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By Jerry Bennett

This report describes the results of a survey of current blast area guarding procedures at surface and underground metal/nonmetal mines. It features five case histories (two surface and three underground mines) of blast guarding methods considered to represent the best systems in use in the U.S. Mining Industry. Elements of an effective blast guarding system are presented along with recommendations for improvements in current blast guarding practices. Industrial and military surveillance and detection technology was reviewed to determine if parallel technology exists for immediate application to blasting site security. While it is concluded that immediate transfer of industrial security technology will be limited, a number of recommendations are advanced for new research to adapt some of that technology for application to the mining environment. Two research areas considered to offer the most potential for improved blast guarding are presented. They are, computerized personnel tracking and blast area intrusion detection using infrared, microwave or E-field type detection systems.

Jan 1, 1981

By J Mauk, J Rowland, S Rabone

Most epithermal Au-Ag deposits in the Hauraki Goldfield are hosted in late Miocene andesites. Broken Hills is an exception, being one of the few economic deposits hosted in rhyolite. Investigation of Broken Hills provides the opportunity to collate structural data that may be compared with that collected from andesite-hosted deposits in order to evaluate the importance of rock type on vein development. The rhyolite host rock at Broken Hills is strongly flow-banded, but this anisotropy does not appear to affect the orientation of mineralised structures. There is a range of structures at Broken Hills: veins, faults, fractures, and large breccia pipes. Veins generally strike north-south, with localised changes in strike and thickness. Slip vectors determined from striations indicate near pure dipslip on the main lode, indicating an extensional tectonic setting. The orientations of vein deflections are parallel to slip vectors. This correlation is common in modern extensional fault arrays where fault growth and linkage produces subvertical deflections in fault orientation (eg TVZ). There are three main types of breccias: 1. Primary breccias related to rhyolite emplacement. 2. Jigsaw type secondary breccias that are that developed during the life of the hydrothermal system. 3. Breccia pipes. Broken Hills was a dynamic epithermal mineralising system.

Jan 1, 2003

By T C. Ooi, L Lu

Owing to ongoing development of new orebodies and changes to existing mining operations, new ore types with distinct mineralogy, porosity and textures are generated as feed for iron and steelmaking. Moreover, further product differentiation occurs as fine ores are increasingly beneficiated to achieve grade. A study was necessary to characterise a suite of iron ore fines in terms of their propensity for formation of quasi-particles and green bed permeability prior to sintering. In this study, two Marra Mamba bedded iron deposit (BID) samples, one Pisolitic channel iron deposit (CID) samples, two dense hematite samples (coarse and fine grained microplaty hematite), one hematite-goethite BID samples and one hematite-goethite bedded/detrital iron deposit (BID-DID) composite sample were investigated. Both Marra Mamba fines and Pisolitic fines exhibit the highest green bed permeability followed closely by hematite-goethite fines, fine microplaty hematite fines, hematite-goethite BID-DID composite fines and coarse microplaty hematite fines at a moderate sintering bed depth of 500 mm. While porous fines generally form better quasi-particles upon granulation than dense fines, the amount of moisture addition increased due to the moisture saturation of the porous fines. As sinter strands become ever larger and deeper, it was necessary to examine the granulation performance of these ore types at a range of bed depths ranging from 300 to 900 mm. On average, the green bed permeability achieved by different ore types, decreased by approximately 7.5 - 9 Japanese Permeability Unit (JPU) as the bed height was increased from 500 mm to 900 mm. In order mitigate the effect of lower bed permeability of the deeper beds, small additions of hydrated lime were investigated as a binding agent to facilitate the formation of strong micro-pellets. With the addition of three per cent hydrated lime, equivalent to approximately 2.3 per cent burnt lime, the majority of fines achieved adequate permeability for deeper bed sintering, with the exception of coarse microplaty hematite fines. In simulated coastal steelmaking sinter blends, it was found that the overall granulation performance of the blend is contributed to by individual fines constituting the blend. Therefore fines possessing favourable granulating properties impart better granulation to the blend as a whole.CITATION:Ooi, T C and Lu, L, 2013. Effects of ore type and binder addition on the formation of quasi-particles and green bed permeability at different sintering bed depths, in Proceedings Iron Ore 2013 , pp 459-466 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By L. J. Kane

Conventional methods for determining the size of dust suspended in a gas require that agglomerates (clusters of particles) first be broken into particles, but in evaluating industrial dust-removing equipment the size of the agglomerates as they actually exist in the gas stream is far more important. This paper presents results of an investigation by the Federal Bureau of Mines to develop methods for determining the size of dust agglomerates suspended in a gas stream. The studies are part of the Bureau's continuing research on synthetic liquid fuels. The size and size-distribution of agglomerates as they exist when the gas reaches the filter was determined by using a membrane filter in conjunction with a dust count under a microscope. A membrane filter is a cellulosic sheet about 150 microns thick containing millions of holes per square centimeter--holes of uniform diameter that run directly through the sheet without interconnection.

