Search Documents

By Robert S. Williams

NO new ferrous alloys have been produced in the last five or six years that are as outstanding contributions to civilization as were the high-speed steels of the early part of the century or the stainless steels announced at the close of the World War. There have been, however, many developments of major importance having to do either with modifications of existing alloys or with new methods of treatment of older iron or steel alloys. Only a limited number of these new developments can be discussed and their selection does not necessarily imply that these are the most important but merely that they are of general interest rather than perhaps of greater importance in highly specialized fields.

Jan 1, 1939

By L. A. Anestiev

A method based on use of calorimetric data for the determination of solidification kinetic parameters is proposed. The method incorporates recent theories of nucleation and growth and allows modeling heat fluxes observed in calorimetric experiment. Statistically optimal estimations of the kinetic parameters, which include the activation's energies of nucleation and growth, are derived from experimental data by means of nonlinear regression analysis. The method is applicable to pure substances and alloys. The evaluation of the kinetic parameters characterizing solidification of pure Al is used for clarifying and exemplifying the method.

Jan 1, 2004

By A. W. Dickerson

Following on from many years of research aimed at improving the effectiveness of truck haulage operations in mines operated by BHP Minerals, BHP Research developed a concept for an Innovative Large Mining Truck, (ILMT) which has the potential to significantly improve the cost effectiveness of rear dump mining trucks. The ILMT concept reduces the empty vehicle weight dramatically, greatly reduces unequal rear tyre loading and improves ride and handling characteristics. The concept has been taken to the "proof of concept" prototype truck stage with the cooperative efforts of BHP Coal, BHP Research, Liebherr Mining Truck, Inc., Liebherr-Australia and Birrana Engineering. Testing of the prototype truck commenced at a coal mine in Queensland, Australia during May 1996. Preliminary results from the testing program are very encouraging. Expectations are being met and in some cases exceeded.

Jan 1, 1997

By Andrew S. Prokopovitsh

The Bureau of Mines is concerned with all the approximately 60 industrial minerals, although its research program currently is focused on 10 of them--bauxite, chromite, clay, manganese, phosphate, potash, refractories, sulfur, titanium, and zirconium. To alleviate reliance on imported materials, particular attention is directed to those minerals having a potential for production from domestic resources. Another important consideration is environmental problems associated with the production of industrial minerals, principally in mining and mineral processing operations, The Bureau also is looking at the opportunities to substitute more abundant minerals for scarce raw materials such as rutile, fluorspar, and bauxite. In its overall minerals surveillance, the Bureau's mining and metallurgical research and development are coordinated with its minerals information activities from which reviews, projections, and forecasts identify the potential for critical disruptions and short supply situations.

Jan 1, 1975

By Daniel Willis, Ryan O’Connell

An 8-foot tall horseshoe adit tunnel located within an abutment of the Mount Morris Dam in Mount Morris, NY required repair of a failed reinforced concrete liner. The adit tunnel is entirely founded within highly weathered shale bedrock units, which induced unloading stress on the original tunnel liner. An epoxy-impregnated carbon fiber fabric wrap manufactured by Sika was chosen to repair the failed adit tunnel liner. Kilduff Underground Engineering completed the design of the tunnel repair utilizing both empirical and numerical methods. Merco Engineering Contractors completed the injection of chemical grout and repair liner installation.

Jun 23, 2024

The selection of the best comminution circuit for the preparation of concentration feed is a compromise based on economics, energy efficiency, labour costs, steel consumption, availability and other factors specific to each case. It is postulated that the selection must be a choice of one of the eight basic comminution circuits which can be divided into two basic groups, (1) autogenous or semi-autogenous primary mills with or without a secondary grinding stage and (2) fine crushing usually in cone crushers followed by a rod mill-ball mill circuit or a single stage ball mill circuit. The accuracy of selection may be improved by pilot plant and laboratory tests which are described in this paper. For (1) above, testing includes media competency tests with standard impact crushing, grindability and abrasion tests followed by pilot plant tests. For (2) above, bench scale crushability, grindability and abrasion testing is available. It is suggested that, through these tests, it should be possible to eliminate all but one in each group of basic comminution circuits. Then engineering and economic studies should lead to the best comminution circuit for the specific requirement.

