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By A. A. Schweizer

Buckhorn ore is hydrous, argillized basaltic andesite, and is at least 60% clay composed of kaolinite and subordinate montmorillonite. Moisture content runs from 10% to 25%. The original crushing plant was a typical compression type, employing a jaw crusher, and two cone crushers. The system was plagued with constant plugging and unable to meet production plans. The three compression crushers were replaced with a Stamler Feeder Breaker followed by a Hazemag Impactor. Production plans are now exceeded. Agglomeration has progressed from an agglomeration drum to cascading conveyors, to introduction of the lime and cement into the primary crusher.

Jan 1, 1987

By Diler Katircioglu-Bayel

This manuscript aimed to examine the impact of operating parameters on the wet grinding of talc in a vertical-type stirred media mill. Within the scope of the research, the effects of operating parameters including media filling ratio, solid mass fraction, grinding media size, and grinding time were studied. The findings were assessed based on the product particle size (d50, d10), surface area (Sw), and energy consumption (Em). As a result of the present research, the following optimum grinding test conditions were determined: 65% media filling ratio, 40% solid mass fraction, 1 mm grinding media size, and 120 min grinding time. After determining the optimum grinding conditions, the Box–Behnken statistical design was used to determine the effect of parameter interactions on the d50 size. The media filling ratio was found to significantly affect the decrease in d50 compared to the other two parameters. Furthermore, the minimum d50 size was also achieved under optimum grinding conditions.

Aug 12, 2020

By Frank Agyemang, Zainab Nasrullah, Richard LaDouceur, Mehran Saddat

To sustain the circular economy, defence applications, and other renewable technologies, recycling rare earth elements (REEs) and other critical elements from their secondary resources is important. This cause has resulted in rigorous research and development for viable extraction and separation of REEs. Previously, Sm-Co recycling has been done with technologies, which fall under the categories of pyrometallurgy, physical separation, and hydrometallurgy. All these methods have limitations associated with energy, cost, and environment. Reportedly, the chemical leaching technology has successfully recovered and separated Sm-Co. Still, it has limitations associated with slow mass transfer and leaching kinetics, and there is a need to intensify the process to make it time efficient. This approach has also adversely impacted the environment by an extensive use of toxic, corrosive, non-selective, and expensive reagents. In this research study, chemical leaching of Sm-Co was performed using this new class of solvents, Deep Eutectic Solvents (DESs), which fall under the category of ion metallurgy. Four different DESs were used, proven to be green, non-toxic, biodegradable, cheap, and selective for cobalt over samarium by 82% leaching conversion. To improve the slow mass transfer and leaching time, this new technology of resonant vibratory mixing (RVM) was also tested. RVM intensifies mixing by establishing near instantaneous, low energy mixing conditions through resonance. It has been shown to improve the adsorption kinetics and was tested for the leaching kinetics. Four combinations of DESs were prepared, which are made up of two quaternary salts: Choline Chloride and Tetra Butyl Ammonium Chloride, and three organic compounds: Oxalic Acid, Urea, and Ethylene Glycol. These combinations were used for chemical leaching of Sm-Co with leaching factors of time, temperature, and type of DESs. After leaching, the samples were tested with and without resonant vibratory mixing with conditions of time, intensity (%), and type of DESs. Samples were analysed with Induced Coupled Plasma - Optical Spectroscopy (ICP - OES). Future work will involve a life-cycle assessment to assess the RVM technology with other conventional mixers, and an extensive study of DES properties to improve selective leaching.

Feb 1, 2025

By A. W. Laughlin

Analytical costs are a major part of exploration programs in developing nations which may lack adequate laboratories. Laser-Induced Breakdown Spectroscopy (LIBS), a variant of atomic emission spectroscopy, can reduce exploration analytical costs and can provide the analytical results in <1 minute. CPI is now marketing battery-powered, backpack mounted analyzers, using LIBS to analyze for many elements of interest to the explorationist. LIBS is well suited to the analysis of elements in industrial minerals. Limits of detection in ppm for some of these are: Li-1, Be-2, Na-100, B-33, Sr-10, Ba-300, Cs-1, K-500, Fe-500, Mg-500, and Ti-500.

