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By Henry Faul

MEASUREMENT of radioactivity of rocks and ores has developed into a complete method of geophysical exploration. The problem falls into three natural categories: (I) surface radiation measurement in the field and underground; (2) radioactivity logging of drillholes; and (3) laboratory analysis of samples. Portable counters are used in the field for tracing radioactive formations and for quantitative estimates of radioactive content of surface rock. Wartime advances in battery design make it possible to construct small precision counters that can be carried easily. Even the smallest conventional diamond drillholes can be logged, and actual content of the radioactive element can be measured. The exact grade of very thin active layers or veins can be estimated only approximately. Samples may be analyzed for their alpha, beta or gamma activity, and beta assaying is the best suited to rapid routine operation. Simple calibration with standard samples is sufficient for rough work, but a density correction is necessary when greater precision is required. Samples with high emanating power should be fixed and stored for three weeks to reestablish the radium-radon equilibrium prior to precision assaying. Carnotite can be fixed by sintering or molding with plastics. Among the important new developments, a low-voltage Geiger tube has been designed recently, and crystal scintillation counters hold great promise for high-efficiency gamma-ray measurement.

Jan 1, 1947

By Raymond E. Kary, John W. Mcklveen

The four unit Cholla coal fired power station at Joseph City, Arizona, consumes coal from the McKinley mine located in western New Mexico. Since coals may contain relatively high uranium or thorium concentrations and may release quantities of detrimental progeny of these elements to the environs, there is concern that releases may pose an adverse environmental impact or even a health hazard to the workers. Thus, an effort was made to quantify the radionuclide content of the coal and compare the results with radionuclide concentrations already present in the vicinity of the plant. Additionally an attempt was made to assess any potential for significant enhancement of the levels of radioactivity in the environment or to plant personnel. Background gamma radiation measurements at and near the plant ranged from 8 to 12 [µ]R/hr (70 to 105 mR/yr) with a few localized anomolies measuring to 18 [u]R/hr (160 mR/yr). Levels on top of the coal storage piles decreased to ~ 6.5 [u]R/hr (60 mR/yr). Apparently the direct radiation emitted from the coal is less than the background levels in the vicinity of the plant. Measurements performed on top of several coal seams at the mine confirmed low radiation levels emanating from coal, but readings more than doubled when the overburden was monitored. Laboratory gamma spectrometry confirmed the lower amounts of natural radioactivity in the coal when compared against soil and water samples obtained in the vicinity of the plant and the overburden at the mine. In an effort to see if there is biological enhancement, animal feces was sampled. The radiation variations were found to be influenced primarily by naturally occurring potassium-40 which varied from ~ 1 to 18 pCi/gm rather than fluctuations in the uranium and thorium series. The potassium-40 concentrated in the ash were similar to the concentrations in the environs around the disposal ponds while Radium-226 concentrated in the fly ash was ~ 3 times that found in the immediate surroundings. Radon-222 gas concentrations in buildings at or near the plant ranged from 0.5 to 1.8 pCi/l and were generally lower than indoor concentrations measured in the Phoenix area. The burning of coal at the Cholla station does not appear to increase ambient levels of radioactivity found in the surrounding environs or to the workers. However, the use of byproduct fly ash for construction purposes may need to be examined.

Jan 1, 1981

By G. Wendel

Uranium is a naturally occurring radioactive material in the earth?s crust. Geological processes have resulted in concentration of uranium into ore mined for its gold content in South Africa. This uranium is present in the form of discrete particles of uranium minerals, generally oxides, which are normally insoluble. Chemical and physical processes during gold mining and extraction, particularly when carried out in conjunction with uranium extraction and sulphuric acid manufacture, act on the uranium minerals and the radioactive decay products of uranium. This may result insignificant accumulations of radioactive materials in certain parts of the process. There are a number of naturally occurring radioactive materials in the earth?s crust, such as Uranium-235, Thorium-232, andPotassium-40. This paper focuses on Uranium-238, together with its decay products, and how they affect the gold mines. Water plays a significant role in the redistribution of radionuclides, both as a physical transport medium, and as a solvent in which chemical reactions take place.

