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By Van Price

Some technical developments of the National Uranium Resource Evaluation Program which are of general application in geochemical exploration are being studied. Results of stream water and suspended and bottom sediment analyses are compared for an area near Williamsport, Pennsylvania. Variations of uranium content of water samples with time in the North Carolina Piedmont are seen to correlate with rainfall. Ground water samples from coastal and piedmont areas were analyzed for helium. All media sampled provide useful information when properly analyzed and interpreted as part of a total geological analysis of an area.

Jan 1, 1979

By Henning R. Norbom

Lime has been produced for many centuries. The simple pot kiln was one of the first devices used in this process. It was constructed of stone often on the side of a hill to reduce construction efforts and provide easy access to the top for feeding of limestone. It was fired from below with wood and coal. The pot kiln was very small and operated on the batch principle. The kiln being cooled between each batch, the fuel consumption was horrendous. The lime quality was poor with perhaps only one half of a batch being lime of suitable quality. Of the remaining half one part would be over burned and another part underburned. For centuries the lime burning technique was improved at a barely recognizable rate. One of the first major steps forward was the introduction of the continuous process vertical lime kiln. Although at first crudely constructed, the kiln had a refractory lining. It was charged with alternate layers of limestone and solid fuel usually in the form of coke. Continuous mode of operation, larger unit size and better heat distribution resulted in greatly improved fuel economy. However, quality of lime produced still left much to be desired. One problem was contamination by ashes from solid fuel.

Jan 1, 1978

By Lyle A. Hale

The subject area known as upper Dry Valley is located 15 miles due east of Soda Springs in Sections 14 and 23, Township 9 South, Range 44 East, Caribou County, Idaho. The railroad extending from Soda Springs to its terminus at El Paso's Maybe Canyon mine is 8z miles to the north in lower Dry Valley. Initial data derived from trench work in 1962 revealed a variety of econom¬ically significant alterations of the phosphatic beds related to the rather unique geomorphic development in the northern part of phosphate lease 1-012989. It was apparent that such conditions, while valid for near-surface beds in a strike direction, would be misleading if projected to the proposed depth limits of strip mining. Consequently, a subsurface mapping program was initiated in 1963 to determine: (1) the depth and horizontal extent of weathering and related phe¬nomena, (2) the depth, thickness, and quality of ore beds and intervening strata, and (3) structural geology as a guide for mining procedures. Successful use of a scintillometer in 1956 to detect the subcrop position of phosphate beds in the Smokey Canyon area of southeastern Idaho led to the conclusion that gamma radiation surveys of drill holes could be a useful aid in subsurface mapping. The objectives of this paper are: (1) briefly to describe geologic features characteristic of the phosphate lease area and (2) to demonstrate the practical application and theory behind gamma radiation logging as an effective tool in the economic evaluation of a phosphate lease.

Jan 1, 1969

By Albert R. Rule

Beneficiation studies were made by the Bureau of Mines to develop a process for concentrating phosphate minerals from the altered rock of the Phosphoria Formation. This report describes research on intermediate - and marginal-grade ores from southeast Idaho, The process developed consists of attrition scrubbing and sizing to produce a coarse concentrate; desliming at about 800 mesh (18.5 microns); flotation of the fine sands; roasting of the combined concentrates for removal of organic carbon and combined water; and leaching with SO2 for removal of magnesium and nonapatitic calcite. Results of continuous tests on three different ore types showed that approximately 80 percent of the available phosphate can be recovered at a grade suitable for phosphoric acid production. While leaching with SO2 is not necessary for all ore types, it is an important step in purifying concentrates containing excessive magnesium.

