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By J. S. Webb

This is one of a series of papers dealing with mining methods, practice, and costs be¬ing published by the United States Bureau of Mires. In this paper a description of the mining practice in vogue at the Braden unit of the Kennecott Copper Corporation is undertaken. PRODUCTION At present (1931) the entire production of ore is being obtained from the Teniente mine. The miring method in use is an adaptation of block undercutting which has been a development of the stoping and pillar caving experience obtained at this property. Improvements in mining practice are constantly being made.

Jan 1, 1932

By SHANTAE LEE, ELAHEH TALEBI, Frank A. Drews, W. Pratt Rogers

Fatigue in mining operations is a serious issue and a significant contributor to incidents and accidents. While mine operators are using or introducing new technology to monitor operator fatigue, there is little work that focuses on the subjective experience of fatigue and the use of fatigue monitoring technology. To investigate this issue, eight focus groups with a total of 44 operators of heavy haulage equipment working for two mining companies in the Mountain West of the USA participated in 1-h focus groups. The topic of the focus groups was the experience of operator fatigue and issues surrounding fatigue at the workplace. The results of the content analyses suggest that operators are well aware of the signs of fatigue, and that they understand the severity of these signs as well. In addition, they are aware of the effect of fatigue on driving performance and are using a wide range of methods to manage fatigue. Finally, based on participants’ assessment, current fatigue monitoring systems lack face validity and reliability and are perceived as not being effective. The results of this study emphasize the importance of a socio-technical systems perspective in the context of miner health and safety management. Only such a comprehensive perspective can result in improvements that are sustainable.

Jun 17, 2020

By R. W. Geehan

The Yellow Pine zinc-lead mine, situated about 3-1/2 miles northwest of Goodsprings, Clark County, Nev., was explored by core drilling during the fall of 1942 and the summer and fall of 1944 by the Bureau of Mines in cooperation with the Federal Geological Survey. The Yellow Pine district was located in 1855. The original claims covering the Yellow Pine mine were located in the following years: Rover, 1892; Hilo, 1897; Bybee, 1900; Radio and Como, 1906. The mine was operated by the Yellow Pine Mining Co. from 1906 to 1929. This company was dissolved in 1935. At a later date, S. E. Yount and the Security First National Bank of Los Angeles, Calif., acquired ownership of the mine. Since 1939, the mine has been operated in a small way by leasers. Production has been at least 175,000 tons averaging about 10 percent lead and 25 percent zinc, with a gross yield of $5,785,174. Virtually all ore produced by this mine consisted chiefly of oxidized zinc and lead minerals and came from long, pipelike shoots in the 100-foot thick Yellow Pine limestone. Ore shoots are sharply defined; elsewhere, the limestone is nearly barren. Numerous faults cut the mine into blocks. Ore is now mined in an open stope, but in the past, large tonnages wore mined in stopes by square-set methods. Ore produced recently was shipped direct to smelters unprocessed; in the past, it was milled by gravity and produced separate lead and zinc concentrates.

Jan 1, 1949

By Stephen G. Downs

PCF?, or Penetrating Cone Fracture, is a propellant-based technique for rock excavation, which has significant potential for the mechanization of narrow-vein mining. The technique is currently being developed for use in the narrow-vein flat-dipping gold and platinum deposits in South Africa in conjunction with major mining companies. The technique is also applicable to steeply dipping vein deposits, such as those found in North America, Australia and elsewhere. The implementation of PCF? in South Africa to date is reviewed and plans for the introduction of PCF? excavation in other areas are highlighted.