Jan 1, 1960

By J. -P. Chilès

The discrete Gaussian model is a very popular change-of-support model for estimating block grade distributions. It is designed for a stationary random function Z(x) that is regarded as the transform of a stationary random function Y(x) with Gaussian marginal. It is based on an assumption that is not fully true and thus constitutes an approximation to the exact solution. We examine the effect of this approximation on the modelling of the marginal distribution of block values of a lognormal random function. The initial discrete Gaussian model and a variant of that model are considered.

Jan 1, 2014

By Yang Jun, Qu Mei, Zheng Yao-wu, Chi Li-yuan

Due to the necessity of the prediction of blasting seismic effect around strip mine bench blasting area, the paper provides a method to predict the blasting seismic effect by employing the superposition of seed waveform at different monitoring points. The method assumes that blasting vibration waveform per hole is similar to seed waveform at monitoring point. Therefore seismic wave consists of the superposition of the waves from all of blast holes. Firstly, via sensors multiple seed waveforms can be achieved at different distances from signature hole. Then, by using the given dose and the distance, the vibration waveform of a certain blast hole can be calculated by the corresponding seed waveforms. Finally, the initiation delay time interval per hole is added to the propagation time to the predicting point. The predictive waveform at the whole blasting area can be obtained by superimposing all of the single waveforms. Considering the vibration waveform of a single blast hole changes greatly with the distance, under different distances condition the seed wave employed to superimpose is achieved from the similar distance. The experiments demonstrate that based on the method the predictive vibration waveform and spectrum are basically consistent with monitoring results around near-field blast. Compared with single seed wave method, the superposition method of multiple seed wave is more reliable to predict the duration of blasting vibration, the peak particle velocity, dominant frequency and frequency distribution.

Jan 1, 2015

The term geochemistry - chcmbtry' of the earth - is almost limitless in its implied subject, but of recent years a major trend of research in this field has been towards economic application in the search for mineral deposits, and in particular for those of some ofthe less common elements for which a demand now exists.Geochemistry is in a state of slow transition from a purely descriptive subject to a fundamental science concerned with the relationships that exist between the distribution of the elements in the earth's crust and the physical characteristics of the atoms of those elements. The progress achieved promises a set of basic principles which will relate the atomic characteristics of an element to the physico-chemical conditions that make for its dispersion or concentration. This means that, given a geological map of an areasufficiently detailed for the physico-chemical conditions existing in past geological eras to be deduced, there is the possibility that the relative distribution throughout that area of any element present, and its likely mode of occurrence, could be predicted from a consideration of its atomic characteristics.Since the atomic characteristics of the elements are becoming increasingly well defined by physical research, the attainment of this ideal of prediction depends upon:(a) the strengthening of geochemical theory; and(b) the development of petrological and mineralogical methods of assessing the conditions of temperature and pressure prevailing in geological formations at various stages in their history.The other prime requirement is a d.etailed geological map - a requirement that is all too often lacking.The fact that there has been very little "geochemical approach" to problems of economic geology in Australia should not be taken to mean that there is little point in trying to develop such an approach here in as active and as rigidly scientific a manner as possible. The degree of success that has attended the attempts so far made, to which reference is made below, suggests the reverse, particularly in view of the relatively slight cost involved if the investigations were properly organised on a centralised basis. There are three aspects of geochemistry that are directly applicable to the search for economic minerals.(a) The classic technique of the prospector can be made more sensitive and reliable by the use of modern equipment coupled with the application of geochemical theory to geological and structural data. The case of the rare alkali elements (see below) is givenhere as an illustration of the way in which the distribution of elements can be predicted from the first principles of geochemistry, thereby replacing the prospector's dependence on his "sixth sense" that enabled him to suggest that a certain area of formation was"favourable" for the occurrence of a certain type of mineral deposit.At its best, this sixth sense amounted to an almost subconscious correlation of all relevant associations and typical occurrences of the particular mineral experienced by the prospector during his...

