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By B. W. Jong

The Bureau of Mines studied reinforcement of sulfur concretes using glass, polyester, and aramid fibers. The objective of this research was to determine the feasibility of fiber-reinforcing the sulfur concrete to enhance the flexural properties. Optimum fiber sulfur concrete compositions were formulated with a cement-to-fiber ratio of 9.0:1 for glass-fiber and polyester-fiber sulfur concretes and 12.1:1 for aramid-fiber sulfur concretes. Test samples were prepared using techniques developed by the Bureau of Mines. Flexural strength values of up to 50 pct of compressive strength values were achieved with fiber additions. With non-fiber-reinforced sulfur concrete, the values ranged up to 20 pct. The impact strength and fracture toughness of sulfur concretes were increased sig-nificantly by reinforcement with glass or with aramid fiber and were adversely affected by use of polyester fiber. Strain tolerance was doubled and failure mode was shifted from catastrophic to noncatastrophic type by adding glass fiber. The glass-fiber and aramid-fiber sulfur concretes are resistant to acid corrosion and have proved durable in freeze-thaw cycles. This laboratory and field evaluation has shown that fiber reinforcement of sulfur concrete is feasible and that it enhances the flexural properties.

Jan 1, 1985

By M Recabarren, A Echeverria, J Ronda, J I. Guzman, R Dodds, G Juarez, E Vila-Echague

A strategic mine plan is a fundamental part of any mining operation. It must provide a realistic and operative extraction and processing schedule, and yield the highest value for the business. For open pit mines, the problem can be modelled as a set of blocks representing the deposit, for each of which we need to decide if it is going to be mined, if so, when and where it will be sent (process, stock or dump).This problem can be proven to be of NP-Hard complexity. The traditional approach used by mining engineers to tackle this complexity is to separate the problem into more tractable components, solving each separately. The first step is to use the Lerchs-Grossman (LG) algorithm to obtain the final pit limit, as well as a set of optimised pit shells (nested pits), using different input prices. Then, using this input, operational phases are designed. Third, the set of phases can be used as an input for a phase-bench style optimisation, usually using a mathematical programming-based algorithm.There are, however, several problems with this approach. First, dividing the problem into simpler parts has the consequence that any compromises made at early stages limit the potential value left for the following steps. Second, LG is a static algorithm, with no concept of the time-value of money, capacity limits, opportunity costs, etc. Phase design is essentially a manual step, for which nested pits provide insufficient information in practice, and therefore the quality of the result in terms of potential net present value (NPV) depends strongly on the experience and expertise of the designer. This means that key input data such as commodity prices, different processes capacities and mine movement limits, are considered only at scheduling, when there is little room for optimisation. This sequential approach limits the potential value in each step, where a simplified problem is addressed, instead of addressing the real, and more complex problem, which is dynamic and should be solved as a whole.We present in this paper an algorithm, and its commercial software implementation, that addresses the dynamic problem as a whole, simultaneously and automatically creating a high-value strategic mine plan that adheres to basic operational constraints, determining dynamic cut-off grades and delivering a set of phases which can serve as a much stronger guide than nested pits for the final design. We discuss some of the key elements of the algorithm and propose a new methodology for strategic mine planning, where phase design dynamically responds to mining strategy definition. Results using different mining and operational parameters on a fictitious copper deposit are used as a demonstrative example.CITATION:Juarez, G, Dodds, R, Echeverria, A, Guzman, J I, Recabarren, M, Ronda, J and Vila-Echague, E, 2014. Open pit strategic mine planning with automatic phase generation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 147–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 years, until in 1936 probably more than 80,000 such units were put into use, According to reports of the Bureau of the Census 75,543 residential stokers mere sold in the first 10 months of 1937 by 108 manufacturers. This rapid expansion has made itself felt in the coal-mining, industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912 in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of tie present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By André de Albuquerque Vicente

