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By E. H. Boyle

The Bureau of Mines has evaluated the potential availability of silver from 436 mines and deposits in 41 market economy countries (MEC?s) comprising five major economic categories of deposits: predominantly silver deposits and predominantly zinc, lead, copper, and gold deposits. This study evaluated the long-term cost and availability of primary silver production from 53 producing and 13 nonproducing predominantly silver properties in 11 MEC's and estimated the total recoverable silver from 370 properties as a coproduct or byproduct of zinc, lead, copper, or gold production. This study resulted in estimates of a demonstrated resource of 5.99 billion tr oz of recoverable silver as of January 1984. Of this total, 23.5 pet is in the 66 mines and deposits classified as predominantly silver properties. The largest quantity of recoverable silver, 43.9 pct, lies in the 121 properties classified as predominantly zinc, with 26.5 pct in 120 properties classified as predominantly copper, 4.1 pet in 21 predominantly lead properties, and 2.0 pct in 108 predominantly gold properties. At current silver prices, the economics of silver production favor silver that is a byproduct or coproduct of zinc, lead, copper, or gold, and much of the silver production in the United States from the predominantly silver mines is at an economic disadvantage in comparison with silver production in other countries.

Jan 1, 1986

By T Sprague, D Pateman

"The Gosowong Gold Project is owned and operated by PT Nusa Halmahera Minerals (PT NHM), an Indonesian company 75 per cent owned by Newcrest. It is located on Halmahera Island, in the North Maluku Province of the Republic of Indonesia, approximately 2450 km north-east of the national capital, Jakarta (Newcrest, 2017).Kencana is one of two underground gold and silver mines at the Gosowong Operation where ground conditions vary from competent to very poor. Development headings occurring in poor rock mass conditions require high capacity ground support including long tendon cable bolts. Manual installation of cable bolts in these development headings has been a time consuming process due to borehole collapse, blockages requiring subsequent re-drilling and a minimum eight hour grout curing time interval. The installation of cable bolts including the setting, plating and tensioning can impact the critical path for development heading advance resulting in development cycle delays.A review was conducted by PT NHM on current industry practices for alternatives to manual cable bolting. PT NHM subsequently approached Minova to assist with the development and trialling of self drilling anchors (SDAs) installed using jumbos with a rapid setting pumpable resin, CARBOTHIXTM. A series of system development trials were conducted and a reliable bolting system was developed utilising the existing jumbo drilling fleet with minimal required modifications.The system developed was a ‘one pass’ bolting process to install and grout SDAs using a two component resin with a remote, mechanised system. Improvements achieved from the system include: eliminating hole closure issues and more immediate support in poor rock mass effectively reducing personnel exposure to poor ground conditions by removing the requirement to access the drive backs reducing grout set time with full installation times for 6 m SDAs averaging 25 min.The resin grouting system has now been successfully implemented to effectively manage areas of poor ground conditions and to accelerate advance rates in high priority headings.CITATION:Pateman, D and Sprague, T, 2017. Development and implementation of a long tendon bolting system utilising resin grouting technology, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 79–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By Sidney Snook

FLUORSPAR production is the most important industry in a compact area in southern Illinois and western Kentucky bordering the Ohio River. Producers' activities do not usually figure much in the mining news of the country, so that few know that the last year or so has been an unusually active one. Mine shipments more than doubled in 1939 compared with the poor year 1938. The average price changed but little, though it is now about one-sixth higher than at the beginning of last year. The outbreak of war in Europe a year ago lent an immediate stimulus to the industry, though only about 15 per cent of the domestic consumption is normally imported, thanks to a tariff of $8.40 per ton, equivalent to about 30 per cent ad valorem. Be- cause of the increased production and many expansions and improvements in the mines and plants, the period since the beginning of 1939 has been the most important one for the industry in the last 15 years.

Jan 1, 1940

By T. Billotte, G. Tirand, J. Zollinger, V. Robin, B. Rouat, D. Daloz

The grain structure prediction of metallic alloys during a welding process is often an issue. In addition to the welding parameters and the alloy nominal composition and properties, the base metal grain structure and chemical homogeneity also play an important role in the formation of the final microstructure. In this paper intensive characterisation of solidification structure in gas tungsten arc welding of Ni base alloy 600 are described. It is shown that in transverse section of the weld, while the grain structure shows some texture following constrained solidification growth, grain density in the weld is similar or greater than grain density in the heat affected zone. This suggests that simulation of the welding structure needs, in order to be predictive, to take into account : epitaxial growth, secondary nucleation events and 3D growth inside the weld pool.