Jan 1, 1950

By R. J. Leary

The technologies of contemporary iron and steel production and of direct reduction processes have been studied to identify and estimate the potential effects of direct reduction on mineral consumption and the problems raised thereby for the Nation's mineral supply to the iron and steel industry. Contemporary patterns of mineral raw material and energy consumption were determined from a study of the 1964-70 period. Major changes were observed in requirements for 14 of 20 principal commodities. Average practice in 1970 was compared to best practice to estimate the potential effects of implementing existing technology without recourse to direct reduction. Potential effects of direct reduction were estimated by comparing the mineral requirements for 95 percent reduced pellets with 1970 best practice technology for two cases of use: (I) complete substitution for hematite pellets in blast furnace burdens, and (11) partial substitution (40 percent) for scrap in electric furnace steel charges. Effects upon mineral supplies are described; important collateral factors are analyzed, and the principal metallurgical, industrial, and environmental consequences of implementing direct reduction are discussed. Major effects of direct reduction on the domestic steel industry and its mineral supply system are foreseeable. Direct reduction will (1) create a large demand for low-gangue iron ore; (2) relieve the dependence of the steel industry on coking coal, and (3) permit great increases in furnace productivity, both in blast furnace ironmaking and electric arc furnace steelmaking.

Jan 1, 1973

By Oliver Bowles

"INTRODUCTION Slate has earned a high reputation as a roofing material, carefully selected and properly placed it is rainproof, attractive, and extraordinarily durable. Despite there qualities in its favor, the slate industry during the past 30 years has suffered marked reduction in volume of sales. An increase in building construction and general improvement in business will doubtless bring renewed activity, but considerable ground has to be recovered before the industry can become prosperous. Influences tending to dwarf this long-established industry producing materials of world-wide reputation are analyzed briefly in the following pages in the hope that they may be rectified.HISTORY OF SLATE PRODUCTIONFigure 1 shows graphically the rise and fall from year to year of sales of roofing slate since 1885. In quantity, the peak was reached in 1902, and the most serious decline was from 1912 to 1918, sales at the end of this 6-year period being only one third those at the beginning. Unlike most building materials, slate experienced only a slight recovery in volume of sales during the post-war period, 1920-29. The value closely parallels the volume up to the World War period. Subsequently, however, as unit values increased the aggregate value rose sharololy above the volume curve, attaining in 1928 the point reached in 1903, although the Lumber of squares sold was scarcely one third as great. The increased unit value was due partly to larger sales of heavy architectural grades."

Nov 1, 1933

By J. M. Singer

In this Bureau of Mines study coal and rock dust beds were entrained by airblasts generated by gas explosions at the closed end of a 0.61-m-diameter explosion tunnel, 49.7 m long. The system was designed to simulate entrainment of mine dust deposits by accidental gas explosion at the coal face of nonintersecting mine passageways. Full-scale mine explosion trials confirmed many of the results of the explosion tunnel experiments and indicated several new features of dust entrainment. Dispersal of 20.3-cm-long stepped dust beds located 35 m from the closed end always began during the early portion of the ascending gradient of the first transient airflow (and pressure) wave, and was usually completed before the end of the first quarter-wave period. Bulk quantities of dust were entrained simultaneously by longitudinal regression from the leading edge of the dust bed and by surface lifting of the top layer. Instantaneous threshold air velocities for bulk quantities of coal and rock dust beds in separate, mixed, and layered configurations were in the same range (5 to 30 m/sec) as previously found under steady-state velocity conditions. Selective lifting of coal dust layers from rock dust occurred when the threshold dispersal velocity of coal dust but not of the underlying rock dust was exceeded.

Jan 1, 1976

By J. Björkvall, S. Ångström, L. Kallin

In this paper results from industrial trials of CaC2 injection during stainless steel production in an electric arc furnace at Sandvik Steel is presented. The main purpose of the investigation was to analyse the effect of the injection on slag foaming and final chromium oxide concentration in slag. The results show that both an increase in slag foaming and a decrease of the final chromium oxide could be obtained during the charges with CaC2injection. On the basis of the results, the economical requirements are also discussed. Both the technical and economical requirements could be achieved for steels alloyed with Mo. In order to secure the economical requirements for all steel grades of interest, the injection technology must be further developed. It would also be important to utilize the positive effect of the slag foaming on the electric energy consumption. The work has been performed as a part of MEFOS frame research programme with participants from Sandvik Steel, AKZO Nobel and Avesta Polarit. Keywords: stainless steel, EAF, slag foaming, injection, CaC2