Jan 1, 1999

By Eva K. Fernandez, Paul Y. Louie, Derek S. Adams, Renée L. Fippin

The Folsom Area Stormwater Improvement Project is part of SFPUC’s flood resilience efforts under the Sewer System Improvement Program. This 4,000-foot-long, 12-footinside- diameter tunnel will help reduce the risk of flooding in San Francisco’s low-lying Inner Mission neighborhood. The project is in a high seismic hazard zone and extends through a complex geologic corridor that includes full-face soft, compressible Bay Mud, Colma Sands, and full-face rock with several stretches of mixed-face conditions. Additional challenges include removal of 99 piles beneath an existing box sewer, tunneling under commuter rail tracks, and an underground tie-in. This paper examines these challenges and how they are being addressed.

Jun 13, 2023

By N. Cruickshank

Gas outbursts occur as sudden eruptions of gas and minerals from the face of a mine heading as the heading approaches potentially burst-prone (or anomalous) zones of rock. Such outbursts have resulted in considerable damage to equipment and in some cases lives have been lost. Characterizing these anomalous zones and detecting their presence is therefore vital to safe mining. Certain significant characteristics associated with the outburst-prone zones are: (1) the presence of fluid inclusions, (2) unstable stress conditions, (3) characteristic geologic structures, (4) certain physical properties of the rock, and (5) micro-seismic activity. Geophysical and engineering methods for detecting these characterisitcs are discussed and are considered with respect to their past success and future potential for predicting gas outbursts.

Jan 1, 1985

By Thomas J. Lien

Granitic Pegmatite deposits are the chief source of commercial feldspar, micas, lithium minerals, tantalum-columbium, beryl, and certain types of kaolin. The output from pegmatite mines in the United States is small compared to other mineral products in terms of bulk or value, and much of it comprises only minor metals and nonmetals. Nevertheless, pegmatite minerals play a vital part in our domestic industrial economy, particularly in the ceramic and electrical industries. Numerous special purpose uses also are important, even though they require small quantities of raw materials. In recent years, realizing the potential importance of the pegmatite minerals, the U.S. Geological Survey, the United States Bureau of Mines, several state Bureaus of Mines, and a few private companies have carried on extensive programs of pegmatite studies in the New England and southeastern states, in the Black Hills area of South Dakota, in the Rocky Mountain region of Wyoming, Colorado, and New Mexico, and in various parts of Washington, Idaho, Utah, Nevada, Arizona, and California. Currently, some of the pegmatite minerals such as micas and spodumene are selectively separated by the flotation process. To a lesser extent a few plants are selectively floating feldspar and quartz. Much of the credit for the above progress goes to the fine work done by U.S. Bureau of Mines (1), and companies such as Foote Minerals (2). Additional research efforts by the New Mexico Bureau of Mines (3) has successfully demonstrated selective separation of micas, beryl, spodumene, lepidolite, microlite, quartz and feldspar from a complex Pegmatite containing all these minerals. Since the nature of the mineralization of various valuable components of a pegmatite deposit is such that selective separation of some of these can be carried out at a coarse size using the Heavy Media Separation technique, it was felt that such a system should be investigated for selective preconcentration of their minerals. It was also felt that of all the :MS systems available, the DYNA WHIRLPOOL (DWP) device which allows a close control and adjustment of specific gravity should provide a means of achieving the above goal. Once the desired preconcentration of one or more of the pegmatite mineral assemblage is achieved, the available selective flotation techniques should provide effective recovery of various minerals into marketable products. This paper presents technical and economic aspects of selective preconcentration of some of the pegmatite minerals followed by selective flotation to produce marketable products.

Jan 1, 1978

By Stephen F. Munsell

The development of transportation systems for mined materials has historically been characterized by steadily increasing sizes in basic hauling units. This is especially true for open pit mines for which success is dependent upon the economical transportation of vast quantities of material. The depletion of high grade ore reserves has mandated a tremendous increase in the size and complexity of the ore haulage systems necessary for open pit mines, These increased demands were served by rail haulage systems in the early large open pit copper mines while later developed properties opted for the flexibility and lower initial costs of truck haulage. Now, we find the trucks being displaced as large overland belt conveyors tackle the problem of handling these ever larger quantities of low-grade ores with accompanying overburden ratios that can run as high as 10:1 or even 15:1. The basic development of large conveyors with shiftable sections and modular belts has generally taken place overseas, during the last few decades. The coal fields of central Europe proved an ideal testing ground for conveyor innovation because the low density and natural friability of the material created an ideal medium for transporting by belt conveyor. Now these proven ideas are being considered for and implemented into both the soft and hard rock mining industries of the United States.

