction of pallets, and usually far from optimum truck handling and loading methods.

Jan 1, 1961

By Robert L. Runkel, D. Kirk Nordstrom, James W. Ball

Low-flow reactive-transport processes in Wightman Fork downstream of the Summitville Mine, south-central Colorado were simulated using the OTIS and OTEQ solute-transport models. The simulation was calibrated using data from a synoptic study conducted during October, 1998. Discharge over the 8-km reach from just below the mine site to the Alamosa River confluence ranged from 0.077 to 0.17 m3/s; travel time was 10.7 hours; pH ranged from 4.6 to 5.7. Simulations revealed that mass balance for SO4 was maintained, and that pH, Fe, and Al were non-conservative. Simulations allowing hydrous ferric and aluminum oxide or hydroxysulfate precipitation matched observed water quality conditions more closely than simulations without precipitation.

Jan 1, 2000

By J. M. Hird

By blending phosphogypsum with thickened mill clays, Texasgulf has successfully resolved the problems of gypsum disposal and reclamation of mined-over areas. In the process, clays are thickened to 10% solids through high rate thickeners, mixed with gypsum from a drained gypsum pile (75%) and a direct discharge from belt filters (25%), then pumped to mined-over areas. The blending of clays and the low pH gypsum yield a mixture with a pH of about 7. Dewatering is rapid to 40-45% solids within 3 months. The material spreads with very shallow slopes and within a year desiccation by high flotation ditching equipment is possible. The artificial soil is classified as a silty loam in texture, lacking only in nitrogenous nutrients. The soil material has proven to support many field crops including small grain, corn, alfalfa, and grasses. Sycamore, green ash, sweetgum and bald cypress have done well in 3 years of growth. The nitrogen source for tree growth will be made up through an alfalfa cover.

Jan 1, 1993

By D. W. Fuerstenau, S. Raghavan

This paper presents a brief summary of some of the thermodynamic aspects of flotation processes. Thermodynamic considerations that control interfacial and wetting behavior in mineral/water/air systems are discussed. Particular attention is given to the thermodynamics of collector adsorption.

Jan 1, 1976

By G. Argyris

A number of important studies, ongoing environment monitoring efforts and mining and road construction projects in the lignite based electrical power production area of Amyntaio ? Ptolemais in North West Greece require an accurate and up to date model of the topography. In recognition of the importance of such a model, a project was initiated by the Laboratory of Mining Information Technology and GIS Applications in the Department of Geotechnology and Environmental Engineering of the Technological Educational Institute of Western Macedonia. A massive surface triangulation model was generated from vector data using an optimized Delaunay based method. Combined with aerial and satellite imagery, the triangulation model provides a complete 3D terrain model of the area characterized by high levels of accuracy, detail and realism. The generated model is easy to modify with new data in order to improve its detail and keep it up to date with ongoing earth moving and development operations in the area.

Jan 1, 2008

By Hongjie Yu, Mike Mooney

Transitions between geological/geotechnical soil units have a critical impact on the operation and performance of a tunnel boring machine (TBM). Geostatistics-based probabilistic modeling is used to quantify the uncertainty in soil transition locations. This paper presents two unique soft-ground tunneling case studies where the results from the geostatistics-based probabilistic modeling are compared to the TBM data and as-encountered ground conditions derived from the actual TBM data. The assessment enhances the confidence in using geostatistics to improve ground awareness for efficient tunnel construction, minimizing different site condition (DSC) claims, and improving decision-making on tunnel projects.

Dec 1, 2022

By Gregory E. Tieman

Hydrologic impacts of longwall mining were studied in 1986 after mining had occurred at mine "Z" in northern West Virginia. This mine is 700 to 1,300 ft deep, with a surface topographic relief of 300 to 500 ft. Five springs and one dug well were reportedly dewatered by mining. All such supplies are above nearby streams in elevation, and at least 800 ft above the subsided mine. Three of these six supplies showed partial recovery within one year. Only supplies within 50 ft in elevation of a nearby stream showed apparent partial recovery. Measured perennial streams showed notable depletion in streamflow over mined longwall panels that were less than two years old. Normal stream discharge was measured over panels more than two years old. Most apparent hydrologic dewatering impacts appear to be temporary, and the most vulnerable areas for these impacts are hill sides.

