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By J. Scheepers, P. Smith, G. (Yunfei) Qiao

High pressure acid leach (HPAL) and pressure oxidation (POx) or pressure leaching extraction processes occur in autoclave vessels operating at elevated temperature and pressure, acidic conditions with abrasive mineral slurries. The harsh process conditions require specialized severe service metal seated ball valves to support operation of the vessels. Over several decades thermally sprayed titanium dioxide (TiO2) and chrome oxide (Cr2O3) coatings have been applied to extend the service life of the ball valves and other high wear critical components. Variability in the coating application quality control and severe process conditions can result in spalling, coating failure and premature failure of the component resulting is decreased autoclave circuit availability. In 2012 MOGAS, together with BRENCO, initiated research and development for ML-381, metallurgically bonded coating. This paper includes the historical development of severe service ball valve coatings, success of the trials and increasing industry adoption of the ML-381 coating for ball valves and other critical autoclave circuit components.

Mar 2, 2022

By Jeffery Leavy, Ken Davis, Kirk H. McDaniel

The Waste Isolation Pilot Plant (WIPP) is a United States Department of Energy facility located in southeastern New Mexico. It is designed for the safe disposal of transuranic radioactive waste in deep geologic salt beds. Westinghouse TRU Solutions, LLC, the managing and operating contractor, undertook a project to simulate the processes at WIPP in order to identify bottlenecks and optimize available resources. The activities simulated in the model included the receipt, processing and disposal of radioactive waste underground, the mining of new areas for future waste disposal and the transportation of salt out of the mine. The complexity of the processes and the interactive requirements between processes required the use of advanced modeling techniques. The simulation model includes a huge number of locations and path network node points, with movement to and from the locations controlled using parameters rather than explicit routing. Information for the timing and sequence of the mining and nuclear waste emplacement operations is brought into the model via spreadsheets. Arrays in the simulation model keep track of past and future events that occur. Routing to the multiple possible positions in the underground mine is done using attributes, and system functions within ProModel in order to allow for a highly flexible sequence of planned events and to reduce the level of effort in creating the ProModel processing. Considerable use of subroutines in the simulation model is utilized for parametric decision-making that is repetitive. This presentation describes the modeling techniques used to accurately simulate the surface and underground operations. The surface and underground operations are considerably different, thus they will be treated in their own sections.

Jan 1, 2002

By James E. Gingrich

The new Track Etch* technique for uranium exploration has been utilized in several survey programs conducted during the last few years. The results from these programs have been very encouraging, and new uranium ore bodies have been discovered by using this new technique. The Track Etch method is being used in several exploration programs in various locations around the world. The Track Etch exploration technique utilizes small pieces of special radiation-sensitive plastic film to detect the presence of radon gas which is released by uranium ore bodies. Because of the selectivity and sensitivity of the technique, ore bodies not normally detected with other surface or airborne monitoring methods are found. Since no large equipment or special training of personnel is needed, the Track Etch technique is easily used in field operations. The basis for the Track Etch method, its application in field exploration programs, and the results obtained to date in locating uranium ore bodies is discussed.

Jan 1, 1974

By H. B. Weaver

The development of a method to manufacture diamonds has been rated as one of the out- standing scientific achievements of our time. The story is both interesting and significant. This paper will quickly review history of diamond and manufactured diamond. Next, it will discuss manufactured diamond as a product -- how good is it -- and what is the significance of this scientific achievement. And finally, present a few thoughts about the future of this technology and this product. For centuries, diamond was found only in alluvial deposits, primarily in the Golconda fields of India. As a result, man knew nothing of the process by which the stones were formed. In 1860, diamonds were found in South Africa under completely different conditions. Here, for the first time, they were found in volcanic pipe -- their mother ground. These volcanic pipes are roughly cylindrical columns of rock which go deep within the earth. The theory as to the formation of diamond was presented by the geologists in that era. The theory states that molten rock was thrust up through a layer of carbonaceous shale where it picked up the carbon necessary for diamond formation. It was generally agreed that diamond was formed approximately 240 miles below the surface of the earth, thus indicating that extremely high temperatures and pressures were involved.

