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By F. Stober, D. Wanblad, J. Ndlovu, L. R. Nelson, L. P. S. de Villiers

The single six-in-line furnace of the Polokwane Smelter is the largest installed high-intensity furnace for platinum group metals (PGM) base metals sulphide smelting in the world. The furnace employs state-of-the art technology to deliver a planned throughput of 650 000 t/a dry concentrate at a design 68 MW power input. This furnace, at double the capacity of previously existing PGM furnaces, offers low unit operating and capital cost through the resulting economies of scale. Key features of the design include:

Jan 1, 2005

It is my great pleasure as mayor of the city of Amsterdam to welcome you today to Amsterdam, and to the 10th International Conference on Piling and Deep Foundations. The history of Amsterdam has been connected intimately with your professions of geo-engineering and geotechnology, since its very first days. It is good to be aware that you are part of a very old tradition. The knowledge that we need today to build and renew the city has been gathered over a century long process so that we fortunately can stand on the shoulders of the giants before us. During the centuries people living in this part of the Netherlands have always struggled against the water. The same waters that brought the opportunity for a seafaring country to discover the world and to build an empire in the 17th century were a threat to the low lying Netherlands.

Jan 1, 2006

By Alla D. Mah

Titanium forms several compounds with oxygen and also is able to dissolve interstitially about 33 atomic percent of oxygen. Starting with titanium dioxide, reduction becomes increasingly difficult as oxygen is removed; and the final step, be reduction of the titanium-oxygen interstitial solutions, is by far the most difficult. The possibility of reducing titanium oxide, or of purifying titanium containing oxygen, by treatment with certain more volatile metals has been a subject of considerable interest. Theoretical appraisal of the limitations of this possibility, however, has been hampered by lack of adequate information on the thermodynamic properties of the titanium-oxygen solutions. The purpose of the present work was to remedy this difficulty by expanding the thermodynamic knowledge regarding these solutions. The experimental work involved three types of calorimetry and furnished the following information: (1) Heats of formation of 11 titanium-oxygen solutions, in the range of 0 to 10 wt.-percent oxygen, were determined at 298.15° K. As a byproduct, an improved value of the heat of formation of rutile was obtained, which, in turn, led to improved values of the heats of formation of the lower titanium-oxygen compounds. (2) Low-temperature heat-capacity data and entropies at 298.15°K in were determined for 2 representative titanium-oxygen interstitial solutions. (3) High-temperature heat-content data were obtained for 2 titanium-oxygen interstitial solutions to about 1,600° K.

Jan 1, 1957

By LeRoy R. Curwick

This Bureau of Mines report presents the results of a study conducted to assess the domestic availability of chromium from superalloy and cast heat- and corrosion-resistant alloy scrap material. Six alloy classes included in this survey were investment cast, hardfacing, and wrought nickel- and cobalt-base alloys, wrought nickel-iron-base alloys, and heat- and corrosion-resistant alloy castings. Data were collected for 1976 on metallic scrap generation, use patterns, and production practices for these alloy producing and using industries. A model was developed that allowed an assessment of the materials flow circuits within the industries that produce these alloys. The types, amounts, sources, secondary products, and ultimate destinations of chromium- containing metallic scrap for the six alloy classes were determined. Regarding the overall recycling efficiency of these alloy producing and using industries, of the 580.9 million pounds of scrap generated from these six alloy classes in 1976, about 72 percent (416.8 million pounds) was remelted by the same alloy-producing industries, about 18 percent (104.9 million pounds) was downgraded into stainless and low-alloy steels, about 3 percent (19.7 million pounds) was exported, and about 7 percent (39.5 million pounds) was lost through landfill or other disposal or service wastage. The lost material is primarily contaminated oxides for which recovery is currently uneconomic. However, the 124.6 million pounds of scrap material downgraded or exported in 197b contained potentially recoverable critical strategic elements. The amount of scrap material lost to the six alloy-producing industries in this manner contained 22.1 million pounds of chromium, 53.4 million pounds of nickel, 5.9 million pounds of cobalt, 35.9 million pounds of iron, and 7.3 million pounds of other alloying elements.

