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By William D. Hissem

For those blasthole applications which require the use of holes ranging from 1” to 5.5” in diameter, the use of top hammer drills has been the equipment of choice for several generations of drillers. Pneumatic compressed air and hydraulic compressed oil systems represent the primary technologies which are available to the drilling practitioner. While both employ the same operating principals, the characteristics of performance, cost, and reliability can be markedly different between technologies and manufacturers.

Jan 1, 1998

By Luino Jr. Dell'osso, Richard L. Every

The enormity of the methane-in-coal problem is discussed, with a brief summary of the state-of-the-art. Laboratory techniques and data on the desorption of methane from Pittsburgh seam coal are presented and discussed and include the effect of time, temperature and vacuum. Under laboratory conditions, it was possible to displace 90 per cent of the residual methane by flooding the coal samples with carbon dioxide. Carbon dioxide was found to be three times more effective than air and almost five times more effective than helium.

Jan 1, 1972

By V. T. Dow

In April 1957 the Bureau of Mines instituted a reconnaissance of titanium-and zirconium-bearing heavy sandstone deposits in the Four-State area of Utah, Wyoming, New Mexico, and Colorado. This report summarizes the study. Eighty-two deposits or groups of deposits, containing an estimated 27,920,000 tons of titaniferous sandstone, were examined in the Four-State area; 16 in southern Utah, 19 in Wyoming, 33 in New Mexico, and 14 in southwestern Colorado. The 16 deposits examined in Utah contain an estimated 1,043,000 tons with an average grade of 17.98 percent TiO2, 5.67 percent ZrO2, 20.98 percent Fe, and 0.09 percent equivalent Th02. The 19 deposits investigated in Wyoming are estimated to contain 21,873,000 tons of titaniferous sandstone having a weighted grade of 5.22 percent 702, 0.55 percent ZrO2, 24.8 percent Fe, and 0.01 percent equivalent Th02.

Jan 1, 1961

By M Tessier, M Pahkala, L Sletmoe

The Red Lake mine is one of the richest gold mines in the world. The primary mining methods are overhand and underhand cut and fill. Starting in 2003, Goldcorp initiated an expansion program at the mine. The expansion includes a new 6.55 m diameter hoisting shaft currently under construction. The shaft will be driven to a length of over 2180 m. The shaft will be used as a primary ventilation intake to the mine. In addition to the new hoisting shaft, a return air raise is being driven approximately 1690 m from surface. This raise will be a parallel return to the existing mine infrastructure. This paper describes the ventilation and climatic analyses performed in support of the expansion project. The study included a full mine ventilation survey, in situ rock mass measurements, analysing options related to mine layout, airway sizing calculations, air heating options, and climatic simulations. Specifications were prepared for an air heating system and main and booster fans. Analyses were also performed related to heat in the stoping areas namely caused by auxiliary fans and backfill with high cement content.

Jan 1, 2005

By James J. Scott

Longwall mining has not received a great deal of attention in the United States; however, this system offers many advantages over the conventional room-and-pillar methods now being used. In order to conserve the coal resources of this country, the U. S. Bureau of Mines has investi¬gated the feasibility of adapting European longwall mining methods to American coal seams. Their studies showed longwall mining to be well suited to thinner seams and, greater depths; and, in addition, permitted almost 100 percent recovery of the coal. Most, experiments with this method resulted in higher overall production-costs than were commonly obtained with highly mechanized room-and-pillar techniques This high cost-was largely due to the excessive amount of labor required to maintain adequate roof support with conventional longwall mining techniques. With the substitution of hydraulic-powered, self-advancing roof support systems for conventional supports, this excessive labor cost has been decreased, and longwall mining costs are now competitive with those of modern room-and-pillar mining.

