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By W. J. Long

As a part of the strategic mineral exploration program, examining engineers of the Bureau of Mines collected samples of ore from four manganese properties in Yavapai, Yuma, Maricopa, and Mohave Counties, Ariz. As all of the ores were too low in grade to be acceptable by manufacturers of ferromanganese beneficiation studies were made to determine the amenability of the ores to concentration.

Jan 1, 1948

By José Cuadros

"El presente trabajo señala el proceso de evolución del método de minado en la mina Chupa, perteneciente a la unidad minera de Iscaycruz. La evolución del método de minado se determinó por la búsqueda de mejores condiciones de seguridad y eficiencia en la operación. En ese sentido, los resultados logrados con cada una de las alternativas de minado por subniveles, indica que se ha logrado optimizar las diferentes variables mineras y cumplir con el plan estratégico de Empresa Minera Iscaycruz S.A. (EMISA). Para cumplir con el citado plan estratégico, se debe optimizar el método de minado de Chupa, a través de una mayor producción a un menor costo,así como del aprovecho de las labores de desarrollo y preparación ejecutadas según el planeamiento inicial del minado. Por ello, la secuencia del avance del minado y la reestructuración del sistema de relleno de la mina son los aspectos importantes para lograr este objetivo. "

Jul 31, 2003

By Henry S. Washington

Introduction. It Still Rains On The Choco ! I Well Remember One Evening A Dozen Years Ago, While. Traveling Toward The Town Of Negua In A Small Champa Or Dug-Out Canoe, The Rain Fell So Heavily That I Had To Work My Hardest To Bail Out The Water With A Large Totuma Or Gourd In Order To Keep The Canoe Afloat, The Senegambian Meanwhile Plying His Paddle In The Stern. If Any One Thinks Bailing Is Easy Work, Let Him Scoop Out A Quart Or More At A Stroke, 40 Times A Minute For Half An Hour, And I Venture That He Will Change His Opinion. These Small Canoes Required Only One Paddler, To Make The 3 Miles An Hour Which Is The Standard Rate Of Aquatic Progress On The Choco. Another Time, On The Atrato River, About Six O'clock In The Afternoon, The Rain Fell So Heavily Than An Empty Gourd, 9 In. In Diameter And 4.5 Deep, Was Filled To The Brim In 90 Sec., Timed By A Watch. Such Downpours Are Typical, But Unless Caught In One It Is Not Specially Noticed. These Downpours Seldom Last More Than An Hour, And Frequently Cover Only A Limited Area, Occasionally Falling On One Bank Of A River And Not On The Other. During The Night-Time,' The Rain, If Gentle, Will Usually Last Until Dawn, And Sometimes An Intermittent Drizzle Will Keep Up All Day As Well, Although, As A Rule, It Rarely Rains During The Day. The Rise Of The Rivers, Due To The Rain-Fall, Varies From A Few Inches To Several Feet. One Night In August, 1899, The Spuds Of The Dredge Margaret, Operating On The Atrato River, Showed A, Rise Of 16 Ft., And For 3 Days Thereafter Occurred The Greatest Flood Known In That District For 32 Years. The Dredge Had All Three Spuds Clown, And The 2-Yd. Shovel Dragging On The Bottom. A 0.75-In. Cable Fast To A Stout Tree, 700 Ft. Away, Stretched Tight

Sep 1, 1908

By John D. Carr

Introduction The Flin Flon zinc plant operates on what is known as the low density or standard sulphate process, that is, the zinc is carried through the plant solution circuit attached to the SO4 or sulphate radical at a concentration not exceeding 175 grams per litre zinc. The process may be described briefly as follows: The zinc is received in the zinc concentrate chemically combined with sulphur and mixed with many other impurities. The concentrate is roasted and most of the sulphur is burned to a gas, which is discharged from the plant. The roasted concentrate, or calcine as it is called, is leached with a weak sulphuric acid solution so that the resulting leach solution contains a high zinc content but a very small proportion of the impurities. The solution is separated from the solids and is purified further by agitation with zinc dust to remove copper, cadmium, and cobalt. This purified zinc sulphate solution is then pumped to the electrolytic department. The solids from the first leach are again leached, but this time with a stronger acid solution to dissolve all of the remaining zinc which is soluble in the strength of acid available. The solids and solution from the leach are then separated. The solids are stock-piled for further treatment at some future date and the solution, carrying a relatively high amount of impurities, is sent to the first leach, where the chemical action is such that the contained impurities are precipitated as solids. The electrolytic department is nothing more than a large number of electroplating cells in which the zinc is plated on aluminium sheets. Since zinc does not plate tightly to aluminium, the zinc plating or sheet is easily stripped from the aluminium and the sheets are collected to be melted and cast into the standard market bars or slabs. In the electro-deposition cells, the zinc sulphate (ZnS04) is split to metallic zinc (Zn) which plates out, and sulphate (S04) which combines with the hydrogen of the water of the solution to form sulphuric acid (H2S04). When one pound of zinc is deposited, about one and one-half pounds of sulphuric acid are formed. This acid is sent to the leaching section, where it dissolves one pound of zinc from the calcine. The solution is purified and is again pumped to the plating cells. The solution travel forms a complete circuit.

