Search Documents

By Allen L. Frank

The uranium mine environment is characterized by airborne radon-222 and its daughter products to which miners are exposed through breathing and by gamma and X rays from the uranium-235 and uranium 238 chains to which the miners are exposed externally. The nature of the radon-daughter concentrations and the methods used to define and measure the exposures are explained through an extensive review of the literature. An improved passive track-etch dosimeter for personal use is proposed which has a measurement range of about 30-400 WLH with a 95% confidence interval to ~25% for individual detector measurements in relatively stable mine air. Some measurements of these dosimeters adapted to environmental use are also presented. A program of development for enhancement of dosimeter sensitivity and greater accuracy of measurement is outlined. Extensive gamma-ray survey measurements were made in two Colorado and three New Mexico mines. Follow-up personal miner dosimetry with LiF TLDs was done at the mine with the highest exposure rates, The average miner exposure rate measured was 4.27 mR per day, or 9.3 of the maximum permissible level averaged over 13 weeks. Comparisons are made with previous mine surveys and their value in estimating miner exposure is discussed. Some depth-dose measurements made using Lucite as the absorber are evaluated.

Jan 1, 1978

By GEORGE S. POPE

This bulletin is a revision of Bulletin 63 and is published by the Bureau of Mines in order that purchasers of coal for Government, State, municipal, or private use may be informed regarding advances or refinements in sampling coal deliveries and preparing specifications for the purchase of coal. The purchase of coal by the Government under specifications depending on the heating value of the coal, its content of ash and of moisture, and other considerations, rather than upon the reputation or trade name of the coal, was based on the fuel investigations begun by the Technologic Branch of the United States Geological Survey in 1904. The plan was first adopted by the Treasury Department in 1906. Since then the plan, variously modified in form, but the same in principle, has been gradually adopted by other departments until, at present, of the coal used by the Government, the total value of which approximates $8,000,000 annually, more than half is purchased under specifications. The Government publications dealing with the adoption by the Government of the specification plan, the number of contracts awarded on that basis, and the quality of the coal delivered under such contracts in the several fiscal years covered by the reports are given in publioations a listed at the end of this bulletin. Under the authority of acts of Congress making appropriations for analyzing and testing fuels belonging to or for the use of the United States Government, a laboratory is maintained at the headquarters of the Bureau of Mines, Washington, D. C., where samples representing deliveries of coal purchased under specifications for Government use are analyzed and tested. At this laboratory more than 1,200 samples have been analyzed and tested in one month. With the complete equipment and the efficient force employed, the analytical work has been so perfected that the analyses and heating-value tests of the samples received are as accurate as may be reasonably expected in laboratory work of this nature. One of the serious drawbacks to the general adoption of the specification method for the purchase of coal is the difficulty of obtaining at reasonable cost samples of coal that can be considered fairly representative of the commercial product delivered in wagons, railroad cars, or ships. Therefore the method of taking and preparing samples for shipment to the laboratory has been given fully as much care as the making of the analyses and tests, and a general plan of collecting samples fairly representative of the delivered coal has been evolved through various modifications and improvements based on experience and increased knowledge of the physical and chemical characteristics of the various coals that are purchased by the Government. The method that is in general use by the Government is described in the following pages. In connection with studies of the coal deposits of the country, of the best methods of preventing waste in mining, and of increasing efficiency in the utilization of coal belonging to or for the use of the Government, geologists and engineers of the United States Geological Survey and of the Bureau of Mines have visited more than 2,500 coal mines scattered through all of the coal-producing States and Territories. From each mine 2 to 8 or more samples were taken, the number depending upon the size of the mine and its output. The analyses and descriptions of the samples collected up to the end of the fiscal year 1913 are published in Bureau of Mines bulletins 22 a and 85,b and those of samples collected in the fiscal years 1914 and 1915 are presented in a bulletin that will soon be published by the bureau. A study of the analyses of these samples and of the samples taken from cars shipped from a number of the same mines shows that the mine samples are as a rule of higher grade than the average commercial shipments, particularly with respect to containing a lower percentage of ash and having a correspondingly higher heating value. This difference is due to the fact that the Government inspector, proceeding on the basis of what can be done by a good miner, usually removes more of the partings of bone, slate, and other extraneous matter from his mine samples than the average miner does in ordinary practice, the aim of the miner being to get the maximum number of tons past the tipple inspection, as his earnings are based on his output. The average miner, therefore, does not always take as much care as he might in rejecting the impurities. The difference may be caused, too, by the presence of pieces of the mine roof and floor in commercial shipments. The Government inspector can readily

