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By Charles G. Zink

Anthracite is widely known as a domestic or space heating fuel. The prevailing market ratio of domestic to industrial consumption was about 80 to 20 up until 1950. Since then it has been shifting until now the ratio index is about 50/50, exclusive of overseas export. Despite a declining domestic space heating market, the demand for industrial anthracite remains good. However, as a result of stringent air pollution regulations, there is a renewed interest in this low sulphur coal which cannot smoke under any conditions. Anthracite serves other important industries such as power generating, metallurgical, cement, ceramic, chemical, water sewage and industrial wastes filtration. Anthracite is an excellent natural source of carbon and may be utilized in many processes.

Jan 1, 1966

By W. F. Quirk

The Missouri-Oklahoma tripoli district was discovered and first mined in 1869 near Seneca, Missouri. Tripoli is a microcrystalline form of high-purity silica that is porous, light- weight, and friable and is derived from a parent siliceous sedimentary rock from which soluble minerals have been leached. Tripoli deposits, 2 to 20 feet thick, occur in cherty limestones of Mississippian age beneath 2 to 10 feet of overburden. They are mined in open pits up to 9 acres in size. The color of tripoli is white, but it also commonly is light pink or red where stained by red iron oxides and clays. Ground tripoli is used commercially as an abrasive or in buffing and polishing compounds and is prized for such physical characteristics as its abrasiveness, porosity, permeability, absorption, and specific gravity.

Jan 1, 1978

By K. K. Cheng, Z. M. Chen, A. L. Mular

INTRODUCTION Since the nineteen fifties, process engineers have been seriously concerned with process models for various purposes (1,2,3). Models serve as subroutines to mathematical flowsheets which simulate circuits of interest. Simulators can serve to increase process know- ledge, assess circuit performance, investigate flowsheet modifications, evaluate new flowsheets, perform off-line optimization, and compare alternative control strategies. This chapter describes a methodology to develop a simulator of a bulk Cu-Mo circuit comprised of roughers, scavengers and 3 stages of cleaning. The simulator was employed to evaluate the influence of water addition at circuit points and to estimate the optimal number of cells for each stage in the circuit. DESCRIPTION OF CIRCUIT Figure 1 is a flowsheet of the Brenda Mines Ltd. (located near Peachland, B. C.) bulk Cu-Mo flotation circuit as simulated prior to an expansion/renovation which involved the installation of large, new flotation cells. Referring to the flowsheet, feed to rougher cells includes fresh feed, scavenger concentrate and 1st cleaner tailing. Rougher con, 1st cleaner (sect ion 2) con and 2nd cleaner tailing are fed to 1st cleaners (section 1). 1st cleaner (section 1) concentrate and 3rd cleaner tailing serve as 2nd cleaner feed, while 2nd cleaner concentrate is fed to the 3rd cleaners which produce a final bulk concentrate. Table 1 lists cell types and specifications important to the circuit. DEVELOPMENT OF MODELS To develop flotation cell models a systematic procedure was employed (4). This involves the selection of responses and factors, proposing models to be fitted, the acquisition of raw data, the statistical adjustment of raw data, fitting models to adjusted data and testing the adequacy of fitted functions. Responses and Factors Responses of interest included recoveries, concentrate grades and concentrate solids/water flow rates for each stage. Factors that influence these responses, such as reagent addition rates, air flow rates to cells, solids and water flow rates to stages and feed grades were not manipulated during the sampling period. Thus, the investigation was limited,

Jan 1, 1986

By M. Stephen Enders

The Little Rocky Mountains host epithermal gold-silver bearing vein and stockwork deposits in a syenite intrusive complex. Pegasus Gold Ltd. is currently mining the oxidized deposits by open-pit methods and recovering gold and silver by heap-leach processes. A geologic program has been designed to effectively determine the basic ore characteristics; 1)mineralization; 2)oxidation; 3)structural setting; 4)lithology; 5)alteration; and ultimately, 6)the leachability of the ore. Geologic mapping, sampling, drilling, assaying, and testing are routinely used in exploration, development, production control, mine planning, and ore reserve estimations. Timely and accurate assay results are essential for the program's success.