Oct 1, 2001

By S. P. Lowe

Introduction In the following pages a general description is presented of the concentrator and cyanide plant of the Hudson Bay Mining and Smelting Company, Limited, at Flin Flon, Manitoba, together with some account of the steps which have led to the adoption of the present practice. For an account of the preliminary test-work and pilot-mill operation, the reader is referred to a recent paper by R. E. Phelan on the History of Flin Flon Mine up to Construction (1). Additional notes may be found in a paper which the writer presented at the Annual Meeting of the Institute in 1930 (2). The first ore was crushed in the present plant on July 1st, 1930, and the first ball-mill was started one month later, on August 1st. Since that time, production has been continuous with the exception of one month lost during a strike in the summer of 1934. There have been no major changes in equipment or methods of treatment since the present plant was built, but many minor changes have contributed to the improvement in results obtained and to the increase in capacity to the large tonnage now being milled. The accompanying flow-sheets indicate the equipment used in the several plants, with the average life and repair cost. As originally built, the concentrator was to treat 3,000 tons per day, but the capacity has been increased to 4,400 tons. The methods adopted to make possible this increase in tonnage will be referred to below. It was the intention to produce two classes of ore: (1) a heavy sulphide, and (2) a disseminated ore. The mill was consequently divided into two sections, each adapted for most efficient treatment of one particular type of ore. However, it was soon found that it would be impossible to mine the two classes of ore separately, so it was decided to treat open-pit ore, which varies greatly in character, in the sulphide section, and underground ore, which is fairly constant, in the disseminated section. This segregation is still maintained.

Jan 1, 1935

By S. Todd Mickleborough

The geostatistical technique of conditional simulation is applied to measure the uncertainty in factor of safety predictions for soil slopes where there is incomplete knowledge of the spatial distribution of soil properties. A case study considers a natural clay slope in Canada. The sequential indicator simulation technique is used as a means for generating a series of spatial maps of soil properties for this site. These maps approximate random draws from the conditional probability density function that characterizes existing uncertainty in the spatial distribution. Factor of safety determinations are then made for each simulated map using the simplified-Janbu approach, where the computations are performed with a new computer program that can operate on irregular spatial profiles of soil properties specified on a discrete grid. A unique capability of this approach is the ability to generate the distribution of factor of safety conditional to the type, position, and value of existing site characterization measurements. This capability should reduce uncertainty in FS predictions.

Jan 1, 1993

By Davis E. Traut

TiC14, AIC13, and VC14 were coreduced simultaneously via a Kroll-type magnesium reduction to form an alloy sponge as part of a research effort by the Bureau of Mines to produce titanium alloy powder. Reduction tem-peratures of 750°, 850°, and 950° C, a range of chloride feed rates from 34 to 152 Ib/(ft2·h), and crucible diameters of 7-3/4 and 10-1/4 in were tested. Microprobe analyses using a 40-um-diam spot showed no effect on alloy microhomogeneity (distribution of Al and V in the Ti, considered critical as a powder property), due to changes in process variables within these ranges. Statistical analysis of these data for alloy sponge indicated greater variation in the chemical composition (AI and V) than that found in commercial Ti-6Al-4V plate or Plasma Rotating Electrode Process (PREP) powder. Therefore, a one-step approach to pow-der, such as grinding the Ti alloy sponge, would not produce a powder product of acceptable chemical homogeneity. An approach that homoge-nized the sponge, such as with a melting step, would produce an accept-able powder product with respect to chemical homogeneity.

Jan 1, 1987

By H. El-Faramawy, A. Ahmed, M. Eissa, M. El-Fawakhry, T. Mattar, S. N. Ghali, E. M. Kotb

As a result of the depletion of high-grade manganese reserves, it has become necessary to consider the exploitation of low-grade manganese ores. The main problem of low-grade manganese ore is the low Mn/Fe ratio, which makes it unfit for the production of manganese ferroalloys. In this work, a selective reduction technique was used for smelting low-manganese ore in the presence of coke and fluxing material in an electric submerged arc furnace to obtain a rich manganese slag and low-manganese pig iron. The product slag was blended with medium-manganese ore and smelted in an electric submerged arc furnace, in the presence of coke and the fluxing agent, to produce silicomanganese alloy. The influence of reducing agent ratio, charge basicity, and charge Mn/Si ratio on the smelting process was investigated. The optimum conditions were found to be a coke ratio of, 1.35, Mn/Si ratio of 2.0, and charge basicity of 2.5. The silicomanganese alloy produced under these conditions satisfies the specifications for Si16Mn63 and Si17Mn65. The experimental results were applied on a pilot scale, producing a silicomanganese alloy with a chemical composition close to that of the standard specifications.

