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By P. Zhang

The Crago “Double Float” process is widely used in upgrading phosphate ore. This process is inefficient, as it floats about 30-40% of the sands in the flotation feed twice and requires a deoiling step. This paper summarizes several research projects on improving phosphate flotation. The University of Utah investigated a new flotation chemistry for efficient flotation of phosphate in a single step. The Florida Institute of Phosphate Research developed several single-collector, all-anionic flotation flowsheets using various sizing schemes. In addition, Eriez invented the HydroFloat separator, which demonstrated great potential for processing coarse flotation feed in one step.

Jan 1, 2004

By A. Subbotin

During developing the Ingulska mine at the Mi-churinske uranium deposit in the central part of Ukraine the radioactive rock dumps have been piled. A height of dumps reaches to 15-25m. They occupy a large territory and can be a source of covering with radioactive dust the area around the Ingulska mine. Uranium content exceeds 0,01% in all dump rocks samples while in the dust fraction samples it ranges from 0,01 to 0,06%. Uranium content in road dust at the dump?s foot reaches 0,137%. A new (for Ukraine) method of f-radiography of tree and bush leaves sampled at the territory about 100km2 has been used. It is based on fission of 235U nucleuses due to heat neutron influence in a nuclear reactor and on following study of the Lausan films with tracks drawn by the fractures of these nucleuses. Uranium content of the dif-fusion-disseminated dust type is (0.9-22.2)?10-6% while in the individual particles it can be considered much more because of burned holes in Lavsan above them. The dust content with uranium in Kirovograd reaches to 20-50 part/cm2 while near the dumps it ranges from 100 part/cm2 to 300 part/cm2 in the radius of 1,5-2km from the Ingulska mine.

Jan 1, 2005

By E. L. Schrader

Statistical Process Control (SPC) is a cooperative arrangement between a component or raw materials supplier and a manufacturing customer. The supplier must analyze his own manufacturing process and determine, predict, and control those variable elements in the circuit which affect finished product characteristics according to the customer's specifications. The results include: control of fluctuations in product characteristics to a narrow range, close communication between supplier and customer, and an increased responsibility for quality control placed on the supplier. In the mining and. processing of airfloated kaolin some unique problems arise with the SPC concept: 1) The SPC system was designed for manufacturing facilities that did not have to deal with natural variations in their raw material; 2) The airfloat process is relatively simple and offers limited opportunity to change processing steps or "fine tune" a circuit for special product needs; 3) Determining adequate sampling frequency for a plant which processes hundreds to thousands of tons per day is statistically difficult; and, 4) Due to the variety of customer industries served, different SPC programs must be set up to deal with widely varying specifications. For airfloated kaolin, SPC is "in line" process control, not after the fact "quality" control. The emphasis must be on statistically valid sampling of the kaolin ore and complete monitoring of its path through the beneficiation circuit.

Jan 1, 1987

By Abb Raymond

Finely processed industrial minerals in "powdered" form have long been utilized by the plastics, paint, rubber, paper, ceramics, and adhesives industries as fillers, extenders, coatings and special additives. These minerals, primarily calcium carbonate, talc, kaolin, titanium dioxide, and the like, have provided economic, uniform and consistent base materials which have, in turn, been used by the referenced industries to manufacture quality products. The focus of this paper will be the development of equipment and systems at ABB Raymond for the dry processing of such non-metallic minerals in order to meet what have become increasingly stringent requirements of the producers of these minerals. Changes in these requirements seem to have been accelerating rapidly during the last ten years, and it is expected this process will continue into the 1990's.

Jan 1, 1990

By D. I. Phillips, P. J. Bethell

This paper focuses on the -1/2 mm cleaning at Elk Run Coal. The original circuitry incorporated desliming cyclones. Problems with slimes entrainment in the cyclone underflow (froth cell feed) resulted in poor froth cell selectivity. Laboratory test work led to the installation of high frequency desliming screens. Consequently, great improvement in cell performance was brought about by enhanced desliming with the ability to use split flotation. The modifications resulted in significant improvement in total plant performance and overall yield while maintaining clean coal quality.