Jan 1, 1980

By W. J. Campbell

This report by the Federal Bureau of Mines Particulate Mineralogy Unit recommends mineralogical definitions and identification-characterization concepts for selected silicate minerals and their asbestiform varieties. Precise definitions acceptable to mineral analysts, regulatory personnel, and medical scientists are essential because of the present lack of conformity in terminology concerned with measuring and controlling asbestiform particulates and their related health effects. Because of the complexity and variability of crystal morphology in different mineral groups, the descriptive terms are generally explained by illustration rather than by numerical values. Applications and limitations of several analytical techniques for particulate identification and characterization are discussed.

Jan 1, 1977

By F. Grant

"General *The mining experiences of the coal mining industry in Western Canada have been extremely varied, with the mining companies having to adjust their operations or fail due to the harsh economy of the country in the first part of the century. The bituminous or mountain mines had the railways as main consumers with, at times, optimism that potential steel producers would require metallurgical coal. The prairie and foothills mines mainly provided household fuels, with the fine coal sold to local thermal power plants at discounted prices. In practically all cases fuel competition was very keen, and the less successful mines ceased operations in short-time spans. Knowledge of the parameters that governed the success or failures of the past coal operations should be of value to the present and future mining companies. The initial coal mines were small and were started to supply local demand. These mines had little in the way of capital machinery, engineering, or transportation equipment; therefore the mining methods and mine plans were very simple. The first industrial-sized mines imported most of their management and mining methods from other mining areas, mainly Great Britain. It took time to change the bias of management and mining methods to the requirements of strata characteristics, with rapid closure to those mines that were slow to adapt working methods. The main markets for coal were for household fuel, thermal power plants and railways, with very few other industrial markets developed. The economy of the period was harsh and cyclic and the coal mines were affected more than most industries by these boom and bust periods. It led to the survival of the fittest or the most efficient. Due to the economy, mechanization was introduced to the mines very slowly, with the inability to sell coal fines at a profit being another reason for the delay. Manual labour with hand tools was the main means of production. The work was heavy and arduous, and the pay was based on contract coal tonnage; therefore both men and management paid close attention to details so that nonessential work could be eliminated. Mine openings were dimensioned so that coal could be loaded easily by hand and support requirements were kept to the minimum. Transporting and handling the timber supports required heavy labour; thus the most efficient dimensions were chosen to suit the strata. On the other hand, during the main production seasons the mines tried to make the strata stress work for them so that the pressure was kept on the coal face to keep the coal loose while the strata, a short distance back, was induced to cave to minimize the abutment stresses. This caused mining to be an art, using skills developed by experience with the strata. This led to the development of efficient mine layouts with the openings dimensioned to the strength of the strata and the type of support available. The lack of capital and mechanization, and the manual labour, induced the mines to correlate their service and haulage systems with their mining methods. This caused many innovations that proved very practical."

Jan 1, 1985

By R. M. Jacobs

Can your company afford to issue a check today for $100,000, $500,000, $2,000,000, or $22,000,000? This is what it might cost your company if it is on the losing end of a product liability suit. During the past 10 to 15 years, the number of product liability actions has grown from a handful per year level to a hundreds of thousands per year level. Settlements and awards in the tens and hundreds of thousands of dollars are not unusual in these days. The largest award that the authors haw heard about is a case involving a private airplane and the death of four men, which was awarded over $22,000,000. In the materials handling field, a fork lift truck, ordered with an overhead guard, was delivered without a guard because one was not available at the time. An accident with serious personal injury followed. Wouldn't it have been better to have waited until the guard was available before delivering the unit? Answer: a quarter of a million dollars better -- the cost of the settlement. Hoisting devices are also not without their liability precedents. In a 1960 case, an employee was injured when a load abruptly fell from a hoist. It was determined that the operator could not possibly have caused such a fall had the hoist been functioning properly. The case was compounded when the manufacturer of the hoist contended that the load had been improperly connected to the device, since the same hoist was used to remove the weight from the injured man without another malfunction.