Jan 2, 2022

By Kefton H. Teague

This paper deals with the practical application of the Dutch State Mines cyclone separator for fine-coal cleaning. The more important operating variables are discussed, and results of a number of continuous-scale tests on various fine coals with a 6-in. cyclone separator are given. Descriptions of the Cyanamid Pilot Plant and the 50 tph Cyclone Separator Plant at the Emma Washery in Holland are included.

Jan 1, 1950

By Michael E. Charles, Jaroslav J. Vocadlo

"The hydraulic transport of solids through pipelines can have many advantages over other modes of transport. Numerous successful applications both within plants and over longer distances have demonstrated the technical and economic feasibility of slurry pipelining. Solids successfully transported include kaolin, coal, iron ore, gilsonite and limestone, and others, such as sulphur and potash, are likely to be transported in Canada in the near future. However, though the technology of solids pipelining is quite advanced the underlying principles have not yet been formulated past the semi-empirical stage. The main objective of this paper is to present a discussion of the important technical and economic considerations in the design of so lids pipeline systems by reference to typical data. The Worthington slurry pumps and pilot facilities are briefly described."

Jan 1, 1972

By G Le Juge, K Waldock

The current suite of bulk mining explosives has been available to the industry for over 20 years. The flexibility and performance of ammonium nitrate based emulsion blend explosives were accepted by the mining industry in the early 1980s. These water resistant explosives rapidly displaced the water gels and slurries developed during the previous two decades. However, since the 1980s there has been no equivalent step change to the basic formulation or application of bulk explosives, although there has been a continuous process of refinement with respect to stability, handling characteristics and most significantly, cost. In the 1980s explosives supply contracts were awarded based on technical evaluations, usually accompanied by field trials. Technical personnel from both mining companies and explosives suppliers dominated the negotiations and there was a strong focus on explosive energy and blasting requirements. Today, explosives from alternative suppliers are difficult to differentiate on the basis of energy so the focus has shifted to aspects of service and price û bulk mining explosives are now largely treated as a commodity and the negotiations are dominated by commercial personnel. Commercial pressures from large mining companies have seen a substantial reduction in the real price of explosives. However, this has come at a cost. In order to reduce manufacturing costs, emulsion formulations have changed. In general they are not only cheaper, but also less energetic. Powder factors have had to increase to achieve the same blasting results, especially in hard ground. It is debatable whether the mining companies have achieved all of the economies they were seeking. This paper discusses these issues and argues that the mining industry would benefit from taking a more technically driven approach to meeting their blasting requirements. Recent trends towards more open contracts between the mining companies and their suppliers can be extended to explosives. To achieve this, mining companies will need to acquire sufficient technical knowledge to take a more pro-active approach to specify the characteristics of the explosives required to maximise the economic performance of their operations.