Jan 1, 1964

By E. E. Caba

Copper smelter flue dusts containing arsenic are hazardous materials requiring environmentally accept-able disposal, preferably with re-source recovery under the RCRA and CRCLA regulations. However, the known resource recovery processes entail capital and operating costs greater than can be justified by the revenue of the recovered metal. Consequently, the smelting industry is tending to forego resource recovery in favor of encapsulation and storage in a certified class I hazardous waste site, or in a dedicated facility located at the source Superfund site. Order of magnitude costs for this option with portland cement encapsulation are estimated at $100 per ton, not including transportation. Industrial adoption of a new resource recovery process re-quires that its cost, including capital amortization, exceed the cost of encapsulation and storage only by the amount of the offsetting revenue from sale of metal. The lime-roast/ammoniacal leaching process is expected to meet this goal.

Jan 1, 1992

By B. Schimm

Improve the mines productivity by simplifying the mining process, for these tasks the Wirtgen Surface Miner offers an attractive alternative. Surface Miners cut, crush and load material in one operation with only one machine. The cutting depth is controlled exactly.

Jan 1, 1997

By Neal P. Cochran

The Office of Coal Research Program has been outlined in our Annual Report for a number of years and reported on by various members of the OCR staff as well as by our contractors. The program is national in scope and is intended to develop new and improved uses for our Nation's coal resources and to maintain coal in a favorable economic position, vis-a-vis, the other energy forms. A program has been developed that includes conversion of coal to gas, gasoline and other petroleum-type products, and to electricity. These projects are only one facet of the OCR program albeit an important one. In many of the conversion projects we have underway, original development work has been done with bituminous and sub-bituminous coal. It is the intention of this paper to present a general outline as to how lignite might fit into one or more of these projects as a raw material. Our national lignite reserves are vast in scope and this has been recognized in the OCR program by development of a project specifically for lignite and by including lignite as a test raw material in many other projects. Project Lignite is intended to develop the Cop Acceptor Process for conversion of lignite to a high B.t.u. gas. In this effort we have included the design, construction, and operation of a lignite gasification plant at Rapid City, South Dakota. The work is being conducted by the Consolidation Coal Company and is an outgrowth of their laboratory development of this process. The first portion of our effort included a detailed economic study of a somewhat arbitrary grouping of States designated Market Area A that could be expected to use gas manufactured in a lignite gasification plant. The area included the Dakotas, Minnesota, Nebraska, and Iowa. This geographical area could readily be served if a process could be developed for converting North Dakota's lignite reserves, estimated at 351 billion tons, to high B.t.u. gas. Our study showed that Market Area A had a potential commercial- industrial market of one trillion cubic feet of gas a year. To meet this demand, we believe that part of the load can be obtained from commercial lignite-to-gas plants. At the time of our original study, we concluded that gas could be delivered to the city gate in Market Area A at about 45¢. As a result of price escalation in the interim, our estimate today might be slightly higher, but not significantly so, since some parts of the process appear better today than they did at the time of the original projection.

Jan 1, 1968

By Luciano Ramos, Daniel Santos

Igarape Bahia Mine, which is currently the largest gold producer in Brazil, belongs to Companhia Vale do Rio Doce - CVRD and is situated 250 miles south of Belem, state of Para, Brazil. It came into operation in 1992 with the startup of the CIP plant, fed with high grade ore, presently at 3.4gAu/t. The ore is totally oxidized, containing extremely fine particles of free gold. The ore is soft and low cyanide consumer, with a maximum work index of 12kwh/sht. In 1993 a Heap Leaching Plant was set into operation, handling low grade ore of · 1.s g Ault. The Heap Leaching Plant has undergone two major expansions. In 1994 its capacity was raised from lMtpy to 2,2Mtpy and in 1998, with a thorough remodeling of crushing operations, it was raised again to 3.5Mtpy. The CIP plant, which was originally designed with a capacity for l. lMtpy of ore, was expanded to a 2.2Mtpy capacity in 1994. Presently, the CIP plant accounts for most of Igarape Bahia's total gold output, with approximately 220,000oz per year. Igarape Bahia's annual output is around 360.000 oz. Over the last three years, work has been intensified to improve performance of both processes, aiming at maximizing productivity of the two industrial plants. Reduced costs and increased revenues have been given a special emphasis in the unified improvement program. Cost · reduction has involved developing methodologies to rationalize consumption of materials and inputs, while increased productivity has been given top priority as a means of generating increasing revenues. Thus, all of the improvement and development efforts have had a common goal: to increase operating income.