Jan 1, 1964

By Claude W. Sill

In the course of a series of investigations on vanadium deposits of the western United States, the Bureau of Mines collected many hundreds of samples for chemical analysis. As uranium is often associated with these vanadium minerals, they were also analyzed for uranium, which was pound to be absent in a large percentage of the samples. Since the usual methods for determining uranium are laborious and time-consuming it is very desirable to have some simple qualitative test that can be applied prior to a quantitative analysis to determine whether uranium is present or absent and thus save the time and expense of applying the quantitative analysis to the large proportion of samples containing no uranium. To be acceptable, the test should be specific for cranium, sensitive enough to detect small amounts of uranium, and. simple enough to make it worthwhile to apply. The available methods for detecting uranium lacked one or more of the desired characteristics. Eventually, however, a method was worked out that satisfied all the requirements. This method is probably more specific and sensitive than the usual qualitative methods for uranium, and its simplicity and speed of application make it ideal for testing samples prior to quantitative analysis.

Jan 1, 1945

By José A. Rios, José A. Vidalôn

The case study of a highland area in the Central Andes of Peru, where many abandoned polymetallic mines are found, is presented. Some of these mines generate metal leaching and acid rock drainage (ML/ARD) or have potentially ARD generating (PAG) tailings/waste rock storage. Effluents are discharged into the first of two lakes in line, which act as reservoirs for irrigating an important valley in the desert coastal region. Drainage fees, their relationship with the deposit and the solid-wastes mineralogy are discussed, as well as variations in water and sediments composition, the benthos, and the aquatic/riparian flora/fauna in these lakes.

Jan 1, 2000

Direct force measurements were conducted using an atomic force microscope (AFM) to study the mechanism of copper-activation of sphalerite. The force measurements were conducted between a sphalerite plate and a hydrophobic glass sphere in xanthate solutions of various pHs. The glass sphere may represent the hydrophobic air bubbles interacting with minerals during flotation. The force measurements conducted with unactivated sphalerite in 10') M KEX solutions did not show the presence of hydrophobic force. On the other hand, the results obtained with copper-activated sphalerite at pH 9.2 and 4.6 showed strong hydrophobic forces. However, the results obtained at pH 6.8 showed no evidence of hydrophobic force, which provides an explanation for the difficulty in floating sphalerite at neutral pH.

Jan 1, 1998

By Michal Stepien, Piotr Palimaka, Stanislaw Pietrzyk

During the steel scrap melting process in an electric arc furnaces, the generated dust may contain a significant amount of zinc. The content of zinc in case of melting galvanized steel scrap is variable and ranges from 15 to 40 wt%. This dust cannot be re-used for the steelmaking process. On the other hand the zinc content is too low to treat the steel dust as a feedstock in pyrometallurgy of zinc. When they are disposed in land fills they have adversely effect the environment. This work presents selected results of research and development of new technology, which was developed in order to utilization steelmaking dust in the sintering process. One of the products (zinc-rich) can be used as a high-quality raw material for production of zinc by pyro- or hydrometallurgical processes. The second one product from the shaft furnace can be used as a feedstock for the steelmaking process.

Mar 1, 2017

By Henrik Saxén, Mikko Helle, Hamid Ghanbari

In this study, a process integration approach in a primary steelmaking is investigated to evaluate future operation concepts of a steelmaking site considering sustainability issues. Mathematical programming is used to study the integration of the steel plant with chemical units for utilization of available off-gases in the system, and carbon capturing and sequestration unit. Different industrial carbon utilization options are considered to find the best route of development. A multi-period optimization model is developed based on site-wide mass and energy balances by considering the availability of the fuels and by-product gases and their consumption in the production system and a conceptual polygeneration system. The objective is to reach maximum economic profit while environmental aspects of integrated system are considered for different fuel systems, alternative blast furnace reductants and implementation of new process technologies. The model can provide useful information concerning techno-environmental and economic aspects for decision-making and can estimate optimal operational condition of current and future primary steelmaking under alternative scenarios. The results of the work illustrate the potential to develop steelmaking towards more sustainable operation in the future.

