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By Robert F. Kehrman

As part of the Bureau of Mines research on the In-Situ Uranium Leaching, various geophysical resistivity measuring techniques were -evaluated to identify a rapid reliable method for detecting the underground migration of lixiviant outside of the planned limits. Surface and downhole galvanic resistivity and controlled source audio-magnetotelluric (AMT) methods were tested at an in-situ uranium mine in Northern Wyoming during start-up of a new mining area. Downhole galvanic and AMT were the most promising techniques.

Jan 1, 1980

By Ronald P. Hollenbeck

This study reviews and discusses the fluorspar industry in the Eastern United States, with emphasis on factors controlling the industry such as production, consumption, uses, and transportation. The greatest potential for increased consumption of fluorspar in the immediate future was found to be in the manufacture of fluorine chemicals and steel. Important factors affecting the future domestic industry include imports and the maintenance of adequate domestic fluorspar reserves. Exploration, commercial deposits, mining and milling, reserves, and new developments in the industry are covered.

Jan 1, 1967

By M. J. Pool, P. J. Spencer

Using liquid tin as the solvent metal, the heats of solution of silver and gold in dilute Ag-Au-Sn alloys have been determined at 723°K by solution calorimetry. From the values obtained, the various enthalpy interaction coefficients in the liquid solutions have been calculated. The self-interaction coefficients Au and Ag values of 2413 and -6322 cal per g-atom in binary Au-Sn and Ag-Sn alloys, respectively. For an alloy containing 0.04 mole fraction Ag, Au is equal to 2443 cal per g-atom, and in an alloy containing 0.04 mole fraction Au, Ag has a value of —8883 cal per g-atom. Ag Au has been determined as —2650 cal per g-atom. ADDITION of a second solute to a dilute binary alloy may cause striking changes in the thermodynamic characteristics of the alloy. As yet, such influences cannot be reliably predicted and it is only by accumulation and critical assessment of data that definite patterns can be established. Solute interactions in dilute solutions were first treated mathematically by Wagner,1 who derived expressions for the Gibbs energy interaction coefficients. For an alloy consisting of. two dilute solutes, i and j, in a solvent s, these coefficients are given by: where yi is the activity coefficient of component i and x represents the mole fraction of solute or solvent. Other interaction coefficients have since been established in terms of the various partial molar thermodynamic properties of an alloy; the definitions of these are summarized in a recent paper by Lupis and Elliott.2 Mathematical and experimental studies of such coefficients have received much attention recently, providing a very useful theoretical background to an understanding of the nature of solute interactions taking place in dilute solutions. One of the definitions to arise from such work has been the extension of Wagner's treatment by Lupis and Elliott4 to include an enthalpy interaction coefficient, defined as. where ?Hi is the relative partial molar enthalpy of component i. ?Hi is related to the relative partial molar enthalpy at infinite dilution, ?Hio, and to the enthalpy interaction coefficients by the expression: Values of ?Hi can often be obtained with a high degree of accuracy by calorimetry, and, if the composition of the alloy is carefully controlled by making calculated solute additions throughout a series of measurements, application of Eq. [2] will enable reliable enthalpy interaction coefficients to be determined. Partial heats of solution must be investigated as a function of solute concentrations down to xi = 0, and, since ? values are obtained from the slope of mi plotted against x, great care must be taken to obtain precise data. The data for binary systems which are presently available often require extrapolation of ?Hi values from compositions as great as xi = 0.05 or even 0.1 to obtain limiting heats of solution. Reliable enthalpy interaction coefficients are thus impossible to obtain from published data for most of the alloy systems already investigated. The aim of the present work was to determine values of Au, Ag, Ag, and Au in the limit xsn -1 for the relatively simple Ag-Au-Sn system and from these results to gain some insight into the possible influence

Jan 1, 1969

By Chester M. F. Peters

The opportunity to make a close study of the available geologic data existing along the line of the California Aqueduct crossing of the Garlock fault in the Tehachapi Mountains was brought about first by my involvement in the prebid examinations, and later with contractors' claim cases. The California Aqueduct crosses through the western end of the Tehachapi Mountains and cuts across the Garlock fault zone at a location about 9 miles east from its junction with the San Andreas fault zone. This is about 65 miles northwest of Los Angeles and 38 miles southeast of Bakersfield (Fig. 1) (1). This map was published after the tunnels were started and shows the corrected geology. At the crossing the fault has north and south branches which extend northeastward for about 22 miles before converging. In the vicinity immediately east of the tunnel line the north branch of the fault starts to converge toward the west. After crossing the line it passes under the upper plate of the apparent easterly extension of the Pastoria thrust fault, so the actual junction with the south branch is obscured. The aqueduct design called for the expected active slip zone of the north Garlock fault branch to be crossed by the 2,800 foot long Pastoria siphon, which connects with the north portal of Tehachapi Tunnel No. 3. The tunnel would extend through the western end of Genghus Ridge which lies between the north branch and the main south Garlock fault zone in Beartrap Canyon. Here again the