O valor do PREN da liga pode levar a uma previsão equivocada da resistência à corrosão por pite pois, caso haja um desbalanceamento das frações volumétricas da ferrita d e da austenita, as composições químicas das fases poderão ser muito diferentes daquela da liga. Neste caso o PREN de uma das fases pode ficar abaixo do PREN da liga. Caracterizou-se três chapas de aços inoxidáveis duplex laminados com diferentes PRENs: UNS S32304 (Lean Duplex), UNS S31803 (Duplex) e UNS S32750 (Super Duplex). Várias técnicas complementares de análise microestrutural foram utilizadas, tais como de espectrometria de emissão ótica, microscopia óptica e microscopia eletrônica de varredura com EDS acoplado. Realizaram-se análises metalográficas quantitativas para a determinação das frações volumétricas de ferrita d e da austenita e análises químicas semi-quantitativas das fases presentes utilizando-se um MEV com EDS acoplado.

Oct 30, 2017

By Jaisen Kohmuench, Michael J. Mankosa

Flotation has long served as the foundation for sulfide mineral recovery. As ore grades decline, however, this traditional approach is being pushed to the limit. Nowhere is this more evident than in the challenge of recovering coarse, partially liberated particles — an area where conventional flotation systems typically underperform due to excessive turbulence. As a result, valuable coarse minerals are often lost to tailings. Fine grinding has become the default solution, although with the added burden of higher operating costs and more challenging tailings disposal. To address the challenge of coarse particle recovery, Eriez developed the HydroFloat, a technology that uses a novel fluidized-bed approach to extend the upper particle size range of flotation significantly. The HydroFloat can recover particles exceeding 0.5 mm in diameter with a sulfide surface expression as little as 2 percent. Coarse particle recovery allows for optimization of comminution circuits for coarse gangue rejection before fine grinding. A substantial increase in overall tailings particle size provides higher water recovery due to improved drainage and allows for consideration of a dry, stacked tailings option instead of a tailings dam/impoundment. The technology’s transformative potential has not gone unnoticed. In recognition of its impact, Eriez was honored with the 2024 Robert E. Murray Innovation Award, commonly referred to as the Murray Award, by the Society for Mining, Metallurgy & Exploration. This prestigious award was established in 2017 to recognize organizations that advance the mining industry through the implementation of technical innovation. The HydroFloat stands as a fitting example of how creative thinking and industry collaboration can solve long-standing technical challenges.

Oct 1, 2025

By P. James

Blue Planet Strategies (BPS) focuses on improved resource utilization and targets converting wastes into resources. New BPS capability (DEMET) wrings extra value from mining and processing wastes by enabling new production from waste and residual sources. This powerful platform technology provides considerable processing flexibility and enables various new economical treatment options to extract key metals from low level and process byproduct stream sources normally left as waste by traditional processing methods.[1]

Feb 23, 2014

By A. R. House, G. W. Shepherd

Newmont USA Limited owns and operates the Phoenix Mine near Battle Mountain, Nevada, USA. The existing milling facility has operated since 2006 (House, 2010). Following the startup of the milling operation, and coupled with the upswing in the copper market, Newmont realized that Phoenix had no process option to treat transition and oxide copper ores. This meant that potentially revenue generating ore would be mined as waste. With no system in place to treat the transition and oxide copper, work began to determine the most feasible approach. After evaluating multiple options, the flow sheet was set for a runof- mine (ROM) heap leach pad and solvent extraction/ electrowinning plant (L-SX/EW). This paper will discuss the eight years of successes and challenges with developing the copper L-SX/EW plant and achieving commercial production of copper cathode.

Jan 1, 2014

By John F. Wiggert

The first signal system used in the Homestake mine between the cagemen and hoisting engineers was a mechanical one. It consisted of small cables or jointed steel rods hung in the cage compartments and counterbalanced with weights or springs. These cables or rod strings were connected to the mechanically operated gongs at the engineers' positions by means of bell cranks and steel wires. At the various stations the bell lines were also fitted with bell cranks and connected levers, so that the cagemen could operate the bells from the stations when they were handling rock or other material and not riding on the cages. Such a system was inherited from the days before extensive electrical development. It served quite well for shallow shafts, but for depths of a thousand feet or more it was very slow and cumbersome. It required consider-able muscular effort to operate it quickly, because of the inertis of its great weight and also because of frictional resistance. The maintenance cost was quite high because of the many wearing parts.