Jan 1, 1935

By F. Bélanger, P. A. Fournier

"Modelling and optimization techniques used in the operation of the Detour Lake Mine leach circuit are contrasted to a 1973 review of contemporary techniques used by a major gold producer. The leach circuit at the Detour Lake Mine was modelled using a full factorial Design of Experiment of stirred tank reactor leach tests using circuit feed. Contour plots of extraction were applied in the plant to optimize addition rates of cyanide and the newly-commissioned lead nitrate system. Contour plot sections were used to understand the impact of sulphur in circuit feed at different operating dissolved oxygen concentrations. The 1973 review paper offers insight into industrially-applied modelling and optimization techniques. In particular, a mathematical model of plant data was developed using multilinear stepwise regression analysis. The model was presented using graphical representations available at the time and applied to optimize the rates of cyanide addition. Off-the-shelf software solutions of today allow mineral processors to quickly and easily visualize data, allowing them to re-allocate time and resources spent processing data to generating raw data and extracting actionable information.IntroductionModelling and optimization in mineral processing is the art of reducing reality through judicious use of assumptions to understand a process and leverage this knowledge to engineer practical solutions to metallurgical problems. Data analysis is at the core of this enterprise.While this paper showcases the modelling work done at the Detour Lake Mine (DLM), the primary objective is to pause and reflect on how far the field has progressed since the 1970’s. A snapshot of state-of-the-art gold cyanidation modelling at that time is a review paper of the Anglo American Group’s capabilities (Brittan & van Vuuren, 1973). The objective of this paper is not a play-by-play of the evolution of modelling and optimization since that time. Rather, it is a comparison of the field at two points in time.In 2016, DLM undertook an extensive bench-scale leach circuit modelling program to better understand the impact of cyanide, dissolved oxygen, lead nitrate, grind size, density, and pH on gold cyanidation (Fournier, 2016). Two major capital expenditure projects were anticipated for 2017: improvements to oxygen control and a lead nitrate distribution system. While the lead nitrate system was planned for construction, the design parameters had not yet been selected. Following the development of the model, plant trials were executed to validate aspects of the model and the methodology was expanded to address other plant issues, in particular the effect of talc chlorite and pyrrhotite in leach feed.The variables of the bench-scale study are summarized in Table 1. Dependent variables were varied using a full factorial design of experiment with two repetitions for each test condition, yielding a total of 300 tests. Test order was randomized to eliminate bias from independent variables."

Jan 1, 2018

By Danielle Nhanqulumanga, Pranith Bhatt, Snehal Patel, Khadeeja Priyan

The Bi-Directional Static Load Test (BDSLT) is a test that determines the capacity of piles when loaded under bi-axial static compression. In recent years the BDSLT has seen an increase in demand due to its safety, speed, and affordability. This innovative foundation testing method has been universally used over the last 50 years, however respective codes and standards have only been published within the recent years. Detailed test procedures and methodology are expatiated in the ASTM D8169 M-18 [1], and the IRC 78 2014 Clause 709.2.5. [2] These standards provide the minimum requirements for the execution of the BDSLT. In this paper we did a comparative study of both standards envisaging to bring attention to the similarities and discrepancies found therein, with an aim to highlight the impacts and challenges that differing provisions of each standard could pose on the conduct of the BDSLT. Discrepancies found have been explained on the basis of geotechnical engineering theories and relevant field occurrences observed by superior engineers. Additionally, we emphasize on the relevance of experienced engineer’s judgement when utilizing the standards.