Jan 1, 1983

By T. Panhorst

Evaluation of through-deck blasthole sample reliability at the Lone Tree gold mine revealed a non-systematic bias in the sampling system. Ore is primarily hosted within the Powerline fault zone. Clay gouge, present in the fault zone and typically enriched in gold content, forms agglomerates during blasthole drilling leading to a segregation error during sampling. Replicated samples split from blasthole cuttings piles show through-deck samples to be either significantly enriched or depleted by 1.5 standard deviations or more from the mean gold content of their respective cuttings pile quality of through-deck samples correlates strongly with quantity of clay present.

Jan 1, 1999

By C. C. Clark

The national Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health, Ground Control Engineering Branch is investigating the use of shotcrete in weak rock mass mines with the objective of reducing fatalities and injuries resulting from rock fall accidents. When shotcrete is used as part of a multi-element ground support system, it is necessary to know when the material has developed a compressive strength of approximately 1 MPa (145 psi), the early threshold for safe re-entry of miner and machine into shotcreted mine workings at this value, the material has developed enough strength to be self-supporting and to allow for installation of other ground support components that require drilling of the shotcrete layer without degradation. NIOSH researchers have developed methods and portable test equipment to measure shotcrete strength on site in the first six hours after application using a partial beam test standard, a STM C 116-90 (1990). These advances were demonstrated in tests with five commercially available shotcrete mixes, sprayed as dry shotcrete using field expedient methods and equipment. The strength values from these tests allowed for real-time identification of the early strength threshold and were consistent with strengths reported using laboratory-type equipment. Measuring the early strength properties of shotcrete directly at the mine site can improve mine safety by identifying appropriate re-entry times and providing a convenient means of conducting on site quality control during shotcrete applications.

Jan 1, 2011

By J. K. Wolski

This paper addresses the effects of using jet fans as booster fans in mine ventilation networks. A method was developed to determine the pressure generated by jet fans using the momentum theory. The influence of a reduction cone and other ventilation parameters on the jet fan pressure was analyzed. Verification experiments conducted in the Waldo Mine are described. Examples are given to demonstrate the conditions for the effective use of jet fans.

Jan 1, 1998

By H. Douglas Dahl

Thank you, Don Gentry, for your generous introduction. It is not adequate simply to say that I appreciate very much the vote of the Award Committee putting forth my name as the winner of the 1992 Daniel C. Jackling Award. To look at the list of previous Jackling Award winners is a humbling experience. The Society for Mining, Metallurgy, and Exploration has been blessed with some exceptional members over the years, and I feel privileged indeed to be included among the Jackling Award winners. During the years of my education at Penn State, my field of specialization was mining engineering, with particular emphasis in my master's and Ph.D. work on rock mechanics. But my career has not been quite so tightly focused as that. I have been involved with coal mining in all its variety - its technical aspects, both theory and practice; and its business side, dealing with management and labor, accountants and lawyers, politicians and environmentalists. And I have also been involved with related fields - construction; exploration; barges, railroads, ships and docks; supply houses; the coke business; you name it. Coming from that practical background, I believe it is most appropriate that I talk with you today about some practical matters. But I will not advise you today how to mine coal or protect roof in a hard-rock mine. You fellows know how to do that. The practical matters that I have in mind relate to policy - national policy. I will acknowledge immediately that national policy is often much less than practical, but bear with me as we explore the subject together. I am reminded of a supervisor I had early in my career. He very strongly advised me, back in 1961, to "get involved in the political process," for without objectivity injected into our national policy making, we will become a second-rate economic power. I have selected as the subject of my remarks today, "Coal and the de facto National Energy Policy." There is an energy policy relating to coal, a de facto one, and it's the one we see as a result of regulation, attitudes and culture from our nation's capital. This de facto policy is the one we in the coal business live with every business day. My thesis is very simple - Coal is, in fact, a vital part of our national energy policy and will remain so, as a practical matter, no matter what politicians may do to us, or not do to us. Coal will prevail - that will be the happy ending to my story in which, of course, we are the good guys in the black hard hats. But first, I must flesh out the plot with some other characters and with some threatening activities. There are five main characters in my story: in order of appearance - Perpetual Politics, Rampant Regulation, Selective Science, Electrification and Confident Coal. The time: the present. Perpetual Politics is always a threat to coal. When you cross the Capital Beltway into Washington, D.C., check your wallet and your gold fillings, because you're not likely to run into any friends. On Feb. 20, 1991, just over one year ago, President Bush presented to Congress his National Energy Strategy. It's a thick document of more than 260 pages, with discussions on securing our future energy supplies, increasing energy effi-