Jan 1, 2004

By STUART R. BRINKLEY, Ruth F. Brinkley

This same phonomonon of diffraction may be transposed into the X-ray domain. All that is necessary is to reduco, in the samo proportion, the wavo length of the light and the diameter of the particlo; thus, with radi- ations whose wave length is of the ordog of angstroms, the dimensions of the active particles go from 10 to 100 A that 18, the dimensions of col- loidal particlos. The evidence of this fact is shown by the following experimental schomo (fig. 1a): A narrow beam of X-rays passes through a thin layer of a modium containing micelles; the photographic film is placed a few centimeters behind the sample, and a small absorbing screen stops the direct beam in order to prevent its fogging the film. The intersect of the direct beam is surrounded by a narrow spot whose blackness decreases with the distance from the center. We will call this the spot of central diffusion (fig. 1b). The phenomenon, in spite of its relatively reat intensity, has been observed only by a few authors, who have simply given a qualitative description without attempting any quantitative de- ductions. This is due to the fact that observation of this phenonenon is not possible with the apparatus generally used to obtain X-ray diagrams, because the parasite foggings in the vicinity of the incident beam are sufficiently important to hide those produced by the sample. With the monochromator, however, used by us to obtain Debye-Sherer diagrams, this parasitic diffusion can be totally suppressed. In this way our attention was again directed to the spot of central diffraction, and we were led to make a detailed quaititative study of it.. then several papers have been published on this subject. Hosemann, using methods of calculation outlined by us, has extended them to the special case of fibrous substances, Kratky, on the other hand, starts from an entirely different theoretical point of view; ho examines the case, not of scattered particles, but of closely packed particles. 6ince We will now describe the experimental methods, summarize the calcu- lations needed in the elaboration of diagrams, and finally review the first results obtained in the vast domain of these new physical-chomical studies.

Dec 1, 1946

By I. I. Betcherman

INTRODUCTION A DISTILLATION process offers one of the most effective methods of refining metals. Its use is particularly attractive in the case of reactive metals which are not readily treated by pyrometallurgical or electrolytic methods. The 1ow vapour pressure of most metals severely restricts the applicability of the disti1lation process and only one or two metals may be effectively treated under atmospheric pressure at a reasonable temperature. If operations are carried out under reduced pressure several additional metals may be effectively distilled. Table I shows the vapour pressure of a number of metals together with a value of the free energy of formation of their ?oxides. Zinc and cadmium head the list and for many years? they have .been effectively refined by distillation. Sodium, magnesium, and calcium follow in descending order, and they may be distilled readily in vacuo and with difficulty at atmospheric pressure. Sodium, which is not of great metallurgical interest, is not considered. Magnesium has recently been produced in considerable tonnages by distillation methods ( 3). This paper describes the vacuum distillation of magnesium and calcium, their separation from each other, and their separation from less volatile impurities.

Jan 1, 1951

By D. E. Wolfson

Twenty-two samples of West Virginia coals were carbonized at 9000 C by the Bureau of Mines-American Gas Association (BM-AGA) method, and yields of products and physical properties of cokes were determined. Eighteen samples represented the Coa1burg, No. 2 Gas, No. 2 Gas and Peerless, Powellton, Eagle, Big Eagle, Lower Eagle, Sewell, Fire Creek, and Pocahontas No.6 beds in Fayette County, and four samples represented the Sewell and Fire Creek beds in Greenbrier County. Expansion characteristics of the majority of samples were determined in the Bureau of Mines sole-heated oven. Chemical analyses were determined for all coals. The coals in Fayette County are high-volatile A, medium-volatile, and low-volatile in rank, and the Greenbrier coals are medium-volatile in rank. Most of the coals are chemically suitable for metallurgical coking. All coke strength indices are within acceptable limits for metallurgical coking coals. All the high-volatile A coals contracted and the medium-and low-volatile coals expanded in the sole-heated oven expansion test.

Jan 1, 1966

By M. Holmes, R. Molnar, E. Norton, K. Baxter, J. Riordan

The Boleo Copper-Cobalt-Zinc-Manganese Project of Baja Mining Corp. is situated adjacent to Santa Rosalia on the Baja Peninsula of Mexico. The El Boleo ore is a mixed oxide-sulfide deposit with major values in copper, cobalt, zinc and manganese. The metallurgical process designed to treat the El Boleo orebody involves a sulfuric acid leach in seawater using oxidative and then reductive leaching to maximize metal extraction. The leach solution is separated from the barren solids via counter current washing through a series of high rate thickeners. Copper is recovered using conventional SX-EW processing as cathode. Zinc and cobalt are extracted from the copper SX raffinate after iron and aluminum precipitation. The CSIRO DSX solvent system (Versatic® 10 and LIX® 63 mixture) are used in this extraction. Manganese remains in the DSX raffinate and is recovered by soda ash addition as a high quality manganese carbonate precipitate. Zinc and cobalt are acid stripped from the loaded DSX solvent. Zinc is then re-extracted away from cobalt using Cyanex® 272 extractant and stripped into a highly concentrated strip liquor (+100 g/L Zn) and directed to either a spray dryer or a granulator for production of zinc sulfate monohydrate. The zinc solvent extraction raffinate, containing cobalt, advances to another SX circuit using Cyanex® 272, for the recovery of cobalt as cobalt cathode. In this paper, the detailed results from bench and integrated pilot plant testing for zinc recovery from the El Boleo ore will be described. The results of this testing are currently being used to engineer the commercial plant at El Boleo.