Jan 1, 1973

By H. L. Retcofsky

Carbon-13 nuclear magnetic resonance (18CNMR) spectra of nine 2-substituted pyridines, seven 3 -substituted pyridines, and nine 4-substituted pyridines have been obtained and analyzed. Substituents included both electron-releasing groups and electron-with hawing groups. Substituent effects on the magnetic shieldings of the ring carbons, except for those in the 2-positions of 2-substituted pyridines, were found to be quite similar to the effects reported for the monosubstituted benzenes, Thus, at least to a first approximation, the two classes of compounds have similar shielding mechanisms. Shieldings of the carbon atoms in the 5-positions of 2-substituted pyridines and those in the 6-positions of 3-substituted pyridines were found to reflect electron release or withdrawal by substituent groups, The pyridinium cation and the compounds 2,2'-dipyridyl and benzonitrile were also investigated.

Jan 1, 1969

By Robert S. Archer

THE proper material of construction for a given purpose is that material which meets the requirements satisfactorily at the lowest ultirnatc cost. It is consistent with this principle that most aluminum castings are made of an alloy containing about 8 per cent. copper. This alloy possesses mechanical properties satisfactory for general engineering purposes together with manufacturing characteristics leading to the production of finished castings at low cost. It is to the aluminum industry what gray iron is to the iron and steel industry. Just as some services require "semi-steel," malleable castings or steel castings instead of gray iron, there is a certain and growing demand for aluminum castings of superior strength or ductility, or both. Since the beginning of .the industry producers and others have sought to develop alloys or processes by which such castings could be made. Out of these efforts have emerged many alloy compositions and special processes, of which only a few have had sufficient merit to survive. It is the purpose of this paper to describe those which seem to the authors to offer the greatest promise for the production on a commercial scale of aluminum castings of superior mechanical properties, with special reference to heat-treated castings. The suitability of an alloy or process for actual manufacture is affected by so many factors that the problem of appraisal is not a simple one. Since this is such an important part of the whole subject it is proposed to discuss briefly some of the requirements. The final verdict is of course the result of commercial trial and experience. It will therefore, perhaps, be profitable to employ a somewhat historical method of treatment in discussing the subject of alloy development. The alloys or processes to be used in the production of aluminum castings are to be considered from the standpoint of their effects on both the utility and the cost of the finished casting. Specific gravity and mechanical properties come under the first head, while the properties

Jan 1, 1927

By R. V. Norris

1. INTRODUCTION. THE anthracite coal trade, with a shipment averaging about 70,000,000 tons per year, differs essentially from other coal business, in the fact that the larger sizes, comprising about 65 per cent. of the total, are used almost exclusively for domestic purposes, principally during the winter months; and that for proper combustion close-sizing is imperative, so that eight sizes are made; broken, egg, stove, and nut, known as prepared sizes, and pea, buckwheat, rice, and barley, known as steam sizes. These sizes are made in the regular course of preparation, and but little variation in the natural percentage of each is practicable. Thus it is necessary either to work the collieries intermittently, or to dispose of all the varying sizes in their fixed proportions. Unfortunately, the market does not at all times absorb the coal in proper proportions, and rather than interfere with the regular operation of the mines it has been found economical to provide storage for the excess. While the cellars of the consumers are the great storage-plants of the country, this capacity is not under the control of the trade, except so far as reduced prices during the spring and summer months may tempt the use of this reserve. The same remark applies but with less force to the retail yards, which,, though usually small, store in the aggregate a large amount of anthracite. While every effort is made to utilize to the utmost the individual storage-capacity of the country, there still remains the necessity for taking care of the irregularities of the market by the construction of storage-plants under the direct control of the producers. Such plants are usually the property of the railroads, and are situated at points most convenient from a traffic stand-point.