Jan 1, 1997

The original and most basic relationship between mining company and explosive supplier was a simple one of consumer and product supplier. The divide between the two was quite clear-cut with neither taking much interest in the activities of the other. The explosive supplier had little understanding or share in the outcome, efficient rock breakage and therefore impact on mining and milling. Likewise, the mining company did not encourage the improvement or development of products. The transactions were limited to product and funds. This environment does not encourage any form of knowledge sharing, trust or optimisation of the mining process.Conversely, there are now a variety of relationships to the point that the mining company may simply be an asset manager whereby all æoperationalÆ aspects are contracted out. For the drill and blast aspect this takes the form of a æRock-On-GroundÆ contract whereby the explosives company takes on design, drill, load and fire responsibilities and is paid a rate per volume of broken rock. This removes the majority of risk to the mining company derived from having to produce broken rock and guarantees the cost of a portion of the overall unit cost of mining. The onus is now on the explosives supplier to break rock to a specification as efficiently as possible.There exist a number of variations between the æbasic supplyÆ and æRock-On-GroundÆ. These contracts may also include value sharing to encourage the explosive supplier to optimise the mining operation to maximise profit.This paper looks at some of the drivers for the change in explosive supplierûconsumer relationships and examines the æprosÆ and æconsÆ of a few of the options.

Jan 1, 2004

By Magnus Evertsson, Rebecka Stomvall, Josefine Berntsson

"Understanding the effect of particle shape on dry rheology is considered to be an important aspect in order to replace natural sand used in concrete with manufactured sand. Crushed particles from solid rock are normally less rounded and have less equally shaped dimensions compared to natural sand. Thus, the flowability and workability of the concrete will be different. In previous research, it has been demonstrated how different crushing techniques affects the shape of the particles. In many cases it is believed that Vertical Shaft Impact (VSI) technology is a way forward to replace natural sand. To be able to study the effect of VSI at the smaller fractions (63-2000 µm) sufficient measurements methods to determine particle shape are required. Optical tools to analyze the aggregates would make it possible to study a large amount of particles at small fractions. The determination of particle shape of aggregates is challenging since the shape is highly irregular and the size span of particles are very large. This study aim to evaluate one of the available optical tools, the Camsizer, for digital imaging determination of shape and size distribution. The available default shape parameters of the Camsizer are studied to understand the meaning of the parameters and their suitability for determining the quality of manufactured sand. To evaluate the capacity to determine particle shape, tests are made with 35 different materials. The results are compared with the dry rheology measured with the standardized "flow cone" test. Dependence has been previously proven between particle shape and the mass flow rate in the cone. Three different shape parameters, aspect ratio, sphericity and symmetry, are studied with the Camsizer and the results are compared with the mass flow rates in the cone. The results indicate a strong linear relationship between the optical parameters and the flow cone test."

Jan 1, 2014

By Chao Li, Hongxu Li, Yang. Xie, Meng Wang, Xiangxin Hao

"With the development and utilization of resources of gold, high quality gold mine resources gradually exhausted, and refractory gold ore has become the main raw material for gold smelting, while the smelting pollutants impacting on the ecological environment is growing, in recent years there have appeared several methods of green extraction of gold such as bio-oxidation. In this paper, the life cycle assessment models about three different gold extraction technologies have been put forward. Material consumption, energy consumption and emissions during each gold production process are analyzed by using GaBi 6 software, and the environmental impact of each process is also evaluated by means of CML2001 methodology. Calculation and analysis results show that the energy consumption and material consumption are the main factors causing the environmental load; and the environmental impacts of the production process mainly attribute to the category of greenhouse effect, resources consumption and environmental acidification. Based on the evaluation, some optimization tips are proposed.IntroductionOver the past decades, as the industry policy environment continues to improve as well as gold exploration and mining smelting capacity continues increasing, gold production shows a prospecting tendency. With the wide use of gold, the demand for gold is growing, while easy smelting gold mine resources become exhausted and refractory gold ore has become the main raw material for gold smelting. In addition, pollutants impact on the ecological environment is also growing year after year.LCA (Life Cycle Assessment) makes evaluation of product “from cradle to grave” as its whole process, up to finding the sources of environmental impacts and solutions, to comprehensively account the use of resources and lower emissions. In the industrial field, life cycle can compare different technologies from different aspects of resource use, energy consumption and environmental emissions [1]. In recent years, using LCA to evaluate metallurgical industry process also has more development. The paper mainly uses LCA and scenario analysis for the gold metallurgical process by GaBi 6, to investigate the environmental impact of three different technologies of gold extraction metallurgical process. The established three evaluation models include the hydrometallurgical, pyro-metallurgical processes and bio-oxidation pretreatment methods respectively. Several environmental indexes would be selected to evaluate the environmental impact in order to find which process has smallest environmental load and some suggestion of reasonable way gold resource utilization."

