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By Berger

A detailed description is given of radio apparatus for controlling a coincidence outfit for relative gravity measurements. This is probably of little interest, since many types of apparatus could be used. The general method employed is the interesting thing about this paper. As long ago as 1883 von Sterneck made a proposal to control two coincidence boxes with the, seine, clock, and many persons have suggested the use of radio for this purpose. In accomplishing this it would appear to the reviewer that this method is probably inferior to that used by the Marland Oil Co., but Berger and Brückner must be given the credit for important advances in the coincidence method. In their apparatus a clock at a central station actuates a relay, which operates a short-wave transmitter (40 m.). At the receiving station the amplification is accomplished at low frequencies... The signal operates a relay which moves a slitted screen in a coincidence apparatus. This screen has been improved considerably, to decrease the mean error in observing a coincidence. As usual, a telescope is used to observe the flashes of light. It has a scale in its focal plane and positions of successive flashes are easily read off and recorded by a second observer. This makes possible' a: higher accuracy in determining the exact instant at which coincidence would have occurred at the zero point on this scale. This method obviously depends on the constance of the mechanical and electrical lag inn both sending and receiving apparatus, and may be adversely criticized from this standpoint. -- A. E. Ruark.

Jan 1, 1929

By James C. Barker

Unverified reports of rare earth element (REE) concentrations in gold placers and radioactive mineral prospects in the Zane Hills were investigated by the U.S. Bureau of Mines as part of the Alaska critical minerals program. REE is reported to occur in dredge concentrates at the Hogatza mine and up to 1.2 pct REE was previously analyzed in alkalic syenite (bostonite) dikes marginal to the pluton. In addition, numerous thorium-rich veins, explored for their uranium content but unevaluated for REE, occur on the western margin of the Zane Hills. The Bureau mapped and sampled all of the reported or suspected REE occurrences. Dredge concentrates contain abundant uranothorianite, a mineral species which incorporates cerium subgroup REE. Bostonite dikes occur in conjunction with a multi-phased zoned alkalic intrusion, however, no significant REE concentrations were found. Thorium-rich veins contain nil to 0.5 pct Y but resource potential is limited by this relatively low grade, the ultimate low tonnage potential, and the lack of uranium as a major economic element. The Zane Hills exhibit attractive exploration targets for uranium deposits, primarily in a sedimentary form. Gold may be found peripheral to the pluton in both placer and lode deposits. Resource potential of REE, however, appears limited to a placer by-product of REE-Zr-Ti that is recoverable only during large scale gold placer mining. Placer exploration of the lower Wheeler and Dakli Creeks is suggested.

Jan 1, 1991

By A. Krause

Shovel-truck systems for loading and hauling material in open pit mines are now routinely analysed using simulation models or off-the-shelf simulation software packages, which can be very expensive for once-off or occasional use. The simulation models invariably produce different estimations of fleet sizes due to their differing estimations of cycle time. No single model or package can accurately estimate the required fleet size because the fleet operating parameters are characteristically random and dynamic. In order to improve confidence in sizing the fleet for a mining project, at least two estimation models should be used. This paper demonstrates that the Machine Repair Model can be modified and used as a model for estimating truck fleet size in an open pit shovel-truck system. The modified Machine Repair Model is first applied to a virtual open pit mine case study. The results compare favourably to output from other estimation models using the same input parameters for the virtual mine. The modified Machine Repair Model is further applied to an existing open pit coal operation, the Kwagga Section of Optimum Colliery as a case study. Again the results confirm those obtained from the virtual mine case study. It is concluded that the Machine Repair Model can be an affordable model compared to off-the-shelf generic software because it is easily modelled in Microsoft Excel, a software platform that most mines already use. This paper reports part of the work of a MSc research study submitted to the University of Witwatersrand, Johannesburg, South Africa. Keywords: simulation, bunching, probability distributions, cycle time, queuing, matching, shovel-truck, OEM.

Jan 1, 2007

By Stephen Semeniuk

Working with junior mining companies as a valuer, my experience with regulators is that simplicity works and the sales comparison method is the way to go. What I like about Mr. Ellis?s approach (as in his Table 7) is the integration of commodity prices with the timing of acquisitions and the implication of price changes in gold on the adjustment of individual project valuations. However, the sample gold-related appraisals in Ellis?s paper are pre-2008 transactions and readers should be made aware of the current market for such projects. Before moving on, to be noted is that the effective date of the Las Brisas appraisal (Ellis?s sample Appraisal 3) is Feb. 10, 2006; given that the subject value of Transaction 9, Choco 10 in Ellis?s Table 6 was listed as $353 million for a 95% interest in the con-cession, I am uncomfortable accepting that the acquisition was suddenly worth the adjusted value of $1,205 million (as given in Ellis?s Table 7). In some cases, illiquidity discounts can apply, and commodity-wise, in the one-month period between the acquisition in January 2006 and the adjustment to the Las Brisas conditions as of February 10, 2006, the indicated gold price change was only 41 cents/g ($12.60/oz); i.e., from $17.50/g to $17.91/g ($544.40/oz to $557/oz).