Jan 1, 1993

By V. G. Hill

The term bauxite was first used by O.P.A.P. Dufrenoy in 1845 for an ore which was discovered by Pierre Berthier in 1821 near the village of Les Beaux de Provence near Arles in southern France. His data suggested that this mineral was an alumina hydrate with two molecules of water. However, it was subsequently shown by thermal analysis that the mineral was a fortuitous mixture of the mono-hydrate and the tri-hydrate. Diaspore had been previously discovered in 1801 and gibbsite in 1822. The term was however retained as a rock name. The name of the village was changed to Les Baux around 1885; Sainte Claire Deville suggested that the mineral name should reflect this, and it was changed to bauxite (Bracewell, 1962, Rkgnier, 1988). Mining of bauxite began around 1860 in the Auriol region in the Bouches du Rhine area in the south of France. This ore was transported toMarseilles by carts and was processed in the Salindres plant, which at that time was the only plant producing alumina using the Deville process and aluminum by the chemical process. During that period white bauxite (low iron content) was particularly sought after for the production of aluminum sulfate, refractory bricks, and quick setting cement. Export of bauxite from France began in 1880 and was initially delivered to Chemische Fabrik, Goldschmischen near Breslau, and to Guilini's Ludwigshafen plant in Germany in 1885. These companies produced alum and aluminum sulfate (RCg- nier, 1988). The next bauxite mining operation was in Antrim County in Northern Ireland in 1873. This was first used for the manufacture of alumina refractory bricks and quick setting cement (Bracewell, 1962). It is important to emphasize that initially almost all of the bauxite which was produced came from France and was mainly used for non-metallurgical purposes. At that time even the production of alumina was mainly for use as a mordant in textile dying. However, with the development of the Hall-Héroult process, the alumina which was available was increasingly used for smelting to aluminum. In spite of this the demand for non-metallurgical bauxite continued to increase and a set of applications were developed. These include refractories, abrasives (including the recently developed proppants), high alumina cements, aluminum chemicals, activated bauxite, and alumina. It became increasingly evident that the high alumina-low alkali raw materials have special advantages. The question however was one of cost benefit. Chin (1989) has pointed out that the non-metallurgical operations have been traditionally grafted on a bauxite/alumina/aluminum industry tree. In this context the non-metallurgical alumina produced was, with few exceptions, regarded as either coproduct or byproduct i.e.: Bauxite Trunk Sector Alumina Trunk Sector Aluminum Trunk Sector

Jan 1, 1994

By F. G. Rinker

World demand for metallized iron continues to increase, keeping pace with steelmaking requirements for lower-cost hot metal. Virgin iron ore and in-plant oxide fines can be reduced to direct reduced iron (DRI) and hot-briquetted iron (HBI). Maumee Research & Engineering Inc. (MR&E) developed an improved coal-based process for the cost-effective production of either DRI or HBI. Starting with dry compaction, the process combines the latest technology for material preparation, rotary hearth furnace construction and environmental control. Coarse iron ore fines are blended with pulverized nonmetallurgical coal to produce a highly metallized (>90%) product. This paper presents production and installation cost data based on operating and under-construction iron oxide reduction facilities.

Jan 1, 2002

By Robert S. Foote

The U.S. Energy Research and Development Administration (ERDA) is currently conducting a national program to survey for uranium the conterminous United States and Alaska by 1980 using airborne and surface techniques. This paper discusses the techniques used and some of the results of airborne surveys conducted to date by Geodata International, Inc. Airborne gamma radiation and the earth's magnetic field data are measured to provide data leading to regions potentially more favorable for the exploration and discovery of uranium ore. High-sensitivity radiometric and magnetic field data have been gathered from an aircraft with an average surface altitude of 400 feet (Figure 1). Under most conditions, data are usable up to an aircraft surface elevation of about 1250 feet where limitations will be discussed. Results of data analysis under GJO-1632, GJ0-1644, GJO-1654 and GJO-1663 will be discussed.