Jan 1, 1987

By Colin C. Harris, Jie Zheng

While applications of stirred media mills for fine particle production have continued to increase, there is a lack of understanding of operating behavior and power requirement. Investigations in laboratory stirred media mills have been carried out with grinding media, limestone and yttria stabilized zirconia. The torque required to rotate impellers immersed in dense particulate media with supernatant versus impeller rotational speed displays four regions marked by sharp transitions: transition from static to dynamic friction; channel- ling; dispersing; and centrifuging. Equations, including dimension- less group correlations of power and modified Reynolds number, for relating power, speed, impeller and tank dimensions and design, media size and density, solid concentration, and other relevant variables have been established. Scale-up guidelines with respect to power consumption are also proposed. The best operating conditions for grinding limestone in the laboratory stirred media mill have been identified. Complexation by the polymer during ultrafine grinding of zirconia has been found to cause extraction of yttrium into solution with possibly significant changes in the surface chemical composition of the product.

Jan 1, 1995

By C. R. Everly

"The purpose of this paper is to review the most effective methods of reducing chloride transfer and chloride removal in the solution extraction and electrowinning (SX/EW) process. Elevated chlorides in electrolyte have various negative effects including a reduction in current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Historical controls that Sierrita has used to control chloride transfer, in order of effectiveness, have been chloride gasification at the EW that is directly correlated to amperage and chloride concentration in electrolyte, wash stage bleed and efficiency, width and velocity of aqueous bands, and electrolyte bleeds. Maintaining high bleed rates and high amperage settings has been a challenge with decreasing pregnant leach solution (PLS) grades, so keeping chlorides out of the electrolyte has become imperative. The effectiveness of reducing aqueous entrainment, optimizing wash stage efficiencies, and improving organic quality to reduce the transfer of chlorides to the electrolyte are illustrated in this study. INTRODUCTION The transfer of impurities from PLS feed streams to electrolyte in the Copper Solution Extraction process is a very common problem and is the reason that the wash stage exists in most SX operations. The main impurities affecting the SX process are iron, chloride, nitrate, and manganese. Elevated chlorides in the electrolyte have various negative effects including reduced current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, increased cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Freeport-McMoRan Sierrita Hydromet is unique in that a high-chloride byproduct stream from the molybdenum process is pumped into the SX raffinate solution pond. This byproduct steam accounts for the majority of chloride introduced to the circuit, and over the years has built up to a point where 4000ppm chloride is consistently in the PLS feed to the SX. Concentrations of chloride over 70 ppm in electrolyte will result in downgraded cathode, so it is important to limit chloride carryover from SX as much as possible. Historically, Sierrita has been able to manage chloride levels with reactive techniques including increasing electrolyte bleeds and rectifier amps. Decreasing copper in PLS has made high amps harder to maintain, and increasing bleed rates have a direct impact on production goals."

Jan 1, 2015

By W. L. Dalmijn, J. M. Versteegen

During the production of silicon carbide, a byproduct is generated that contains a mixture of crystalline and amorphous silicon carbide. Utilizing the difference in density, shape, and surface properties of the crystalline and amorphous silicon carbide, separation tests were carried out with gravity concentration. The processing of the coarse fraction of the silicon carbide mixture by jigs resulted in a high grade crystalline SiC concentrate with the desired specifications. The separation was largely influenced by the shape factor. A jig with a newly designed hydraulic drive was used to carry out the test program.

Jan 1, 1991

By A. Founie

The United States continues to be the world’s leading producer and consumer of diatomite. Production of diatomite in the United States during 2005 was estimated to be 653 kt (720,000 st). This was a 5-percent increase compared with 2004. The value of processed diatomite in the U.S. was about $179 million in 2005. Production was from six companies with 12 processing facilities in four states. California and Nevada were the principal producing states. They accounted for about 70 percent of U.S. production in 2005. U.S. diatomite exports were about 144 kt (159,000 st). Imports were negligible. The internal structure and chemical inertness make diatomite an excellent raw material for filtration, absorbent and filler applications. Filtration, especially the purification of beer, liquors and wine and the cleansing of greases and oils, continued to be the largest end use for diatomite. Other applications include the removal of microbial contaminants, such as bacteria, protozoa and viruses in public water systems, and the filtration of human blood plasma. The use of diatomite as fillers and in pharmaceutical applications, including the filtration of human blood plasma, continues to increase as has its use as an insecticide base and as pozzolan. The relative rank of end uses of diatomite were filter aids, 75 percent; fillers, 11 percent; absorbents, 7 percent and other (mostly cement manufacture), 7 percent.

