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By J. F. Wright

During the last three years prospecting has been active in southeastern Manitoba and a number of interesting gold, nickel and copper deposits have been discovered within an area 90 miles north of the international boundary, and extending about 40 miles westerly from between mileage 60 and 110 on the Manitoba-Ontario boundary. As known at present, two-thirds of this area of 2,000 square miles is underlain by pre Cambrian granite and granite gneiss and is not likely to contain mineral deposits of economic importance. The remaining one-third is underlain by metamorphosed sediments and lavas (greenstones), penetrated by the granite and granite gneiss and, at various localities, cut by bosses, sills, or dykes of gabbro, diorite, granodiorite, and other types of intrusives. The nickel, copper, and gold mineralization accompanied or followed the intrusion of these different rock types. The gold deposits are limited in distribution, so far as known, to the northern part of this prospecting area and occur along Manigotagan and Wanipigow rivers. These deposits have recently been described in some detail, (3) and therefore only the copper and copper-nickel deposits of the southern part of this area, along Oiseau and Maskwa rivers, will be described in this paper.

Jan 1, 1925

By Luis Lizárraga

El presente texto señala la perforación diamantina como el método más adecuado y rápido para la exploración de minas. Este sistema permite tener un testigo del terreno atravezado del suelo y aunque es el más caro, es el único que provee de un núcleo continuo. En este núcleo o testigo se puede estudiar de forma objetiva la estructura, consistencia y naturaleza química de las rocas atravezadas, en especial de la roca encajonante adyacente al depósito mineral. Entre sus principales aplicaciones tenemos: la exploración y desarrollo de depósitos minerales, la explotación de depósitos en los cuales se requiere perforaciones a profundidades en las que los métodos de percusión resultan no aplicables, así como su aplicación en la industria del petróleo.

May 1, 1970

By Daniel C. Boteler

Five lignites from the northern Great Plains province were carbonized at temperatures from 500° to 1,000° C in a bench-scale unit. A replicated Greco-Latin square experimental design was employed to allow testing of four independent variables at five levels. Independent variables investigated were temperature, source of lignite (mine), weight of charge, and moisture content of charge. Dependent variables were char yield, tar yield, light-oil yield, tar plus light-oil yield, carbonization gas yield, and carbonization gas heat yield. An analysis of variance indicated that, at the 99-percent confidence level, the independent variables of carbonization temperature, source of lignite, and weight of charge were significant for yields of char, tar plus light oil, and carbonization gas, whereas moisture content was only significant for carbonization gas yields. At the 95-percent confidence level, moisture content significantly influenced the carbonization gas heat yield per pound of lignite charge and the yields of dry tar plus light oil. All dependent variables were determined on a moisture- and ash-free basis. Multiple regression equations for predicting seven different factors of carbonization yields as functions of carbonization temperature and initial composition were developed using computer techniques. Equations for yields of char, tar plus light oil, and carbonization gas were compared with equations previously developed by others at the 500° C level.

Jan 1, 1970

By L Torckler, R L. Brathwaite

At Neavesville gold-silver (electrum) mineralisation occurs in steeply-dipping zones of intense fracturing, brecciation and quartz veining within rhyolitic pyroclastics, carbohaceous shales and andesites. Hydrothermal alteration extends over an area of greater than 3 by 1.5 km. In rhyolitic tuffs, highly silicified zones containing quartz-adularia-illite assemblages are flanked by less silicified assemblages composed of albite, illite-montmorillonite and chlorite. The mineralogy and sequence of alteration are comparable with the alteration zones which envelop the steam-producing fissures of the active Wairakei and Broadlands geothermal fields. Primary fluid inclusions in quartz from five fissure veins in the Neavesville field show maximum homogenisation temperatures ranging from 220 - 260¦C and salinities of 0.0 - 1.1 wt per cent NaCl equivalent, which cover a similar range to actual measured temperatures and salinities in geothermal fluids at Wairakei and Broadlands. The age of the rhyolitic pyroclastics and related alteration and mineralisation is probably Pliocene and Neavesville therefore represents a fossil geothermal system. The intensely fractured zones containing the gold-silver mineralisation were probably produced by hydraulic fracturing generated by accumulation under pressure of hydrothermal fluid in blind fault zones. Study of fluid inclusions indicates that hydrothermal quartz associated with electrum was deposited under boiling conditions. High grade electrum mineralisation at Graces workings appears to be localised by reaction of hydrothermal fluid with sedimentary marcasite in black shale.