Jan 1, 1937

By Kirk Carlton

The Athabasca tar sands of Alberta are an increasingly important source of crude oil for the North American continent. Published figures indicate estimates of recoverable resources in the tar sands at some 300 billion barrels of synthetic crude of which some 86 billion barrels can be recovered by surface mining techniques. At the present time, two commercial plants are in operation, Great Canadian Oil Sands Limited and Syncrude Canada Ltd. Their present combined capacity is approximately 150,000 barrels per day. Some of the factors which will make this oil expensive will be noted here. The location of the present producing plants is 500 kilometres north of Edmonton at an elevation of approximately 320 metres. Recorded temperatures range from +38 to -55 degrees Celsius. Wind velocities are not high but the chill factor with even a slight breeze and minus 40 degrees is very uncomfortable.

Jan 1, 1979

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 rears, until in 1936 probably more than 90,000 such units were put into use. According to reports of the Bureau of the Census 79,543 residential stokers were sold in the first 10 months of 1937 by 109 manufacturers. This rapid expansion has made itself felt in the coal-mining industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912; in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of the present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By Charles W. Perdue

This U.S. Bureau of Mines report considers, from a psychological perspective, the perceptual process by which miners recognize and respond to mining hazards. It proposes that if the hazard recognition skills of miners can be improved, mining accidents may be reduced to a significant degree. Prior studies of hazard perception in mining are considered, as are relevant studies from investigations of military target identification, pilot and gunnery officer training, transportation safety, automobile operator behavior, research into sensory functioning and visual information processing. A general model of perception is introduced, and selected concepts from the psychology of perception that are applicable to the detection of mining hazards are reviewed. Hazard recognition is discussed as a function of the perceptual cues available to the miner as well as the cognitive resources and strategies employed by the miner. The development of expertise in responding to hazards is related to individual differences in the experience, aptitude, and personality of the worker. Potential applications to miner safety and training are presented.

Jan 1, 1995

In 2007, a total of 7,199 sand and gravel mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 ? Sand and gravel mines were the largest mining sector, comprising 48.4% of all mining operations. ? Sand and gravel mines were found throughout all 50 states and Puerto Rico.

Aug 1, 2009

By P. A. Lilly, W. Sarunic

In most cases, slope movement monitoring data are collected on a temporal basis and displacement or velocity is plotted against time in order to assist the engineer to make judgements about slope behaviour. Once an unusual behaviour pattern has been established, the data are then analysed to estimate when the key inflection points occur in the data, when the slope movements start to accelerate and, ultimately, when the slope is expected to collapse. The identification of these inflection points is sometimes difficult to achieve with the naked eye. This paper presents the application of a trend analysis technique, known as cusums, to assist in this process. The authors have presented a range of data from various real life examples which highlight the effectiveness of the cusums technique. A key aspect of the cusums technique is the use of a constant (K) against which data trends are assessed. This constant is best derived from slope performance data at each site, as each rock mass will behave in its own unique way. The authors have experienced slopes that have had threshold values ranging from 0.1mm/day through to 10mm/day, and therefore a conservative approach should be adopted when assessing the performance of slopes.

Jan 1, 2006

By R Benton

Since commencement of underground production in March 2006 the Kencana K1 orebody has delivered over 0.9 Mt of ore containing 1.18 Moz Au until April 2009. The Kencana deposits are part of the Gosowong goldfield located on the island of Halmahera in eastern Indonesia. The district has produced over 2.3 Moz since mining commenced in 1999 with the first two deposits extracted by open pit methods. The K1 deposit is technically challenging being a vein style deposit with poor to very poor ground conditions and a relatively low overall dip of around 45 degrees to mine grid east. It is mined under geological control by underhand cut and fill methods utilising cemented paste backfill aiming for 100 per cent extraction. With these conditions the operation was mine limited in the initial two years of production resulting in low stockpile levels for mill feed blending and hand-to-mouth mine to mill production. Mill feed rates have increased from 30 t/h to 55 t/h over this period following business improvement projects while mine production has escalated to match this increase as deeper levels of the deposit are accessed. The operation has now become mill limited. Monthly mill gold production from Kencana has ranged up to 50 000 oz with head grades ranging between 8 g/t and 122 g/t Au on a daily basis. As individual grade control assays can extend into the per cent Au range there are challenges in sampling, modelling, mining, blending and milling the Kencana orebody. At the time of commencement of ore driving in K1 the national geology team had little prior experience in underground mining and systems were in early development. The variances in feed grade and tonnages have been reduced with time as the operation evolves and business improvement initiatives are undertaken to smooth peaks and troughs in ore supply. Two such initiatives in the geology department have added over US$20 M of additional revenue per annum.