Jan 1, 1916

By Alex Naudts

Pre-excavation grouting is a predictable and reliable technique performed to prevent or minimize settlement in advance of, or during the tunneling operation. It safeguards the infrastructure above the tunnel alignment. Cement based suspension grouts and sodium silicate based grouts are frequently injected to consolidate and strengthen the formation and create a reinforced canopy above the tunnel trajectory. Grouting is typically performed through permeation and permeation in conjunction with hydrofracturing. Multiple injection passes through steel sleeve pipes are ideal, since they create an effective forespiling system to facilitate tunneling without causing unacceptable settlement, even with minimal overburden thickness. Ten pre-excavation grouting projects performed in the North America are discussed in this paper.

Jan 1, 2008

By Hiroaki Nakano, Kenji Hara, Shunsuke Kawano, Takeshi Ohgai, Michiaki Ikeda, Hisaaki Fukushima, Shinji Yamashita, Tetsuya Akiyama, Hisayuki Kaku

"Ni-Fe alloys have an inverse magnetostrictive effect (Villari effect) in which its permeability varies according to the ·applied strain. This alloy film has a potential for application as force sensors such as torque sensors, tension sensors and so on. Electrodeposition is promising as a technique for preparing Ni-Fe alloy film because of its convenience and economy. In this paper, the effects of electrolysis conditions on the magnetic properties of electrodeposited Ni-Fe alloy films were investigated. Hysteresis loops of Ni-Fe alloy films on copper substrates from sulfate bath were measured by a vibrating sample magnetometer (VSM). The films of low coercivity, which were preferred when used as a force sensor were obtained by introducing certain additives to the sulfate type bath.INTRODUCTIONNi-Fe alloys show an inverse magnetostrictive effect (Villari effect) that their permeability varies depending on the applied strain. The films of this alloy have a potential for application as force sensors such as torque sensors, tension sensors and so on. The authors et al. tried to prepare Ni-Fe alloy films using the sputtering technique, and produced a prototype of Ni-Fe alloy torque sensor [I]. The sensitivity was higher in the torque sensor thus produced than the strain gauge type one, and this torque sensor enables non-contacted detection. It showed excellent durability and reliability. However, the formation of Ni-Fe alloys by sputtering requires higher costs and brought an another problem that the shape of the substrate on which the film was formed was considerably limited. This causes a hindrance to the wide-range application of the force sensors. Electrodeposition is promising as the technique for preparing Ni-Fe alloy films because of its convenience and economy. In this paper, the effects of the conditions of electrodeposition on the magnetic properties of Ni-Fe alloy films were studied."