Jan 1, 2006

By K. Biswas, S. J. Jung

Health and safety of workers in mineral industry in the U.S. is still a vey important issue as Mining along with Agriculture, Forestry and Fishing and Construction industries have contributed most of the fatal occupational injuries ill between 1980 - 1995 (Worker Health Chartbook, 2000). Health and safety issues, especially for the mining or related excavation industries, arise either from exposures of the human workers to the contaminants liberated or generated by mining operations that have adverse effects on human health (for example coal dust etc.) or from the exposures of the human workers to hazardous working environment that constitutes mining operations (for example blasting etc.). One of the biggest challenges is to understand the combinatorial effect of numerous work-condition (e.g. exposure to dust) and human-factor (e.g. smoking habit) variables on a health or safety-condition variable (e.g. incidence rate of a disease). This paper uses an example dataset on Coal miners' cough problem to illustrate the applicability of Generalized Linear Modeling (GLM) in understanding the relation between cough and other response variables, such as, age, height, smoking habits, time of underground exposure etc.

Jan 1, 2002

By D. Veigel, J. D. McKay

Model enhanced Expert control has been implemented at the Newmont Lone Tree mill grinding plant as well as rule based Expert control for flotation and thickening circuits. The project has been successful in producing benefits but more importantly has contributed to an ongoing effort for continuous process improvement. This paper discusses how the control at Lone Tree has evolved and the part that Expert control has played in the overall improvements made. Specific examples of how the advanced control has integrated with instrumentation and stabilizing control are given and illustrations of how it has been effective in defining limitations and bottlenecks in the process or process control areas are provided.

Jan 1, 2002

By A. I. Kalugin, A. A. Abramov, D. E. Kozlov, D. V. Magazanik

Based on theoretical and experimental researches of phosphate and carbonate minerals flotation in the presence of soluable glass at various pH values and sodium silicate concentrations, it has been established that the presence of soluble glass in solution leads to formation of silicate compounds on the surface of phosphate and carbonate minerals causing change in their floatability for the worse. The harmful influence of soluable salts is done by tying of collector as metallic soaps, forming precipitates on the surface of minerals to be floated and causing their depression of flotation, and breaching of the froth etc. Depressing action of slimes and products of interaction with collector depends on the ratio of values and signs of potentials of the mineral surfaces. The possibility of phosphate and gangue minerals separation can be evaluated by comparing the minimum-necessary concentrations of collector required for their flotation.

Jan 1, 2002

By V. Srajer

This paper deals with the problem of efficiently selecting the most appropriate loading and hauling equipment for surface mines. Problems and factors that affect productivity and operating cost are identified. During the course of collecting the information for this study, mining companies and equipment manufacturers were interviewed to define their selection practices. The majority of mining companies prepare general specifications and ask the suppliers to mate those specifications to their product line. The mining company then evaluates various proposals on the basis of the best available deal. The following 'mines from western Canada provided information for this study: Coal Mountain, Line Creek, Quintette, Westar's Harmer mine from the Province of British Columbia, and Coal Valley, Gregg River, Highvale, Luscar from the Province of Alberta.

Jan 1, 1989

Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operating point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. This paper discusses some of the unique features of the Lone Tree sulfide deposit and its amenability to low-temperature oxidation. Problems encountered during pilot plant operation and their solutions are discussed.

Jan 1, 1995

By Edehran Lotfi, Terrence Stobbe

INTRODUCTION Mobile excavating and handling equipment are important 'tools of trade' in the mining and construction industries. The handling of this equipment must be mastered so that its limitations are learned and its harmonic use with other pieces of equipment is practiced. he sudden growth in mobile excavating and handling equipment type, size, complexity, and application started after the Second World War. This growth has not been accompanied by pertinent human factors research. Investigations into the proper and safe handling of such equipment with due regard for human and machine limitations are lacking. One such piece of equipment is the front-end loader (FEL), which during one cycle of operation excavates, loads, and hauls, (Lotfi and Adler, 1981). The diversity of action by FEL is archetypical among excavating and handling equipment. Front-end loaders are the most rapidly proliferating type of equipment in the industry. Also, front-end loaders are involved in the highest number of accidents involving mobile excavating and handling equipment. In the period 1970 to 1978, FEL's were involved in 27% of all mobile equipment accidents in surface mining (Adkins, 1980). Improving operational safety and efficiency will reduce the frequency of accidents. The performance of the operators can be evaluated and improved by the following steps: first, define the operating conditions and the operator workload intensity (Adler and Lotfi, 1983), second, monitor the operator to evaluate his task performance, and third, make recommendations based on the findings. The stressful nature of the equipment operating task is an acknowledged fact (Field, 1980). However, a systematic measurement of stress evaluation is lacking. In this paper, methods for measuring mental stress and fatigue, are defined, the mental load which caused the stress is outlined, and stress measurement methods are proposed. MENTAL STRESS Mental stress has been described as a "specific somatic response to damage or the threat of damage by several environmental agents"