Jan 1, 2000

By J. Mastoris

The problem of defining the optimum final limits of an open pit mine has challenged the mining industry for the last three decades, mainly due to the great number of variables involved and the sheer computational effort required in real life applications. An actual lignite deposit is used in this study in order to introduce and apply a methodology to be used as a basis for surface mine design optimization. A geologic reserves model of the deposit is first developed with the use of an integrated geostatistical modeling package. The model is transformed into an economic one through the use of flexible objective function formulation(s). The optimization of the final open pit limits is then enabled with the use of a competent, commercial optimizer, and comparative sensitivity analyses are performed in order to study the effect of some basic mining and economic parameters on the optimal pit design. The conclusions drawn can develop useful guidelines for decision making by the mine operator.

Jan 1, 1995

By Andrew M. Wala

The determination of air quantity needed to dilute the exhaust gases to a safe level has to be individually evaluated for particular cases. The diesel powered machines are doing some specific operations in the cyclic order required by the technical process. The dynamics of this process in certain conditions has an essential influence on environmental health conditions in the working area. The main purpose of this paper is to show, using computer simulation, how the movement (dynamic) of diesel vehicles effects environmental health standards and also how to determine the required air quantity for certain conditions

Jan 1, 1983

By G. E. Sreedhar, R. Kumar

The pockets of high silica blue dust across the entire high grade hematite deposits in the Bailadila sector bothers the excavation activity due their iron content, which is higher than the threshold value specified by the Indian Bureau of Mines and the agony of stacking them separately due to their fragile & powdery nature. The physical nature of blue dust and its negligible alumina content makes these a potential source of hematite, which is a blessing in disguise. As most of the particles are in the form of an independent grain making it appropriately suitable feed for dry magnetic separation and thus the dry beneficiation has turned a bane into boon by enabling to produce concentrate either suitable for using as DSO or amenable for blending. The emphasis on carrying out dry beneficiation studies in the present context serves the purpose of mineral conservation, mitigates the issues of excavation and stacking as well as conservation of water resource. This paper describes the laboratory and pilot scale dry beneficiation studies carried out on blue dust of 48 – 60%Fe and Silica up to 30% at 25 Kg/hour to 400 Kg/hour, resulting in production of concentrate assaying 60 – 65%Fe. INTRODUCTION High silica blue dust (HSBD) is associated with Banded Hematite Quartzite (BHQ) and is available in abundance in various pockets across the Iron ore body in the Bailadila region of Chhattisgarh state. High Silica Blue dust occurs in the form of free granular particles and also as friable lumps. The chemical quality of this falls under sub-grade category (45 – 55%Fe) and as per the guidelines of Indian Bureau of Mines, these are to be stacked and conserved as future resources of Iron if it can’t be utilized in the present circumstances. Due to its friable nature, stacking of HSBD is a challenge and it is also compounding the problem by polluting the air under high velocity wind conditions. Because of its physical nature and occurrence in pockets pose challenge to systematic mining. The existing processing set up of the operating mines is designed to treat either Direct Shipping ore (DSO) or Run-of-Mine (ROM) have grade >60% Fe. The present practice of beneficiating iron ore fines (<1 mm) comprise combination of two or more processes such as desliming, hydraulic classification, magnetic separation and flotation apart from requirement of grinding depending on liberation characteristics. The HSBD which is predominantly occur as free granular particles, is significantly low in its alumina content. This gives us an opportunity to utilize them by exploring a suitable beneficiation process so that the concentrate produced can be used as a sweetener for alumina rich iron ore/concentrate. Thus, in the present study, an attempt has been made to adopt dry high intensity magnetic separation technique to explore the amenability of the high silica blue dust for beneficiation.

Jan 1, 2019

By Harley G. Pyles

Rotary Percussion drilling has shown great improvement over rotary drilling, when hard roof is encountered. In addition, Rotary Percussion drills have eliminated the need for air drills in many applications. Improved drilling rates have been achieved but roof bolting is still a bottleneck in many operations and the demand for further improvement will continue. Drilling rates beyond current performance is limited by the capabilities of existing drill steels and bits to resist increased horsepower input. The most apparent immediate solution to improved drilling is to increase the strength and rigidity of the drill steels. Drilling experience indicates that a l-1/2" diameter or 1-5/8" diameter hole can be drilled as rapidly or &apos;more rapidly than the standard 1-3/8" diameter hole. Greater torque and thrust capacities can be achieved through the use of larger O. D. and I. D, steels, however, this is only possible if the larger hole sizes can be made allowable. Large diameter anchorage shells can be made available at a slight extra cost.