Jan 1, 1976

By Jameel Menashi

A process has been developed for recovering the refractory metal values contained in mixed secondary source materials such as contaminated grinding wastes, oxides and sludges. The wastes are calcined with sodium carbonate in air to convert the refractory metals to water soluble Na2CrO4, Na3V04, Na2Mo04 and Na2W04. The base metals, Fe, Ni, Co and Cu, are converted to water insoluble oxides. An aqueous leach of the calcine effectively separates the refractory metals from the insoluble base metals. Co, Ni and Cu can be recovered from the oxidic residue by conventional processing methods. The leach solution is purified and then treated to recover the refractory metals as Cr203, NH4VO3, (NH4)6Mo7024?4H2O and H2WO4. The purity of the products is sufficient for their use in many metallurgical applications. The Na+ values in the leach solution are recovered as Na2CO3(or NaHC03) and are recycled to the calcination step. It is shown that the process can accommodate a wide range of feed compositions and generates a minimum of aqueous effluents.

Jan 1, 1984

By Kendall Y. Keuhey

The Mercur Mine, developed and operated by Getty Mining Company, is designed to process 3,000 tons/day of gold ore from the historical Mercur Hill mining district. The mill process involves crushing, grinding, and cyanide carbon in leach for recovery of gold ores ranging from 0.08 to 0.10 oz/ton. During the mining of normal grade ore, a substantial tonnage of material containing 0.02 to 0.05 oz/ton is mined and would be available for heap leaching. Also, Getty Mining is developing methods to test and prepare lower grade material for heap leaching by rejecting a course rock fraction from the grinding circuit SAG mill. This lower grade fraction is suitable for heap leaching, and its removal will upgrade the regular mill feed. Other test methods are directed toward leaching techniques on some 4.0 million tons of tailings that resulted from roasting and/or cyanide leaching Mercur ores in the early 1900s. The natural carbons associated with the Mercur deposits require special treatment to reduce their gold adsorption effects when leached with cyanide.

Jan 1, 1983

By T. Qiu

"The purpose of this study is to investigate the effect of the dosage of sodium hypochlorite as activator on the flotations of depressed marmatite and depressed chalcopyrite, with a focus on activation-flotation kinetics. Four flotation kinetic models were applied to test data using 1stOpt statistical analysis software to estimate the relationships between the maximum flotation recovery rates for the depressed marmatite and depressed chalcopyrite, the flotation rate constants and the sodium hypochlorite dosages. Within the range investigated, the highest flotation performances of depressed marmatite and depressed chalcopyrite were obtained at 2.5 mL/L sodium hypochlorite with zinc recovery rate of 93.8 percent and 3 mL/L sodium hypochlorite with copper recovery rate of 94.6 percent, respectively, after four minutes of flotation. A second-order model with rectangular distribution of flotabilities gave the best fit to test data collected at various sodium hypochlorite dosages. For the highest flotation performances of depressed marmatite and depressed chalcopyrite, the respective equations of their flotation models were derived and presented.IntroductionCyanidation tailings are the solid residues generated by gold plants that use cyanide to extract gold (Lv, Ding and Qian, 2015; Zhang, Li and Yu, 2013). Because of increasing demand for gold, the Chinese gold industry has developed rapidly, with production amounting to 451.799 tons in 2014, an increase of 5.5 percent from 2013. Chinese gold production has been the highest in the world for eight consecutive years. As a result, more than 2.45 million tons of cyanidation tailings are estimated to be discharged into tailings ponds every year (Li et al., 2010; Lv, Ding and Qian et al., 2015; Wang et al., 2015; Zhang, Li and Yu, 2013; Zhang, Li and Yu, 2012), and approximately 300 million tons of cyanide tailings are stockpiled in China, with the potential to cause serious environmental pollution as well as death to wildlife (Adams and Lloyd, 2008; Donato et al., 2007; Hewitt, Breuer and Jeffery, 2012; Velasquez-Lopez et al., 2011; Stephen et al., 2009; Zagury, Oudjehani and Deschenes, 2004). Concerns over cyanidation tailings are not exclusively environmental but also economic, as tailings occupy considerable land area, and tailings storage facilities increase the production costs of gold enterprises (Donato et al., 2007). Tailings often contain other valuable metals such as zinc, lead and copper. For example, the cyanidation tailings of Gaoyao Hetai Gold Plant in Guangdong Province contain 2.5 percent copper (Cu), 0.31 percent lead (Pb), 0.23 percent zinc (Zn) and 15.36 percent iron (Fe) (Shi, 2008), and the tailings of Tianshui Gold Plant in Gansu Province contain 1.94 percent Cu, 5.96 percent Pb, 0.27 percent Zn and 24.62 percent Fe. Cyanidation tailings have therefore been increasingly viewed as a secondary resource rather than waste."