Sep 1, 2022

By Alan E. Cameron

WE assemble again today in this comfortable, hospitable Inn to begin this, the 58th, Meeting of our Society. It is just a year ago when last we met but that year was, probably, the most portentious year in the whole history of mankind. In that year, the German 'Atlantic Wall' was broached, the Rhine was crossed, and Germany, as a Nation, has ceased to be. The agony of Europe is over; convalescence may be, probably will be, slow. But blood no longer flows in Europe. Time will heal the sores, cover the scars, regenerate the industries, rebuild the cities, and re-establish the people. True, the war of all wars is not yet over. True, a bloody conflict remains . But, the power of the United Nations now converges on one target. The rain of blood will be heavy. We can hope the storm will be short. The sun is on the horizon. The light of peace 1s in the sky. What of that Peace? Are we ready for it? Have we a 'sure foundation ' for our future world? Are the footings under that foundation broad and substantial? Can we look forward with confidence to a lasting peace and a fruitful life? The United Nations, even as this is being written, are in conference in San Francisco, placing the footings, rearing the foundations for a world edifice. There are bickerings; there are jealousies. The world is tired, and a tired family always squabbles. We can, we must, believe that the decisions they make, the edifices they rear, will be better than anything we each could effect separately. It will be a compromise, probably; it will carry things that will hurt us, just as it will carry things that will hurt others. We can, we must, believe that the good of the whole is a greater good than the good of the part. Each Nation within the United Nations must sacrifice something, each part of each Nation must sacrifice something, each individual within each part of each nation must contribute something, if the whole is to be wholesome. Sacrifice and contribution must be the order of the day if the New World we are about to build is to be worth while. What of Nova Scotia? The world has travelled far in the last year; how far has Nova Scotia gone? Canada has preparations for the Peace under way; what has Nova Scotia done? Is Nova Scotia preparing counter measures for the sacrifices it must make? Is each of us ready to contribute his share?

Jan 1, 1945

These proceedings consist of papers presented at two Bureau of Mines Technology Transfer Seminars for the purpose of disseminating recent advances in mining technology related to coal mine fire and explosion prevention. Primary, although not exclusive, emphasis is placed on underground coal mining. The papers address research accomplishments ranging from methods for detecting mine fires to remote sealing systems for extinguishing coal mine fires. Each paper represents the current state-of-the-art in the respective research categories. Presentations include research occurring from both Bureau in-house and contract efforts.

Jan 1, 1978

By J. P. McCullough

In 1943, the Federal Bureau of Mines began a program of thermodynamic investigations of petroleum constituents and related compounds. These systematic, long-range studies, which were conducted in the thermodynamics laboratory of the Bartlesville Petroleum Research Center and are still continuing, have resulted in a substantial quantity of data valuable to the petroleum industry and science in general. As separate phases of these studies were completed, the findings were promptly reported in the scientific press. During the past 16 years, 89 journal articles, giving the results obtained for individual compounds and small groups of related compounds, were published, mainly in the Journal of the American Chemical Society and the Journal of Physical Chemistry. In addition, members of the Bureau staff have contributed six chapters to specialized reference books. This circular, prepared in response to many requests, lists these 95 published papers, giving an abstract of the contents of each, as well as titles, authors, and literature citations. The journal articles are listed in the order of their preparation, which closely approximates the chronological order of their publication; hence, the item number to the left of each citation corresponds to the assigned contribution number. For the convenience of the reader, the abstract section is followed by a condensed bibliography, arranged alphabetically by senior author and keyed to the abstracts by appropriate contribution numbers in parentheses after the entry.

Jan 1, 1961

By J W. Hedenquist

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Epithermal deposits (Au or Ag dominant, ± base metals) form within ~1 km of the surface in volcanic belts, both arcs and rifts, with the different tectonic settings reflected in distinctly different characteristics. Within arcs, deposits are typically intrusion centred and commonly associated with hypogene advanced argillic alteration, both in lithocaps and as halos to shallow or proximal portions of some veins; such alteration is coupled with processes that form porphyry Cu-Au deposits at depths of ~1–3 km. Introduction of metals is related to the subsequent phyllic-stage overprint; if this fluid rises to the level of the lithocap or into epithermal veins, Au mineralisation with Cu or Ag may occur, associated with sulfate minerals or muscovite. By contrast, Au-rich (both low Ag:Au ratio and bonanza grade) colloform quartz veins form at shallow depths in volcanic rifts, typically within a few hundred metres of the surface, with clay halos and topped by silica sinter if the palaeosurface is preserved. The geologic variability in volcanic belts, including host rocks, structures and hydraulic gradients, means that many epithermal deposits vary from the end-member features of the principal styles. Effective exploration requires familiarity with end-member styles as well as potential variations, plus the mineralogical indicators of palaeotemperature (eg evidence for erosion depth, fluid flow channels). This knowledge helps the geologist in the field to imagine what might be buried and where, and how to best test the target with drilling.CITATION:Hedenquist, J W, 2015. Recent developments in understanding of and exploration for epithermal deposits in volcanic arcs , in Proceedings PACRIM 2015 Congress, pp 11–16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Thomas Lardner