Jan 1, 1965

By G. W. Cutting

It is well known in both the research field and in commercial flotation processes that the grades and recoveries obtained from flotation plants are heavily influenced by the structure and height of the froths produced in the flotation cells. The development of steady-state mathematical models of flotation processes based upon practical and readily obtained parameters have demanded detailed information about the structure of flotation froths. The important parameters are the distribution of floating values, gangue and water in the froth with respect to froth height, cell pulp density, cell air flow rates and flotation inducing additives. Little work has been conducted in this field although considerable attention has been paid to bubble loading and other factors close to the cell froth/pulp interface. Laboratory batch tests are prefaced for the derivation of the above mentioned parameters for both practical and economic reasons. The standard laboratory flotation tests using a batch cell produces a froth of low height (1 to 3 cms generally) together with a varying cell pulp density as the test progresses due to the addition of top up water and the removal of froth from the cell. This form of test can be considered only as giving information about froth conditions close to the cell froth/pulp interface under conditions of widely varying cell pulp densities. In commercial processes the froth heights are much larger (frequently greater than 10 cms); therefore the laboratory batch test, although useful in many ways, does not directly yield parameters relating the state of the froth flowing over the cell lip to process operating conditions. To investigate flotation conditions, where more realistic froth heights are developed, an equilibrium type of batch cell has been developed at Warren Spring 1 Laboratory . In this a tank with high walls is used to contain the pulp and whole froth and, after a short period of operation, an equilibrium between froth

Jan 1, 1975

By Dapeng Zhang, Brij Moudgil, Shibo Zheng, Chunhui Feng, Wenyi Song, Wending Xiao, Patrick Zhang

The separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. More than 50 percent of the phosphate reserve in Florida contains too much dolomite to process using current industry practice. The current way of producing phosphoric acid requires less than one percent MgO in the phosphate concentrate as the feed material. The Florida Industrial and Phosphate Research (FIPR) Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered three feasible options. Option I entails three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand, which could reduce MgO content in the final concentrate by 20 to 40 percent. Option II involves the crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9 percent MgO at about 87 percent P2O5 recovery. Option III is a gravity separation technique using an innovative separation jig, and its full potential remains to be demonstrated.

By Frank E. Kottlowski

Widespread high-calcium (HC) limestones in New Mexico and adjoining areas, are low in magnesium, but some units include shale interbeds that would be deleterious for usage in sulfur removal. In southwest New Mexico, southeast Arizona, and adjoining parts of Mexico, limestones in the thick Mississippian Escabrosa, Pennsylvanian-Permian Horquilla, and Cretaceous U-Bar units are HC as are strata in the Mississippian Lake Valley, Pennsylvanian formations, Permian Hueco, and parts of the Permian Capitan Limestone of south-central and southeast New Mexico and west Texas. In north-central and central New Mexico, many limestones in the Pennsylvanian Madera Formation are HC as are some of the Cenozoic travertines. In northwest New Mexico, where the present-day mine-mouth coal- fired power plants occur, there are no HC limestones, but to the north in southwest Colorado some beds of the Mississippian Leadville Limestone and Pennsylvanian Hermosa Formations are HC. HC limestones considered contain at least 95 percent calcium carbonate and less than 3 to 5 percent magnesium carbonate. Limits for other impurities are alumina, 1 percent; silica, 2 percent; sulfur 0.05 percent; phosphorous, 0.02 percent; and iron oxide, about 1 percent. Chemical and physical requirements differ slightly depending upon the ultimate use.