Jan 1, 1966

By A. H. Kaksonen

Numerous reactor designs for biological sulfate reduction have been reported. Fluidized-bed bioreactors (FBR) can efficiently retain biomass and allow high mass transfer and reaction rates. This work reviews the development of various sulfate-reducing FBR processes for treating acidic metal- and sulfate-containing waters and recovering metals from bioleaching liquors. The FBR process performance was evaluated with continuous flow experiments under various operational conditions: fluidization rates, influent pH values, metal, sulfate and salt concentrations, hydraulic retention times, electron and carbon sources, and temperatures. Substrate utilization and sulfide inhibition kinetics were determined with batch FBR-kinetic experiments. An artificial neural network (ANN) model was used to predict the performance of the FBR. Sulfate-reducing bacteria (SRB) were characterized in FBRs with molecular and culture-based approaches with the aim to gain a better understating of the bioprocesses. Based on the studies, FBRs are well suited for the combined removal of metals, acidity and sulfate from water.

Jan 1, 2010

By Richard J. Waxweiler, Frank E. Lundin, Robert J. Roscoe, Victor E. Archer, Michael J. Thun, Joseph K. Wagoner

[Introduction] Since excess lung cancer mortality was first noted in the late 1800's among Joachimsthal-Schneeberg miners, there have been a number of studies of the long term health effects among various types of miners exposed to elevated levels of radon and its radioactive decay daughters. Substantial excesses of lung cancer have been noted among miners in the Joachimsthal mines (Sevc, 1976) , lead-zinc miners in Sweden (Axelson, 1979) , fluorspar miners in Canada (DeVilliers, 1971) , iron miners in Sweden (Renard, 1974) , uranium miners in Canada (Hewitt, 1976), and metal (Wagoner, 1963) and uranium miners in the United States (Lundin, 1971; Archer, 1976). The latter prospective cohort has also been shown to be at an excess risk of death due to tuberculosis, nonmalignant respiratory disease, and accidents when followed through September 30, 1974 (Archer, 1976). This report extends the followup of this cohort of miners through December 31, 1977 and expands the mortality analysis to investigate more cause-specific categories. [Methods] During the decade beginning with July, 1950, medical teams from the United States Public Health Service (USPHS) examined 3362 white and approximately 780 nonwhite males who had worked underground in uranium mines in the Colorado Plateau at least one month by January 1, 1964. Occupational, medical, and smoking histories were obtained during the examinations and often updated/confirmed during subsequent annual censuses of the miners conducted by the USPHS. The white miners now have been followed-up through December 31, 1977 using the Social Security Administration, Internal Revenue Service, direct telephoning and various other sources. Death certificates were obtained for the deceased and coded directly into the Seventh Revision of the International Classification of Diseases, Adapted, using the rules in effect at the time of death. Deceased miners for whom no certificate has yet been located were assumed dead on the date specified by the reporting agency, cause of death unknown. The uranium miners cohort was analyzed using a modified life-table system developed by the National Institute for Occupational Safety and Health (NIOSH). Person-years at risk of dying (PYAR) were calculated for each miner from his first USPHS medical examination date or date upon completion of one month of underground uranium mining if that was later. PYAR were calculated specific for five-year age groups, calendar periods, and periods after first underground uranium mining. The numbers of cause-specific observed deaths among the cohort occurring by December 31, 1977 were compared to the numbers of expected deaths. The expected deaths were calculated by multiplying the appropriate PYAR by the United States death rates for white males specific for five-year age groups, five-year calendar periods, and cause. The results were summed over the age and calendar period specific categories to obtain the total expected deaths for each cause. Standardized Mortality Ratios (SMR's) were calculated for each cause by dividing the observed number of deaths by the expected number of deaths and multiplying by 100. In some tables, two-sided 95% confidence intervals for the SMR's were computed using either Fisher exact confidence limits, if the observed frequency was less than eight, or approximate confidence limits, if the observed frequency was eight or greater, to indicate statistical significance. Because a priori hypotheses had been well established, one-sided lower confidence limits were used for tuberculosis, lung cancer, other nonmalignant respiratory disease (ONMRD), accidents, and total mortality. [Results] The cohort included 589 miners first examined in either 1950, 1951 or 1953; 753 first examined in 1954; 1235 first examined in 1957; 5 first examined in 1958; and 782 first examined in 1960. In Figure 1 the distribution of the cohort by first year of underground uranium mining indicates that 13.7% started before 1947 and would have thus had an opportunity to be followed beyond 30 years