Jan 1, 1986

By S. E. Phillipson

Slickensides cause potentially hazardous ground conditions in underground coal mines. Investigations by MSHA’s Roof Control Division indicate that many slickensides represent bedding plane faults and drag folds that formed during coal bed decollement, a style of faulting that occurs in shale units above coal seams. These slickensides formed in response to regional tectonic compressional stresses, rather than by differential compaction, and are parallel to folds and thrust faults. This paper relates slickensides in the Appalachian, Illinois, and Black Warrior basins to the structural grain of the Appalachian Mountains, provides descriptions of slickensides, and advocates geologic mapping as a predictive method for identifying areas with adverse ground conditions.

Jan 1, 2003

By C. D. Hebert, T. Gregor, M. Ghazi, G. J. E. Kramer

This paper describes the recent application of gasketed, precast concrete segmental lining design that has improved tunneling productivity and quality. The speci?c segment arrangement includes: six-piece ring with equal 60 degree gasketed segments, juxtaposed key and counter-key segments, trapezoidal and parallelogram shaped segments, inclined and skewed radial joints and plastic circumferential joint connectors. This allows rapid, but accurate ring erection, reducing mine cycle times. The design avoids cruciform joints, minimizes potential gasket damage and eliminates the need for separate left and right ring molds. The implementation on the Los Angeles ECIS and NEIS sewer projects is described.

Jan 1, 2003

By Zoltan F. Oszter

Feeding bulk solids from bins or bunkers sometimes poses a problem to the materials handling engineer. The paper describes, by practical examples, how material flow can be improved on existing installations, and how difficult-to-handle materials can be successfully drawn from storage and fed to fully automated process systems. The examples illustrated are based on actual experience with projects designed for the mining and metallurgical industry. Maintenance costs, where available, are also indicated.

Jan 1, 1966

By Ratnakar Singh, Raj Kishore, Kisor Kumar Sahu, Ranjeet Kumar Singh, Ganesh Chalavadi

The Falcon concentrator is capable of separating minerals in fine size classes based on their differential density. Separation of mineral particles depends upon the fluid flow characteristics and relative movement of particles in a fluid. In the present study, a fluid flow characteristic inside the Falcon concentrator was established through experimentation and modeling. The Falcon concentrator has two fluid entry points: (a) Fluid entering through gravity assisted feeding system and (b) Fluid entering through the fluidized hole on the concentrator wall. In order to identify the role of fluid entering the concentrator, a tracer was injected into the system. As per the tracer based experimentation, it was established that fluid entering through the gravity based feeding system is responsible for thin flowing film formation in the stratification zone where particles are stratified based on their relative density. The momentum balance and continuity equations were simplified for a high centrifugal force field, and the fluid velocity profile was estimated inside the thin flowing film. Estimated fluid flow profiles will help to simulate the particle trajectories inside the Falcon concentrator. The influence of rotational speed, fluid flow rate, and cone angle on the fluid velocity profile were investigated. Fluid thickness over the concentrator wall is also estimated, and it is typically of the order of ~150–200 μm.

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 C. W. Hoffman

A fairly recent development in the field of particle separation is now under investigation to determine its value to the mining industry. The method employed is probability sizing through a vibrating network of decreasing screen openings. While probability sizing as such is not new, the possibility of using it for coarse, highly abrasive ores at high tonnage rates has only recently appeared to merit practical consideration. The advantages to be gained by the use of probability sizing vs. conventional screening methods are: reduced space requirements for a high capacity unit, fewer moving parts, more versatile product sizing selection, reduced maintenance requirements and lower power consumption.

Jan 1, 1968

By Paul Javor

Optimization of a process is achieved by selecting, 'from all the known options, the most beneficial method of obtaining a product. It is rare that the optimum process is arrived at by conventional methods, because of the great amount of time required for developing and comparing all the options. On the other hand, it is now possible, by means of an optimization program based on special mathematical formulas involving an algorithm and implemented by a computer, to plot the optimum process realizing considerable savings and in a reasonably short time. The flow sheet arrived at in accordance with the optimization program described in this paper investigates and develops all the possible options and, with the aid of the computer, makes it possible to select the most economical ore beneficiation process. The options in an ore beneficiation process are all the possible trajectories that can be traced through the particle sizes to which the ore is reducible in the extraction of its valuable minerals. Although an ore can have a wide range of composition and several valuable minerals that can be extracted, this paper is concerned with the special case in which only one mineral is extracted from the ore and in which the maximum allowable percentage of impurities in the end product is defined.

Jan 1, 1971