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By Sotiris N. Kamenopoulos, Zach Agioutantis

Rare earth elements (REEs) are considered critical minerals for the industrial and defense sectors. In 2018, the U.S. Department of the Interior presented the final list of critical minerals that are vital to the U.S. economy and defense [1], which included REEs among other mineral commodities. REEs are not rare, despite their name, but economically viable deposits of REEs can be found only in certain geographical areas, and the political and social conditions characterizing these areas may not always be in favor of mining operations. Mining operations may be placed in great operational and financial risk if operations are planned in such areas. Erroneous decisions by decision makers may lead to a chain of events that can completely shut down a mining project. 

By J. W. MacDonald

Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review, These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work.

Jan 1, 1960

By R. Y. Wan

Recent research efforts have shown have shown selective solvation extraction of a gold cyanide ion-pair complex from alkaline cyanide solution is possible with organic phosphorus esters. These alkyl phosphorus esters such as tributyl phosphate (TBP) and di-n-butyl n-butyl phosphonate (DBBP) can selectively load gold to rather high levels, even in excess of 30 gpl. However, traditional stripping techniques are not particularly effective. In this regard, gold recovery by direct electrolysis of the organic phase has been found to be an interesting possibility. Further, the rate of direct electrodeposition from the organic phase can be improved significantly by using an aqueous/organic mixture. Direct electrodeposition of sheet gold from loaded DBBP was successfully accomplished at a current density of 8x10 4 amp/cm2 and 55°C from such a two-phase mixture with the aqueous phase as the continuous phase. No appreciable degradation the DBBP was found after 5 cycles of extraction and, electrodeposition. Finally, the applicability of the process strategy for an industrial situation was demonstrated by the successful treatment of waste gold cyanide electroplating solutions.

Jan 1, 1986

By A. R. Rule

As part of the Federal effort to help maintain an adequate supply of fertilizer minerals, the Bureau of Mines is conducting research to characterize complex, low-grade western phosphate rock and to develop methods for economic recovery of phosphate. The rock varies from soft, friable, altered phosphatic shale to hard, tightly cemented, unaltered phosphate rock. To supplement current beneficiation by sizing, a flotation procedure was devised that included depression of phosphate minerals with H2SiF6 and anionic flotation of carbonate minerals, followed immediately by cationic flotation of silicate minerals. Application of the procedure to several different ores resulted in phosphate concentrates that ranged from 28 to 31 pct P20S in grade and from 60 to 70 pct in phosphate recovery.

Jan 1, 1977

By William Detty

An architect representing the Atlanta office of the Brick Institute of America periodically presents a slide lecture to interested groups entitled "The First 10,000 Years of Brick". The title signifies the fact that brick, man's oldest manufactured building material, has been around for quite some time and will continue to be utilized by architects and builders in the foreseeable future. This is not to say that the brick industry can rest on its laurels and ignore the competition presented by newer more innovative products. The industry will have to be equally inovative and market oriented in order to maintain its market share of the predicted construction boom between now and the year 2000. The implication is made, however, that brick can be produced under rudimentary conditions and that the desire to use the product has been long standing. In addition, history has sham that there has been plentiful clay available to produce the product. This paper is an attempt to assess the climate in which the brick industry will operate during the next 26 years. An analysis of regulatory conditions affecting the manufacture of the product will be followed by an assessment of the materials environment in which the industry will be operating. These factors are then reconciled with a projected demand for the product to determine the ability of the industry to satisfy future demand for brick. From a mineral point of view this paper will address itself generally to the availability of and demand for clay. However, other than a brief overview of the uses of other specific types of clay, it will concentrate on the clays utilized in the production of structural clay products, specifically brick.