Jan 1, 1978

By Louis A. Panek

Using an approach based on the theory of similitude, the author develops a general equation and related concepts that provide new insights to an old problem. The load-bearing capacity (strength) of a square, rectangular, or cylindrical prism of a brittle material such as rock, coal, or concrete is expressed as the mathematical product of a size effect, a shape effect, and a function of the mechanical properties (deformability, cleat/joint spacing, and friction) of the pillar, roof and floor materials. Through an application of multivariate statistical analysis, the results of assorted tests and observations of failed pillars can be combined into a fundamental scaling equation, which provides a unified, consistent approach to the estimation of mine pillar strength. The form of the equation is sufficiently general to be able to incorporate refinements in the characterization of the basis factors, as they become available through future experimentation and analysis.

Jan 1, 1979

By S. Veeramasuneni

The sign of the surface charge for alkali halides in their saturated brines has been established from non equilibrium electrophoresis measurements and on this basis the flotation response of alkali halides was explained based on the adsorption of oppositely charged collector colloids by heterocoagulation. These surface charge results for alkali halides are generally as expected from simplified lattice ion hydration theory with some exceptions, specifically LiF, KCI, NaCl, KBr, RbBr, KI, and Rbl .The presence of natural oxygen defect states in the crystal lattice and the inaccuracies involved in the gaseous ion hydration free energy values used appear, in past, to be responsible for these deviations. The presence of natural oxygen defect states in KCI, KBr, RbBr, and Rbl as characterized by UV Nis absorption, was found to account for their anomalous surface charge. Further, other positively charged alkali halides, LiF, NaCl and KI, were found to be free of oxygen defect states. Nevertheless, oxygen defects can be created in these alkali halides to make them negatively charged and has been demonstrated for NaCl. Such negatively charged NaCl can be readily floated with positively charged amine collector colloids thus confirming the surface charge/collector colloid adsorption theory.

Jan 1, 1996

The recent mine disasters in Australian coal mines have initiated an introduction of Self-Contained Self-Rescuer (SCSR) as component in the development of new escape strategies for miners. These self-contained self-rescuers are closed circuit, demand sensitive breathing apparatus that make oxygen available to the wearer for a nominal period of time. Their operation is completely independent of the surrounding atmosphere. Once properly donned, the SCSR can assist a miner to escape from an area containing smoke, toxic gases or an oxygen deficient atmosphere. The duration of a typical SCSR is usually taken at the point of complete collapse of the breathing bag which is accompanied by an increase in breathing resistance and inhaled levels of carbon dioxide. Because the oxygen consumption (V02) and the heart rate are correlated, a prediction of V02 and consequently the duration of an SCSR can be made by monitoring the heart rate. Thirty-seven volunteers participated in field simulated escape trials at four underground coal mines. The results from the field trials suggested that oxygen consumption depends on the heart rate, the body weight and exercise rating of the miner. All the volunteers were asked to fill out the questionnaires to evaluate the performance of the units. The miners indicated that they could tolerate the inhaled temperature without any difficulty to breathing resistance. A complete statistical analysis of the field results is also presented.

Jan 1, 1997

By Phillip E. Butler

Since early 1973, the Pennsylvania Department of Transportation (PennDOT) has been actively engaged in the utilization of coal mine refuse in the design and construction of highway embankments. The Soils and Geological Engineering Division of the Bureau of Materials, Testing and Research has the task of managing the program which includes field investigations, laboratory testing, engineering evaluation, planning, coordination, implementation, construction control, and review of construction performance. The objectives of the utilization program, in removing colliery refuse banks and utilizing the material in construction, are the environmental and aesthetic rehabilitation of those areas in the Anthracite and Bituminous coal fields which have been plagued for such a long time by air and water pollution, and unsightly landscapes; and the economic rehabilitation of those areas occupied by refuse banks by providing usable land which can now be developed as residential, business, or industrial sites.

Jan 1, 1975

By Jian Zhou, Shuai Huang, Wenqin Xi, Kun Du

The deep oceans harbor a wide variety of mineral resources that are characterized by their abundance and high quality. Nations worldwide are actively pursuing the exploration and extraction of these resources. This paper provides a concise overview of the mineral resources found in the deep sea, highlighting the challenges associated with their exploitation. Furthermore, it presents a comprehensive analysis of the historical development of deep-sea mining technology and equipment, offering valuable insights into this field. By examining the current issues and obstacles faced in deep-sea mineral extraction, this study concludes that the future of deep-sea mining lies in the direction of automation, intelligence, and standardization. Additionally, it identifies the key technological advancements that need to be achieved in order to overcome the challenges associated with deep-sea mining.