Jan 1, 2000

By G Pizarro, O Miranda, D Rosales

In panel/block caving mines, large amounts of information are collected at the operations. This information includes grades and extracted tonnage, fragmentation, lithology, design of stopes and main infrastructure, geotechnical information, overbreak progress, seismicity, numerical modelling and many other mine variables. To improve the reliability of the production plan it is required to integrate the mine data into one platform. In this paper, the logic of a new technological platform is presented for analysis, modelling and design in panel/block caving mines. The platform includes an acquisition system for mine data and geotechnical information, a back-analysis module for calibrating statistical models and a module of visualisation of the results. The application and benefits of the platform is illustrated for mining induced seismic risk for panel/block caving mining operation. The platform can be used in the mine design and planning processes and is useful for reducing uncertainty in the mining business of panel/block caving operations.CITATION:Miranda, O, Rosales, D, Pizarro, G and Vallejos, J, 2016. Development of an integrated platform for the analysis, modelling and design in panel caving mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 237–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Using a series-model of an automotive short range radar sensor (SRR) and a recently completed experimental radar system, field tests have been performed in a surface mine. It was examined, to what extent low-cost electronically scanning radar sensors can provide useful data for assistance systems on large scale mining machines. Simple sensors are useful for anti-collision safety zones or hopper car automation. The more complex and sophisticated experimental radar system using digital beam-forming can clearly detect and map the contours of trenches and slopes. The overall promising results refer to many more potential applications for electronically scanning radar in surface and underground mining as a reliable alternative to mechanical laser scanners.

Jan 1, 2007

By Joseph M. Chelini

The report shows the sensitivity that nine different cash-flow factors have on the discounted rate of return calculated from feasibiliity- studies on potenital open-pit orebodies of silver, copper, and uranium. Cash-flow factors of "grade", "market value", and "recovery" are. the most sensitive. This verifies the need of reliable estimates for these factors. The cost of evaluation of "preproduction cost" is the least sensitive. This gives credence to the fact that more consideration should be given to compiling sufficient data, as the largest financial losses are not in the cost of evaluation but rather in the abandonment of an unprofitable mining operation after a commitment of capital is made on the basis of an incomplete evaluation. Sensitivity analysis of cash-flow factors enhances evaluation programs by disciplining the collection of data and allowing more realistic distribution of evaluation monies.

Jan 1, 1971

By Patrick F. R. Murphy

The mechanization of platinum group metal (PGM) underground reef mining in South Africa has posed a challenge to mining engineers for several decades. This is primarily due to the shallow dip angles and narrow thickness (<1.1m) of the tabular orebodies mined, and the issues faced in developing reliable drilling, bolting and loading machines suitable for such hard-rock mining applications. Presently, mining is typically conducted using hand drills and scraper shovels. These methods, however, are intensive in terms of manual labor, and limited in terms of productivity, and improved methods are desired. This paper will review the technical features of a 4 tonne, low-profile, LHD for narrow-reef PGM mining, developed by EJC Loaders Division.

May 1, 2003

By M. Maccagni, J. Nielsen

"The recovery of lead from battery paste has been investigated for a long time and with the use of many different electrolytes. A number of processes have been presented, but none of them reached even the demonstration step. Engitec has developed a new concept for the battery paste electrowinning using a chloride electrolyte fed through a very innovative flow cell. The process has passed the lab and the demo scale and it is ready to be introduced on the market. In this paper, a description of the process will be provided.INTRODUCTIONThe need for improved energy storage systems as well as the introduction of commercially viable electric vehicles is providing a strong compulsion toward the research of new batteries. The lead battery is playing an important role because it is inexpensive, reliable and it is the most recycled material. This last aspect marks the lead acid battery as quite peculiar making it both the primary lead based product and the main raw material for lead production.In the last years the legislative pressure has become very strong and has forced the lead production to react through the introduction of important process innovations and market changes. The dispersive products, such as additives for paints and for fuel as well as bullets, have been practically banned all over the world while the battery market continues to grow. The lead acid battery remains the cheapest and most integrated energy storage system available and is improving to meet the new technical challenges. This is testified by the news coming from the development of new and more efficient lead acid batteries which are confirming their leading position.Unfortunately, the image of lead is very negative in the public opinion and some important actions are required to try changing this sentiment. Among them, better information to the market and users and the introduction of new and cleaner technologies in the production of lead can help."