Jan 1, 1998

By H. Landsberg

MANY of the sedimentary rocks contain small amounts of radioactive constituents. These vary in quantity in different layers. Some recent deposits show rather high activity as; for example, the deep sea oozes and some lake deposits.1,2. Measurements made in boreholes have also shown considerable changes in activity from horizon to horizon. The first to publish data on this fact was Ambronn,3 and recently Russian geophysicists have shown remarkable variations of activity from one layer to the next in various wells. Spak4 felt even that he was able to line up horizons from data measured in two neighboring wells. ? The measuring of radioactive radiation is fairly difficult. Large errors are possible by the circulation of gaseous emanations in the well and porous strata. It is, therefore, never certain whether the activity of the layer where the instrumental device or collector is located will be measured, or that of some adjacent layer, For this reason it seemed to be advantageous to take samples of rocks into the laboratory and test them therefor their contents of radioactive material, Such a method has been followed in the past to distinguish radioactive ore from other rocks. Radioactivity of rocks, especially of the igneous type, was also deter-mined in the laboratory by numerous authors for absolute age investi-gations.6 Corresponding data from studies of sedimentary formations are scarce. Specimens taken from a core of the Bradford oil sandstone were tested by Landsberg and Ingham,7 with the results illustrated in Fig. 1, which shows that within relatively small vertical distances the differences of relative activity were considerable. If one assumes that the distribution of radioactive material is fairly uniform throughout a layer, measurements of radioactive radiation in various horizons would offer additional information for stratigraphic

Jan 1, 1939

By Jim V. Rouse

Adverse water-quality impacts of uranium mining and milling activities on both surface- and ground-water resources in the Grants Mineral Belt have recently been documented.1 In some cases, the impacts resulted in violation of existing regulations and license conditions and have endangered public health. Unfortunately, industry-sponsored ground-water monitoring programs do not adequately record the actual impacts of mining and milling on ground-water quality.

Jan 1, 1976

By J. Dille

Metallic cobalt exist in two allotropic forms : the hexagonal compact a which is stable at low temperature ( ( 420') and the cubic form 0 stable at higher temperature. This latest form is the only one which is ductile. During the electrode position of Co, in moderate acidic conditions, we noticed a code position of both a and B forms. The influence of several parameters on the B/a ratio in the deposit was investigated. High acidity and the presence of Fe increased its ratio; on the opposite, high temperature promote the a phase. No significant influence on the material were noticed. The differentiation of a and B forms of Co is rather difficult and the method of J. Scoyer was improved quite successfully.

Jan 1, 1988

By P. Davey Wheeler

San Francisco meeting, September, 1915) IN an article in the General Electric Review, January, 1915, reference was made to the X-ray examination of a steel casting 9/16 in. thick. Fig. 1 shows one of the radiographs thus obtained. All these radiographs showed plainly the tool marks on the surface of the casting. All but one showed peculiar markings the shape of which strongly suggested that they were indeed the pictures of holes in the interior. A circular piece, 1 in. in diameter, was punched from the casting at a point where the radiograph shown in Fig. 1 indicated that a blow-hole should be found. (Location of sample shown by circle in Fig. 1.) Fig. 2 is a photograph of the end of the punching, showing the .hole that was found. Since that article was written it has seemed desirable: (1) to obtain data from which the exposure necessary for any thickness of steel could be at once calculated; (2) to find the thickness of the smallest air inclusion which could be radiographed in a given thickness of steel; (3) to determine in what direction to hope for further progress; and (4) to develop the technique of, radiographing metals. In order to gain some preliminary data, several pieces of ½ -in(12.5mm.) boiler plate were obtained, 5 by 7 in. (12.5 by 17.5 cm.) in size. In one of these, holes were drilled in such a way that the axis of each hole was midway between the faces of the steel and parallel to those faces. The diameters of these holes were as follows: Hole number Diameter 1 1/4 in. = 6.3 mm 2 1/8 in. = 3.1 mm. 3 1/16 in. = 1.6 mm. 4 1/32 in. = 0.8 mm. 5 1/64 in. = 0.4 mm.