Jan 1, 2015

By Harry V. Makar

As part of a continuing research program for conserving domestic mineral resources, the Bureau of Mines is investigating new and improved scrap identification techniques to improve sorted mixed scrap purity. This report focuses on various classes of wrought and cast copper alloys produced with recycled scrap. Based on a survey of the literature, principal alloys, such as the brasses and bronzes, are examined with respect to impurity elements and their effects on metallurgical behavior. Effects of elements such as lead, antimony, iron, chromium, and aluminum are discussed. The metallurgical effects described include hot shortness, fire cracking, and undesirable phase transformations.

Jan 1, 1985

By J. Stiksma, R. Kalanchey, M. J. Collins, G. Owusu, R. Raudsepp, K. R. Buban, L. A. Barta, L. Masters

This paper describes the results of testwork for the treatment of Ambatovy laterite by an acid pressure leach process, with recovery of the soluble nickel and cobalt values as mixed sulphide intermediate by precipitation with hydrogen sulphide, and subsequent refining of the mixed sulphide to nickel and cobalt metals. These process development studies were carried out primarily in 2004, as part of a bankable feasibility study for the Ambatovy Nickel Project.

Jan 1, 2004

By Sarkis G. Ampian

Published optical microscopic and X- ray diffraction characteristics of the following compounds are critically evaluated and compared with Bureau of Mines data : Tricalcium aluminate , calcium monoa luminate , dodecacalcium heptaluminate , dicalcium silicate , tricalcium silicate , and sodium aluminate . A recommended set of definitive optical and X- ray diffraction characteristics is presented . These values are used to identify products of the lime soda sinter process for production of alumina . Polymorphism of gamma- , beta- , and alpha prime - dicalcium silicate is reexamined , and new data are presented on polymorphism of tricalcium silicate and sodium aluminate by high- temperature X- ray diffractometry . Polymorphism is not observed for tricalcium aluminate , calcium monoaluminate , and dodecacalcium heptaluminate . Bureau of Mines data indicating a stoichiometry of 12Ca0.7A10 for the phase 5Ca0.3A1 0₂ are discussed . A critical review of the literature concerning calcium dia luminate and sodium undecaluminate ( 8 -A10 ) is also included .

Jan 1, 1964

By James Westfield

This report covers the calendar year 1953 and has been prepared and submitted in accordance with the provisions of Sec. 106(a) and Sec. 212(c) of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U.S.C. Secs. 451-483). During this first full calendar year of operations under the Federal Coal Mine Safety Act, the coal-mining industry of the United States attained the best injury records in its history - improving the former best records (made in 1952) by 91 fatal and 10,020 nonfatal injuries. Whereas, the mandatory provisions of the act were intended and designed to prevent major mine disasters, apparently the effects have reached beyond the scope thereof in reducing mine accidents generally.

Jan 1, 1954

By B. Garcia-Egocheaga, J. Rutten, N. Goicoechea, U. Meurer, Mager K., W. Saage, Simonettim F.

Because of the increasing use of zinc as an active and passive anticorrosion agent for steel, leading to constantly growing return rates of galvanized steel components, especially through the automotive industry, major Electric Arc Furnace (EAF) flue dust amounts with higher zinc contents will accumulate in future. Landfilling of steel plant flue dusts is no longer allowable for ecological reasons. These dusts are classified as hazardous by law. Waelz technology is safe and reliable. The range .of treatable feed materials has been extended by process modifications and state-of-the-art offgas technology. Waelz oxide, the product, is delivered to metal smelters for zinc production and the byproduct, Waelz slag, can be used in road construction. Despite the fact that Waelz technology is among the best available techniques (BAT), it is continuously being optimized further with respect to energy input, product and offgas quality in order to comply with the ever more stringent environmental regulations. However, if these flue-dusts are treated, the loops between the steel and the zinc industry can be closed by reusing recovered zinc which in tum leads to savings in natural resources and a more reasonable use of landfills.