Jan 1, 2015

By K. Fukushima, K. Baba, H. Kurokawa, M. Yamagiwa

"The Toyo smelter has expanded its anode production capacity from 126,500 to 239,000 t/year by introducing technical oxygen into blast air for flash and converter furnaces and improving smelting facilities. Significant efforts were made in the expansion not to increase the number of workers, which mean development of some automation systems for the copper converters and anode casting wheel. The efforts have resulted in the above-mentioned increase in productivity and a saving of production cost as well as a decrease in the number of workers for the anode casting operation.IntroductionThe Toyo smelter has been performing a highly stable and pollution free operation since its commencement in 1971 (1). Its distinctive features are the on-line control by process computer (2) and the high productivity without trouble. But owing to the so-called oil crisis in 1979, we were faced with a sharp increase in production cost. To decrease the production cost, some measures for saving of energy were planned and carried out, such as conversion from oil to coal in a flash furnace (3), the heat recovery from converter slag and the introduction of technical oxygen in blast air with the intention of energy saving as much as possible.The first increase in production capacity and some savings of production cost were attained in 1982 by the introduction of technical oxygen in blast air for the flash furnace without major modification of the furnace as shown in Table I. The capacity of an oxygen plant is 7,800 Nm3/H as 90% O2 . Part of oxygen from the plant is also supplied to tuyeres of copper converters through an oxygen holding tank with a volume of 830 m3 at 7 kg/cm2-G."

Jan 1, 1989

By B. Arsenault

Aluminum coatings can provide galvanic cathodic protection for several metals and alloys, In order to be a suitable protective solution on structural components, the mechanical integrity of the component must be preserved, In particular, fatigue properties are a challenge for thermal-spray protective coatings on mechanical structures, To address the issue of the fatigue integrity of 7075 aluminum alloy with an arc-sprayed protective coating, different surface preparations prior to arc spraying were considered, In the present work, a feasibility study was performed using laser ablation as a surface-preparation technique before or during arc spraying of coatings, This was collaborative effort between the LERMPS laboratory in France, the National Research Council Canada and the Royal Military College of Canada, Both fatigue and adhesive properties of aluminum coatings were evaluated in relation to substrate-surface-preparation techniques including laser ablation (Protal® process), grit blasting and shot peening. Results indicate that a combination of key conditions, including the use of nitrogen as the arc spray gas, shot peening, and proper laser energy density for ablation, provide high fatigue resistance of metallic coated 7075 alloy substrates. Specimens prepared under these conditions show a similar fatigue resistance to uncoated substrates.

Jan 1, 2005

By B. M. Larsen

A discussion based on three commercial furnace tests and electrical analogue calculations is presented. It shows that while regenerator efficiency is mainly dependent on loading or relative amount of heat exchange surface plus the heat transfer coefficients as effected by flow velocity, the actual air preheat temperature can be high or low, largely independent of regenerator efficiency, mainly due to the diluting or unbalancing effects of cold air leakage into various parts of the furnace system. THERE are many signs of a renewal of interest in the heat regeneration aspect of the open hearth process, among them being the recent paper by Marsh,' the introduction of auxiliary checkers in the stacks of the Isley furnace design, and a number of recent installations of two-pass checkers in new and old furnaces. However, there are also signs of yielding to the usual temptation of oversimplifying a problem. Faced with the job of obtaining better draft on a furnace, for example, a good designer always recognizes that focusing attention on some one factor, such as height of the stack or capacity of the exhaust fan, does not make his problem any easier; rather he must look at the whole system, including such items as valve resistances, bends in the flues, and flow resistance in the waste heat boiler; then he must make his design in relation to the available draft so as to avoid any serious bottleneck in the system. Yet this example is really much simpler than the problem of air preheating, and again, the latter problem is not really made easier by concentrating on air temperature in uptakes and on the more obvious methods for making this air as hot as possible. Also to be considered are such things as the total amount of air needed theoretically for complete combustion at any selected fuel rate, together with that needed for oxygen absorbed into the bath and for burning the combustible gases given out from the bath, plus some excess air. Furthermore, how does this total air requirement relate to the regenerator efficiency at various loadings? How much of the total air equivalent in stack gases will come from preheated air passed through the whole length of the incoming regenerator and how much from air leakage into various zones of the whole furnace system? Does the effect of leakage air differ depending on whether it leaks into the ingoing regenerator, the furnace above floor level, the outgoing regenerator, or the stack zone? Over a number of years we have in this Laboratory experimented with methods for measuring hot gas temperatures; we have measured, approximately, the efficiency of a few regenerators on commercial furnaces and we have developed an electrical analogue' for calculations of regenerator efficiency. The whole problem is too complex to cover in one paper even with a more complete background of data than we possess, but we can attempt here to clarify certain aspects in a general way, hoping to assist specific plant studies on individual furnaces. Some of our earlier experience has been incorporated into chaps. 4, 19, 20, and 21 in the book "Basic Open Hearth Steelmaking,"" and on the assumption that this text is available to most readers, this discussion has been shortened by references to that book. The most recent design of a flowing-gas thermocouple which we are now using for measurement