Jan 1, 2014

By V. Kecojevic

The objective of this research was to establish the relationship between production, consumption and energy cost in the surface mining of bituminous coal. Specific energy sources such as diesel, gasoline, electricity, explosives and bituminous coal were considered in this study. Gain in net energy, proportion of the cost of energy consumption and total energy cost relative to total revenue of extracted coal were determined, and a new energy efficiency index and a new energy-cost ratio were established. A case study on an operating surface coal mine was carried out to demonstrate the application of the newly developed method. The results of this study can be used by the mine operators in establishing strategies for the optimization of energy production and consumption, and for reducing the cost of bituminous coal extraction.

Jan 1, 2014

By E. Hulthén

Cone crushers are used in the mineral, mining, and aggregate industry for fragmentation of rock materials. Control systems for cone crusher settings are widely used to compensate for wear and to protect the machines. The eccentric speed in a cone crusher affects the number of compressions the material is exposed to and thus the particle size distribution of the product. Eccentric speed also affects crusher capacity. However, the speed of the crusher is mostly fixed, because speed changes must be made by shifting pulleys, a process which is quite time-consuming. By applying a frequency converter, which has decreased in cost during recent years, it has become possible to adjust the speed continuously. By also applying mass-flow sensors to the process, the crusher can be run optimally to yield the most sellable products in a given moment. Existing systems normally only protect the machine. The sensors can be mass-flow meters, e.g., conveyor-belt scales. To analyze data from the process and calculate the appropriate value for the speed, an algorithm has been developed. The developed algorithm was tested and evolved at a crushing plant for aggregates that produces around 350 kton a year. The algorithm was implemented in a computer that could communicate with the frequency controller, retrieve data from four mass-flow meters, and also interact with the opera-tor. The computer was reachable over the Internet for the researchers at Chalmers and the algorithm was tuned and improved on-line. The result is a crushing stage that consistently and maximally produces the most desirable product. The performance (yield of required products) increased by 4%. As a bonus, the lifetime of the mantles increased 27% on the evaluated crusher.

Jan 1, 2014

By G. W. Weems

The Bureau of Mines combined preconcentrating techniques and mass spectrometry to develop a parts-per-billion general analysis of impurities in helium. The impurities are preconcentrated using a Bureau trace-impurity analyzer; 35-mm Hg pressure of helium is left in the concentration trap to sweep the impurities into the mass spectrometry and provide a 10-mm Hg sample pressure.

Jan 1, 1966

By Dorsey A. Lyon, Robert M. Keeney

The utilization of hydro-electriic power in electro-metallurgical industries, aside from purely mechanical operations, may be of two kinds. The electric energy may be used to supply the heat necessary for the performance of the chemical reactions of a metallurgical process, or the electrolytic action of a direct current may be employed for extraction of metals, either in a reduction process or a refining process. In discussing this subject, it is well to distinguish between established industries, which are producing metals and alloys at a, profit by use of the electric current, and the many processes which are either still in the experimental stage or have not even passed the paper stage of development of a patent. That is, we consider electro-metallurgical industries as commercial operations which are now consuming large blocks of electric energy, while processes which are not in commercial operation are only prospective consumers. Also, owing to the difliculty and risk of any attempt to foresee the effect of the European war upon electro-metallurgical industries, we have felt obliged to disregard the war entirely, and state our opinions regardless of its existence. Application of Electric Energy to Metallurgy Disregarding electrolytic refining processes, the applications of electric energy to metallurgy, when considered from a commercial viewpoint, may be classified as follows: Industries Experimental Processes Manufacture of aluminum Electric-furnace smelting of: Electric-furnace manufacture of: Ferro-alloys Copper ore Pig iron Zinc ore Steel In this paper only the above industries and experimental processes will be considered as possible consumers of hydro-electric power in large quan-