Jan 5, 2024

By Felicia F. Peng

The manganese removal from aqueous solution containing high Mn2+ concentration by adsorption and oxidation was studied using manganese oxide particles as the adsorbent. The operating parameters including pH, flow rate, initial manganese concentrations, and oxidant dosage affect the performance of Mn2+ removal were evaluated in a laboratory packed column. In the multi-column adsorption tests, each additional column doubled the time for complete manganese removal. No further decrease of pH was also observed once it was lowered to pH 4.5 to 5. This finding implied the possibility of complete high manganese removal without further pH adjustment during adsorption. Oxidation of Mn2+ by dissolved oxygen was found to be insignificant for manganese removal for high Mn2+ concentration. Adsorption was the predominated mechanism involved with manganese removal. Extremely low H+/Mn2+ stoichiometry compared to the reported values was measured. These low values suggested that different adsorption mechanisms such as chemisorption other than H+/Mn2+ ion exchange might play an important role at low pH. This paper presents the quantity and explanation of the results obtained for the mechanism of adsorption and oxidation of high concentration manganese on the manganese ore particles.

Jan 1, 1997

By W. B. Greer

The performance of seals in boreholes, shafts, and tunnels is an important concern in mine safety, in the control of effluents from operating and abandoned mines, and in the underground containment of hazardous wastes (Einarson and Abel, 1990; Mining Waste Study, 1988). Despite the clear need for effective seals, few documented test results are available concerning the performance of in-situ seals. Some evidence indicates that horizontal or near-horizontal holes are especially difficult to seal properly (Kelsall and others, 1982). This research involved the installation, extensive hydraulic testing, removal, and post-test examination of a l0-cm-long by 10-cm-diameter cement grout seal in a near-horizontal borehole in limestone. The work was performed in an underground mine on Marble peak in the Santa Catalina Mountains, Arizona. A test hole was diamond cored in the re-crystallized limestone of the Escabrosa formation. The hole is 33.24 m long, 10 cm in diameter, and dips at 10.4 degrees. The hole extends between two drifts and thus is accessible from both ends.

Jan 1, 1992

By James W. Echerd

Anthracite preparation developments, particularly in the early days of the anthracite industry, formed the basis for the modern coal preparation plants that have become so essential to the coal industry today. The anthracite industry, from early in the 19th century until relatively recently, was a leader in mining, preparation and marketing of coal, and played a leading role in the development of the industrial America we know today. Anthracite was discovered in America in about 1760--the story of Necho Allen is well known--but the rediscoveries leading to mining operations took place about 50 years later. The Wurtz brothers in 1815 at Scranton, the Smith brothers at Wilkes-Barre in 1807, Beach in Hazleton in about 1814, and Boyd in 1816 at Shamokin were all instrumental in promoting early mining and marketing of anthracite (J3. The early canals and railroads were built for the specific purpose of moving anthracite to the market areas. Eventually, the industry grew until, in 1917, it reached a production zenith of a little over 100,000,000 tons, representing about 20 percent of the total coal output in the United States. Almost half of the anthracite produced that year was consumed for domestic heating, a utilization that had dominated the industry for almost 100 years. Initially, anthracite had to be used by gunsmiths and blacksmiths, after which had followed the consumption of extensive quantities for railroads, blast furnaces and foundries, and electric power generation. Most of the markets have been lost to coke, oil, and natural gas. Near the anthracite regions, however, significant quantities are still used for domestic heating, power generation, carbon black manufacture, blending with bituminous coal to make metallurgical coke and fuel, and for other industrial purposes. Thus, anthracite production has not been entirely committed to history, but remains an active industry that follows modern practices in the mining, preparation, shipping, and utilization of a fuel that is still a valuable adjunct to the national economy. In fact, its inherent low sulfur content may make it an important fuel of the future. Estimates indicate there are reserves of anthracite to last for 300 years at a consumption rate of 50,000,000 tons/year. Anthracite Preparation Yesterday A 170-year history of the anthracite industry obviously is not the purpose of this discussion. A complete history of anthracite preparation, the rather unglamorous step in the processing of "mine run" hard coal to make it suitable for the user, is also not practical. Hence, the purpose of this report is to trace the development of some of the most important processes used through the years to meet a part of the demand for energy developed by our modern society. Anthracite preparation in the early days of the industry consisted solely of separating slate from the coal, by hand, underground (Z). This method prevailed for almost 20 years until wrought iron hand rakes were introduced to separate the large and small sizes. Shortly thereafter, the first attempts were made to size and clean the coal aboveground. The coal was dumped on a perforated cast iron plate, and men used sledge hammers to break the larger pieces into smaller sizes suitable for the market. The smallest sizes--that is, the material that went through the plate--were thrown away because they had no value at that time--a concept that existed for many years and actually was the basis for the subsequent "river" coal production and the many silt banks which are landmarks in the anthracite region. The larger sizes, at that time, sold for 50 cents per ton. The Batten breaker, or roll crusher, was invented in 1844, followed soon thereafter by the Snell-Diehm breaker (A). The latter had disadvantages, including excessive waste and fixed product size, but it later was improved in these respects. A breaker was also developed at Minersville, Pa., at about the same time that processed 200 tons of coal per day, using roll crushers and circular screens (1). Handpicking, from the beginning of anthracite preparation, was an important part of the cleaning process and was still being practiced as late as 1950. It was this process that involved the "breaker" boys of coal region lore. How much good handpicking accomplished depended on how much impurity was present in the coal--the more the impurities, the greater the reduction in ash. Thus, high-impurity streams were significantly improved, whereas picking of relatively clean coal was mainly to show an effort to make a quality product. As indicated, picking is largely a visual operation. It was and is wasteful of coal in the larger sizes since some good coal is always associated with the bad. However, it was probably much more effective&apos; in the larger than the smaller sizes.