Jan 1, 1980

By X. J. Lyu, Q. Liu, M. J. Lian, X. Q. Cao, X. F. You, B. O. Erdenekhuyag, H. Y. Zang

The slag-tailings based artificial reef concrete (ARC) is made of CaO-CaSO4 activated granulated blast furnace slag (GBFS) as cementitious material and deslimed gold ore tailings as aggregate. In order to investigate the potential application of the material as ARC, the strength development, hydration characteristics and application performance were investigated under different preparation conditions. Results indicated that using seawater as the mixing water can effectively promote the hydration of slag and generate a large amount of hydration products such as ettringite, CSH gel, hydrotalcite and Friedel ’s salt in the early curing period and so render the material with good early compressive strength. Seawater curing can also accelerate the hydration reaction in the early stage of hydration. The hydration reaction of slag and the compressive strength of ARC can be effectively promoted by increasing the specific surface area of slag. The 28-day compressive strength of the slag-tailings based ARC prepared with 30-50% CaO-CaSO4 activated slag and 50-70% tailings can reach to 19.88-42.87 MPa. Also, the material has a low surface pH value, good resistance to chloride ion penetration, and sulfate corrosion. Keywords: Artificial reef concrete, granulated blast furnace slag, deslimed gold ore tailings, compressive strength, hydration characteristics

Jan 1, 2020

By T Baumgartl, D R. Mulligan, D Doley, A Schneider

In arid and semi-arid areas evapotranspiration (ET) cover systems are often used to mitigate contaminated seepage from hazardous mine waste into the adjacent environment. The theory of ET covers is based on the water balance equation with the aim of minimising seepage. While cover systems are commonly trialled, the influences of variability in climate and cover structure on water balance equation parameters are seldom investigated.Water balance equation parameters and their variability were analysed for two ET cover trials constructed from benign waste rock in semi-arid Australia. Seasonal and inter-annual variations in rainfall critically influence cover performance. For successful cover system operation, the average return periods for higher than average rainfall should be taken into account. In addition, failure of ET covers has a higher probability in areas with marked rainfall seasonality. Water holding capacity and plant available water content are low in covers constructed from waste rock. Changes in water holding capacity due to variation in particle size distribution are likely and critically influence cover performance. The application of topsoil can be beneficial for water ingress control through run-off, but a balance has to be struck between run-off, erosion and plant available water. Changes in vegetation composition only influence evapotranspiration water losses at plant coverage exceeding 50 per cent, which is unrealistic in semi-arid areas. This study showed that the capacity of ET cover systems to hold and dispose of received rainfall is often lower than assumed by industry practitioners. Furthermore, in order to improve reliability of long term cover performance, the variability of rainfall and water holding capacity of the cover has to be included in water balance models.CITATION:Schneider, A, Baumgartl, T, Doley, D and Mulligan, D R, 2012. Variability in parameters of the water balance equation and their influence on evapotranspiration cover performance, in Proceedings Life-of-Mine 2012 , pp 293-300 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Renaud Adams, Vladimir Salatic