Jan 1, 2016

By Richard E. J. Putman

THE MINERALS INDUSTRY has always been a heavy user of energy in most of its unit operations: power in the mining, comminution, flotation and electro-winning processes; fuel in its smelting and other metallurgical processes; and, of course, fuel in the on-site generation of power and steam. Many of the techniques for using computers to perform energy management and conservation tasks have been known for some time, but they have not been widely implemented because the return on investment has hitherto been insufficient. Recent trends, however, have not only caused the dollar return to rise due to higher purchased energy costs, but the cost of the investment to fall. One trend has been the generally lower cost of computer control systems themselves, due to vendors having adopted the newer, lower-cost and more reliable electronic component technologies now becoming universally available. The second trend is the development of low-cost, but high-speed, remote multiplexing devices, which have reduced considerably the expense of bringing data from points scattered over a wide area, which is typically the case when applying energy management systems to a minerals processing plant. By taking advantage of these and related developments, computer control systems can now have a rewarding impact on plant energy management and conservation practices, and recent advances in application technology have opened up new and additional opportunities for energy cost reduction and control.

Jan 1, 1978

By Henry Chumienski

Next to the paper industry, the steel industry is a major user of water. Without an adequate and reliable source of “good” water, steel cannot be produced. The use of water has a direct impact on steel quality and on our environment. Used improperly, water can also add unnecessary costs. Used properly, water can maintain and improve steel quality, enhance our environment and control or reduce the “total cost of operation”. Water needs to be more than just “wet and not lumpy”. Water quality needs to be based on the end use. This paper discusses ways to manage many of the water systems. With little or no capital investment it is possible to develop operating practices that protect your initial investment, ensure that the water systems do not have a negative impact on quality or your production costs and also minimize your chance of having an environmental incident.

Jul 30, 2018

By V. Duddempudi, B. Goertz, J. Brune, G. Bogin, F. S. Barreto

"INTRODUCTION In designing a new pneumatic Dust Sampling Device (DSD) for coal mines, it was essential to analyze the air and particle flow inside the device in detail using Computational Fluid Dynamics (CFD) modeling. Several CFD models were developed to simulate the air and dust flow and sample collecting process of the DSD. These CFD models were developed to assist in the design of the DSD instrument prototypes for laboratory testing. Nozzle and injection parameters such as geometry, air velocity and pressure, were varied across a wide range to obtain the optimal settings to accurately simulate the fluid dynamics of the multi-phase flow within the DSD. Accordingly, these parameters were used as a guide for the design of the DSD and to verify the dust scouring dynamics, which is designed to represent the dust entrainment during an actual methane or coal dust explosion. BACKGROUND The 2010 explosion at the Upper Big Branch mine has demonstrated the destructive violence of a coal dust explosion. A major contributing factor for this disaster was that the mine operators did not have a reliable, direct-reading method to collect mine dust and determine inert content and combustibility. This led to the development of a new prototype handheld, pneumatic mine dust sampling device (DSD), which blows a puff of air and entrains the mine dust by mimicking the entrainment process during a mine explosion. A computational Fluid Dynamics (CFD) model is used to analyze the air and dust flow inside the DSD. The objective of the CFD modeling effort is to find the optimum design of the DSD prototype, nozzle orientation, air pressure and pulse length by analyzing and varying these parameters so that the scouring action collects a valid, representative and repeatable mine dust sample. CFD MODEL DESIGN Figure 1 shows a wireframe image of the DSD which is utilized in the setup of the CFD model. The DSD has a triangular cross section and is 10 cm wide. Two nozzles with cross-sectional dimension of 2.8 cm by 0.25 cm act as inlets at the narrow end of the triangular cross section. The CFD model includes a reference plane 6 cm away from the nozzle to measure the quantity of dust collected. The geometry shown in Figure 1 was created for the model and it matches with the design of the actual device shown in the figure 2. Symmetry, along the plane X-Y through the center of the device, is used to reduce the number of computational cells in the CFD model. Figure 2 shows the prototype device used for experimental testing. CFD MODEL SETUP Figure 3 shows a hexahedral mesh with a cell size of 0.8 mm and the total number of cells is around 650,000. The ANSYS Fluent® pressure based solver with a transient case was used with a total duration of 40 ms. The 40 ms simulation time is based on experimental measurements to capture the injection of air and initial scouring of dust."