Jan 1, 1995

By F. Feichtinger, M. Riess, A. Lammer

Introduction This article discusses the unique range of properties of platinum and its applications as a high technology metal. World reserves of this strategic and precious metal are confined mostly to South Africa and, to a far lesser extent, the Soviet Union. An analysis is given of past trends in world platinum output. The timepath is computed for the world platinum output rate, covering a period of more than 350 years. This is based on the postulate that the industrial conversion of a virgin resource progresses according to a Sigmoid curve. This computation is performed by means of a nonlinear, three-stage optimization model employing a multiform Sigmoid function. Finally, the price dynamics are examined. Platinum is the most important of the group of the platinum metals to which it gives its name. Other platinum group metals are iridium, osmium, palladium, rhodium, and rhutenium. The metals occur in nature in close association and are chemically very similar to each other. Three members of the group - platinum, iridium, and osmium - are the heaviest metals known to man. Platinum&apos;s density is 11% heavier than gold and about twice the weight of the same volume of silver or lead. Properties Platinum is a typical grayish-white metal. Its special properties were known 1000 years ago to the American Indian craftsmen of what is now Ecuador and Colombia. From those distant beginnings, platinum is now firmly established as the most precious and distinctive metallic element known to mankind. It is shown in Table 1, platinum has a unique wide range of physical, chemical, and mechanical properties including high melting point, resistance to chemical attack, high catalytic activity, mechanical strength, and malleability. These properties make it indispensable for use in many industries. Application Platinum is first and foremost a high technology metal. During the last few decades, fertile scientific minds searched for and developed widespread cost-effective uses for this precious metal. Its unique properties render it irreplaceable in many key industrial processes. Important major fields of application include: • protection of man&apos;s natural environment (pollution control), • defense, • fuel production, • fertilizer manufacture, • glass and glass fiber manufacture, • pollution-free energy generation - replacement of nuclear and fuel operated power plants, • electronics, • dentistry, • medicine, and • jewelry. Besides these industrial markets, platinum is increasingly finding a place in investment portfolios around the world as investors switch from gold and silver holdings to this relatively scarce and strategic commodity. Platinum has a growing popularity among private investors. This is being accelerated by the predicted "big crash" of the US dollar and its associated weak currencies, which American financial analysts are expecting towards the end of the decade. Figure 1 shows the demand for platinum in various applications throughout the western world in 1986. The total demand amounted to 88.6 t (97.6 st) of which autocatalyst usage accounted for 32.8 t (36 st) or 37%, the biggest share. Catalytic converter technology is increasingly centered on rhodium-platinum three-way catalysts. These catalysts are able to deal with all three pollutants - carbon monoxide, hydrocarbons, and nitrogen oxides - in a single catalytic unit. The introduction of these three-way converters will result in a further steep rise in the platinum demand for autocatalysts. Among all the metals used in the antipollution devices for automobiles, platinum remains

Jan 2, 1988

By H. K. Conn

This paper discusses briefly the evaluation of chrysotile asbestos deposits in ultramafic rocks. Such deposits are limited to serpentinized peridotite and/or dunites. The purpose of any evaluation is to determine whether a deposit contains sufficient ore mineral to justify profitable exploitation. Dimensions of a mineral zone are established by conventional methods, such as mapping, ground magnetic surveys, diamond drilling or underground exploration. The value of the contained asbestos fibre Is dependent on numerous physical properties such as fibre length, strength, flexibility, as well as the actual amount of fibre present. The determination of grade is difficult. The Quebec Standard Test (Q.S.T.) is used to grade fibre according to the proportionate lengths of fibre present. A method of visual vein counting allows calculation of an approximate percent fibre together with a simulated Q.S.T. Various drilling methods are discussed, diamond drilling is favored. Bulk sampling is required to determine fibre quality. Correlation of visual techniques and laboratory methods are often difficult. Reasons for any variance are discussed. Underground bulk sampling of most potential ore zones is strongly recommended to confirm the viability of the property. Evaluation of slip fibre deposits requires greater reliance on laboratory testing as visual methods are difficult to apply. Cross fibre has greater inherent strength.

Jan 1, 1971

By J. J. Schwoebel

Resource Enterprises, Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REI?s pilot project at the Soldier Canyon Mine, Carbon County, Utah, REI has drilled nearly 15,250 m of horizontal in- seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1986