Jan 1, 2008

By B D. Burford

High intensity stirred milling using the IsaMill has been the enabling technology for many projects by transforming the economics of fine grinding and simplifying circuit design. IsaMill grinding technology was originally developed for large-scale grinding to P80 sizings of 7 ¦m. The IsaMill is a high throughput, high efficiency mill that produces sharp product size distributions in open circuit configuration. The ability to grind in an inert environment, using a wide variety of media types, can give further metallurgical and economic benefits. The high energy intensity results in a small footprint that enhances the ability to distribute grinding power throughout the circuit, applying grinding energy to the minerals that need it. Recent scale up developments in IsaMill technology have enabled the benefits to be extended to large-scale conventional grind sizes, until now the domain of ball and tower mills. This paper will examine the crossover of IsaMill technology from ultrafine applications into the more conventional grinding area (P80 20 - 150 ¦m). Scale-up developments in IsaMill technology that have enabled this are reviewed. The upcoming commissioning of a 3.0 MW M10,000 IsaMill, the most powerful to date, grinding to P80 55 ¦m at PPL in South Africa will be discussed, as will the recent commissioning of a 2.6 MW M10,000 IsaMill at Kumtor. Recent testwork at McArthur River, where an IsaMill is being considered as an addition to the primary grinding circuit to replace the current tower mill will be reviewed. The potential combination of HPGR and IsaMill to transform concentrator grinding economics will also be discussed. Large-scale IsaMill technology has the ability to transform circuit design and energy efficiency for both coarse and fine grinding.

Jan 1, 2006

By Robert H. Merrill, James V. Williamson, David M. Ropchan, George H. Kruse

In- situ rock stresses were determined by flatjack and borehole - deformation methods . Estimates of the stress distribution around a flatjack were obtained by a combination of flatjack and borehole - gage techniques . The investigations were part of a study , conducted jointly by the State of California and the Federal Bureau of Mines , to determine the stress in rock at the site of an underground powerplant for the Oroville Dam near Oroville , California . The stress distribution around each of three flatjacks was nonsymmetric ; however , stresses obtained from 9 flatjack and 157 borehole measurements are considered reasonably accurate for engineering purposes . The stress near the edge of the openings is between 800 and 1,600 psi ; the stress in the undisturbed rock is approximately 500 psi , nearly hydrostatic .

Jan 1, 1964

By D. R. Pyke, R. S. Middleton

"Three main types of base metal sulphide mineralization are present in the Timmins area:(1) -Massive and stringer-type copper-zinc deposits occurring mainly in pyroclastic rocks, as typified by the mines of Kam-Kotia, Jameland and Canadian Jamieson, or within or close to possible breccia pipes as shown by the Genex and Kidd Creek mines. With the exception of the Kidd Creek mine, all of these orebodies occur northwest of Timmins (Kamiskotia area) and appear to lie within or close to a major center of volcanic activity characterized by a thick accumulation of felsic pyroclastic rocks and subordinate epizonal intrusions. The margins of the rhyolitic pile are interfingered with mafic volcanics; overlying sedi-ments mark the termination of a vol-canic cycle. The copper-zinc deposits in the Kamiskotia area are confined to a particular stratigraphic unit. Ore-bearing solutions were probably derived from the intrusive complex of the volcanic pile.(2) -Porphyry copper deposit of the Mcintyre mine. The deposit occurs in a quarz porphyry intrusion related to the volcanism in the area (Hurst, 1936). Mineralization was probably introduced at the time of intrusion, and subsequently redistributed within the porphyry during deformation. (3) -Massive and disseminated nickel mineralization, associated with serpentinized alpine-type ultramafic intrusions, as shown by the Alexo, McWatters, Hart, Inco and Texmont deposits. The nickel mineralization occurs at or near contacts of the serpentinites with felsic or mafic volcanics, or sulphide-bearing iron formations. The nickel deposits south of Timmins are confined to a particular stratigraphic unit along the margins of domical-shaped structures which appear to outline former volcanic centers. Sulphurization as pro-posed by Naldrett (1966) appears to be a workable hypothesis for the formation of some of the deposits."