"The El Mochito Mine located in Honduras, Central America, has produced lead, zinc and silver in concentrates since the 1950s. The paper discusses changes made in both lead and zinc circuits to reduce costs while maintaining production during the recent period of low metal prices.The intent of this paper is to show that sometimes thinking “outside the box” is beneficial for progress. Also, in striving for better metallurgical results we should not forget the basics of flotation. Sometimes the latest trends may not be applicable to the ore we are treating and may not meet the operating cost constraints.A major beneficial impact on El Mochito metallurgy was achieved when the overall grind was coarsened, eliminating the significant percentage of slimes. Switching from two parallel twostage grinding circuits to one circuit with three-stage series grinding has resulted in a significant reduction in power and steel consumption. With minor layout/reagent modifications, both lead and zinc circuits gained not only in retention time but as well in producing better grade products.Of course, the challenges are still there; they exist and only with the full support of operational data collection and metallurgical laboratory investigation success can come. That is why, we as professionals, can never stop in trying to make the most of what we have.INTRODUCTIONThe El Mochito Mine is owned by American Pacific Honduras S.A. de C.V. (AMPAC) a subsidiary of Breakwater Resources Ltd. Of Toronto, Canada. The mine is located in western Honduras, approximately 220 kilometers northwest of the capital city, Tegucigalpa and 90 kilometers south of the country’s second largest city, San Pedro Sula. The mine began operating in 1948 and to date has produced more than 19 million tonnes grading 240 g/t Ag, 3.5% Pb and 7.4% Zn. Production in 2005 was 700,190 tonnes grading 87 g/t Ag, 1.85% Pb and 6.61% Zn.Decreasing metal content in the ore followed by the lowest zinc price on the market in the last 15 years (see Figure 1) has reduced the cash flow and endangered to stop the operation."

Jan 1, 2007

The Main Seam occurs in two 'pods', termed North and South, separated by an east-west oriented 'want' zone (most probably a palaeo-channel). The seam on either side of the 'want' area reaches thicknesses of over 30 metres but the North Main Seam adjacent to the 'want' zone has been split into multiple seams of 10 to 15 m thickness. Rock types in the inter-burden of this area are characterised by inter-bedded sandstones and carbonaceous mudstones varying in thickness from 0.5 to 5 m. In the South Main Seam, an area of un-split coal exists and is characterised by few inorganic partings. Overburden in this area varies geographically from relatively thick mudstones in the south and east part of the coal deposit to inter-bedded sandstones and carbonaceous mudstones adjacent to the 'want' area. The sandstone/mudstone overburden probably represents a splay or splay-channel complex emanating from the larger 'want' area palaeo-channel. Modelling lithological variability is of use because it is one of the factors used in predicting cavability and roof support system design. The coal in both the north and south deposits were found to exhibit highly predictable quality and breakage parameters in relation to the coal geometry. Although ash yield and sulphur are mostly low and not variable, volatile matter and thus fixed carbon, varied in relation to seam thickness. In general, volatile matter (dat) decreased and moisture increased with decreasing seam thickness whereas moisture increased with decreasing seam thickness. In addition to these parameters it was found that the energy needed to crush the coal was lowest at the top and bottom of the seam and, on a whole seam basis, decreased with seam thickness. All of these parameters were found to vary in relation to the vitrain band content of the coal which itself was controlled by seam geometry. These parameters can therefore be modelled and inputted into mining plans and quality control operations.

Jan 1, 1996

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 B. Fagerberg

Crushing and grinding practice in Sweden follows largely the international pattern. Certain special circumstances, however, have had an influence on the development. Most mines are worked underground in either quite small or in very large units. To utilize small sulphide ores, custom milling is rather common. Apart from the cement industry, the rock species treated are hard and abrasive. Another important factor is the increasingly strict requirements placed on the mechanical condition of different products, especially lump ores and coarse iron ore concentrates. A significant feature in the design and development of Swedish crushing and grinding practice has also been close cooperation between machinery manufacturers and the users. An account of these conditions and an outline of the crushing and grinding techniques employed in Sweden are presented in this paper with emphasis on the mining industry. For background purposes it may be mentioned that crude ore production in Sweden last year included 45 mill. tonsx) of iron ore, of which some 20 mill. tons from Kiruna alone, and 4 mill. tons of sulphide ore from 22 other mines, fig. 1. In addition 8 mill. tons of limestone were quarried for cement production and several million tons of stone and sand for roads, aerated concrete, etc.

Jan 1, 1968

By Vinicius Oliveira dos Santos

Este trabalho tem como objetivo estabelecer um quadro comparativo – baseado na literatura científica vigente – entre o comportamento mecânico sob irradiação neutrônica dos Aços Inoxidáveis Austeníticos e as ligas de Zircônio empregados ostensivamente em componentes estruturais de instalações nucleares, como reatores e submarinos. O conhecimento do dano induzido pela irradiação nos materiais é de fundamental importância para os projetos de engenharia para minimização das probabilidades de risco de acidentes.