By A. S. Paschoa, A. W. Nóbrega

INTRODUCTION There are now over twenty years since the radiological characteristics of the brazilian regions of Araxá, Tapira and Barreiros, three locations adjacent to each other, in the state of Minas Gerais, Brazil, started being surveyed by investigators from the Instituto de Biofísica da Universidade Federal do Rio de Janeiro (IB/UFRJ), Pontifícia Universidade Católica do Rio de Janeiro (PUC/RJ), and New York University (NYU) (Roser and Cullen, 1958; Cullen et al, 1980). The importance of the Araxá apatite – Ca5,(P04)3(OH, F, Cl) - and pyrochlore - NaCaNB206F - for the production of large quantities of fertilizers and niobium was early recognized (Roser and Cullen, 1958). Interesting data have been gathered and published throughout the years on the contents of naturally occurring radionuclides in geologic materials, soils, grass, foods and waters of the Araxá region (Eisenbud, et al., 1964; Penna Franca, et al., 1965a, b; Roser et al., 1966; Penna Franca et al., 1970; Cullen, 1977; Penna Franca, 1977; Cullen and Paschoa, 1978; and Cullen et al., 1980). The radioactivity of the Araxá region is associated with mineral deposits of niobium rich pyrochlore and phosphate rich apatite. There are in this region mineral ores with 3 to 5% pyrochlore with 2 to 2.5% Th as Th02 and 50 to 150 ppm U308 in the matrix, while the apatite deposits contain up to 150 ppm U308 and a thorium concentration similar to that of the pyrochlore deposits (Paschoa and Palacios, 1981). As an indication of the high thorium content of the Araxá soils the 228Ra and 224Ra activity concentrations were reported to range from 10.6±0.2 to 62.4±0.7 pCi228Ra/g soil in 7 samples and 2.1±0.1 to 104±1 pCi224Ra/g soil in 19 samples (Cullen, et al., 1966). The uptake of radium isotopes by edible roots vegatables and fruits growing in the soils of the Araxá region can be illustrated by the data listed in Table I. The biological availability of natural radium isotopes in some segments of the Araxá soil allows a large variation in the 228Ra, 224Ra and 226Ra concentrations in vegetables and edible roots, as can be seen in Table I. This fact makes quite difficult a quantitative local assessment of the radiological implications of mining the Araxá mineral deposits of pyrochlore and apatite for production of niobium and phosphate fertilizers, respectively; since one cannot easily separate the naturally occurring from the technogically enhanced radionuclide contents of foods. The position of the city of Araxá inside the contour of the state of Minas Gerais appears in the upper part of Figure 1, which shows the outlined map of Brazil with the positions of the cities Brasilia and Rio de Janeiro also indicated. The lower part of Figure 1 is a representation of the Araxá region in an expanded scale, which indicates the locations of the pyrochlore and apatite deposits in relation to the city of Araxá, as well as the nearby hydrographic basins. The distance between the city of Araxá and the pyrochlore deposit is about 8 km, and between the pyrochlore and apatite deposits is 4 km. This paper deals tentatively with the radiological implications of the industrial operations taking place in the Araxá region for the exploration of the pyrochlore and apatite deposits. However, one must bear in mind, firstly, that the radiological implications of these industrial activities are by far too complex to be covered adequately by the limited amount of data to be presented in this paper, and secondly, that such implications cannot be considered of local character only. INDUSTRIAL OPERATIONS The commercial exploration of the Araxá deposits of pyrochlore and apatite started only few years ago, motivated by the increasing demand of niobium and phosphate fertilizers in Brazil and the world. As a consequence of the industrial operations in Araxá, a redistribution of the uranium, thorium, and radium originally present in the local deposits of pyrochlore and apatite started occurring in the seventies, with possible radiological implications for the Araxá region and its immediate surroundings, not to mention the destinations of the end products of such industrial operations. A literature review on the radioactivity associated with the extration industries of selected minerals was made by the USEPA (Bliss, 1978). The low level radioactive wastes of the industries for copper ore mining and rare metals processing have been object of particular attention (Fitzgerald, Jr., 1976; Eng, et al., 1979), but the short and long term implications of the radioactivity associated with the niobium industry were also subjects of concern (Knight and Makepeace, 1978). Recently, high 232Th and 226Ra concentrations in samples from the tin mining industry in West Malaysia were reported (Hu et al., 1981). A great deal of attention has been dedicated to the implications of the redistribution of radionuclides originally present in the mineral ores used by the phosphate fertilizer industry (Moore, 1967; Menzel, 1968; Spalding and Sackett, 1972; Eisenbud, 1973; Guimond and Windham, 1975; Guimond, 1976; Roessler,

Jan 1, 1981

By R. E. Wagner

Consistent increase has been the mark of North American potassium (K) consumption. In 23 of the last 25 years there was upward progress The pace of usage has quickened in the past three or four years This, together with a predicted accelerated future demand, has created unprecedented interest -and activity in the potash industry. Potassium enjoyed a ninefold increase in consumption from 1940 to the present time in North America (Figure 1). Since 1950, it increased from just over a million tons of potash (K20) annually to nearly three million tons in 1964. World-wide usage exclusive of mainland China is now about 10 million metric tons. Some predictions call for another doubling in consumption in the next 10 to 15 years, About 20 percent of the four million tons of K20 produced in North America is now exported overseas and this percentage is likely to increase in the years ahead. Ten years ago, exports represented only 3-1/2 percent of total K2O production from this continent.

Jan 1, 1966