Jan 1, 2016

By K. F. Unrug

An overview of the history of mining technology, both past and present, shows that some of the new concepts being successfully applied have changed the reserve categorization and are having an overall impact on production. Past coal mining operations in the eastern coal fields, and especially in Appalachia, extensively utilized stripping with the predominately applied contour method. As a result, vast mountainous areas have abandoned benches left behind by past mining operations. While thicker seams previously stripped were usually mined by underground or mountain top removal methods, thin seams beyond technical or economical limits were left intact after contour mining had reached the ultimate height of the wall. These thin seams quite often contain high BTU, low ash and sulfur coal that makes them attractive for a secondary recovery due to the market requirements. Secondary highwall recovery has obvious potential and is economically attractive; however, with the present state of industrial experience and lack of analysis of site data, a trial and error approach is used by operators.

Jan 1, 1983

By Michael Edesess

The salt gradient solar pond has been the focal point of accelerating international attention and interest in recent months. Only recently have most investigators in the renewable energy field come to realize the versatility of the solar pond, and its ability to overcome certain problems usually associated with solar technologies. These realizations, together with clear demonstrations in Israel and elsewhere of its technical feasibility, have combined to bring the solar pond to the forefront of renewable energy technologies. The solar pond is a natural or site-built pond, about one to five meters or more in depth, which has been altered to retard the loss of absorbed solar energy. The absorbed solar energy is usually lost through upward buoyancy of the warmed water, followed by the loss of its heat to the atmosphere. The chief solar pond technology -the salt gradient, or "nonconvective" solar pond-prevents this upward buoyancy by means of a vertical density gradient achieved with dissolved salt. The deep waters in the solar pond reach high temperatures, up to and even above the boiling point of pure water.

Jan 1, 1981

By R. K. Mensah-Biney, M. T. Hepworth, K. J. Reid

The loading characteristics of gold-bromide species onto activated carbon were evaluated using a batch system. The overall loading of gold onto activated carbon was rapid for the first few hours, but it continued without cessation as a result of the reduction of gold. Therefore, conventional equilibrium considerations were not applicable. Although loading continued slowly after several days, an abnormally high, loading capacity value of 10-12 meq/g carbon (650-800 kg Au/t) could be attained in 72 hours. The loading of gold-bromo species by activated carbon was by the mass transfer of (AuBr4)- species to the external surface to be reduced to metallic gold by carbon. Elution of gold from loaded carbon was feasible provided the carbon had not been loaded to high capacity values. If loading is carried to high levels, complete elution becomes impractical, and the gold may be recovered by ashing the carbon. For the high loading capacities observed, this option would appear to be cost effective. The effect of several variables on the loading capacity of the activated carbon for gold-bromo species is discussed.