Jan 1, 2000

By Allan M. Hale

The central Florida phosphate industry is not a recent development. The first phosphate mining occurred in approximately 1888 (1). Many of the original mining companies were "wildcat" operations operated with rapid phosphate extraction as the sole purpose and no long-term commitment to development. Many of the early pioneers were ill-equipped to mine phosphate at either a practical or economical level; as a result many of these early companies "folded" after only a brief period of operation. However, as these early companies went out of business, several large companies developed, expanded their mining territories bought up the folding companies and by 1903 (little more than 10 years after the first mines were started), approximately 37 of the original 60 mines were control- led by three major companies (1). In the early period, mining reclamation was nonexistent. The mined out areas were left to revegetate and reclaim "naturally" over the period of many years. Reclamation practices were only started relatively recently and the various reclamation techniques developed and used in the past have continued to be employed with varying degrees of success through the present time. The reclamation techniques used in the past and currently include land and lakes restoration, sand tailing reclamation, slime ponds reclamation and overburden fill.

Jan 1, 1980

"The Code was developed in 2004 through the Collaboration Agreement between Institution of Mining Engineers of Chile (IIMCh) and the Ministry of Mining (Chile) in Dec 2002. It is an amalgamation of current practices with respect to standards and procedures for exploration prospects, mineral resources, and reserves for the purpose of public reporting. Certification is required to prepare and issue information on mineral assets according to the guidelines that regulate the technical, economic, and environmental aspects that satisfy the conditions set by the Chilean capital and financial markets.The Mineral Resources Committee of the Instititution of Mining Engineers of Chile (IIMCh) is pleased to introduce theCode for the Certification of Exploration Prospects, Mineral Resources and Reserves which is the result of a Collaboration Agreement between the IIMCh and the Ministry of Mining established in December, 2002.This code synthetizes the present practice of the mining industry in regard to standards and procedures applied to exploration prospects, mineral resources, and reserves with the purpose of reporting publicly on financial instruments based on these mine assets in the capital markets. These standards follow general criteria already adopted and applied by capital markets in those countries characterized by a very dynamic and well developed mining sector such as Australia, Canada, Southafrica, United Kingdom, and others. The work done by the Mineral Resources Committee of the IIMCh has had the recognition of the Combined Reserves International Reporting Standards Committee (CRIRSCO) that leads the establishement of an international code in these matters. CRIRISCO is an entity formed by representatives of the countries previously mentioned, a representative of the Society of Mining Engineers of the UStates and a representative of the IIMCh. The Institution thanks the Ministry of Mining, the representatives of these Ministry in the Mineral Resources Committee, and specially the Minister of Mining, Sr. Alfonso Dulanto Rencoret due to the genuine support given to the IIMCh in the preparation of this Code.The Institution also thanks the Superintendencia de Valores y Seguros (SVS) because of the help given continuously to the Committee as well as by the interchange of opinions and suggestions received during the preparation of this document."

Jan 1, 2003

By E. C. Strycula

Solid-state equipment offers a number of potential advantages in the coal mining industry. These advantages can only be realized, however, through careful and judicious design of the control and protection circuitry. Problems relating to the interaction of solid-state equipment on the electrical system and the special design considerations which apply to solid-state circuitry are examined. Design guidelines are provided for solid-state applications in the areas of: (a) equipment operated from a DC trolley wire, (b) drive systems for surface mining equipment, (c) AC motor starters, and (d) electromagnetic interference.