Excavation for The Bow, EnCana, in downtown Calgary, occurred between May 2007 and September 2008. A monitoring programme was used to determine the behaviour of the shoring wall, soil and bedrock during the excavation for the 21 metre (69 ft) deep excavation with a footprint of approximately 17,000 m2 (183,000 sq ft). Results from the inclinometer readings indicated that significant horizontal movement due to a weak rock layer and shear band effect. These modes of movement account for up to 100 mm (4.0 in) and 45 mm (1.8 in) of lateral deflection, respectively. Based upon the results of the monitoring programme, rock samples were collected from the weak mudstone bedrock, with great difficulty, to determine the strength and deformation parameters. Results from the uniaxial compression tests indicate a UCS around 830 kPa (120 psi) and elastic modulus between 80 and 180 MPa (11 and 26 ksi). Mohr-Columb parameters were determined to be c' = 340 kPa (49 psi) and f' = 24°. Residual strengths were determined to be c'r = 0 and f'r = 15°. Using the results of the laboratory tests and field investigation records, an initial finite element analysis was conducted. Results of the analysis show good correlation when compared with the observed monitoring deformation, indicating accurate portrayal of rock parameters. Additional analysis and investigation is required to determine the principal horizontal stresses in magnitude and direction.

Jan 1, 2010

By J J. J Chen, J C. Zhao

A water/air model was developed to simulate the refining of molten aluminium by the sparging of gas through an impeller. The optimal gas dispersion depends upon selecting the correct gas rate for a given impeller rotational velocity to prevent flooding or channelling. Correlations illustrating this flooding behaviour exist for standard impellers within standard tank geometries. However the validity of these correlations has not been substantiated for gas dispersion in high temperature molten metals with non-standard tank and impeller dimensions. Metal refining is most efficient when fine bubbles are generated and uniformly distributed within the treatment tank. The application of some measuring technique able to detect this distribution within a non transparent operating treatment tank would be invaluable, enabling the optimisation of gas flow and impeller speed.   A technique has been developed to measure the pressure fluctuation levels at specific points in the water model. Comparison of these pressure fluctuation data with photographic evidence obtained in the water model suggests that the flow regime in the metal treatment unit may be determined using this technique.

Jan 1, 1995

By Albert L. Toenges

A phase in strip mining of bituminous coal is the overturning of the surface of the land. The ;purpose of this report is to acquaint the operators and others interested in stripping with the work that has been done in certain States to reclaim the surface of land from which the coal has been removed by this method of mining. The preparation of this manuscript follows an extensive study of the subject in the field in the course of which a large number of strip mines were visited. ACKNOWLEDGMENTS The information used in the report was obtained through the courtesy and cooperation of the operators of the mines visited, State officials and educational institutions, and others interested in the subject.

Jan 1, 1939

By James Pirie

"The major Archean gold deposits in the Red Lake greenstone belt, which have produced over 374 million grams of gold since 1930, occur near the top of the lower komatiitic to tholeiitic mafic to ultramafic metavolcanic sequence. The upper calc-alkalic mafic to felsic rocks form three discrete and separate ediftces overlymg this lower sequence.The gold deposits are classified according to their stratigraphic or lithologic associations into:1) mafic-volcanic-hosted deposits;2) felsic-intrusive-hosted deposits; and3) stratabound deposits.Group 1 and to a lesser extent Group 2 deposits occur within zones of alteration several square kilometres in extent. The nature of this pervasive alteration can be characterized by comparison of petrochemical data from the altered rocks and their fresher equivalents some distance away. The altered rocks have substantial addition of SiO2> CO2, K2O, As and Sb and subtraction of Na20, CaO, MgO and total Fe. Cr, Ni, Co and Zr appear to have been relatively immobile. Hydrothermal alteration and gold deposition probably accompanied early fumarolic activity and continued during subsequent deformation the metavolcanic sequence, with gold eventually being mobtltzed and concentrated into major vein structures to form the present orebodies. The smaller Group 2 deposits formed by emplacement of felsic intrusions into already altered, anomalously gold-bearing mafic metavolcanics, with the heat from the intrusions setting up parasitic hydrothermal systems which mobilized the gold and deposited it along with minor sulphides in fractures in the cooling intrusions."