Jun 1, 1911

By R. D. Berkenkotter

This report describes a weighted method for evaluating the mean and variance of assay data from samples of different length . The method , which produces unbiased estimates from which valid confidence limits can be computed , is appropriate for bedded deposits of variable bed thickness and for vein deposits of variable vein width . Assay data from the bedded Florida phosphate deposit is used to illustrate the procedure .

Jan 1, 1964

By G. Graves, J. A. Walker

"Abstract - The Mount Fronsac North volcanogenic massive sulfide deposit is the most recently discovered massive sulfide body in the Bathurst Mining Camp. The deposit occurs within a sequence of intercalated fine-grained felsic tuff and sedimentary rocks (Little Falls member), at the top of the Nepisiguit Falls Formation. Aphyric to sparsely feldspar-phyric rhyolite and related volcanic rocks of the Flat Landing Brook Formation overlie the host sequence. The massive and semimassive parts of the deposit have a north-south strike length of 525 m and a dip of ~45°E; the deposit is continuous downdip for 600 m, and thickness varies from 2 to 20 m. The deposit contains an estimated geologic resource of 14 Mt of low-grade, semimassive (>60%) to locally massive sulfides, and includes a high-grade zone of 1.26 Mt grading 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, and 0.40 g/t Au. The semimassive to massive sulfide intersections occur in an envelope of quartz-sericite±chlorite schist, which is interpreted to be intensely deformed felsic tuff. This sequence has a maximum thickness of 140 m and contains significant (up to 50%) fine- to coarse-grained disseminated pyrite. The pyritic envelope has a strike length of 900 m and extends over 1000 m downdip. Massive sulfides are found throughout this alteration envelope, but more commonly occur at or near the upper contact. The significance of the discovery of this deposit is that it represents a near surface discovery of a large tonnage sulfide body in a mature mining camp, one in which the possibility of discovery of a new shallow deposit had been all but discounted. This opens the possibility for future discoveries in this part of the Bathurst Mining Camp. Sommaire - Le gîte de sulfures massifs volcanogènes du Mont Fronsac Nord est la découverte de sulfures massifs la plus récente dans le Camp Minier de Bathurst. Le gisement est situé dans une séquence de tufs felsiques à grains fins interlités de roches sédimentaires (membre de Little Falls, au sommet de la Formation de Nepisiguit Falls. La partie massive et la semimassive s’étendent du nord au sud sur 525 m et ont un pendage de ~45°E; le gisement est continu sur 600 m en angle de chute et son épaisseur varie de 2 à 20 m. Le gisement contient une ressource géologique évaluée à 14 Mt de sulfures semimassifs (>60%) localement massifs à basse teneur, incluant une zone à haute teneur de 1.26 Mt titrant 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, et 0.40 g/t Au. Les intersections de sulfures semimassifs à massifs se situent dans une enveloppe de schiste à quartz-sericite ± chlorite interprétée comme un tuf felsique intensément déformé. Cette séquence contient une quantité importante (jusqu’à 50%) de pyrite disséminée dont le grain varie de fin à grossier et son épaisseur maximale est de 140 m. L’enveloppe pyriteuse s’étend latéralement sur 900 m et a été tracée jusqu’à 1000 m en angle de chute. Des sulfures massifs sont trouvés partout à l’intérieur de cette enveloppe d’altération, mais ils sont plus fréquents près du contact supérieur. L’importance de cette découverte tient à ce qu’elle est un exemple d’un gisement à fort tonnage nouvellement découvert à une faible profondeur dans un camp minier mature, i.e., un camp ou l’on ne croyait plus qu’il était possible de trouver un gisement près de la surface. Ceci ouvre la porte à la possibilité d’autres découvertes dans cette partie du Camp Minier de Bathurst."