Jan 1, 2016

By Shengqin Zhang, Yousef Mohassab, Feng Chen, Hong Yong Sohn, Mohamed Elzohiery, Amr Abdelghany

A novel ironmaking process is under development at the University of Utah aimed at producing iron directly from iron oxide concentrate in a flash reactor. This process will reduce hazardous emissions and save energy. The kinetics of magnetite reduction with hydrogen was previously investigated in our laboratory in the temperature range 1150 to 1400 oC at large temperature increments (~100 oC increments). Due to the significant melting that occurs above 1350 oC, the reduction kinetics was measured and analyzed in two distinct temperature ranges of 1150 to 1350 oC and 1350 to 1600 oC (~50 oC increments). Experiments were performed using magnetite concentrate particles of different sizes under various hydrogen partial pressures and residence times. Reduction degrees of more than 90 % were achieved in a few seconds at temperatures as low as 1250 ºC. Different rate expressions were needed to obtain reliable agreement with experimental data.

Jan 1, 2016

By D Reid, A Fourie, J Ayala

This paper discusses cone penetration test correlations for loose gold tailings that were developed within a critical state soil mechanics framework. The development of a new calibration chamber for cone penetration testing that consists of a modified triaxial cell is described. Some of the early development and commissioning issues that were encountered, as well as the solutions adopted are outlined, including the system to prepare the samples and to acquire high-quality data from the testing. Also, the triaxial laboratory testing required to achieve the critical state line is described, including some of the basic precautions considered necessary as good practice. Additionally, the system adopted for volume tracking of the calibration chamber sample is described, which is essential for ensuring a reliable state parameter comparison against the acquired cone penetration test data. Finally, some laboratory test data from the calibration chamber is plotted against the soil behaviour type charts currently available from various authors.

Jul 1, 2021

By S. D. Zhang

The first reinforced earth railway bridge abutment in China has been successfully constructed of September, 1985 under the supervision of the Reinforced Earth Researth Group of Shanghai Institute of Railway Technology. In order to verify the reliability of the designed structure and its behaviuors, the 1:10 reduced scale model tests in laboratory and field tests on the actual structure during construction were proceeded. Various loads of different positions were charged, the vertical and lateral earth pressure in the filling soil, the stresses developed in the reinforcements, and the deformations of the models or the actual structure were recorded in those tests. The behaviors recorded are presented and discussed in this paper.

Jan 1, 2010

By D. B. Dow

"In the natural-gas Gasoline industry, the methods used in determining the amount of gasoline in natural gas are many and varied; they include the specific-gravity test, laboratory tests involving absorption, charge in volume of the gas or in the absorption medium, absorption in charcoal with subsequent distillation, compression of the gas which results in the condensation of the gasoline, and the absorption of the gasoline vapors in an absorption oil, from which the gasoline is distilled and measured. Each of these various tests has advantages, and disadvantages. It is however, conceded in the industry that the tests in which the gasoline is obtained and measured as such are the more reliable.This paper deals with certain factors which should be considered in making absorption tests using ""mineral seal oil"" as an absorbent; this method of testing is widely used not only in the field, but in control work in absorption gasoline plants where the gasoline content of the intake and discharge gas is determined daily. In control work it is frequently found that the plant produces more gasoline than the tests show, which gives the plant the appearance of making more gasoline than is actually present in the gas treated, or in other words operating at more than one hundred per cent efficiency. Obviously then, the tests as made in these cases are in error, and in hope of correcting some of these variances, the following factors have been studied at the U. S. Bureau of Mines petroleum station at Bartlesville, Oklahoma."