Jan 1, 1981

By V. Gangrade, J. Addis, S. Vanderslice

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are conducting research to improve the ventilation of large-opening underground stone mines. The mine ventilation in these mines are characterized by: (1) challenges related to keeping airflow velocities high enough to effectively remove or dilute airborne contaminants, (2) low pressure losses needed to move large air volumes of air, and (3) costly stoppings needed to direct ventilation airflows. Each of two field studies was dedicated to specific focus areas. The first focus area was the characterization of underground mine ventilation airflow. The primary means of airflow control in stone mines is through the use of freestanding booster fans. The primary goal of this study was to identify the effectiveness of various fan types and optimize their placement. Both traverse and grid-based airflow readings were taken at various distances from the fans, ranging from 70 ft to 425 ft away from the fan. The air readings were taken using a vane-anemometer and a handheld hotwire anemometer. The data was used to develop precise computational fluid dynamics models. The second focus area was to determine diesel particulate matter (DPM) concentrations in the mine. For large-opening underground stone mines, controlling DPM exposures dictates the design of the ventilation system. Therefore, researchers carried out the DPM sampling campaign to identify potential areas of concern within the mine. The samples collected during the campaign were analyzed using NIOSH Method 5040. The sampling was done using the Mine Safety and Health Administration’s (MSHA) compliance sampling methodology.

Feb 1, 2023

By C. G. Anderson

Extraction of valuable resources from complex orebodies will become more common. This is obvious for two reasons. First, the cleaner and more readily processed ores have continually been depleted through centuries of mining. Second, new technologies have evolved for effectively handling complex ores. One of these new processes has been in place at Sunshine since 1984. Based on sulfuric acid oxygen pressure leaching with nitric acid as an oxidizer, this patented technology allows silver and copper to be efficiently recovered from a complex sulfide concentrate. As efficient as it is, this process represents novel technology found nowhere else on an industrial scale. As such, a research program was undertaken in 1989 to optimize this leach process and to better understand it. From this study, several potential plant improvements were found and recommended. As a result, two of these options, nitric acid replacement by sodium nitrite and concentrate regrind are now used in day to day operation at Sunshine. Patenting of these changes was recently accomplished (1). Thus, the development, perceived mechanisms, plant integration and potential applicability of this technology will be covered in this paper.

Jan 1, 1994

By Nathaniel Arbiter

A fully-instrumented driving mechanism has been constructed to study the power, aerating and solid suspension characteristics of several laboratory flotation machines. Machines operating over normal flotation speed ranges give constant power numbers in liquid' systems indicating that they operate under fully baffled turbulent flow conditions. Owing to lack of geometrical scaling, power numbers for different sizes of cells of the same make are different. Even larger differences occur between cells of different manufactures. For a given impeller, varying the tank size did not significantly affect the power consumption. Tank geometry and baffling has a slight effect on power consumption with shrouded impellers. For a given impeller speed, suspension height decreases while power increases with increasing mass of solids in suspension. While power consumption is hardly affected by particle size and clearance between the impeller and tank bottom, the suspension height significantly increases as clearance increases and as particle size decreases. Aeration was found to affect not only power but also the suspension characteristics of the machine. For closely sized particles drastic sedimentation occurred when a critical value of the air flow number was exceeded. The critical air flow number decreased with increasing particle size. This effect was less marked with a wide particle size range. The self-aerating capacity of flotation machines increases with cell size at a given speed for the same impeller-shroud system, but decreases in the presence of frother and solids. Equations have been established for correlating all of the studied variables. Data taken from the literature were also correlated with these equations.