Aug 8, 2018

By R. Frim, S. D. Ukeles

The present U.S. production of bromine is from inland brines located in Arkansas and Michigan. The most concentrated domestic brines (up to 5,000 ppm bromide)are situated in Arkansas. Less concentrated brines(about 2,500 ppm bromide) are located in Michigan. The amount of bromine sold or used in the United States came from three companies operating in those two states. Its value was $191 million. In 2004, the estimated U.S. bromine production was 222 kt (244,000 st). That compared with 216 kt (238,000st) produced in 2003.

Jan 1, 2005

By Lassi Klemettinen

For better understanding and maximal value utilization of the WEEE smelting process, the behavior and distribution of different trace elements must be known. In this study, the behavior of nickel as a trace element was studied in an equilibrium system with metallic copper—spinel saturated iron silicate slag (with 3 wt-% K2O)—iron aluminous spinel—gas. The experiments were conducted in alumina crucibles at 1300 °C, in oxygen pressure range of 10−10–10−5 atm. A time series of 15–60 min experiments was also conducted for investigating the formation rate of the primary spinel phase in the system. The results show that the distribution coefficient of nickel between metallic copper and liquid slag changes from approximately 70 to 0.4 along the increasing oxygen pressure range. In addition, a significant part of the nickel deports into the spinel phase. The spinel formation was investigated based on composition analysis results and visual observations from SEM-images.

By Lulie H. Crump

Salient historical data on consumption of fuels and energy have been summarized by State and census district for the years 1960 through 1972. This Information Circular covers States east of the Mississippi, and Information Circular 8705 covers States west of the Mississippi. These data replace previously published compilations of energy consumption statistics by States and districts. Future annual studies are planned using the same Btu conversion factors applied in these two. Information Circulars.

Jan 1, 1976

By C. H. Riggs

This petroleum-engineering study of the Healdton oil field in Carter County, Okla., describes the geology and production history of that field and estimates the oil reserves that could be produced by efficient secondary-recovery methods. The Healdton field, in western Carter County approximately 20 miles west of Ardmore, Okla., was discovered in 1913 and was one of the early important oil-producing areas in the State. Although the volume of oil recovered from the Healdton sands has been comparatively high, studies show that a large reserve remains in the pressure-depleted sand, which can be recovered by efficient water-flood operations. In making this study of the Healdton-sand reservoir, the writers utilized many data already available in company and Government offices. Most of the fluid samples were collected by Bureau of Mines personnel and analyzed in the Bureau's laboratories at Bartlesville, Okla.; but other data, including logs, core analyses, and production records, were obtained from outside sources. These data were examined critically but were not verified, and possible errors in the original data may be reflected in the conclusions. In this study, attempts were made to consider only those aspects of the available information that would contribute to a clear and concise engineering report on the Healdton-sand reservoir. Other phases of the data, as well as those concerning associated reservoirs, were eliminated from consideration as being irrelevant to the particular problem. Cores and drill cuttings of the Healdton sands were analyzed and studied to determine the nature of the reservoir rocks. Analyses of samples of produced oil, water, and gas were studied to fix the different types, the limits of their occurrence, and the suitability of different waters for injection into the Healdton sands. Records of oil, gas, and water produced and of gas and water injected were studied to interpret the production behavior of the field and of certain individual leases. Theoretical calculations were made to predict the probable water-flood behavior and oil recovery, at constant water-injection rates, for individual sands on two leases.

Jan 1, 1953

Since early-2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of the refractory gold flotation concentrate. A second UFG mill was installed in 2002 taking the total UFG capacity to over 20 tph while grinding to 11 to 12 microns and achieving over 90 per cent gold recovery. A development program in 2002/3 involving plant trials, pilot plants and laboratory testwork resulted in process improvements and a better understanding of the milling and gold leach processes that assisted in narrowing the gap between UFG and roasting. This paper details the operation of the ultra fine grinding process at KCGM as a non oxidative treatment for the extraction of gold from a refractory ores.