Jan 1, 1984

By John F. O'Leary

The paper review the process the minerals industry and the materials revolution. For a long time, Latin América attemps at industrialization have been attempts in part, by need to important some of the many raw materials that industrial nations must have. However, the industrial sistem may be in for some of the many raw materials that drastic changes would increase the mineral self sufficiency of countries that are industrialized. In this way, the materials revolution would be a boom to Latin America, it would reduce some of the serious obstacles to the goals which all Americans seem to share.

Nov 20, 1969

By Katherine A. Margolis

Refuge Chamber Expectations Training was created by a multidisciplinary team at the National Institute for Occupational Safety and Health (NIOSH) to inform miners of what to expect psychologically and physically if it became necessary to use a refuge chamber in a mine emergency. The presentation can be used either for one large group or for individual miners. The training is a multimedia Adobe Flash presentation containing pictures, audio, video, and interviews with miners who have used a refuge chamber in an emergency. It must be run on a computer with Adobe Flash Player installed (refer to the computer system requirements section).

Oct 1, 2009

By C. A. Mitke

(Butte Meeting, August, 1913.) 1. Character of Gases which Caused Helmets to Get Out of Order. DURING September, -1911, the fire area in the Lowell mine continually increased and gases resulting from the fire came through the upcast shaft. These gases contained such a large percentage of sulphur dioxide that the men were unable to go up and down on cages, and, within a comparatively short time, repairs in the shaft were found to be necessary. Since the fire was in sulphide ores and extended into certain timbered sections, the gases contained varying amounts of SO2 CO2, and perhaps, at times, CO. The temperature in the shaft was generally about 97°, and the relative humidity from 97 to 99.5 per cent. The corrosive action of the fumes became apparent when the cables had to be changed more often than usual, the heads of lag screws .in the guides of the shaft disappeared, and the cages needed frequent repairs. It also became necessary to repair two compartments of the shaft by putting in 150 ft. of new guides between the 600 and 800 levels and lag screws in nearly all the old guides from the surface to the 800 level. 2. Ordinary Methods of Testing Helmets which were Unsatisfactory. These conditions required all work to be done by men wearing oxygen helmets. The Draeger type was tried, and was used until all repairs were completed. At first the helmets were. tested for air circulation and air tightness and the injector was tested by water gauge according to the methods recommended by the Draeger Oxygen Apparatus Co. Six arrangements, covering .these different tests, are illustrated in the catalogue and circulars of the company.

Jan 7, 1913

In October 2005 Phelps Dodge mining, a US based company, visited several Australian mining companies and mine sites to ascertain the current applications of risk management methods in the organisation. The results of this review, documented by the author, indicated a ælayeredÆ approach from high level site or major hazard analysis through to face level, æstop and lookÆ, methods. The approaches of several companies were summarised in one simple layered model. This model is helpful to other sites and companies to identify potential improvements but also offers an image of best practice that may assist with the governance of OH&S by both company boards and community regulators. The issue is particularly relevant as we discuss national consistency in mining regulation. This paper examines the layered model, the company and site approaches that helped define the model, as well as the suggested implications of the layered model to governance.