Jan 1, 1916

By Eric R. Borys, Amaneh E. Kenarsari, Brett Gitskin

This case study discusses impacts of excessive Earth Retention System (ERS) lateral movement at a project in city of Chicago. The ERS (cantilevered sheeting) moved inward towards the excavation and caused lateral displacement and cracks in six drilled shafts located about 1 to 2 lateral feet (0.3 to 0.6 m) from the face of the sheet pile wall. Up to 9 inches (23 cm) of horizontal movement was observed on top of the supporting sheet-pile. Similarly, survey measurements showed the top of the drilled shafts moved laterally up to 8 inches (20.3 cm). To evaluate the cause of failure and determine a remediation solution, the soil, shaft and site conditions were investigated. Pile Integrity Tests (PIT) were conducted at the affected drilled shafts. The shafts with identified anomalies were cored and video-recorded. The cause of the failure was determined to be related to variable soil conditions across the site, deeper excavation (i.e., increased effective ERS wall height), and other differences between design and as-built conditions. Internal bracing, in the form of walers and rakers, was installed to limit further movement of the sheet pile as a short-term solution, with additional grade beams framed into the basement slab-on-grade as a long- term solution. Five of the six cracked shafts were spliced with reinforcing bars and high strength grout and one shaft was replaced. INTRODUCTION The subsoil in the Chicago Area mostly consists of glacial till clays underlain by water-bearing granular soil over bedrock. The glacial clays have very soft to medium consistencies for a typical thickness of 30 to 50 feet (9.1 to 15.2 m) below which hard clays (Hardpan, i.e., heavily over-consolidated clay soils) are encountered. The soft clays are often referred to as the “Chicago Blue Clay”. Beach Sands are also found above upper soft clays in several areas, especially within a three-mile strip near Lake Michigan (Peck and Reed 1954). Due to the existence of soft clay in Chicago area, supporting the mid to high rise buildings on drilled shafts extended to Hardpan is a common practice in modern building design. In the early 19th century it used to take about 3 weeks to excavate 1 shaft hole and about 1½ days to fill the shaft with concrete in Chicago (Manierre 1916). The early 19th century methodology of excavating a shaft consisted of hand digging the shaft, installing wood lagging as temporary shoring with spoils removed with a rope and pulley system from the surface. Today, the excavation of a typical drilled shaft in Chicago uses heavy drilling equipment and requires much less time for excavation and concrete placement. It is not uncommon for contractors to excavate shafts and place concrete at a rate of about 2 to 5 drilled shafts per day (with one drill rig).

Jan 1, 2018

By Steve Kral

The Society for Mining, Metallurgy and Exploration’s origins can be traced back to 1871. This was when 22 Pennsylvania coal mining engineers founded the American Institute of Mining Engineers (AIME). The organization’s objective was to “promote the arts and sciences connected with economic production of the useful minerals and metals, and the welfare of those employed in those industries by all lawful means.” Metallurgy and Petroleum were added to the AIME name in 1919 and 1956, respectively. Divisions of AIME were formed throughout the following years in recognition of the increasing trend toward specialization among mineral industry engineers. At the time, SME’s divisions consisted of the Coal Division (1930, now known as the Coal and Energy Division), the Industrial Minerals Division (1935), the Mineral and Metallurgical Processing Division (1948) and the Mining and Exploration Division (1949). The Environmental Division was created in 1997.

Jan 1, 2007

By G. S. Rice

The recommendations of the Bureau of Mines on rock-dusting practices are embodied, except in a few details, in the Recommended American Practice for Rock-Dusting Coal Mines to Prevent Coal-Dust Explosions,5 approved by the. American Engineering Standards Committee,6 December 30, 1925 It is specified that the dust to be used is of a size that all will pass through a sieve having 20 meshes per linear inch and that 50 per cent or more will pass through a sieve having 200 meshes per linear inch.

Jan 1, 1930

By Magnus Troilius

The method of using the bromine process of determining sulphur in steel, described below, is in successful use at the Midvale Steel Works. Ten grams of drillings are weighed out and put into the 1/2-liter flask A, with long neck. The flask is connected with a wide glass tube C', which, in its turn, is connected with the absorption bulbs B, containing HCI, 1.12 specific gravity, and ahout 5 C.C. of bromine. The wide tnbe C causes the vapor to condense and flow back into the flask A during boiling. The bulbs B connect with a long glass tnbe, which may be made to carry off the bromine fumes through a hole in a window, or, better still, through a flue with powerful draught. The connections being made, 100 C.C. of boiling water are run in through the thistle tube T. The air is thus completely driven out of the flask. 100 C.C. of HC1 (about 1.19 specific gravity) are then run in. When the gas begins to run rattler slowly through B, heat is applied until boiling gradually ensues. The steel being completely dissolved, the apparatus is disconnected, and the contents of B rinsed out into a beaker of 100 C.C. capacity, into which a few C.C. of a concentrated solution of BaCI, have been previously introduced. Heat is then applied (best by means of the hot iron plate) until the bromine is completely driven off and the BaSO, has settled nicely to the bottom. The BaSO4, is then filtered off on a small