Jan 1, 2009

By L. F. Pease, J. H. Brophy

A phase diagram for the Ta-Zr system is presented. The system is of the minimum-melting point type with the 0-zirconium phase decomposing monotectoidally at 785°C and 95.5 at. pct Zr. The minimum solidus temperature is 1875°C and the temperature of the top of the monotectoid loop is 1775°C. Techniques employed included X-ray diffraction and fluorescmce, electron microprobe analyses, diffusion couples, metallography, and melting-point measurements. Errors due to interstitial solutes and in melting observations are particularly common in this system, and their occurrence is discussed. SEVERAL versions of the Ta-Zr phase diagram have been reported in the literature.lm7 Williams et al.' report a diagram of the minimum-melting point type with a monotectoid reaction at 800°C and 12 wt pct Ta. The minimum in the solidus occurs at 1820°C and 25 wt pct Ta, while the top of the monotectoid gap is located at 1780°C and 80 wt pct Ta. The experimental techniques employed were metallography, electrical resistance variation with temperature, dilatometry, X-ray diffraction, and direct observation of melting by the technique of Pirani and ~lterthum.' Experience in the Nb-Zr phase diagram has shown that small changes in the interstitial content can cause large shifts in the positions of the phase boundaries. Small amounts of inter -stitials can cause similar changes in the Ta-Zr system and may be responsible for the wide variations in the phase diagrams previously reported.'-' The authors15 have found that alloys containing 0.75 wt pct 0 and 1.0 wt pct Ni with tantalum contents from 19 to 85 at. pct often contain a lamellar or cellular precipitate after annealing above 1400°C. This precipitate is very similar to that reported by pollack,12 Ralls," and Donlevy17 for the Ni-Zr system. In the present investigation, a wider variety of experimental techniques and improved alloy purity were applied to the resolution of errors in diagrams for this system as they now appear in the literature. New results have been obtained in the areas of alloy homogeneity and purity. Errors in the common techniques of direct melting observation in binary alloys have been demonstrated. In the commercially important high-tantalum region, the more accurate metallographic method of solidus determination has been employed. EXPERIMENTAL PROCEDURE Nominal analyses of the materials employed are given in Table I. The zirconium was low hafnium reactor grade iodide crystal bar, and the tantalum was in the form of high-purity sheet. Powders were impossible to use because of gas content. Alloys were melted on a water-cooled copper hearth, with a thoriated tungsten-tipped nonconsumable electrode in 2/3 atm of Zr "gettered" argon. Alloys were

Jan 1, 1963

By J J. Grobler

The George Fisher Underground Mine at Mount Isa applies the long hole open stoping methodology. During the reconciliation process of transverse stopes in the George Fisher North mine it was identified that excessive underbreak was regularly experienced, with the major contribution coming from the toe area inside the stope.While over break and the resultant dilution was well investigated and well understood, limited work was done on underbreak improvement. It was decided that a re-engineering process would be followed in an attempt to improve results. The prevailing stoping practices were scrutinised and the possible causes were listed.Some of the identified causes were design, drilling accuracy, equipment condition, mucking practices and direction of firing. It was identified that in most instances the underbreak was initiated in the slot area of the stope during the first firings. Once this happened, it was impossible to get good recoveries on the rest of the stope. The slot area was carefully scrutinised and the blasting practices were changed individually.During the following two years several different strategies were trialled to increase the toe recoveries. The results indicated an overall improvement of six per cent reduction in underbreak on average, by ensuring drilling accuracy and changing the direction of firing. The economic significance of these results outweighed the time and additional work load expended to establish the cause of the problem. This paper outlines the continuous improvement process undertaken to identify and rectify the major contributing factors to the problem. It also presents a set of recommendations to be followed in order to achieve positive results.