Jan 8, 1915

By George W. Sheary

Situated 45 miles west of Philadelphia and 50 miles southwest of Bethlehem Steel Company's Bethlehem plant, the integrated Grace mine facilities produce 4000 tpd of high-quality iron ore pellets. Startup of the Grace mill was in November 1958, and iron concentrates were shipped until March 1960, when the pellet plant went into operation. The underground mine, when fully developed, will hoist about 9000 tpd, including development rock. The crude ore, which has an iron content of approximately 42%, is magnetically cobbed and crushed in closed circuit with 3/4-in. slotted vibrating screens. The ore is washed and screened in the mill and the plus 1/4 in. screen product is again cobbed prior to feeding to the rod mills. Grinding is done in rod mills, and in ball mills that are in closed circuit with 30 in, cyclones, to 1% on 100 mesh and 65% minus 325 mesh. The ground ore is magnetically concentrated by three-drum permanent type finisher magnets to 67% Fe. The magnetite concentrate is pumped from the mill to a 50 ft thickener in the pellet plant. The thickened magnetite concentrate is relayed to the filters through a two-stage pump arrangement. The filter cake is fed by belt from filter concentrate bins to mixer-muller belts where it is intimately mixed with bentonite and a slight amount of water for moisture control. The fluffed concentrate then drops into balling cones. The green pellets from the balling cones are fed in a prescribed feed pattern to shaft furnaces through the use of shuttle car mechanisms. The green pellets are dried, heated to 2500°F and cooled to 1200°F as they descend through the furnace and into pellet coolers where the pellets are further reduced in temperature to 250°F. Heat is recovered in the cooling process through the use of air-to-air heat exchangers. The cooled pellets discharge on a rubber conveyor belt and are transferred to 6000-ton pellet railroad loading bin. The final pellet product consists of 90% plus 1/4 in. material (after tumble testing1) and contains 66% Fe plus 3% silica.

Jan 5, 1962

By Bruce W. Smith

Non-contacting, radioisotope density and level gauges are discussed. The characteristics of the more commonly used isotopes, the techniques of detection and the methods of presenting information are reviewed. The gauge parameters of accuracy, response time and long-term stability are tabulated with reference to calibration techniques and operating requirements. Automatic control systems, both pneumatic and electrical, are used in conjunction with density gauges on filter feeds, and in thickener underflow and heavy media processes. These systems are described. Procedures for installation, start-up and operator training are outlined, along with considerations of preventative maintenance and service requirements. Typical gauge system costs, including capital expenditure, installation, start-up and service, are presented, wherever possible, in order to provide a basis of comparison with more conventional systems.

Jan 1, 1964

By L. R. Wilkinson, W. J. Howarth, G. J. Wenk

Over a period of three years, a cooperative program in Australia has resulted in the development of radioisotope immersion probes for the on-stream analysis of mineral slurries. Two basic probe types are now available on a commercial basis - fluorescence and absorption probes - and within each type there are a number of variations so that optimum sensitivities can be obtained for elements with atomic number greater than titanium (22), thus covering most metals of interest to modern metallurgy.

Jan 1, 1973

By Adrian Molinari

A radioisotope probe (Minexan 202) capable of simultaneously analyzing a mineral slurry for five elements and pulp density has been developed by Outokumpu Oy, Finland. The probe is designed to operate immersed directly in a process stream, or it can be equipped with a flow cell through which passes a continuous sample of the main stream. A minicomputer (PDPII) is used to control the probes and calculate the assay data. This paper describes the probe as applied to slurry analysis and compares it to the conventional x-ray on-stream analyzer (Courier 300).