Jan 1, 2006

By Z. Duran, M. Genc, B. Erdem, T. Dogan

This study aims to develop a model for particulate matter concentration during the loading process in open pit mining. The researchers conducted simultaneous measurements of particulate matter and meteorological parameters and collected samples to determine the moisture content of the loaded materials. The analysis used 7,895 measurement data points from gypsum and limestone quarries, employing two data analysis programs, SPSS® and Waikato Environment for Knowledge Analysis, to derive equations for predicting particulate matter release. In the modelling, particulate matter measurements were the dependent variables, while meteorological parameters, laboratory measurement results, and loader bucket capacities were the independent variables. The classical regression models did not adequately capture the dependent variable, thus, the researchers explored the decision tree approach for further modelling. The M5P algorithm was used to generate regression equations for the different data sets, and the findings showed that the models had a satisfactory degree of predictive capability. The number of fine particles released during loading is influenced by various weather factors. Temperature, humidity, wind speed, and station pressure can all affect the dispersal of these particles. Additionally, the moisture content of the loaded material and the capacity of the loading equipment contribute to this process. The M5P decision tree algorithm, which is rarely used in particulate matter concentration models, provides an innovative approach to developing local concentration estimates for non-coal surface mining.

May 8, 2026

By E. J. Kloos, R. H. Schutz, B. I. Ferber

To Assist users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines has established five schedules of minimum performance requirements for the approval of respirators . The current revisions of these schedules include 13D for self-contained breathing apparatus, 14F for gas masks , 19B and the amendments to 19B for suppliedair respirators , 21B for dust , fume, and mist respirators , and 23B for chemical cartridge respirators . Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pittsburgh , Pa . , 15213 . Approval tests on respirators are performed only at the request of the manufacturer of the respirator and at his expense. If the device meets the approval requirements , a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines be used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators. At frequent intervals, the Bureau of Mines purchases approved respirators and replacement parts on the open market. These are examined for conformity to the approved status, and are checked to insure that the manufacturer's production facilities are maintaining a satisfactory quality control .

Jan 1, 1966

By K. L. Paciorek

The aim of this program was to develop a reliable and meaning-ful basts for assessing certain safety aspects, namely fire and, in particular, toxicity hazards of articles employed in underground coal mining operations. This investigation was centered on the thermal oxidative degradation of "pure" ingredients used specifically in the formulation of conveyor beltings. To achieve this goal all products formed on thermal oxidative degradation of the materials studied were analyzed, identified I and the amount of each individual species present was determined quantitatively on a weight of product per weight of material basis. The weight/weight data thus obtained can then be factorized to reflect the relative toxicity of each individual species present, using for example the Threshold Limit Values adopted by the American Conference of Governmental and Industrial Hygienists, whereby an overall "toxicity index" can be arrived at which makes it possible to compare the different potential formulation components in a quantitative manner insofar as their "toxicity" is concerned. Furthermore, knowing the off-gassing characteristics of the commonly used additives I their contribution to the product mix obtained from actual belting can be postulated. Conversely, from the species obtained on thermal oxidative degradation of conveyor belts the type and to a degree the content of additives can be deduced. Based on the se data meaningful regulations governing the material selection for underground use can be developed. For these studies a quiescent system at 370°C was employed. Thermogravimetric and differential thermal analyses were performed to supplement and extend the sealed system investigations and to provide information regarding thermal oxidative behavior under dynamic conditions.

Jan 1, 1975

By Alan D. Akerman

This paper describes the significant advantages and improvements in operational availability, reduced breakdowns, and overall cost reductions that can be achieved through the application of a Reliability Centred Maintenance (RCM) program, including Condition Based Maintenance (CBM) and Equipment Health Monitoring (EHM), in a mine environment. It uses a case study to illustrate the essential elements that constitute the basic requirements to establish such programs. This CBM case study analyzed the Load-Haul- Dump (LHD) vehicle sub-systems and their dominant failure modes, as a precursor to the development of condition indicators. The case study describes a disciplined process to enable condition indicator development and qualification in support of a CBM program. The identified condition indicators vary from readily applicable off-the-shelf monitoring systems and techniques, through to "leading edge" technologies that require further research and development. The paper also explores the developments that have been made in the combination of expert system software associated with modern computer based control systems, and the availability of "intelligent? sensor technology that complement the control system capability.