Jan 1, 1971

By S. Chander

A series of nonionic and anionic surfactants were tested to enhance the flotation response of a low rank coal. An ethoxylated octyl phenol and several polypropylene polyethylene block copolymers were tested as nonionic surfactants. The anionic surfactant was a dioctyl sulfosuccinate. All the surfactants employed improved the yield significantly but the influence on grade was complex. Separate studies were conducted to determine the emulsification behavior of the surfactants. For the nonionic water soluble reagents tested, a correlation between emulsifying power of the surfactant and flotation was observed. An increase in the number of droplets produced in surfactant containing systems was considered to be the main reason for increase in the yield. Since it increased the number of collisions between dodecane droplets and coal particles. When a surfactant was introduced into the flotation pulp prior to addition of dodecane, it decreased the benefits of the surfactant significantly. The decrease was attributed to an increase in the wettability of coal and a decrease in the surfactant available for emulsification. When a suitable surfactant was added as a solution dissolved in the oily collector, a considerable increase in yield was observed.

Jan 1, 1993

By Takashi Goto

In 1968 three historical rockbursts had occurred at Bibai Coal Mine in Hokkaido. At the time they had been observed by several seismic observatories as natural earthquakes away more than 100km from Bibai City. These facts taught us that the occuerrence of failure yielded in underground opening that was accompanied with seismic wave could be observed by seismometer on the surface. After two years from this desaster, the study concerning to microseismic events generated from underground mining panels has been begun by researchers with heart-throb.

Jan 1, 1982

By L. D. Boughton

Solution mining projects are conducted through one or more boreholes which penetrate en ore body. Proper drilling, completion and maintenance of the boreholes, therefore, is essential to the success of any solution mining operation. Wells drilled for solution mining encounter problems quite similar to problems encountered by the petroleum industry in drilling, completing and maintaining wells for the production of oil, gas or water. Many of the services developed and much of the experience gained by the petroleum industry is applicable to solution mining wells. As in the petroleum industry, each individual wellbore and ore body in a solution mining project provides its own problems. These vary greatly from well to well, and it is not possible to set down data or outline programs that will apply to all wells. Instead, the design of the drilling, completion, production and maintenance programs should be worked out for each individual well. The purpose of this paper, then, is to generally describe materials, equipment and techniques available for these programs and to discuss the purpose and sequence of their use.

Jan 1, 1971

By Terry Owen

Business development process. Throughout Cyprus Amax&apos;s early months in Russia, the company stayed focused on what was needed from a deposit for economic success. Cyprus Amax&apos;s reason for success in Russia is that all involved - its Russian partners, the workforce and expatriates - provided a focused effort that served the project as it worked through the tender process and the Russian regulations. The company developed an understanding of the regulatory process by working with solid, ethical partners. Infused into the Kubaka management structure were Russians with the knowledge to facilitate the process and a professional group of expatriates. Developing credibility and a solid rapport with the Russian mining authority was critical to the success of this venture. Identifying and gaining the trust of key Russian individuals was also critical during the early stages. Gaining their trust and building credibility was part of the process. These key Russians were brought to the United States to visit existing Cyprus Amax mines. These efforts proved valuable in building an understanding with the Russians about the kind of company Cyprus Amax is and the kind of efficient operations that it can run. This was a learning process for all parties. Fortunately, the company was dealing with intelligent and educated people.

Jan 1, 1997