Jan 1, 1968

By N. Ripepi

"The Langmuir model has been widely used for the coal-methane sorption process via an isothermal test. However, even though the temperature-dependent Langmuir model were recognized theoretically and experimentally, the quantitative relationship between the Langmuir’s constants (a & b) and temperature have not been clarified and confirmed by lab test data. This paper collects 158 methane-coal sorption data under different temperatures, which apply the Langmuir model to consider the relationship between Langmuir’s constants (a & b) and temperature (see APPENDIX I). Even though the Langmuir model cannot be used to show the physical state of methane adsorption on coal, it is widely used because of its simplicity and the reasonable explanation of its parameters (a & b). The results from these published isothermal tests confirm that 1) there is no consistent relationship between Langmuir’s constant-a and temperature; 2) the Langmuir model is a temperature-dependent model, and the temperature-dependent feature is mainly shown by the relationship between Langmuir’s constant-b and temperature; 3) The relationship between Langmuir’s constant-b and temperature can be described by both the exponential and linear relationship with dried coal. This paper provides a database for temperature-dependent Langmuir’s model, which can be used for reservoir simulation of coalbed methane reservoir, coal seam degasification modeling for underground coal mines considering the heating effect induced by geotherm and heat injection (via hot water, hot steam, ultrasonic, etc.). INTRODUCTION The isothermal test for gas sorption on coal is one of the fundamental tests in Coalbed Methane (CBM) recovery fields, such as underground coal mine methane degasification, CBM gas-in-place estimation, and carbon dioxide sequestration in un-minable coal seams. Generally, two methods, volumetric and gravimetric, are employed to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012). Based on these two approaches, a series of commercial and self-assembled instruments are built and several calculation methods are used to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012, Gasparik, K., 2014; Goodman, A. L., et al, 2004; Zhang, L., et al, 2013). In the post-processing stage, many models are provided to analyze isothermal data in order to understand the storage mechanism of gas in coal. Common models include the Langmuir model (and its extended forms), the pore-filling model, multilayer adsorption model (BET), and the Gibbs’ model. Among these models, the Langmuir model is the most widely used for its simplicity and functionality. The Langmuir model is expressed as follows:"

Jan 1, 2016

By R. Woods, J. D. Wright

INTRODUCTION The Endako deposit was first explored in 1926, but development waited until the early nineteen sixties. It first came under the control of Placer Development in 1963, and early in 1964 a decision to bring it into production was reached. The deposit is located near the geographic center of British Columbia, and is served by an east-west communication system including a paved highway, mainline railway and good telephone, teletype, and computer facilities. The plant area is shown in Figure 1. The operation is known as the Endako Mines Division of Canex Placer Limited of Vancouver. First production was achieved in June, 1965, at a nominal rate of 10,000 tons per day, but it soon was closer to 15,000 tons per day. In 1967, two new grinding and flotation sections brought capacity to the present rate of approximately 27,000 tons per day. With mill heads of around 0.15 percent MoS2, production is about 14,000,000 pounds of molybdenum per year. A flowsheet of the operation is given in Figure 2. A legend for this flowsheet is given in Table 1. Published ore reserves are estimated at 214,500,000 tons at an average grade of 0.143 percent MoS2. PRIMARY CRUSHING The 85 or 100-ton haulage trucks dump over a grizzly into a 42 inch x 65 inch C.A.C. (Canadian Allis Chalmers) gyratory crusher.