May 1, 2002

By R. A. Friedel

THE IMPORTANCE of infrared and ultraviolet-visible spectrometry in studies of the structure of coal and similar substances is described. Special experimental techniques have been developed for these studies. Thin sections of coal are preferred, but halide pellets are easier to prepare. Information obtained from infrared spectra on chemical functional groups has been discussed; the importance of both intensities and wavelengths of absorption bands has been emphasized. Functional groups assigned include aliphatic and aromatic CH, methylene and methyl groups, hydrogen-bonded hydroxyls, hydrogen-bonded and chelated carbonyls, phenolic structures, minerals, and aromatic structures that are benzenoid or polynuclear. Infrared studies of structures of coal extracts, distillates, and reaction products of various processes, both chemical and physical, are discussed. Coallike infrared spectra of chars of model compounds have been utilized extensively in studies of coal structure. Ultraviolet-visible absorption spectra of coals show a lack of fine structure and low spectral intensities. These results have been applied to the questions of the chemical and physical structure of coal, particularly the question of polynuclear aromaticity of coals. The color of coal is also treated. The physical-chemical origin of the color of coal may be due to free radicals, as interesting correlations of ultraviolet-visible spectra with electron paramagnetic resonance have been obtained. The optical color of coal has been explained and simulation of the color changes observed in thin sections has been carried out, The spectra and structure of coal derivatives and other carbonaceous materials are also discussed. Possible sources of error in absorption spectral measurements are pointed out. Limited measurements of the ultraviolet-visible reflectance spectra of coal are described.

Jan 1, 1967

By C. P. Mishra

The Bureau of Mines performed a study of the availability of cobalt from market economy countries. The study entailed the detailed analysis of 97 deposits which contain 3.9 billion lb of cobalt at the demonstrated level; in 94 of the deposits cobalt is recovered as a byproduct, and in 3 it is considered the primary product. Since 97 pet of all recoverable cobalt is derived as a byproduct from copper and nickel deposits, the report focused on these two sources. At an assumed market price of $0.89flb for copper, $3.45/lb for nickel, $475/tr 021 for platinum, and $7/lb for cobalt, 1,330 million lb of cobalt at the demonstrated level are potentially available. This total includes 1,105 million lb of cobalt from copper properties, 190 million lb from nickel, 29 million lb from platinum, and 6 million lb from primary cobalt. This analysis indicates that the production cost for 589 million lb of cobalt can be totally covered by the revenues obtained from the other metals produced. The impacts of increases in capital investment and energy costs are also discussed.

Jan 1, 1985

By David E. Siskind

The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17-to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pct of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

Jan 1, 2010

By H. R. Shell

The work on synthetic mica and related subjects is being reported in a series of technical articles (see Supplementary Bibliography), each of which describes some special aspect of the subject. This is the final report on chemical analysis of the fluoride-containing silicates. A condensation of this report has been published (26).3/ Chemical analysis affords one of the best means of ascertaining the final com-position of either a heterogeneous mass or a single pure crystal, particularly where some constituents may be volatile. The analysis of fluoride-containing silicates was not so well known or understood that highly accurate results were commonplace. For example, on synthetic mica a university laboratory reported 11.6 and 9.2 percent fluoride when at least 13.3 and 11.3 percent were present, respectively; a commercial testing laboratory reported 9.14 percent as compared to 12.6 percent; and a glass company reported 7.0 percent as compared to 9.0 percent present. No intimation is made that these analysts could not have done better, but the point to be stressed is that the methods in use were long, tedious, and generally required a certain familiarity for best results.

Jan 1, 1956