Jan 1, 1884

By Qingguo Xue, Jingsong Wang, Yingli Liu, Guang Wang

In the dropping zone of blast furnace (BF), primary slag absorbing ash of pulverized coal and coke become to be intermediate slag. Due to viscosity and surface tension of slag and the pore between cokes, some slag remained in coke layer and affected the permeability of blast furnace. The flow behavior of slag with different basicity (0.55–1.10) and Al/Si (0.35–0.50) were studied. Meanwhile, the viscosity and surface tension of slag were calculated. The results showed that, with the increasing basicity of slag, surface tension increased and viscosity decreased. With the Al/Si increase, surface tension and viscosity increased. The smallest pore that all slag can pass through was 4.5 mm. However, the height between slag droplets and the bottom of crucible indicated that the ability of slag to pass through pore were weakened with the increasing basicity and Al/Si. Thus, slag which absorbed ash from fuel become difficult to pass through coke layer.

Mar 1, 2017

By V. Prasad, A. Afacan, K. Popli, S. Dubljevic

Froth flotation is one of the most common and widely used separation processes in the mineral processing industry; however, its complexity means that complete understanding of the process has not yet been achieved. A dynamic fundamental model is needed to enhance the understanding of the process and to improve process control. It is challenging to capture all the phenomena involved; hence, we propose a multiscale modeling approach with a framework ranging from macroscopic (equipment scale) to microscopic (attachment, detachment) models along with distribution models for ore particle sizes. Real-time froth properties are obtained using a vision-based sensing system. These measurements can be used for developing a soft sensor for grade using statistical methods such as PCR (principal component regression) and PLS (partial least squares) regression. The fundamental model is updated in real-time using extended Kalman filtering. Attachment dynamics are studied for different particle size distributions. The modeling and soft sensing is tested on batch flotation cell for the pure mineral galena with different particle size distributions using Xanthate and MIBC as collector and frother, respectively. The model, online measurements and soft sensor are useful in developing monitoring methods for froth flotation.

Jan 1, 2015

By Sam F. Harrison

The National Board of Boiler and Pressure Vessel Inspectors again sends out this recommendation: If you have an air compressor that is mounted directly on the air tank, get it off. Characteristically, small- to intermediate-sized air receivers are thin-walled vessels, and as such are prone to failure when subjected to external loading. Many of these vessels, if not a great majority, are bought by a distributor of air compressor systems, who provides the compressor, motor, switchgear and other accoutrements-all of which are very frequently mounted on a base which is then welded to the shell of the receiver. These welds at the points of attachment transmit external loading to the tank in the form of weight and vibration, frequently resulting in stress-induced cracks.

Jan 3, 1978

Paper 1: Risk of gastrointestinal cancers from inhalation and ingestion of asbestos, John F. Gamble Selikoff suggested the hypothesis that asbestos exposure is causally associated with increased risk of gastrointestinal (GI) cancers in an early study of insulation workers. In this paper, John Gamble reports on his extensive review and reanalysis studies that address the relationship between asbestos exposure and GI cancers. The purpose of the review was to evaluate the association between asbestos exposure and risks of stomach, colorectal, colon, and rectal cancers separately. Gamble evaluated exposure?response (E?R) relationships using surrogate exposure methods ??because few individual studies of GI cancer have reported exposure? response analyses.?? The principal asbestos exposure surrogates are: (1) the rate ratio (RR) for lung cancer; and (2) the percent of mesothelioma among exposed workers. Analyzing SMRs for GI cancers from individual studies versus the risk of lung cancer and mesothelioma provides crude estimates of E?Rs for asbestos exposure and GI cancer. Briefly, Gamble justifies the surrogate approach as follows:

Jan 1, 2007

By F. X. Tartaron

This report describes work done by the Bureau of Mines to simplify the design and operation of the vortex cone, a new device for prerefining blast furnace iron. Three new apparatus arrangements were tested. Results with one of these arrangements average 74.2 pct silicon removal and 61 pet oxygen efficiency (disregarding removal of carbon and manganese).

Jan 1, 1965