Jan 1, 1994

By Milos Krofta, Donald B. Aulenbach, James P. Van Dyke

INTRODUCTION An innovative Ø.1-MGD (378.5-m3/day) biological and phyicochemical wastewater treatment system at Hancock, Massachusetts, USA, has been treating the domestic sewage generated from the four-season Jiminy Peak timeshare resort since 1985. The influent raw sewage is collected and equalized in an equalization tank, then biologically treated by two rotating biological contactors (RBC). A portion of the RBC effluent is discharged to a secondary sedimentation tank to simulate conventional waste treatment by a conventional RBC system. For parallel treatment the remaining portion of the RBC effluent is discharged to an innovative Sandfloat (SASF-8) clarifier to simulate a two-stage biological and physicochemical treatment by RBC-Sandfloat. Both secondary sedimentation effluent and Saandfloat effluent are later combined together and discharged to a tertiary sand filter and two UV disinfection'units for final polishing. The operation and performance data of Jiminy Peak plant in the period of May 1985 to March 1988 was fully documented in the Lenox Institute technical report No. LIR/Ø3-88/292 (391 pages, March 1988). This report presents only background information and complete plant data in the period of April 1988 to January 1989. Dr. Lawrence K. Wang and Mr. James P. Van Dyke have been the Consulting Engineer and Director of Special Projects, respectively, for the Jiminy Peak Project since 1985. (Key Words) Innovative and Alternative Technology, Rotating Biological Contactor, Sandfloat, Dissolved Air Flotation, Sedimentation, Tertiary Filtration, Ultraviolet, Disinfection. BACKGROUND INFORMATION Jimmy Peak, Inc., Hancock, Massachusetts, has designed and constructed a secondary wastewater treatment system consisting of preliminary/primary treatment facilities, two rotating biological contactors, a dissolved air flotation clarifier, a secondary sedimentation clarifier, a sand filter and two ultraviolet (UV) disinfection units. Total average wastewater flow is approximately Ø.1 ) (378.5 cubic meters per day). In accordance with the Consulting Engineer's preliminary design, the total wastewater stream is initially collected and equalized by an equalization tank, and then biologically treated by rotating biological contactors (RBC). Part of the RBC effluent is diverted to a Krofta Sandfloat (SASF-8) for physicochemical clarification in order to simulate an innovative RBC-Sandfloat two-stage waste treatment system. The remaining part of the RBC effluent is diverted to a sedimentation tank for secondary clarification in order to siumulate a conventional secondary RBC-sedimentation waste treatment system for the purpose of parallel comparison. Both Sandfloat effluent and sedimentation effluent are later combined together and discharged to the subsequent sand filter and UV disinfection unit for final polishing. Figure 1 shows the flow diagram of Jiminy Peak Plant. The Massachusetts Clean Waters Act (M.G.L.c.2l,s.26-53) was amended by Chapter 246 of the Acts of 1973 to authorize the Massachusetts Department of Environmental Quality Engineering (DEQE), Division of water Pollution Control, Boston, Massachusetts, to regulate discharges into all waters of the Commonwealth of Massachusetts, including groundwaters. The DEQE regulates discharges through the issuance of discharge permits which impose limitations on the amount of pollutants which may be discharged in the effluent, together with monitoring and reporting requirements and other conditions to insure adequate treatment of all liquid wastes prior to discharge. The DEQE reviewed the application submitted on behalf of Jiminy Peak, Inc. for a permit to discharge sanitary wastes from the Jiminy Peak secondary wastewater treatment system located off Brodie Mountain Road, Hancock, Massachusetts, and subsequently developed the conditions contained in the Groundwater Discharge Permit No. Ø-188. More specifically, Jiminy Peak, Inc. (i.e. the permittee) has been authorized to discharge into the ground from the Jimmy Peak secondary wastewater treatment facilities for which the Permit No. Ø-188 was issued, a treated effluent

Jan 1, 1989

By H. E. Rutherford

Monterey Coal Company has begun a geologic monitoring program in order to better understand our in-mine geologic conditions and to apply the knowledge gained to our mining operations. Two methods are used to collect information. The first is a monthly examination of conditions throughout the mine using a rapid mapping technique. The second is the detailed mapping of specific events encountered during mining such as faults and roof falls. The data gathered from both methods is correlated with operational statistics to create a geologic/production database. From the database, a monthly evaluation of mining conditions is made. Also, the database has proved useful in such areas as forecasting roof conditions and examining how faulting has affected mining operations.

Jan 1, 1984

By Shiou-Chuan Sun

Notwithstanding the fact that unsaturated fatty acids are used in preference to saturated acids for most flotation purposes, information regarding their collecting properties is sketchy. Keck, Eggleston, and Lowry1 reported in 1939 that the collecting power of fatty acids on hematite decreased in the order of oleic, lauric, myristic, palmitic, and caprylic acid. Keck and Jasberg2 described in the same year that "unsaturated oleic acid with 18 carbon atoms was a better collector than saturated stearic acid" for floating magnetite. Gaudin and Cole3 stated in 1953 that the double bonds of oleic and linoleic acid were not oxidized during the flotation of fluorite, whereas the double bonds of linolenic acid were measurably altered even after one single flotation step. In August, 1953, Hukki and Vartiainen4 concluded that the collecting power of palmitic, oleic, linoleic, and linolenic acids on ilmenite, magnetite, pyrite, and rutile increased with an increasing number of double bonds in the acid molecules. This was subsequently proved to be generally true for the flotation of mapganese5, phosphate6, and magnetite7. The above cited literature indicates that, prior to the present paper, only about ten minerals were tested with pure unsaturated fatty acids as collectors.

Jan 1, 1959