Jan 1, 2012

By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994

By A. B. Cecala

It has long been known that ventilation is a cost-effective method to lower respirable dust concentrations in all types of mining applications. The National Institute for Occupational Safety and Health has been working on a number of different research techniques that use ventilation as a critical component to lower respirable dust levels at surface and metal/nonmetal operations in the United States. This article presents five such research efforts. The first research area discusses how improving the ventilation flow patterns in an iron ore mill facility lowered respirable dust concentrations by 31 pct throughout the primary grinding area. The second research area examines how respirable dust levels were lowered at a dimensional stone shop by using air cleaning units suspended from the ceiling. A third area discusses how improvements in ventilation at underground limestone mines lowered respirable dust concentrations. The fourth area examines how improvements in dust filtration and pressurization systems significantly impacted the air quality in enclosed cabs of surface mining equipment. The last area presents a newly developed clothes cleaning technique. This technique uses an air spray manifold to blow dust from a worker?s clothing in an enclosed booth, which confines the dust for capture and removal by a baghouse dust collector. These research areas represent an array of different control technologies to lower respirable dust concentrations. Ventilation is an integral part of these control technologies.

Jan 1, 2006

By Sir Robert Hadfield

SINCE the writer has been intimately connected with the development of manganese steel for many years, some remarks upon the early work with regard to the rolling and forging of this material might he of interest, and particularly as to the question of rails of special quality and of superior wearing qualities. In a paper on Iron Alloys, with Special Deference to Manganese Steel, read before this Institute at the International Engineering Congress in Chicago in 1893,1 the writer mentioned that, about 20 years ago, his firm in Sheffield produced railroad material, such as tires and axles, of forged and rolled manganese steel, thus showing that this product could be manipulated and worked up into the various required forms. The tires illustrated in the paper referred to above formed a particularly difficult class of work to produce in a special steel, but no special obstacles were met with Although there was no difficulty at that time in making and producing manganese steel in various forms, forged, rolled or pressed; nevertheless, on account of its higher expense, sufficient encouragement

Jan 2, 1914

By A. W. Gauger

WITHOUT QUESTION the Commonwealth of Pennsylvania contains the most remarkable coal deposits of the whole world. Within its borders ,are to be found excellent coals ranging in rank from the high volatile bituminous of the western part of 'the state through the low volatile or semi-bituminous of central Pennsylvania to that aristocrat of solid fuels, anthracite, found in the East. . . . But while other states and even the Federa1 Government have recognized the needs of the coal industry, Pennsylvania has not. Though bituminous coal represents one of the most important industries in the state, far more important in annual productive wealth than agriculture, for example, hundreds, of thousands of dollars have been spent on agricultural research whereas little or nothing has been spent on coal investigation.

Jan 1, 1932

For tax purposes a mining company is a New Zealand company whose principal source of income is from the business of mining, or exploring for certain specified minerals in New Zealand. New Zealand tax law distinguishes between a non-resident mining operator and a mining company, with the only major difference in tax treatment being the corporate tax rates. New Zealand mining companies are taxed at 28 per cent, whereas non-resident mining operators are taxed at 33 per cent of taxable income. These provisions also apply to the petroleum mining industry. Individuals who carry on the business of mining are also specifically defined in the Act. They are termed as 'resident mining operators'. Non-resident mining operators are non-residents of New Zealand who carry on mining ventures as a business in New Zealand. Mining ventures are defined as the exploring, searching and mining of specified minerals, including development work carried out for profits. Similar provisions apply to the petroleum mining sector. Specified minerals are defined in the Income Tax Act 1976 ('the Act') and while no useful purpose is obtained by listing them in the paper, they include a larger number of industrial and commercial minerals. The Minister of Finance is also empowered to add to the list by publishing his determination in the Gazette.