Jan 1, 2004

By J. Martinovic

The large proportion of gangue minerals present in platinum bearing ores in South Africa provides challenges to the flotation and downstream processes. In order to take effective measures to reduce their recovery in flotation, an understanding of the mechanisms and factors influencing their behaviour is needed. Typical gangue minerals are pyroxene, feldspar, quartz, chromite and talc. Of these, talc is a naturally hydrophobic mineral and although it is present in relatively small quantities, it has a disproportionate effect as it has a strong froth stabilizing effect, increasing the recovery of other gangue minerals by entrainment. Talc recovery is effectively reduced with the addition of polymeric depressants. Although the other gangue minerals are assumed to be hydrophilic and their recovery by entrainment is expected to follow the water recovery, there is some evidence that they may be activated by the typical reagent suites used. Reagents such as copper sulphate, added as an activator, and collectors are used to selectively induce hydrophobicity on the sulphides. It has been shown that some of these gangue minerals can be activated. This research work investigates whether inadvertent copper activation is mineral specific and evaluates the mechanisms and factors affecting the reversal of activation with the addition of the depressants using electrokinetic measurements, adsorption and microflotation tests. Results are presented that show that the selected minerals do respond differently and that the reversal of activation is dependent on mineral type, depressant type, dosage and ionic strength of the electrolyte.

Jan 1, 2005

By Swapan Bhattacharya

United States federal and state regulatory authorities require underground mine operators to adopt adequate measures to minimize material damage to the surface caused by nine subsidence. This paper presents an approach to define and determine the extent of material damage due to subsidence from underground coal mining. The basic steps involved in the development of adequate criteria have been enumerated together with the approaches and methodologies used.

Jan 1, 1984

By Wilfred P. Schmoe

Introduction An integrated oil company has two options in approaching strategic planning. It has to decide whether it is in business for the long-term. I state this in all seriousness. Those who help manage public companies have the responsibility of good stewardship of other people's money. We must decide whether continued investment in our basic business will generate a reasonable rate of return. With a world surplus of petroleum production capacity, and continuing downward pressure on prices, this question should be addressed by all oil companies. And a positive answer is not necessarily a foregone conclusion in all cases. The decision should be made based on proven competence in finding and developing petroleum reserves on a cost-competitive basis with other producers, and on a frank analysis of future prospects. This should include a realistic assessment of the projected rate of return on specific investment projects. If a company did not pass these tests, its strategy could take one of four paths. Diversification First, it could diversify. But recent history suggests that oil companies are not good at managing other businesses. Second, it could seek a buyer for its business at the optimum return for its owners. Third, it could sell its assets on a piecemeal basis. And, fourth, it could adopt a longer-range plan of self-liquidation by living off current recoverable reserves. In other words, by not investing in exploration and development, it could maximize short-term profit and pass the money back to shareholders in the form of dividends. The Conoco component of DuPont has a below-average cost of finding petroleum, a good track record of efficient production, and a full plate of projects that pass the test of return-on-investment. In short, Conoco is in business for the long-term. That fact, in itself, determines at least one key element in strategy. This is to extend the life of the petroleum reserve base while at the same time maintaining maximum efficient rates of production to provide a strong cash flow. A company that is able to maintain a strong reserve base will ultimately see the value of those reserves escalate as world oil supplies tighten. Our planners expect this tightening to occur within the next decade as demand grows and production in non-OPEC areas of the world begins to decline. An exploration program tailored to meet the requirements of reserve replacement and current production should have two basic parts. The first is relatively low-risk exploration in proven oil provinces. This is augmented by

Jan 6, 1985

By A Kurniawan, A Sjadat and M Akhasyah

PT Freeport Indonesia’s Deep Ore Zone (DOZ) is a block cave mining operation that has been in production for 15 years. DOZ is located approximately 900 m below surface and has an average production rate of more than 5000 t/d. The footprint of the extraction level will ultimately be 900 m long and average more than 200 m wide. The undercut level is located 20 m above the extraction level.While developing Panel 1K on the northern portion of the extraction level, a major geotechnical problem was encountered when there was a change in lithology and an associated fault intersection. A large collapse of the hanging wall of the extraction level drifts occurred in the area of the fault intersection between February and March 2011. This was followed by a collapse of one of the undercut level drifts directly above the extraction level in May 2011.It was suggested that the best approach to mitigate risk during rehabilitation was to systematically open up the failed area under the protection of a steel set support system. To achieve this, approximately 60 t of grout was injected from the undercut level to fill the voids created when the rock mass between the two levels failed. A ground penetrating radar system was used to survey the condition of the rock mass between the two levels before and after the injection of grout. After the grout injection phase was completed to a satisfactory level of confidence, rehabilitation activities started on the extraction level by taking out the now consolidated material from inside the drift in 2 m advances from under steel sets initially constructed in secured ground.Controlled blasting was the key aspect to the success of the initiative to open up just enough of the drift to systematically support the rock mass before the next set was installed. The systematic support consisted of in-cycle shotcrete sprayed over mesh pinned to the exposed rock, as effectively as possible, with splitsets before spiling the next advance’s protection canopy with rebar. Once secure, a combination of steel set and pumped concrete was installed as the final support. This final support provided a safe platform to repeat the process until the failed zone was safely traversed.CITATION:Kurniawan, A, Sjadat, A and Akhasyah, M, 2016. Rehabilitation of the collapsed panel 1K north in the Deep Ore Zone block cave mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 763–768 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