Jan 1, 1976

By Milan Yekich, Emanuele Cauda, Justin Patts, Cody Wolfe

A worker’s personal exposure to respirable dust in occupational environments has traditionally been monitored using established methodologies which entail the collection of an 8-hour representative sample that is sent away for laboratory analysis. While these methods are very accurate, they only provide information on the average exposure during a specific time period, generally a worker’s shift. The availability of relatively inexpensive aerosol sensors can allow researchers and practitioners to generate real-time data with unprecedented spatial and temporal granularity. Low-cost dust monitors (LCDM) were developed and marketed for air pollution monitoring and are mostly being used to help communities understand their local and even hyper-local air quality. Most of these integrated sensing packages cost less than $300 per unit, in contrast to wearable or area dust monitors specifically built for mining applications which have been around for decades but still average around $5,000 each. At the National Institute for Occupational Safety and Health (NIOSH), we are leveraging the power of high-volume data collection from networks of LCDM to establish baseline respirable hazard levels and to monitor for changes on a seasonal basis as well as following any application of control technologies. We have seen the effective use and advantages of monitoring live data before, during, and after events like shift changes, operational changes, ventilation upgrades, adverse weather events, and machine maintenance. However, many factors have prevented a systematic adoption of LCDMs for exposure monitoring: concern for their analytical performance, the complexity of use, and lack of understanding of their value are some factors. This contribution outlines a one-year case study at a mine in Wisconsin USA, covering the installation, maintenance, data visualizations, and collaboration between NIOSH researchers and the industrial hygiene professionals at the mine.

Feb 1, 2024

By R. M. Rowe, T. E. Irwin

A flowsheet was developed for upgrading Climax tin concentrate to about 45 percent Sn. Bench-scale test work conducted at AMAX Extractive Research and Development, Inc., was used to design a multiple-stage tin- processing flowsheet which included screening, high-intensity magnetic separation, and high- tension (electric- static) separation. Formal engineering and plant installation was accomplished in-house by Climax mill personnel. The successful start-up operation of the facility was the joint effort of the AMAX R&D and Climax-mill staffs.

Jan 1, 1986

By Frank Matter

The production of ultrafine slurries and powders is possible with small media made out of Si02, A1203, Fe203, Zr03 or other raw materials due to the fact that since approximately 12 years from now, entirely new machines have been developed which allow to use this small media for the production of ultrafine pigments. Basically we distinguish between two grinding methods which are: A.) Dry Grinding with Air Classification: This method is used for more than fifty years but only since four years this technology is realized with small grinding media. Many problems like cooling, abrasion, control of the media flow, separation media from product, grinding media recycling etc. had to be resolved before it was possible to get in full production with this new system. Hereafter a flow-sheet of such a TRZK mill with an air classifier especially designed to produce end products with a top size between 2,5 and 3,0 micron and with an average particle size between 0,3 and 0,5 micron.

Jan 1, 1983

By S. A. McGhee

ASARCO Incorporated embarked on a modernization and expansion program to improve overall operating efficiencies and to more effectively develop the large mineral reserve at the Ray Complex Open-Pit Mining operation located near Kearny, Arizona. Major elements of this Ray Modernization and Concentrator Expansion Project included engineering and construction of a 54,400 MTPD (60,000 STPD) In-Pit Crusher and Overland Conveying System. and a 24,200 MTPD (30,000 STPD) Copper SAG Concentrator and Tailings Disposal System. Detailed engineering, procurement, and construction management were initiated in November 1989 under contract with Bechtel Corporation. Field construction commenced in May 1990 leading to mechanical completion and start-up during February 1992.

Jan 1, 1993

By J. P. Allen

Cobalt, nickel, and manganese can be recovered quickly, cleanly, and selectively from cobalt-rich manganese crust by leaching in dilute acid solutions in the presence of hydrogen peroxide. Common selective precipitation methods can then be used to recover these metals from the leach liquor. The leaching reaction produces only oxygen as a byproduct, and the waste residue from leaching was tested and found to be non-hazardous under existing EPA specifications. The leaching process is effective in either fresh water or seawater. This research is a part of the Bureau of Mines program to identify the mineral resources of the Exclusive Economic Zone and devise methods for recovering their valuable components.

Jan 1, 1990

By P. W. Finck

Detailed mapping, using a large diameter diamond-drill in conjunction with high resolution reflection seismics, has increased known resources of kaolin clay and glass-grade silica sand from scattered deposits generally < 1 km2 to large areas of Cretaceous valley fill up to 130 m thick. Detailed chemical and physical analysis of drill core is presently underway. Silica sand deposits intersected in this study are up to 99.4 % SiO2 without beneficiation. Light grey to white kaolin clays identified by XRD and DT A have concentrations values (without beneficiation) up to 47.28% SiO2, 37.44% Al2O3, 0.45% Fe2O3, 0.49% K2O, 0.07% Nap, 0.07% CaO and 0.39% MgO.