Jan 1, 1974

By R. J. Gray

Oxidation of coal can best be described as a process of deterioration, since most of the uses of coal, such as for fuel and by-product chemical and coke production, are adversely affected by coal oxidation, and the inclusion of oxidized coal in most coal products detracts from their value. There are probably many mechanisms of coal oxidation, and the ways oxygen molecules combine as complexes with coal macromolecules to form new substances have been dealt with and speculated upon by many workers1)* but are not dealt with in the present work. This study deals with tests and methods of detecting oxidized coal, with particular emphasis on the microscopically discernible changes that accompany the chemical and physical changes that affect the technological properties of coal during oxidation.

Jan 1, 1974

By Kenneth R. Krivanek

In recent years the widespread problems of air and water pollution generated by both population and industrial expansion have become a major public concern. Therefore, many municipalities are striving to achieve more efficient wastewater treatment processes so these wastewater's can be reintroduced into the waterways of our nation with little or no detrimental effects on the future beneficial use of that water. With this, improved treatment comes an ever increasing volume of wastewater sludge which must be disposed of in a manner of minimal impact on the environment. Furthermore, with demand for energy continually accelerating in this nation, our concern over high oil prices and our increasing dependency on foreign oil sources, there has been an ever growing interest in the largest energy source that are nation has, coal. However, surface mining of coal can cause many environmental problems when adequate precautions are not faithfully adhered to. These problems include water pollution from silt and/or clay erosion and acid runoff, produced by oxidation and hydrolysis of pyrite; i.e., FeS2 + 3/02 + H20 + FeSO4 + H2SO4. One method of wastewater sludge disposal which can utilize large volumes of sludge for a beneficial project that may not compound our environmental problems is spray irrigation, to either depleted farmland or to abandoned strip-mined soils. Sludge is characteristically high in organics, as well as having near neutral to alkaline pH properties. With these two qualities it possesses a potential for neutralizing acid strip mine spoils, which would enhance the establishment of a vegetative ground cover. Sludge can accomplish this by lowering the oxidation potential, reducing the solubility of iron and aluminum and by the chelation of metals, thereby

Jan 1, 1977

By R. W. Waytulonis

New exhaust control techniques and devices may be necessary to meet future diesel particulate matter emission standards in underground coal mines. This paper reviews conventional work practices and devices used to control diesel exhaust emissions, and new techniques being tested by the Bureau of Mines. Discussions will center on important work practices and on the function and efficiency of exhaust after-treatment devices. An industry/government cooperative research project to develop and test an exhaust after-treatment system for part 36 equipment is also discussed.

Jan 1, 1990

By Stephen D. Schwochow

Aggregate producers nationwide well recognize the numerous problems often faced in securing local approval to open and operate new gravel pits and rock quarries. Similar problems are faced in Colorado, but this region also presents certain political, social, and geological complexities that have become particularly troublesome in the last 10 years. The gravity of the local permitting dilemma can be related directly to the worsening supply-demand imbalance for aggregates in the state's most populated area, the Front Range urban corridor, particularly the Denver metropolitan area. The drive to develop crushed-rock reserves to supplement dwindling alluvial supplies and to meet increasing regional growth demands was somewhat predictable but perhaps more a "last resort" alternative forced onto producers by a hesitant and often apathetic government.

Jan 1, 1982

By Mohamed A. Younis, Robert J. F. Goodfellow

This paper investigates the design approaches taken and the philosophy employed during the construction of the Metropolitan Airport Commission (MAC) storm tunnels, part of the Phase 4 Segment of the MAC Trunk Storm Sewer Project at Minneapolis St.-Paul International Airport, located in Minneapolis, Minnesota. URS Corporation was retained to provide a design and Construction Management (CM)services for the MAC Trunk Storm Sewer Project. A case history of the design and construction challenges of the project is presented. The MAC storm tunnels consisted of the construction of twin 10-foot inside diameter (I.D.) tunnels within 7 feet of an existing 72-inch I.D. storm pipe at the base of a 70-foot high highway embankment. The analysis required during the design stage of the project is discussed. This analysis and our design approach provided a defensible framework and justification to make design decisions on relevant issues including: allowable spacing of new and existing structures; preferred order of construction; expected ground deformation behavior; response of lining types to adjacent construction; and effects of proposed changes to design at the submittal stage and during construction.