Jan 1, 1988

By J. C. Bradley

THE relation of annealing temperature to conductivity of copper wire has been determined. Conductivity hard was 98.26 per cent. After a 10-min. heating at 200°C. it was 98.69. By annealing 10 min. at 300° C. a large increase, to 100.93, occurred. Maximum conductivity, 101.15, was attained after a 500° C. anneal; thereafter it decreased to 100.53 after a 950° C. anneal. If copper is gassed the decrease is much more than this. Materials and Methods The work was done on high grade electrolytic copper, 99.942 per cent. copper plus silver, silver 0.0008 per cent. It was hot-rolled to >/4 in., then cold drawn to 0.080 in. The wire was cut into 25 5-ft. lengths and numbered 1 to 25 as cut. Four samples were tested hard. The others were wound into 5-in. diameter coils. For the 100° C. heating a coil was put into water, the water brought to boiling, and the wire kept at this temperature for 10 min. For the higher temperatures the coils were placed in envelopes of sheet copper, a little water added, and the envelopes sealed by folding over the edges twice, and hammering them together. This kept the air out very well. The envelope and wire 'were brought to the desired temperature; this was maintained for 10 min., then the whole was water-quenched.

Jan 1, 1927

By J. R. Finlay

BEFORE entering into the statistical part of this article, some general comments may be ln order. Each important war seems to introduce a new atmosphere and a new epoch. The Civil War led to the period of great interior development in North America, of the transcontinental railroads, and of large-scale manufactures. The first World War introduced the general use of the automobile, the building of a huge network of highways, the radio, and household engineering. Now I expect World War II also to introduce some new ways of living. Transocean aviation will become a commonplace; we shall probably have much more of an eye to our military and naval establishments and be more conscious of Eastern Hemisphere affairs instead of thinking so exclusively of the Western. Each war has also multiplied government expenditures and taxes; and to this rule the present one will certainly be no exception.

Jan 1, 1944

By G Eastwood, C Joyce, P Ryan, G M. Johnston

Over the years, predictive techniques for Acid Mine Drainage (AMD) and the natural processes affecting acid generation have received considerable attention. Less emphasis has been placed on the sampling strategy and the integration of testwork results with the geological data base. The sampling strategy employed and the development of a geological model to determine the spatial distribution and volume of acid producing material are often crucial for developing cost-effective containment and mitigation measures. The geological model provides a link between the occurrence, timing, destination and placement of mined waste rock. Careful and accurate interrogation of a comprehensive geological database provides this linkage. The AMD testwork program at Cadia in NSW has been designed to identify the temporal selective handling requirements that will be required during operation. Sampling involved collection of representative combinations of all waste rock types identified within an extensive geological database. These samples were subjected to static, kinetic and accelerated weathering predictive tests. Preliminary results have been used to construct a waste block model for the deposit that identifies the quantity and distribution of acid producing material. Integration of the block model with the mine scheduling determines when the material will be mined.

Jan 1, 1996

By RENARDIR PEIXOTO MACIEL JUNIOR

A importância do desenvolvimento sustentável, tendo como base um ambiente saudável para as gerações futuras, leva a se pensar em como as organizações poderiam desenvolver materiais menos danosos ao ambiente com boas propriedades e pelo menor custo. A proposta de aproveitamento de fibras vegetais para utilização em desenvolvimento de compósitos de matriz polimérica reforçados pelas mesmas é a motivação da pesquisa visando obter um compósito com melhores propriedades mecânicas e químicas do que sua matéria prima. Por virtude da importância do desenvolvimento desses materiais, a caracterização mecânica da fibra, da matriz e, finalmente, do compósito através de ensaios destrutivos e não destrutivos é fundamental para estudo de sua aplicação. Após a obtenção dos dados, percebeu-se que a adição das fibras melhorou as propriedades mecânicas do compósito resultante. Mostrando, portanto, resultados promissores para o desenvolvimento desses materiais, promovendo assim um material mais barato e de melhor propriedade mecânica, além de uma alta leveza. Em suma, os resultados estão de acordo com o esperado, impulsionando assim um melhor estudo desses materiais, por exemplo, realizando outros ensaios, como ensaios de impacto.

Oct 30, 2017

By G. N. Carlson, C. H. Hazelroth, D. R. Dorrance

"Located on the north shore of the St. Lawrence River at Pointe Noire, Quebec are the agglomeration and ship-ping facilities of the Wabush Mines complex. Here, the specular hematite concentrate from the Scully Mine is received for further processing. Modern facilities for handling the ore, either to the 1plant or to stockpile, provide quick and efficient operation of the ore receiving station. Physical preparation of the ore for balling is accomplished with regrind ball mills, filters, bentonite crushing and drying facilities, pumps and related conveying circuits. Rotating table feeders deliver the reground and de-watered ore from storage bins to balling drums, where green ball or green pellet formation is achieved. The green balls are then conveyed to the indurating section. Three Dravo-Lurgi travelling grates, producing a total of 6,000,000 long dry tons of pellets per year, are used in the indurating phase of the operation. These grates, having 38 windboxes and firing at a temperature of 2,500°F, harden the pellets for shipment to various blast furnaces throughout the world."