Jan 1, 1986

By Paul G. Schmidt

Exxon Minerals Co. was exploring for mineral deposits in Precambrian terranes of the US portion of the Lake Superior region in the late 1960s. Exploration drilling and other activities had been concentrated on massive sulfide prospects in northeastern Minnesota, but general exploration studies and competitor scouting were conducted in other areas of the region. These activities drew attention to Wisconsin in 1969 when it became apparent that Bear Creek Mining Co. had made a discovery near Ladysmith in the northwestern part of the state. Observation of their drill hole pattern suggested that a massive sulfide deposit, since named the Flambeau deposit (Schwenk, 1977), had been found. With this background, Exxon initiated an exploration program for Precambrian massive sulfide deposits in northern Wisconsin in 1970 (Figs. 1 and 2). Northern Wisconsin is extensively mantled by Pleistocene glacial drift and bedrock outcrop is sparse. Other than iron mines in the extensive iron formations along the Wisconsin-Michigan border and Jackson County, no significant mineral deposits were known in the Wisconsin portion of the Precambrian Shield until the discovery of the Flambeau deposit. Until the mid-1970s, the only specific published literature on the Wisconsin Precambrian consisted of old outcrop locations and descriptions in journals of the Wisconsin Geological and Natural History Survey (Chamberlain, 1882; [ ] Weidman, 1907; Hotchkiss, 1915) and the summary maps of Dutton and Bradley (1970).

Jan 1, 1991

By G. J. Hartman

The Fort Cady in situ borate mining project involves recovery of boron from a mineral deposit located over 1400 feet below the surface. The resource recovery method is being developed using in situ mining technology employing weak acid solution injected directly into the ore body. As the acid contacts the calcium based ore (primarily natural colemanite), the contained borate values are digested as boric acid. This boric acid solution is then pumped to the surface by use of submersible pumps. At the surface the borate values are recovered as a finely divided solid white powder after a series of chemical reactions and precipitations resulting in the production of calcium borate. The refined product is then sold under the trade name CADYCAL 100.TM All environmental permits for up to a production rate of 90,000 tons per year have been obtained. These permits required an Environmental Impact study (EIS) for federal lands and an Environmental Impact Report (EIR) for the private portion of the property. Regulatory permitting required over 5 years to obtain all the various authorizations for this project. The ore body has an average thickness of 118 feet extending over 273 acres. At a production rate of 90,000 tons per year with only a 70 percent resource recovery allowance, in place reserves are sufficient to sustain production for over one hundred years.

Jan 1, 1997

By T. S. Mackey

The industrial types, sources, and quantities of US tin residues are identified and the methods of treatment reviewed. The effect of a lower tin price, due to a current major world surplus of tin metal, is mentioned and covered in some detail. The names and locations of over 100 US firms recovering tin residues are listed. Current smelting and refining charges are included to convert the residues into tin metal and alloy. The impact of the complete with-drawal of the LME daily tin price since Oct. 24, 1985, and the collapse of the International Tin Council, which at one time supported the Buffer Stock Manager, are reported with comments.

Jan 1, 1987

By G. Wang

Industrial minerals processing has gained importance lately, not only due to its wide range of new and regular applications in processing different industrial minerals, but also due to the strict specs under which products are commercialized. Among the processes applied to industrial minerals, flotation is a leading technology. The laboratory study and commercial operation demonstrate that the sulfonated reagents are very effective collectors for industrial minerals. This paper compares synthetic petroleum sulfonate with fatty acid on iron reduction in glass sand processing and describes the effect of conditioning pH on iron reduction using synthetic petroleum sulfonate as collector, the effect of molecular weight of natural and synthetic petroleum sulfonates on their flotation performance and the enhancement made for certain products.

Jan 1, 2011

By Jan K. Wolski

This paper addresses jet fans used as booster fans within mine ventilation networks. The static pressure developed by the jet fan was determined using the momentum theory. The influence of various parameters on this pressure was analyzed. A method was proposed for determination of the jet fan characteristic curve . The distance between the jet fan and a point where the fully developed static pressure can be measured was determined. It was shown that a reduction cone can significantly improve the jet fan performance. Verification experiments conducted in the Waldo mine are described.

Jan 1, 1995