Aug 1, 1920

By Agbo Chima

Low-lying sections of open-pit mines accumulate water, especially during the rainy seasons, preventing access to resource-bearing areas. To sustain mining operations, the water must be lifted out of the flooded pits at a high flow rate using pumps. These pumps need to be mobile so that they can be removed during drill-and-blast operations. Most mobile pumps rely on diesel engines with high maintenance requirements. A special pump design was developed to address the unique needs of open-pit mining while making the dewatering process more sustainable. Using the target flow rate and head data, an efficient pump was designed, encased, and deployed in the open pit. A variable speed drive (VSD) was installed in a protective skid so that the pump could be tuned to match the preferred flow rate at any point during its operation. This system was tied to the national electrical grid instead of being powered by diesel pumps, which reduced the carbon intensity per kilowatt-hour. The high availability, low maintenance requirement, and greater reliability reduced the use of spare parts, the fuel consumption, and the logistics associated with operating the pump. This further reduced the carbon footprint of the dewatering process. This paper provides some of the two-year performance metrics for a deployment in West Africa. With a focus on availability, maintenance costs, average cost per volume lifted, and carbon footprint, this encased pump system is compared to the diesel-driven pumps that it aims to replace.

Jan 1, 2023

By M Coleman

Information is a key ingredient for successful mineral exploration and development. Whether identifying potential exploration localities from a map, interpreting technical reports or searching a register for operators past and present, the common aim is a parcel of information from which the enquirer can make a decision. Traditional information gathering often requires days or weeks of manual research, studying maps, files, reports etc, before consolidating the results into an investment proposal. In recent times, such methods have largely been replaced by Information Technology, making the process much faster, easier and more centralised. However, notwithstanding some very successful technology implementations, the general rush to computerise everything in sight has left many organisations struggling to cope with the management of large volumes of diverse information. Information management is now recognised as the most important factor in determining the success of information technology implementation. The Northern Territory Department of Mines and Energy (DME) has established a detailed information management strategy to underpin the rapid advance of computer technology within the organisation. A broad base of timely and reliable information is gradually becoming more accessible. It is envisaged that the availability of combined spatial, textual and scientific information will provide a sound basis for decision-making within the Department and the mining industry at large. Although information held by DME will be available at all times (24 hours on-line), its security and confidentiality will be guaranteed. The production of the DME system is aimed at satisfying the corporate objective to facilitate and promote mineral exploration and development. This paper outlines some current developments in the system.

Jan 1, 1994

By Martin Fischer

A new method for the quantitative image analysis of complex microstructures in steel is presented. Microstructures in modern steel grades on the one hand become more and more complex while on the other hand the size of the constituents is scaled down ever further. For these reasons it is increasingly difficult or even impossible to access reliable quantitative information on ratios, shapes and spatial distributions of individual phases and constituents by utilising traditional metallographic analysis methods. The presented new analysis approach is object-based. Its basic processing units are so-called ?image objects? which reflect the pictured structures by merged groups of likely related pixels. By the use of image objects, information on shape, graphical texture and spatial distribution of the microstructural constituents can be processed. With these additional data available, it is possible to quantitatively analyse complex microstructures. This is demonstrated by the application of the method to SEM images of different multiphase steel grades. Because the analysis routine is fully automated, the analysis of large amounts of image data is possible and thereby the investigation of statistically relevant areas of microstructures.

Jan 1, 2009

By C. J. Gilbert

The mining method at the Cannon Mine uses heading and bench stopes, which are subsequently backfilled with cemented high-strength fill prior to pillar removal. The dimensions of the pillars, 24 feet wide by G5 to 95 feet high, re-quire careful blasting in order to not damage the rock, compromising pillar strength and complicating later removal. Additionally, the proximity of dwellings makes vibration control a must for good-neighbor relations. A blast monitoring study was conducted in order to optimize bench blasting practices to maximize fragmentation, reduce costs, minimize well damage, and minimize ground vibration.

Jan 1, 1989