Jan 1, 2003

By James W. Myers

The Bureau of Mines studied factors affecting ignition of coal mine refuse and on methods for control of burning. Laboratory experiments showed that air permeates more readily through segregated than through nonsegregated refuse and that air permeability is greater through coarse than through fine particle refuse. Minus 3-1/4-inch refuse ignites spontaneously more readily than minus 1/4-inch refuse. The burning of a 1,000-pound conical coal pile was con-trolled by capping with an 18-inch-thick layer of minus 1/4-inch refuse containing 37 percent combustible. In field trials, the burning of refuse at operating mines was controlled by capping with a layer of fine refuse. Water, applied as a spray or by injection, quenched surface flames and cooled the burning waste. Inspection of refuse piles at operating mines showed that the spontaneous ignition tendency is affected by the exposed surface relative to the total volume and the segregation of particles during dumping.

Jan 1, 1966

By J. A. Caldwell, G. E. Blight

The metropolitan area of the Witwatersrand has grown up around the Witwatersrand gold mines. Most of the mines have now been abandoned, but deposits of waste material remain and have been surrounded, and in some instances covered, by urban and industrial sprawl. This paper describes the development of geotechnical measures for the abatement of air and water pollution from abandoned gold-residue dams in the Witwatersrand area. The measures include the stabilization of the surfaces of the dams to prevent wind and water erosion, the terracing of slopes to minimize erosion, and the construction of catchment walls and dams. The measures were developed in terms of the set of guidelines for environmental protection adopted by the Chamber of Mines of South Africa in 1979.

Jan 1, 1983

By Tom Shumka

"All mineral processing facilities that use girth gear driven mills need to inspect the gear teeth on a routine basis, whether it be every six months to every three years. The inspection frequency depends on gear tooth condition, and the objective is to ensure the operational integrity of the gear teeth. Conventional methods such as magnetic particle testing, visual inspection or dye penetrant examinations rely heavily on operator interpretation. At best, these techniques can determine whether a defect exists, but are unable to provide information on defect severity. This paper describes the use of combining combined eddy current array (eca) and alternating current field measurement (acfm) to provide a complete survey of all surface breaking indications on the whole gear tooth depth. This method accurately determines the size, length and depth of any cracks found on the surface.INTRODUCTION In order to gain a fundamental understanding of the evolving operational and production behavior of a piece of machinery over a specified time period as part of an effective condition monitoring program, a robust data collection process must be firmly established and adhered to. To be effectively implemented within an organization, a condition monitoring program must have support of not only the maintenance, production and engineering staffs, but also executive management support to ensure successful roll out to realize the maximum productivity of the machinery and subsequent cost-savings. One of the key elements of a mineral processing facility that use gear driven SAG Mills as a primary stage for grinding solution, is the integrity of the critical gear unit that drive the mill. For the maintenance team, condition monitoring on the gear unit is crucial for preventative maintenance. A catastrophic failure in the critical gear unit would require a minimum of ten days to replace the gear set, depending on the damage occurred. This, of course, would only be applicable if the client had a spare critical gear set in inventory. If a gear set had to be ordered, it could take from four months to two years to receive a new gear set. For example, in 2007, there was a global backlog of these types of gears sets resulting in a two year delivery. The maintenance costs associated with a catastrophic failure of this type would easily cost in the millions."

Jan 1, 2012

By C. M. McKinney

This report contains Bureau of Mines routine analyses of 492 samples of crude petroleum from 470 United States oilfields, each of which produced 2,500 barrels a day or more during at least 1 of the years 1946-56. The fields are listed alphabetically by State and field names in table 1, with information on the geographical and geological sources of the samples. Table 2 summarizes the general characteristics of the crude oils and analytical and computed data determined from the analyses. A previous report 4 contains similar analyses of 283 important United States oilfields; some of them are repeated in this report. Many fields for which analyses previously were published are represented by new analyses, which include data not previously reported. Refractive index nu and specific dispersion, ng minus nD divided by the density, for some of the distillate fractions are included in the analyses of 316 of the crude-oil samples. This is the first Bureau of Mines report on analysis of crude oils to contain such data, and their use in calculating hydrocarbon-type composition of the fractions is explained.

Jan 1, 1957