Jan 1, 1977

By J. Ostachowicz, B. Holynska, M. Lankosz

The paper presents an analyzer and the method for the continuous determination of weight percentage of ore grains with diameter smaller than 75 µm in mineral slurries. The method is based upon the measurement of characteristic x-rays of copper excited by primary radiation of two different energies 16.5 keV and 60 keV from Pu238 and Am241 sources respectively. Additionally the backscattered primary radiation is measured in order to correct the variations of the solids content in the slurry. Since the particle size distribution of slurry can be described by the Rosin-Rammler formula, some calculations have been carried out in order to evaluate the influence of distribution parameters upon the results of the measurements of weight percentage U75 of particles smaller than 75 µm. The influence of solids content and of the copper concentration variation on the results has been also evaluated.1 It resulted from the calculations that the ratio rl/rz, where rl and r2 are the relative intensities of copper characteristic x-rays excited with 16.5 keV and 60 keV photons respectively does not depend on the copper content within the range 1 % to 4% of copper and is slightly dependent on the solids weight fraction and its chemical composition. The change of the dispersion parameter of the Rosin- Rammler distribution from 0.5 to 0.9 results in a change of value of U75 of approximately 3.0%. The results of calculations have been confirmed by the results of laboratory experiments. Therefore, a prototype of industrial analyzer for continuous determination of weight percentage of particles smaller than 75 µm has been designed and made. Its schematic drawing is shown in [Fig. 1]. Slurry is flowing down through steel flow-cell of the length equal to approx. 2 m. In the center, two XRF measuring heads (1) and (2) are located. Each of the heads comprises a rigid waterproof cover (3) with the mylar window (4), in which a proportional counter of resolution 15% for 6.4 keV is mounted with a preamplifier (5). The low- energy isotope source (6) is centrally located above the detector

Jan 1, 1980

By J. Ostachowicz, B. Holynska, M. Lankosz

The paper presents an analyzer and the method for the continuous determination of weight percentage of ore grains with diameter smaller than 75 pm in mineral slurries. The method is based upon the measurement of characteristic x-rays of copper excited by primary radiation of two different energies 16.5 keV and 60 keV from Pu238 and Am241 sources respectively. Additionally the backscattered primary radiation is measured in order to correct the variations of the solids content in the slurry.

Jan 11, 1979

By P. F. Berry

X-ray fluorescence analytical techniques are fairly well established in the mining and metallurgical industries. In recent years, instruments utilizing radioactive isotopes have been developed which, owing to their more compact size, greater reliability and independence of substantial power supplies, are often preferred to X-ray tube installations. Analyses can now readily be carried out in the field, on the factory floor and in otherwise difficult locations. This paper describes many examples of radioisotope X-ray fluorescence for the analysis of metallic minerals, finished metals and alloys and also for the continuous measurement of metallic coatings, such as tin and zinc, on steel. Radiation scatter techniques are also described for certain analyses and for thickness and density measurements.

Jan 1, 1967

The radiolarian biostratigraphy of the western part of the Gympie Province, north of Brisbane, has been examined. This part of the province comprises mainly the Amamoor beds and the Gympie Group, which have been assigned Permian ages on the basis of localised marine macrofossils. This study has shown that the Amamoor beds and the Gympie Group include older strata than previously supposed.The Amamoor beds consist of at least two tectonic units, namely a melange unit (unit A) and a well stratified sequence of sedimentary rocks (unit B). The former unit, regarded as an accretionary subduction complex, contains chert blocks ranging from Late Devonian to Earliest Carboniferous, while the latter unit yields Permian radiolarians. Latest Devonian to Earliest Carboniferous bedded cherts occur in sequence previously mapped as Amamoor beds and Gympie Group.