Jan 1, 1969

By R. J. Pugh

In addition to directly analyzing the surfaces of minerals using high vacuum instrumentation methods, some important surface properties of mineral fillers can be determined indirectly by using reactive chemical probe molecules. This technique enables the strength and the number of the surface reactive sites to evaluation and this type of information is useful in predicting interfacial behaviour of minerals. One method of classifying these surface sites is by using Lewis acid/base theory and this type of approach could enable one to predict the adsorption of functional groups in dispersants, thickeners, pigments, etc. Also the adhesion of polymer matrices to the filler surface may be improved.

Jan 1, 1992

By S F. Simmons, J Fleming

Alteration and mineralisation at the Island Copper deposit is related to the intrusion of Early Jurassic quartz feldspar porphyry dykes into surrounding comagmatic Bonanza volcanic rocks. The pyrophyilite alteration zone forms an upward flaring cone, largely hosted within a breccia body that cross-cuts the Co, Mo, and Au-rich ore shell. This alteration zone contains pyrophyllite, dumortierite and diaspore and resembles alteration occurring in some high-sulfidation deposits, but which is barren. Fluid-mineral equilibria and fluid inclusion studies indicate formation at approximately 300 ¦C from fluids dominated by steam and gases. These fluids appear highly acidic, but sulfur poor, leading to extreme base leaching within the breccia body and surrounding rocks.

Jan 1, 1995

By Stephen H. Chung

The SABREX computer blast simulation program permits the study of the effective use of explosive energies and predicts the total performance of a blast in terms of:fragment size distribution: muckpile profile; breakage at grade, column and collar with respect to the control case; crack penetration; damage envelope behind and beneath blastholes; a complete cost analysis including explosives, drilling and accessory costs

Jan 1, 1995

By L. Lehasa

The purpose of the project was to investigate the challenges faced by Khutala Colliery pertaining to underground road construction and maintenance. Furthermore the influence of these challenges on productivity and safety requirements were taken into consideration. The operating standards required for the construction and maintenance of the 2 seam road transport infrastructure was investigated, together with reasons why the standards of operating procedure are not met. The Code of Practice put in place by Khutala Colliery was used to view the standard operating procedures. Leading practices on underground road construction were researched. The project aims to discover the gaps that Khutala Colliery must bridge to implement enhanced practices with regards to underground road construction. During the period of study, observations were carried out to determine whether the road construction standards of operating procedure were being adhered to at all times for both road construction and road maintenance. Khutala Colliery has put in place a traffic management plan, which includes safety practices and work policies that must be adhered to while travelling on underground transport roads.

Jan 1, 2012

By Jack I. Paige

The Bureau of Mines conducted studies to provide data on the room temperature mechanical properties of Ti-6Al-4V alloy cast in waterglass-bonded zircon sand and to determine the effect of hot iso-static pressing (HIP) on these properties. Data on the cast and annealed Ti-6Al-4V alloy were compared with published data for forged and investment-cast Ti-6Al-4V alloy. The average Charpy V-notch impact strength compared favorably with the typical values of 17 ft?lbf for wrought material and 19.2 ft?lbf for investment-cast material. The room temperature mechanical proper-ties of cast and annealed material compared favorably with published values for investment-cast Ti-6Al-4V alloy and exceeded the specifications for (1) titanium and titanium alloy castings, grade C-5 according to ASTM B367-69, and (2) titanium alloy bars and forgings as specified in AMS4928H, except for the AMS4928H minimum requirement for reduction in area (25 pct). The minimum requirements are: tensile strength, 130 ksi; yield strength, 120 ksi (0.2 pct); and elongation, 6 pct. None of the specimens tested met the AMS4928H minimum requirement for reduction in area. The HIP process healed the internal casting porosity in the test specimens, but the fatigue strength was not significantly improved. The fatigue properties of both the cast and cast plus hot isostatically pressed castings were significantly lower than those of wrought products.

Jan 1, 1984

As the mining industry looks to new technologies for a safe work environment and increased production rates, so should emergency response teams when dealing with organisational incidents. Implementation of technology has transformed the nature of incidents within the international mining community with lower frequency, high impact events replacing high frequency, low impact incidents of the past. In turn the approach to mines rescue response and preparation has naturally diversified. New rescue technologies when applied effectively can only further advance preparation and the response of mine rescues teams. This paper discusses some of the changes associated with mines rescue as the industry embraces technology. It highlights some recent rescue responses and their approach and gives examples of some of the new technologies being used for improved mines rescue.

Jan 1, 2004