Mar 21, 2011

By Rosa H. Harris

The world's largest gold dump leach operation, Minera Yanacocha S.A., has installed community assistance programs in Peru concerned with health, education, electrification, agricultural assistance and road improvements. The programs are conducted in a joint venture fashion in association with various organizations.

Jan 1, 1998

By Thomas M. Sweeney

This open-file map is a quick reference containing location, ownership, and general lithology information on 124 active or significant Nevada gold mines. The map includes all counties, significant towns, and major highways in Nevada to aid in mine location. Several geologic trends with which the mines are associated are also depicted. General ore genesis for each deposit, including sedimentary, volcanic, plutonic, and placer-hosted deposits, are also identified. Gold mines are also listed alphabetically, by mine name, on the map. Each entry includes the appropriate county, percent of company ownership, operating company, and the property status as of May 1992. For additional information, contact Thomas M. Sweeney, U.S. Bureau of Mines, Western Field Operations Center, 360 East Third Avenue, Spokane, WA 99202; telephone (509) 353-2700.

Jan 1, 1993

By AIME AIME

RECENT experiments in reflected sunlight photography in mine shaft's' and. slopes in the McAlester, Oklahoma, coal-mining district have been so satisfactory as to indicate that such a method has definite scientific value. The entrances to abandoned deep shafts and slopes on Choctaw and Chickasaw Indian coal lands in Oklahoma are being filled or bulk-headed by the U. S. Geological Survey under Public Works Project F. P. 63-C&C. Inasmuch as these mines may be reopened at some future time when there is a demand for coal, H. I. Smith, Chief of the Mining Division, suggested that photographs of deep shafts would be of value. Such photographs would show timber details and the general condition of the walls. Photographic records of the exact status of shafts when filled will facilitate operations in reopening.

Jan 1, 1936

By J. M. Sabio, A. W. Stalberg

Keywords: Pyrometallurgy, furnace, calcium carbide, acetylene, Newcastle The manufacture of calcium carbide in Newcastle, South Africa, was started in the late 1950s by a company called South African Carbide, at the Ballengeich site. In 1978, this operation was bought by the forerunner to the present AECI Ltd, a large producer of commodity chemicals at the time. Production continued at this site until 1992. In the meantime, Karbochem, an operating division of Sentrachem Ltd, was also manufacturing carbide in Newcastle, as a building block for the manufacture of synthetic rubber. In 1990, the Karbochem calcium carbide operation was closed down. In 1992, the AECI carbide business and the Karbochem production facility were amalgamated, and production continued under the Karbochem name. In 1997, the Dow Chemical Company bought the holding company of Karbochem, and the carbide business continued operations until 2003. In June 2003, the business was sold to a management consortium as SA Calcium Carbide (Pty) Ltd. Later, in October 2004, 100% of the shares were acquired by the Andina Group. Today, the Andina Group, consisting of SACC from South Africa, CIL from UK, and ANDINA from Argentina, has become a global leader in the manufacture and supply of calcium carbide and calcium silicon, ferro silicon 75% and derivatives, recarburizers with low nitrogen content, acetylene, carbon black, micro-silica, and silicon metal. The production facilities at Newcastle comprise a 52 MVA submerged arc furnace of a closed design, carbon monoxide gas recovery, recovery of fine raw materials via a hollow electrode system, and an extensive computer-controlled process. These all enable an efficient state-of-the-art operation. The downstream processing facilities consist of screening and drumming facilities, milling facilities, an acetylene generation plant, and an acetylene carbon black plant. Clearly, SA Calcium Carbide (Pty) Ltd has a long history of supplying quality calcium carbide to the industries that it proudly serves.

Jan 1, 2006