Jan 1, 1971

By N. L. Kozlinsky, B. W. Gandrud

"The Marvel mines 1 and 3 of the Roden Coal Co. are located in the Cahaba field in Bibb County, Ala., nearly southwest from Birmingham, an airline distance of roughly 30 miles. The coal of the Clark seam at this point has some coking properties, but at present it is sold exclusively as a domestic and steaming coal.This paper, which is the second of a series on the washability of Alabama coals, like its predecessor dealing with the Mary Lee seam,5 contains screen-sizing and float-and-sink tests of a representative sample of the raw slack, and slotted-screen tests showing the proportions of flaky particles in certain selected sizes; inasmuch as this coal is not used for coke manufacture, no crushing tests have been made. These data have been obtained in connection with an exhaustive study of coal preparation in Alabama, now being conducted by the United States Bureau of Mines and the University of Alabama with the cooperation of the different coal operators. As the work progresses, other papers will follow containing further data on Alabama coals and giving results obtained in preparing these coals by various methods.The only published investigative work on the Clark seam is that of Forbes,6 who gives a number of sections of this seam in Marvel No. 3 mine with proximate and ultimate analyses of face samples taken in the mine and also some analyses of delivered coal.The available information on this coal indicated that the preparation problem was one of ash reduction. In order to substantiate this information a complete analysis of the 3/4 by 3/16 inch size, and sulphur determinations and ash-fusibility tests of the float-and-sink fractions have been made; these results are given in Tables 1 and 2. As these results also indicate that the preparation problem is one of ash reduction, the tests and discussion have been devoted to that subject."

Jun 1, 1930

By P. Kostuik

"Recent interest in the pipeline transport of solid mate-als has been sparked by the idea that, in an inflationary onomy, pipeline costs are more stable than the costs of any other transport systems. Pipelines have proved over 1e years to be dependable, records indicate that main-•nance and operating costs are comparatively low, and 1eir amenability to automation is of considerable im->rtance.The concept of hydraulic hoisting of solids from under-round, or cross-country hydraulic transportation of con-~ntrates and ores, is currently of prime interest to the ining industry. In general, this paper deals with a preliminary investi-ation of energy losses incurred while transporting a rela-vely heavy, crushed mine product, namely magnetite, oth vertically and horizontally. The basis and validity of everal equations derived by other experimenters to com-ute these losses is discussed. A theoretical analysis of ydraulic hoi:,,ting is made, and, based upon test results, calculation of horsepower requirements for hoisting an re under a given set of conditions is presented. Results indicate that:n vertical transport, the friction head losses are identical to those of clear water, and the total energy requirement for hydraulic hoisting then becomes a function of height of lift, concentration and specific gravity of the solids being hoisted. .-In horizontal transport, friction head losses can be calculated with reasonable accuracy using Bonning-ton's correlation curve. Losses computed utilizing Durand's correlation (K = 85) result in estimates which are too low by 10 to 30 per cent, an<l those calculated using Newitt's correlation (K = 1,100, K = 66) give friction loss values which are too high by 10 to 30 per cent . . -The theoretical horsepower (RMS-hp.) required for hoisting hydraulically is approximately half of that required for conventional double-drum skip hoisting."

Jan 1, 1966