Jan 1, 1990

By L. M. Lowe, D. B. Chambers, D. G. Feasby

"Potentially economic deposits of rare earth elements (REE) often contain elevated levels of naturally occurring radioactive materials (NORM), primarily thorium and uranium and their associated radioactive decay products. The concentrations of NORM usually exceed typical background levels of natural radioactivity, sometimes by factors of ten or more, and can be of concern relative to occupational radiation protection and the management and disposal of REE mineral processing and metallurgical wastes. This paper provides a summary of the radiological issues normally encountered in the REE concentrate production industry. In addition to an introduction to background radiation and radioactivity, including the thorium and uranium radioactive decay series, radiation levels expected to be encountered in REE concentrate production are outlined. The occupational, environmental and regulatory aspects of REE production related to NORM, including radiation dose limits, radioactive waste disposal guidelines, and threshold VALUES (for the application of transport regulations, are presented.INTRODUCTIONConcurrent with the increasing demand for new sources of rare earth elements (REE) to meet modern industrial needs, there is also an increasing awareness of the radioactivity associated with the REE ores and resources. This is an especially important consideration in addressing questions from the public and local communities who are often concerned about “radiation” and “radioactivity”. Public concern is heightened by reference to legacy issues that arose during times of less regulatory oversight; as well, the benefits of modern technologies, practices and regulation are overlooked. Such concerns are also often inflamed by unfounded claims by non-governmental organizations (NGO’s). Thus, it is important that all concerned have a full understanding of just what the potential risks from radiation associated with REE are, or are not. This paper provides an overview of the sources of radioactivity, the potential implications of radiation and radioactivity in the REE industry, and a brief discussion of established and reliable methods of managing exposure to radiation and radioactivity."

Jan 1, 2012

By Steven H. Brown

Ore bodies which were once uneconomical to mine by conventional methods such as tunneling or open pits, have become attractive due to the development of nonconventional techniques, involving considerably less capital expenditure. Technologies such as uranium solution mining or in-situ leaching, have enabled commercial scale mining and milling of relatively small ore pockets of lower grade, and may make a significant contribution to overall U.S. uranium supplies during the next 20 years. Commercial size solution mining production facilities have operated since late 1975. Solution mining involves the pumping of ground water, fortified with oxidizing and complexing agents into an ore body, leaching and solubilizing the uranium in-situ, and then pumping the solutions to the surface where they are fed to a processing plant. Processing involves ion exchange, precipitation, calcining, and packaging operations. This paper presents an overview of the solution mining process and the health physics monitoring programs developed over the last four years at several production facilities as a result of the radiological character of these processes. Although many radiological aspects of the process are similar to that of conventional mills, conventional-type tailings as such are not generated. Some special monitoring considerations are presented which are required due to the manner in which radon gas is evolved in the process and the unique aspects of controlling solution flow patterns underground. An overview of the major aspects of the health physics compliance and monitoring programs that have been developed are discussed.

Jan 1, 1981

By Wylie A. W, Jarrett R. G

Two versions of a radiometric-type caliper for measuring borehole diameter are described. One, based on the bow-spring principle, is suitable for percussion (exploration) drill holes. The other, which utilizes hemispherical wall contactors actuated by springs, is suitable for blast holes. Both utilize low-power radioactive sources and employ a scintillation detector to measure the "inverse-square law" response of the device to changes in borehole radius. The performance of the device is examined and examples of its use are illustrated.

Jan 1, 1976

By Radoslav Despotovic

The developed radiometric method of particle system analysis has been applied to investigate the bulk properties of particles precipitated from solutions. The nature and principles of the method applied are described briefly, and some possible models in the field of fine colloid particles precipitation discussed. Changes in radionuclide distribution were followed during the solid phase formation and the data were used to calculate changes in bulk composition of colloid precipitates. The radiometric data show interesting phenomena closely connected with the characteristic of bulk particles. The measured radiometric data are highly reproducible, the applied methods have proved to be sensitive, and the developed techniques have been tested by various standard procedures.

Jan 1, 1980

By C Smit

SYNOPSIS A prototype collimated radiometric face scanner was tested in the Harmony Gold Mine. The results obtained during the pilot study indicate that in situ radiometric uranium assays are statistically indistinguishable from those obtained conventionally from channel chip samples. In addition, the study demonstrated that reasonably reliable gold estimates can be deduced from the radiometric measurements, by use of the ratio of gold to uranium within a mine. The instrumentation, calibration procedures, and background determination are described briefly.

Jan 1, 1985