Jan 1, 2006

On 15 August 1998 the first section of the PUTRA LRT system was opened to the public as a free service prior to official commencement of revenue service on 1 September 1998. It is a remarkable achievement to open a highly advanced medium capacity urban railway scheme in four years after the outline concept began. Even more remarkable is the implementation of the next stage which is the underground section planned to be operational in mid-1999. The decision to build the first underground railway in any major urban centre is a technical challenge. The PUTRA LRT System can be likened to Hong Kong when the initial MTR system began in the 1970s and Singapore MRT in the 1980s. Prior to the PUTRA railway very little bored tunnelling had been undertaken in Kuala Lumpur. A few shallow sewer tunnels had been built but the main experience of tunnelling in Malaysia had been for water, hydroelectric and road tunnels usually through granite formations. The ground conditions in Kuala Lumpur were known mainly from experience of piled foundations and occasional deep excavations. The suitability and likely difficulties to be experienced during bored tunnelling could only be theoretically predicted. In both Hong Kong and Singapore, government owned corporations were set up to implement the scheme, but in Kuala Lumpur the whole project has been undertaken by a private company PUTRA, a wholly owned subsidiary of Renong Berhad.

Jan 1, 1999

By T. A. Laser

"INTRODUCTION A positive workplace environmental, health, and safety (EHS) culture affords organizations and corporations many benefits, including increased trust and employee morale, sustainable EHS performance improvements, and reliable productivity and profit margin growth. Unfortunately, many leaders and EHS professionals struggle daily to achieve and maintain positive workplace cultures and consistent business results. While lack of management support, corporate or employee buy-in, resources, and time are common factors that conflict with an EHS culture and safe work behaviors and processes, there are many other actions that threaten the positive attributes of an organization’s culture. Often these culture killers are not recognized, or worse yet, ignored because they are considered taboo. For example, voicing observations or questioning long-held management practices or process that were initially designed to promote EHS values, but no longer do so. Unfortunately, this could be viewed as challenging authority, not being a team player or even not valuing EHS. And for those that speak up, the potential for negative consequences can be real impediments to positive change. Having an open mind, constantly striving to identify culture killers, and putting forth the effort to eliminate them are the first steps to begin reaping the benefits of having a sound workplace culture. This paper helps readers to: • Recognize culture killers that negatively impact fostering and maintaining sustainable EHS cultures in the workplace. • Understand how to prevent, avoid, and respond to culture killers, before they wreak havoc in your organization. • Assess EHS culture strength, and implement plans to continuously improve it. The desire to draw boundaries around concepts, put things into boxes, and nail down requirements for something that is virtually impossible to solidify for any length of time is quite fascinating! These desires can pose challenges when trying to define what the perfect EHS culture should look like. The very act of trying to define our culture tends to create silos, and these silos, in turn, can become “culture killers”. The following is one of the most common culture killers. UNBALANCED ORGANIZATIONS TRIGGER CULTURE KILLERS Unbalanced organizations occur when an organization’s constantly shifting focus forces other important needs to take a back seat--until the focus changes again. This balancing act can be detrimental and lead to catastrophic results including low morale, lack of trust, employee dissatisfaction, high turnover, increased incidents, poor profit margins, loss of market share, and ultimately into organization-wide failure."

Jan 1, 2018

By Marc Boyer

Modern civilization, modern industry, and modern standards of living, bring into, sharp relief the present-day essentiality of metals .and minerals, and the wide and diversified use which is made of them. Any attempt, therefore, to appraise the international situation today must take into consideration the metal and mineral resources of the world. If, as some believe, the world is divided into two distinct ideologies of political belief, one unalterably opposed to the other, so that armed conflict is unavoidable, then the question of national strength in mineral resources becomes of paramount importance. If, however, it is possible to avoid war by raising the standard of living in the underdeveloped ?areas of the world, thus ensuring all peoples everywhere against the dread spectres of starvation and disease, then the development of the world's mineral resources assumes even greater importance. Today it is difficult to realize that, prior to the industrial revolution in Great Britain, only a few of the metals and minerals now in common use entered into the everyday life of the people. !iron and steel, copper, lead, tin, and zinc, usually in .their unalloyed forms, along with the more common industrial minerals, were those most widely used, and then only in limited amount. With the advance of technology in metallurgy and in fabricating skills, the list of commercial metals and minerals has expanded until today they number more than eighty.