Jan 1, 1982

By Philip Thompson

Many new evaluation tools have been developed since the early 1990’s to aid the minerals processing test engineer. The areas of comminution, gravity concentration, flotation, and process mineralogy have received particular attention. This paper will describe new laboratory procedures in the areas of SAG mill testing, gravity concentration, and flotation testing. Computer assisted mineralogical examination equipment, new generations of mass balancing programs, and simulation programs will also be discussed.

Sep 12, 2005

By G. St. J. Perrott, N. A. Tolch

"The measured strength of an explosive depends to a certain extent on which it is determined. An earlier investigation showed the relative propulsive strength of dynamites as determined in one type of apparatus, ballistic pendulum.4 The aim of this paper is to precept strength data on these same dynamites determined in another type of apparatus, the Trauzl lead block, and to compare the results with those of the ballistic pendulum. Trauzl lead block have been in use many years for the determination of thy strength of explosives, under moderate confinement.5 The common practice is to shoot 10 grams of explosive, in tinfoil wrapper,- and then to measure the volume of the cavity produced by the shot. The volume of the original borehole is deducted from the gross expansion and sometimes a correction is made for the expansion produced by the detonator. Dry sand is used for stemming the charge.It has been found that the expansion in Trauzl blocks is not strictly proportional to the charge. Naoum5 believed that for scientific accuracy the charge should undoubtedly be regulated to give the same average expansion for each sample tested, but for expansions of 200 to 400 cubic, centimeters the deviation from proportionality is not sufficient to give results appreciably in error.Neubner7 found that the proportionality curve is tangent to the charge-expansion curve at about 300 cubic centimeters expansion, provided that no deductions are made for the volume of the original borehole or the effect of the detonator; the total or gross expansion is proportional to the charge between expansions of 250 to 350 cubic centimeters without serious error."

Oct 1, 1930

By Richard F. Zaffarano

The Bureau of Mines compiled information for the nonspecialist about natural gas liquids recovery from hydrocarbon streams in natural gas processing plants. Attention is directed to the impact of the technology of processing and the quality of gas processed in view of the increased availability of natural gas for processing. Significant changes in product and market trends within the natural gas processing industry are highlighted. Fixed capital-plant costs for grassroots, refrigerated-oil absorption and conventional adsorption schemes, adapted from published studies, are presented giving ranges of cost estimates for medium-sized plants. Marketed products of the natural gas processing industry are briefly discussed in relation to automotive air pollution problems and approaches to their control.

Jan 1, 1970

By Reno M. Pappas, Christopher Mark

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining. Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a lab- oratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship, was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the secant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.

Jan 1, 1993

The strippable reserves of bituminous coal and lignite in the United States were calculated in accordance with the prevailing conditions of seam thickness and depth of overburden in each of the several coal-producing areas of the Nation. Within defined limits of seam thickness and depth of overburden, it is estimated that there was a remaining strippable resource of 118 billion tons of raw bituminous coal and lignite as of January 1, 1968. Because of topography, natural and manmade features, and other limitations, only 45 billion tons of the resource are strippable reserves. Of this, 32 billion tons is considered low-sulfur (less than 1 percent), 4 billion tons is medium-sulfur (1 to 2 percent), and 9 billion tons is high-sulfur (over 2 percent) coal. Owing to a cleaning loss affecting that portion of strip coal that is mechanically cleaned, the 45 billion tons of strippable reserves are reduced to 39.6 billion tons of marketable coal. A brief discussion is given for each coal-producing State, summarizing past and present production, historical background, and outlook. Appendix A contains reserve data by State, county, seam, and sulfur content. Appendix B contains the general information and requirements necessary to comply with the current strip mining laws covering 20 States.

Jan 1, 1971

By Vance G. Leak

A technique for recovering copper and steel from metallic scrap has been developed by the Bureau of Mines based on preferential melting in molten salt baths at 1,150° to 1,250° C, The molten salt, preferably barium chloride or calcium chloride, both minimizes oxidation of the metals and promotes heat transfer. Cleanest separations (0.01 percent copper remaining in iron) have been achieved by pretreatment (dipping or spraying) with sodium sulphate or sodium silicate, which alters and coats the surface of the iron to inhibit the alloying or brazing with copper. An economic evaluation of the process was carried out on six combinations of sweating media and inhibiting reagents. On the basis of the postulated model, a cost of about $0.20 per pound of copper recovered has been determined for the sweating treatment operation.

Jan 1, 1973