This report is a proceedings of a briefing recently sponsored by the Bureau of Mines at which Bureau personnel presented findings from their research efforts to improve steelmaking techology currently used in the United States. The papers contained in this report address many areas of concern to the iron and steelmaking industry. Among these are improving arc stability in electric arc furnaces, preheating ferrous scrap to reduce energy consumption, fluorspar substitutes in steel-making, basic steelmaking refractories, corrosion of iron-based materials, improvements in stainless steel acid pickling processes, recycling of stainless steel dusts and other wastes, and use of wastes as a source of zinc for electro/galvanizing.

Jan 1, 1988

Council for 1996/97 President Dr N.A. Barcza President Elect R.P. Mohring Vice Presidents Senior J.R. Dixon Junior M.H. Rogers Immediate Past President D.A.J. Ross-Watt Honorary Treasurer J.A. Cruise

Jan 1, 1997

By F. D. Everett

This report summarizes the results of a nationwide investigation completed in 1964 to determine the nonferrous base metal ore reserves and potential sources of ore and to evaluate criteria for their ultimate exploitation. Engineers of the Bureau of Mines contacted mining company officials, reviewed reports and Government records, and where necessary made personal appraisals in arriving at the results. The estimates are presented by metals in ores in geographic regions and include some of the problems affecting the reserves and potential sources. The recoverable metal in the measured ore category and in the total ore reserves was estimated as follows: [ ] At the 1963 rate of domestic mine production these total reserves would be adequate to provide copper for 62 years, lead for 121 years, and zinc for 42 years. Data also are given for gold, silver, and other coproducts. Reserve estimates greatly exceed those of previous investigations; some prior estimates of copper reserves are included for comparison (table 23). Projections of requirements for base metals indicated the United States will need approximately 45 percent more copper in 1970 and 110 percent more by 1980 than was consumed in 1960; similar projections for lead indicate increases of 20 percent by 1970 and 45 percent by 1980; zinc projections are 40 percent more by 1970 and 90 percent by 1980. Much of the production of gold and silver is a coproduct of base metals recovery and the projected need for the precious metals exceeds all the United States can produce. Some problems of the industry are mentioned. A graphic evaluation of the economic availability of the reserve and potential sources is shown.

Jan 1, 1967

By H Saw, M Cordova

Cemented rock fill (CRF) is often used to support open stope voids. This allows for the full recovery of ore while achieving global mine stability. In such cases, the exposed CRF masses require adequate compressive strength and stiffness to resist the forces and limit the displacement associated with movements in the rock mass surrounding the excavations. The CRF material preparation often involves the use of large particles, either from crushed rock or development mining waste. This means that conventional laboratory samples cannot be readily used to determine the laboratory strength. Consequently, a research project was undertaken to determine the influence of sample size on uniaxial compressive strength. This paper presents the results from CRF samples that were prepared using the same mix design and then cast into moulds with diameters of 150, 240, 300 and 400 mm. The laboratory testing also allowed a better understanding of the effect of particle size distribution upon the overall strength of a rock fill mass. The laboratory results were compared to a database of large-scale results from the testing of fill masses from a number of mine sites.CITATION:Cordova, M, Saw, H and Villaescusa, E, 2016. Laboratory testing of cemented rock fill for open stope support, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Rather like the mythical "Economic Man" "an employer" in this context must necessarily be an abstraction, and the views possessed by such an abstraction, a composite of many views known to have been expressed. Not even the complex Conciliation and Arbitration legislation in this country provides any helpful specifications, except in one peculiar particular. The Australian Conciliation and Arbitration Act provides an almost totally tautological definition, except in that one oddity referred to above. It is this : "An employer means any employer in any industry, and includes any person who is usually an employer in an industry, and also includes a Club." No doubt there is some perfectly justifiable reason for such specific and unique particularity in an otherwise meaning- less definition. That need not trouble us in this exercise.

Jan 1, 1982