Jan 1, 1951

By Qingjun Zheng, Robert Vasinko

Cladding by plasma transferred arc (PTA) welding is widely used for enhancing the surface properties of a metallic component, in particular wear, high temperature and corrosion resistances. This paper presents the application of Kennametal Stellite PTA cladding technology, especially the DuraStell PTA process technique, for tungsten carbide composite cladding for boiler tube application. DuraStell PTA process gives low heat input to the substrate and fast deposition rate. The cladded boiler tube samples showed more uniform carbide dispersion in the cladding, less base metal dilution, and insignificant effect on the microstructure and mechanical properties of the substrate base metal, in comparison of the traditional PTA and other arc welding process.

Mar 1, 2017

By Hang Goo Kim

A computer simulation has been carried out to predict the distribution behavior of minor elements such as Pb. Zn, Bi, Sb and As in recently proposed copper smelting and converting processes with submerged oxygen injection in which tonnage oxygen is used with a shielding gas. In this study the technique of stepwise equilibrium modeling was employed and some of the thermodynamic data were updated or reassessed. The volatilization and slagging of undesirable elements were investigated in copper smelting (steady-state) system, copper matte converting (batch) system, and the combined (smelting + converting) system at extremly high oxygen-enrichment levels. The predicted minor-element behavior under high oxygen- enrichment was compared with that in the Noranda process (normally 42% oxygen-enrichment in smelting and 24% in converting) and the reverberatory process using air. The effects of various operating parameters such as temperature, the final matte grade in smelting, the initial matte grade in converting and the O/Fe ratio in slag on the behavior of minor elements are discussed.

Jan 1, 1991

By Yoshinobu Fukumori, Testuya Watanabe, Futoshi Shikata, Hiroyuki Tokumitsu, Hideki Ichikawa, Masahito Miyamoto

Nano-particulate systems have attracted much attention recently in pharmaceutical field as drug carriers and functional components of pharmaceutical dosage forms. This paper describes our approaches in design and preparation of nano-particulate systems, including lipid nano-emulsions, chitosan nanoparticles and thermosensitive acrylic nanoparticles, for certain pharmaceutical applications mentioned below. The lipid nano-emulsions with their particle size smaller than 100 nm were prepared for gadolinium neutron-capture therapy (Gd-NCT) of cancer by a thin-film hydration method with sonication, and intraperitoneally injected into Greene's melanoma (melanotic No. 179)-bearing Syrian hamsters. This provided such a high gadolinium concentraton in tumor as 107 µg/g tumor (wet basis) at 48 h after administration. As an alternative gadolinium nano-carrier for Gd-NCT, biodegradable and highly gadopentetate-loaded chitosan nanoparticles (Gd-nanoCPs, 426 mTI in particle diameter and 9.3% in Gd content) were prepared by a novel emulsion-droplet coalescence technique. A significant tumor-killing effect could be obtained when Gd-nanoCP suspension was injected intratumorally twice 24 and 8 hours before neutron irradiation into B 16Fl O melanoma-bearing mice and subsequently thermalneutron was irradiated toward tumor site with a flux of 2 x 109 n/cm2/sec for 60 min. As one another application of nanoparticles, a novel acrylic composite latex with a hydrophobic core and a thermosenstively swellable shell was designed for fabricating microcapsules showing thermosensitive mode of drug release. The microcapsules with the composite latex-dispersing membranes exhibited an exceptionally rapid on-off response of drug-release in a thermosensitive manner.

Jan 1, 2000

By R. B. Fermor

"The tyndalloscope is used in Europe for dust-hazard assessments in both coal and metal mines. Dust-hazard conditions can be directly evaluated by the tyndalloscope in many underground working situations, once the basic standard table or tables have been prepared from representative mine-rock samples.The tyndalloscope is excellent, in many cases, for diagnostic dust sampling during a working shift, because individual readings can be taken to within three-minute intervals. The limitations of the tyndalloscope are also discussed.The author suggests that a combination of both the tyndalloscope and gravimetric sampling methods would be an ideal match for most mine dust-hazard assessments."