Jan 1, 1955

By E. Yalçin

The data set often contains one or more secondary variables. These secondary variables are usually spatially cross correlated with the primary variable. The addition of the cross-correlated information reduces the variance of the estimation error by using the cokriging method. The grade estimation results of ordinary kriging and cokriging methods are evaluated and it was found that the estimation variance of cokriging method is slightly lower than ordinary kriging. The effect of variation of block dimension on the estimation results is also investigated and it was seen that the cokriging estimation variance values also decrease as the block dimension increases.

Jan 1, 2005

By C. Hsu

Underground coal gasification (UCG) is becoming more popular as the reserves of good quality, mineable coal are starting to diminish, and yet the global energy demand from coal is still increasing. The purpose of this research project was to investigate cavity formation within a coal block due to the combustion reactions in the context of UCG. The cavity plays a pivotal role in the UCG process, as it is essentially the gasification reactor. Cavity formation in an in situ gasification process using the forward combustion linking method (FCL) had been investigated, and a laboratory model was created to simulate the process. The experiment was performed by drilling a U-shaped tunnel into a coal block, which was then combusted internally with air that was fed through an injection hole. A heating element (at approximately 500°C) was used to supply the required heat for combustion at the base of the injection well. The coal blocks were analysed using micro-focus X-ray tomography. The tomography results showed that the coal tended to crack along the bedding plane after a short duration of combustion, due to either the formation of clinker or the expansion of swelling vitrinite along the horizontal tunnel. The deposit was thicker at the base of the injection well compared to the base of the production well; this may have been caused by the turbulence of the air flow and the relatively high oxygen concentration at the base of the injection well. A comparison of the results with work by Daggupati et al. (2010) showed the same trend, despite the slightly different methodology applied.

Jan 1, 2014

A pilot plant was constructed for the low temperature carbonization of Wallarah (N.S.W.) coal at the rate of 300 lb/hr. The design was based on an entrained state carbonizer developed by Parry and D.S. Bureau of Mines co-workers. Prior to delivery to the client, the plant was successfully operated over periods of several days duration.INTRODUCTIONIn September 1961, the Australian Mineral Development Laboratories (A.M.D.L.) was engaged by the Broken Hill Pty. Co. Ltd. (B.H.P.) to design, construct and test an entrained state coal carbonizer with a capacity of 300 lb/hr of Wallarah (N.S.W.) coal. Char product was required within the specification 15·5 -I- 1 per cent volatile matter. The design was to be based on a pilot plant developed by Parry and others in the D.S. Bureau of Mines Coal Research Laboratory at Denver, D.S.A. The method involved the carbonization of fine coal by entrainment with air in an externally heated reactor. The heat required for the carbonization of the coal was to be supplied to the bed both through the reactor walls, and also by internal combustion of products in the bed. Several D.S. Bureau of Mines Reports of Investigations weFe used as the main guide to the physical layout and proportions of the plant. However, the individual units required detailed designing, before engineering drawings could be prepared and fabrication begun.A 10 ton sample of crushed Wallarah coal was used for preliminary testing of the plant. The first test run on the pilot plant was carried out in February, 1962. After some modification a second test of longer duration was conducted in August, 1962. These operations aimed at running in the plant and also at determining the operating temperature to produce specification char and the maximum capacity of the...