Jan 1, 1981

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021

By Clarence Hall, Spencer P. Howell

Among the more important factors involved in the use of high explosives in blasting operations is the means employed to bring about the detonation of the charge. When flame is applied to high explosives many of them may burn if not confined; but all of them when burning under certain conditions of confinement may detonate. Detonation may also be effected by mechanical means, such as frictional impact caused by a blow or by rubbing between surfaces. By this means, however, the full effect of the explosive charge may not be developed, so that a partial detonation, often accompanied by the burning of the explosive, results. When nitroglycerin was first used it was fired by the application of flame, but considerable difficulty was experienced in exploding it with certainty and in obtaining uniform resl'llts. In 1864 Allred Noble, a Swedish engineer, discovered that nitroglycerin could be surely and completely detonated by exploding in contact with it a small quantity of an initiatory explosive. Mercury fulminate was the substance then found capable of producing the best results There are many other fulminates and other substances that will produce complete detonation of commercial" high" explosives, but detonators or electric detonators containing mercury fulminate as the characteristic ingredient are still almost exclusively used in this country. The term" detonator" is used in the publications of the Bureau of Mines to designate what the miner calls a "blasting cap "-a copper capsule containing a small quantity of some detonating compound that is ignited by a fuse. The term" electric detonator" is applied to a blasting cap that is similar except for being ignited by means of a small wire which is heated to incandescence or fused by the passage of an electric current. One of the conditions prescribed by the Bureau of Mines for a permissible explosive a is that it shall be :fired by a detonator, or preferably an electric detonator, having a charge equivalent to that of the standard detonator used at the Pittsburgh testing station. A further requirement is that this charge shall consist by weight of 90 parts of mercury fulminate and 10 parts of potassium chlorate (or their equivalents). At the request of a manufacturer of permissible explosives, an investigation was undertaken by the bureau to determine the relative strength of detonators and electric detonators having different compositions. The tests of electric detonators herein reported were conducted by H. F. Braddock, junior chemist; J. W. Koster, J. E. Tiffany, junior mining engineers; and A. S. Crossfield, junior explosives chemist, at the Pittsburgh testing station of the bureau. Similar tests of detonators were not conducted because it was believed that the results would not show sufficient variation to warrant such tests. It is hoped that the conclusions drawn from the tests made will be of service to those using explosives by enabling them to select the grade of detonator or electric detonator that will insure the most effective results. The conclusions are given in this bulletin, which is published by the Bureau of Mines as one of a series of publications dealing with the testing of explosives and the precautions that should be taken to increase safety and efficiency in the use of explosives in mining operations. The results of tho experiments described in this bulletin show that the average percentage of failures of explosives to detonate was increased more than 20 per cent when the lower grades of electric detonators were used instead of No. 6 electric detonators, and was increased more than 50 per cent when these lower grades were used instead of No. 8 electric detonators. It is noteworthy, however, that when sensitive explosives, such as 40 per cent strength ammonia dynamite (p. 33), were tested under conditions ideal for detonation, the same energy was developed irrespective of the electric detonator used. When tests were made with a less sensitive explosive, such as a 40 per cent strength ammonia dynamite containing nitrosubstitution compounds (p. 32), the energy developed increased with the grade of the electric detonator used. For example, the average efficiency of four different explosives was increased 10.4 per cent when a No.6 electric detonator was used instead of a No.4 electric detonator, and 14.9 per cent when aN 0.8 electric detonator was used (see tabulation onp.45). The results of the tests emphasize the importance of using explosives in a fresh condition, but as fresh explosives can not always be had in mining work, strong detonators should be used in order to offset any deterioration of explosives from age.

Jan 1, 1913

By C. A. Meissner

THE following is a further discussion of the paper of James Gayley, " The Application of Dry-Air Blast to the Manufacture of Iron " (Trans., xxxv., 746), with special reference to his sup-plementary paper (Bi-Monthly Bulletin, No. 4, July, 1905, pp. 797 to 819), and. to the paper of J. E. Johnson, Jr., "Notes on the Physical Action of the Blast Furnace " (Bi-Monthly Bulletin, No. 5, September, 1905, pp. 1111 to 1146). Mr. Gayley's paper has been discussed also by E. Windsor Richards, R. W. Raymond, E. H. Saniter, W. J. Foster, H. M. Howe, V. Pendred, B. H. Thwaite, James Gayley and Alexander Pourcel (Trans., xxxv., pp. 1022 to 1042), Joseph W. Richards (Bi-Monthly Bulletin, No. 4, July, 1905, pp. 703 to 718); T. W. Robinson (Bi-Monthly Bulletin, No. 4, July, 1905, pp. 788 to 796) ; C. B. Dudley, R. W. Raymond, J. E. Johnson, Jr., W. F. Mattes, James Gayley, David Baker, John Birkinbine and F. E. Bachman (Bi-Monthly Bulletin, No. 5, September, 1905, pp. 1147 to 1152);.E. de Mille Campbell (Bi-Monthly Bulletin., No. 1, January, 1906, pp. 25 to 50) ; John Birkinbine (Bi-Monthly Bulletin, No. 1, January, 1906, pp. 137, 138). At the Washington meeting of the Institute, May, 1905, a very instructive and interesting paper was presented by Mr. J. E. Johnson, Jr., entitled " Notes on the Physical Action of the Blast Furnace,"' in which reference is made to Mr. Gayley's dry-blast process. A few of Mr. Johnson's conclusions, as summarized in the last pages of his paper, do not appear to me to be in complete accordance with the results obtained at the Isabella furnaces; and I therefore present the following notes which may throw further light on this subject: Mr. Gayley has called attention to the fact that the moisture in the air is an extremely variable and uncertain factor; and

May 1, 1906

By P. H. Willis

Since the 14th CMMI conference, held in Edinburgh in 1990, at which a paper was presented by the author (Willis, 1990) reviewing the role of integrating new technology as a survival strategy for South African gold mines, considerable change has occurred in the South African mining industry. This paper reviews the current state of the industry and provides an update on the technologies discussed ten years ago. It reviews available technology and provides a broad economic assessment of these technologies if they were to be introduced in an integrated mining system with a focus on deep level mining below 3000 m. It also reviews possible future technologies currently being researched and developed by CSIR: Division of Mining Technology (Miningtek).