Jan 1, 1970

By Frederic Souche, Andrew R. Klaetsch, Brian Hann, Nick Goodenow

This paper describes support of excavation (SOE) design and construction for three large diameter shafts excavated through glacial soil and controlled blasting in complex sedimentary rock formations. SOE in soil consists of unreinforced secant pile rings designed to resist lateral pressure in circumferential compression, eliminating costly steel core beam reinforcing. Controlled blasting at the shafts, adits, and tunnels in densely populated neighborhoods requires managing risks to the public, buildings, and utilities. Controlled blasting approaches limited adverse impacts to receptors nearby while achieving adequate production and fragmentation. A site-specific observational approach was used to adjust blasting parameters, limiting the impact on local stakeholders while maintaining daily progress and managing overbreak.

Jun 13, 2023

By Charles Camsell

If it were necessary to preface a discussion of the mineral position of the Empire by justifying one's interest in that subject, there are two points that at once suggest themselves by way of vindication. Tremendous Growth of MINERAL Consumption The first of these points has to do with the general question of the world's mineral consumption. Most thinking persons appreciate in a more or less vague way the vital rôle that has been, and is being, played by mineral products in building up the material side of our modern civilization. But, apart from that casual and almost subconscious appreciation, very few have any precise knowledge of the extent to which the growth and the operation of our vast present-day industrial structure has been made possible by, and only by, a tremendous increase in the consumption of mineral products of all kinds. The increasing use of minerals confronts us today at almost every turn. It does not matter in what direction we look-at the expansion and the change in transportation facilities, in the air as well as on land and on sea; at the increasing mechanization, not only in factory and mill but even in our domestic life; or at the constantly widening use of machinery for all phases of farm production-everywhere we meet the same phenomena of rapidly growing uses of equipment produced mainly from minerals. Without resorting to any tiresome statistics, a few figures may suffice to indicate with what enormous strides the world's mineral consumption has been advancing. The figures for recent years may be open to objection on the plea that, ever since the outbreak of the world war, conditions have hardly been sufficiently normal to give us trustworthy data-we have been living under extremes either of depression or of abnormal stimulation. During the last decade before the war, however, from 1903 to 1913, the world was moving along in a quietly prosperous manner; and we have figures, or at least reasonably reliable estimates, as to the growth in mineral consumption during that decade.

Jan 1, 1932

By Hans E. Madeisky, Bruce W. Downing

The acid rock drainage (ARD) buffering capacity of mine waste is governed by its bulk chemical composition and its mineral assemblage. Conventional acid base accounting (ABA) tests can be used to predict short-term buffering, but should be used with caution to model or predict the long-term ARD buffering capacity of mine waste. ABA data for mine waste samples from four different deposit types: an orthosite-hosted magmatic sul?de nickel, dunite-hosted magmatic sul?denickel, porphyry copper-gold, and volcanic-hosted high sul?dation epithermal silver, were compared with whole-rock geochemical and petrographic data obtained from the same samples. Our objective was to devise and test a method of predicting ARD buffering capacity based on bulk chemistry and modal mineralogy. In other words, we developed a quantitative theoretical method for calculating neutralizing potential, relying on easily obtainable and relatively inexpensive whole-rock and sulfur XRF analyses, which could substitute for conventional ABA procedures in situations where these procedures are either too costly or too time consuming. For each deposit type, models were devised that reasonably approximate the net neutralization potential estimated by the ABA data obtained from laboratory tests. Once an appropriate model has been developed and tested, portable X-ray ?uorescence equipment, already used for grade control at many mine sites, could provide the whole-rock and sulfur analyses required to estimate the ARD potential of the waste material. Although this approach is not intended as a substitute for the legally mandated ABA test procedure, it could facilitate the timely and cost-effective management and mitigation of ARD at a mine site.

Jan 1, 1997