Jan 1, 2003

By T. H. Bagan

The Sixteen-to-One Mine was originally designed and operated using Blasthole Stoping with end slicing as the primary mining method. This method changed to Modified VCR Stoping in response to efforts to control dilution. The new method combines Blasthole Stoping with shrinkage methods, pillars, and reduced sublevel intervals to provide the most practical dilution control avail- able for low cost bulk mining.

Jan 1, 1987

By P. C. van Aswegen

The Bacterial Oxidation (BIOX®) process for the pre-treatment of refractory ores for gold recovery developed by Genmin, the mining division of Gencor, has been operating successfully at the Fairview mine since October 1986. The continuous operation of a pilot plant at Genmin Process Research has resulted in further process developments to improve plant operating efficiencies. These new developments which include a higher solids content of the pulp feed to BIOX®, lower retention times, higher operating temperatures, lower power utilization for oxygen dispersion .and reduced nutrient addition have all been successfully implemented on the Fairview plant.lt has furthermore been confirmed that the arsenic precipitate formed in the neutralization of effluent solutions complies to the United States of America EPA standards. Continuous cyanidation pilot plant work conducted on BIOX® product has indicated that cyanide consumption can be drastically decreased if a continuous flowsheet is implemented in preference to a batch leaching system.

Jan 1, 1991

By M. A. Giralico

Solvent Extraction (SX) technology has undergone significant refinements including outright process changes to achieve greater copper production rates with lower organic entrainment levels. LIGHTNIN has completed a detailed study aimed at improving on the conventional Holmes & Narver and Davy Power Gas type impeller designs1 by optimizing the mixing through the use of high efficiency pumper turbines instead of making system changes as others are doing. Since each individual installation requires a different design head and flow, LIGHTNIN has developed the R320 "family" of high efficiency, curved blade pumper turbines. These impellers are designed to maximize head and flow while reducing entrainment through lower power consumption, less shear generation and turbulence, elimination of air incorporation, production of the optimum droplet distribution, and lower tip speeds. These improvements also maintain the required mass transfer and copper recovery of the traditional impeller designs. The R320 impeller benefits have been quantified using Laser Doppler Velocimetry (LDV) and proven in multiple domestic and foreign installations at flow rates exceeding 15,000 GPM. Design comparisons of this improved impeller type versus traditional technology impellers in head, flow, power and entrainment are presented for review. In addition, the inherent benefits of axial flow, high efficiency impellers like the A3 1 0 and A6000 in auxiliary mix chambers will be discussed. The high flow, low shear characteristics of these patented impellers provide the necessary dispersion stability for mass transfer while speeding phase disengagement in the settlers due to low power and low shear input.

Jan 1, 1995

By S. S. Klima, H. Jiang, T. W. Beck, Y. Zheng

Researchers at NIOSH’s Pittsburgh Mining Research Division (PMRD) performed comparative testing of six different water sprays at pressures ranging from 689 kPa (100 psi) to 6,895 kPa (1,000 psi) in a 14.5-m3 (512-ft3) confined dust chamber. Testing was conducted to determine the effect of various pressures on each spray’s respirable coal dust knockdown ability. It is known that higher water pressures are typically preferred for lowering airborne dust concentrations, but it was important to determine at what pressure range the dust knockdown ability of each spray plateaus or reaches its minimum dust concentration. Results from this testing showed that several sprays saw up to 100% decrease in dust concentrations during the five-minute water spray testing period, with some occurring well below the maximum 6,895 kPa (1,000 psi) spray pressure.

Feb 1, 2023

By M. L. Clark

Advances in the recovery of gold from heap leaching are being made daily, but of all the systems vital to the maximum recovery of gold from a leach pile, none is more important than the methods used to construct the pile in preparation for the leaching operation. The technology described in this paper illustrates the latest systems developed to minimize compaction in the pile during its construction and reduce the cost of placement of ore on the pile. The Florida Canyon Mine of Pegasus is evaluated in detail to show reasons for its high degree of success to date.