Jan 1, 2000

By Dale Zacherl, Andreas Buhr, Rainer Kockegey-Lorenz

"The microporous calcium hexaluminate insulating material SLA-92 has been introduced as an alternative to refractory ceramic fiber and other insulating refractory materials. Key properties associated with this product include: high chemical purity, long term high temperature stability up to 1500 °C, low thermal conductivity up to 1500 °C, and high thermal shock resistance. The properties of the new material and various applications in the steel and ceramic industries have been reported in previous papers. The current paper summarizes the industrial application experiences with innovative refractories based on SLA- 92 and discusses potential new applications in various manufacturing as well as energyrelated industries.IntroductionSLA-92 was introduced to the refractories industry in 1998 by van Garsel, et al. [1] as a new insulating raw material for high temperature applications, followed by investigations [2] of long term temperature stability for this new lightweight aggregate up to 1500°C.SLA-92 was developed as an innovative alternative to commonly used refractory ceramic fibers. It has unique properties regarding chemical purity and mineral composition and is a microporous, silica-free calcium hexaluminate (CA6 – mineral name: hibonite)."

Jan 1, 2010

By Ambarish Ghosh, Rituparna Dey, Indrajit Chowdhury

"In port and harbor facilities, jetties and cargo berth terminals are usually installed on piles that remain partially embedded in soil, while a part of it behaves as columns supporting top deck. Technology in vogue adapts a pseudo static analysis in computer where the top deck including piles are analyzed as an integrated system based on finite element method when the piles are modeled as beam elements, while the soil in which it is embedded is modeled as linear or nonlinear springs. Typical berthing force of the ship is considered as a pseudo static force where the dynamic characteristics of the force is taken into consideration by an equivalent impact factor and little study exists on the actual behavior of these type of piles under the transient shock due to berthing impact. Present paper proposes an analytical solution based on which one can compute the dynamic response of such jetty piles considering shear modulus of soil constant with depth. Considering the solution is analytical in nature no special software is needed and can well be adapted fordesign office practice using generic utility software like MATHCAD, MATLAB etc. that makes theproposed model computationally very efficient.INTRODUCTIONResponse of piles under dynamic load has been an important study in the realms of civil engineering, where significant research has been carried out on its dynamic behavior under harmonic loads like one experienced in a machine foundation or under seismic force.A number of researchers have given solution to this problem like Parmelee et al (1964), Tajimi (1966), Penzien (1970), Novak et al (1974, 1983), Banerjee and Sen (1987), Dobry and Gazetas (1988),Chowdhury and Dasgupta (2008).However, most of these theories are based on piles loaded under harmonic load and valid for long piles where structural failure precedes the soil failure considering the piles are long and flexible."

Jan 1, 2015

By Mark David Rankin

This paper represents a general assessment of the primary factors driving the market for mobile offshore drilling rigs and the utility of those factors as choice variables for the offshore drilling program planner.

Jan 1, 1982

By R. C. FLEMING

MINING rock asphalt for use as a paving material is an industry which has grown with the spread of the good roads movement. "Mineral Industry During 1930" reports asphaltic pavements constructed, including maintenance and repair but excluding pavement constructed with road-oil, cut-back or emulsified asphalt, as grown from 23 million square yards in 1911 to a high of 144 million in 1927. In 1930 the same source reports 106 million square yards of such paving laid and, in that year, 664,871 tons of native rock asphalt were so utilized. Many states contain rock asphalt deposits of greater or less importance but in only a few places are the de¬posits being mined commercially. In the year cited Ken¬tucky produced 305,024 tons of bituminous sandstone, Texas 270,138 tons, mostly bituminous limestone, while Alabama, Oklahoma, California and Utah produced 89,709 tons of bituminous rock for road construction. In addition Utah produced 37,906 tons of the purer asphaltic products, gilsonite, wurtzilite and ozokerite, for other uses. Speaking generally, the rock asphalt is a sandstone or limestone naturally impregnated with asphalt to an extent that makes it an ideal road surfacing material without mixing or treatment other than crushing. The asphalt content of the commercial product runs 8 to 12 per cent.

Jan 1, 1933