Jan 1, 1963

By X Sun, L B. Zhou, H Yi, X Tang, P Ning

The rapid industrialisation in China has consumed large amounts of various industrial raw materials, which has left behind large quantities of industrial solid wastes produced from the processes of mining, mineral processing and smelting. The storage of huge quantities of industrial solid wastes is an obvious risk to the environment and human well-being. As the first step to fully appreciate the scale of this risk, it is necessary to carry out research for developing a pollution source environmental risk assessment system (PSERAS), especially for the typical staple industrial solid waste (TSISW). This paper aims to discuss the frame of the PSERAS for TSISW for large scale production. This system consists of two aspects: predicted factors and accidental ones, which involve physical, chemical and biological risk assessments, on-site and during transportation process. Two analysis methods, the analytic hierarchy process (AHP) and fuzzy logic assessment (FLA) were used to handle the complexity of environment and non-quantitative data. The risk assessment system for such a complex objective is difficult and the assessment of relative factors is problematic through the usual quantitative analysis. With the proposed PSERAS, it is possible to define the risk class of pollution sources. Furthermore, the risk assessment results will be helpful to the decision-maker, especially when facing unknown risks in the environmental management of industrial solid wastes. In addition, by means of the PSERAS, risk factors can be ranked against their contributions to environmental risk, in order to calculate their relative priorities in decision-making.CITATION:Sun, X, Ning, P, Tang, X, Yi, H and Zhou, L B, 2012. Environmental risk assessment system for typical staple industrial solid wastes, in Proceedings Life-of-Mine 2012 , pp 301-304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Daniel Richards, Dr Rob Farnfield, Dr Geoff Adderley

The 8-millisecond rule has been in use for many years as a basic technique to help minimize vibration levels from surface blasting operations. The rule was based on work carried out in the 1960’s by the USBM by recording the vibration levels from a series of test blasts in a quarry over a range of distances. This work included the firing of a series of single hole blasts and a number of single row production blasts using a variety of inter-hole delay times. The delay times employed were limited by the technology available at that time to instantaneous, 9, 17 and 34 milliseconds. There have been several papers in recent years suggesting that the use of the 8-millisecond rule is no longer required, when using electronic detonators, due to their enhanced accuracy and greater initiation pattern design flexibility. This paper examines this proposition by revisiting the original work and employing the linear superposition technique to reprocess some of the original recordings. Similar techniques are then applied to a large database of single hole vibration recordings for a range of rock types, distances, and number of decks, with calculated reinforcements compared to the minimum separations in typical patterns. The results suggest that there is some validity to the 8-millisecond rule when applied to electronic detonators but not in the way it is traditionally applied. Simple guidance is suggested for those designing blasts with electronic detonators to minimize vibration levels even if the benefits of linear superposition trials are not available.

Jan 21, 2025

Politicians and economists talk glibly about the so-called knowledge revolution. The reality is that knowledge is fundamental to economic progress. Consequently there have been many technological revolutions. The global impacts of the invention of the steam engine and the development of the frozen meat industry are well known. Another less publicised technological advance occurred in Central Otago late in the nineteenth century. This was the adaptation of the bucketladder dredge to the mining of placer deposits. A product of over 30 years experimentation and innovation, New Zealand dredging technology was taken to the Risdon Iron and Locomotive Works, San Francisco by R H Postlethwaite, a Dunedin based mining engineer. New Zealand-style dredges built by Risdon operated successfully in California, Alaska and the Yukon. Californian engineers assimilated the best features of the New Zealand dredges with American (Bucyrus) designs to produce a standard for the worldwide placer mining industry.

Jan 1, 2003

By M. G. Pelipetz

High-pressure, high-temperature hydrogenation of coal has been known and practiced for many years. A full' understanding of the mechanism in this process by which coal is converted to oil and gas must rest on a critical interpretation of the manner in which external variables influence the rate and the course of the coal-hydrogenation reactions. Same Bureau of Mines studies on the effect of temperature, catalyst, and rank of coal on these reactions have been published. The effect of pressure was not studied in this earlier work, and the effect of reaction time was complicated by the interruption of long reaction periods in order to refill the autoclave with hydrogen. It is the purpose of this paper to present data from more recent autoclave experiments that extend the results of Storch, et al, on the kinetics of coal hydrogenation. These data must be explained by any comprehensive theory of coal hydrogenation; their detailed evaluation, however, will be deferred until a later publication.

Jan 1, 1949