Jan 1, 1988

By J. L. Fuller

Mine ventilation surveys were conducted by Technical Support engineers during June 1987 and September 1989 at the Dutch Creek Hine. The mine is located near Redstone, Colorado and is operated by Mid-Continent Resources, Inc. Following completion of the initial survey, several recommended improvements were incorporated into the ventilation system by mine personnel. The second survey permitted documentation of the effects of those changes on the ventilation system performance. This paper describes the processes involved in the implementation of the recommended changes. The substantial improvements in system efficiency and reduced operating costs are also described.

Jan 1, 1991

By C. Iglesias

Innovation in the tilemaking ceramic industry is stressing properties like powder flowability, ability to toughen green tiles, so turning technological requirements of ball clays ever stricter in terms of plasticity, dispersion in water, rheological behavior, workability in the green state, refractoriness and firing colour. Technological performance of ball clays was improved by taking as benchmark the highest quality raw materials on the market. The mineralogy, plasticity, methylene blue index and ceramic response of the Patagonian ball clays are analogous to those of European clays, but improvement is needed to approach the highest quality materials. On this basis, the Frente A, Super, Puma, and Lote 8 deposits were selected and their characteristics enhanced by additions of highly plastic and white-firing corrective clays targeted on the benchmark. Porcelain stoneware formulations, containing improved ball clay mixes, were experimented at both laboratory and industrial scale. The improved ball clays behave like the best raw materials currently used, although modest changes occur in the mechanical properties, water absorption and whiteness of the fired products.

Jan 1, 2010

By Pratama Mochamad Rizki, Andika Satya

High-risk area in open-pit mining should always be monitored by the operational supervisor because of its nature. One of this type is the soft soil dump area. Due to the unstable bearing capacity of the soil, it’s highly possible for us to find cracks in the area. This paper aims to build computer vision which able to detect truck’s distance from safe limit allowed during dumping activity. The system will warn the truck’s driver if the truck has crossed that predetermined safe limit.

Jun 25, 2023

Operation of a pilot-scale Floatex density separator was studied using a pyrite concentrate slurry feed. Experimental measurements were further utilized in parameterization of a hindered settling simulation model. The model incorporates particle slip velocity calculation and also a separation efficiency function, adjusted to describe the feed material characteristics. The model was used to compute the overflow and underflow compositions when both fluidization bed pressure and teeter water flow rates were varied. In addition, prediction accuracy and the model validity were evaluated. The simulations gave good results when the teeter interstitial velocities were moderate enough to avoid excessive turbulence in the fluidization. Prediction of the cumulative overflow and underflow size distributions in most experiments yielded essentially less than 10% relative error between the sample data and the estimated value of the 50% passing sizes.

Jan 1, 2011

By Yosry A. Attia

One of the most significant advances in Mineral Processing in recent years, is the development of the selective flocculation technology. The technology is primarily aimed at recovering the mineral values from ultrafine ore suspensions. This is achieved by selectively aggregating the mineral particles in question to such size as to enable their effective separation from the suspension. Selective flocculation utilizes the differences in the physical-chemical properties of the various mineral components in the mixed suspension. It is based on the preferential ad- sorption of an organic flocculant on the particular solids to be flocculated, leaving the remainder of the particles in suspension. In order to understand the mechanics of this process, selective flocculation may be divided into four major sub processes; these being: ore slurry dispersion, in which all the particles are stably and uniformly distributed in the suspension with the individual particles being essentially separate; flocculant selective adsorption and floc formation; floc conditioning, which aims at obtaining flocs with desire properties for their subsequent separation and with minimum entrapment of dispersed particles; and floc separation from the suspension. These sub processes will be reviewed later in this article.

Jan 1, 1982