Jan 1, 1996

By William F. Lawrence

Due to the immense volumes of municipal wastes that are generated in this nation every year, it has become imperative that effective measures be developed to utilize all or portions of these materials in a productive and efficient manner. Nany larger municipalities employ incineration to reduce the bulk of material to be removed to disposal sites: but, even after incineration, approximately one-fourth of the original waste material in the form of non-combustible residue and flyash remain. It has been found that the flyash fraction of the incinerator residue contains varying amounts of copper, silver, gold, aluminum, iron and titanium along with many other important metals. The serious loss of these natural resources contained within the flyash and the monetary expense of current disposal methods present a serious and rapidly increasing problem to the public and to the Federal Government. The growing emphasis upon environmental control, rapidly increasing urban population and "convenience packaging" &apos;with its attendant increased waste production has led to the initiation of a broad range of studies concerning municipal waste. For example, the U. S. Bureau of I-lines is investigating all aspects of the incineration of municipal waste under its solid waste disposal program.l "In-house" studies range from improved incinerator design to potential recovery and recycling of the various components within the incinerator residue. A major portion of the latter research is being performed at the U. S. Bureau of ;-lines, College Park, Maryland facility while grants for specific areas of study have been issued to several universities and research institutes. In addition, the Department of Health, Education and Welfare has supported programs examining the potential recovery of paper; glass, metals and other components of unincinerated refuse followed by disposal in sanitary landfills.

Jan 1, 1971

By S. Corrent, F. A. V. Guimarães, M. G. Barbosa

"INTRODUCTION Moisture can be a villain, so new technologies have been explored to make more viable the production of high moisture iron ores. The current work presents the attempt of the utilization of a superabsorbent polymer (SAP) to aid in the screening process and in the ore handling process, such as stockpiles reclaiming and vessels/trains discharge in sub-zero temperature conditions. The results have shown that the polymer can be used in certain cases to improve productivity and increase safety in the process of handling the material (by increasing the TML). However, for size separation no advantages were found upon the use of the polymers. WATER ADSORPTION MECHANISMS The use of water in mineral processing is constant as its utilization brings an increase in the efficiency of separation. Although we have better results in the processing with water, materials with a high content of “natural” moisture can be very difficult to be treated by the conventional methods of separation. Nowadays many studies have been conducted in order to understand the effect of adsorption of water in the particles of complex minerals. Those studies have being divided in many different lines of research such as contact angle of a drop of water and the surface of the mineral to determine hydrophobicity, the particle size distribution and the porosity of particles. Mainly two forms of adsorption of water by the particles are possible: one the water is retained inside porosity of the particles. Laboratory tests developed in China have showed that capillary adsorption is faster in coarser particles that achieve the saturation degree earlier than finer particles (Xuewei Lv et al., 2011). The so called non-porous model considers the effect of water in the bulk sample of iron ores, in a physical connection when all the water works as a binder between particles as shown in the figure 1.If we take into account the compressibility of the system and compaction due to the weight of the bed over the particles, the thickness of the water film between particles is the same but the volume inside different particle size systems is much higher than in a system with particles of same size."

Jan 1, 2018

By Y. J. Zhang

This paper presents the results of a recent study on the development of an in-situ testing method for determining the coal strength in mine pillars. The strength testing is performed in the horizontal holes drilled into the coal rib using the penetrometer. It is a hydraulically powered device that uses an indenter to press the surface of the borehole until the load reaches the failure point of coal. The pressure and the penetration of the loading pin are recorded by the data acquisition unit. The results collected from several coal mines indicate that this testing method is ideally suited for the realistic coal strength measurements. The new testing system not only improves the accuracy of pillar strength determination, but it is more cost efficient than the conventional method.

Jan 1, 1995