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By James Logan

BC Alkaline CuBC Cu--Au PorphyriesAu Porphyries ?Formed over narrow time interval ~205 Ma ?from silica deficientvsalkali-enriched magmas ?At shallowdepths ?Structuralcontrol ?Cu-Au-Ag, trace Mo ?Oxidized system anhydrite, magnetite ?Multipleintrusions & multiplemineralized centres

May 1, 2006

By Terry J. Close

Between 1986 and 1989, at the request of the U. S. Bureau of Land Management, personnel from the U. S. Bureau of Mines Western Field Operations Center studied the highly-mineralized, 25,335-acre, Crack Canyon Wilderness Study Area (UT-060-028A), to evaluate its identified mineral resources. The 16-mi-long, 2-mi to 4-mi-wide stud/ area is on the southeast side of the San Rafael Swell, about 40 mi southwest of Green River, Emery County, southeast-central Utah. The study area is underlain by Mesozoic sedimentary beds. Uranium, the principle mineral resource, occurs in two formations. The principle uranium deposits are in mudstone, sandstone, and conglomerate lenses in the 22-mi-long outcrop of the Triassic Chinle Formation which parallels and straddles the northwest boundary of the study area, Some small low-grade uranium occurrences and an extensive gypsum deposit are hosted by the Jurassic-age rocks that underlie the southeast part of the study area.

Jan 1, 1989

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine to determine the extent that Semi-Autogenous Grinding (SAG) mill throughput could be increased by using electronic detonators. The Julius Kruttschnitt Mineral Research Centre (JKMRC) blast fragmentation, jaw crusher, and SAG mill breakage models were used to relate changes in the blast fragmentation measured with the SPLIT image analysis system to the SAG mill performance. For optimum performance a SAG mill requires a particular size distribution; a number of large rocks to facilitate breakage by impact, as few as possible middle size rocks that become critical size, and the maximum fines which will pass quickly through an open-circuit mill. Physical constraints of drill and charging equipment size limit the extent that pattern geometry can be changed, and the powder factor increased, to maximize fines. However, a growing number of studies have shown that the use of electronic detonators can lead to increased fragmentation and greater muckpile uniformity, providing an alternate means of increasing primary breakage by blasting. Unfortunately results in the literature rarely quantified the changes to the fragmentation distribution. The measured gyratory crusher fragmentation of 2,750,000t of ore was used to compare stockpiles constructed from shots using pyrotechnic detonators to those using Orica i-kon electronic detonators. In the first stage of the study, stockpiles shot using 25 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using the same inter-hole timing with electronic detonators. In the second stage of the study, stockpiles shot using 17 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using 8 ms inter-hole timing with electronic detonators. When electronic detonators were used with the inter-hole timing kept constant, fragmentation uniformity was slightly increased, but mean fragment size increased by 20%. When electronic detonators were used with faster inter-hole timing, fragmentation uniformity was slightly reduced, but mean fragment size decreased by 30%. Modeling was used to determine the SAG mill throughput which could be expected from this change in fragmentation to determine the pairs of pyrotechnic and electronic blast pattern geometries that would provide similar throughput. The economic benefit from the electronic detonator shots was calculated to assist in determining the optimum blast designs for their use.

Jan 1, 2010

By Eric Lutz

"Great effort has been expended for more than 40 years to improve the workplace safety and health of surface and underground miners across the United States. When looking at the past decade, withstanding the 2010, Upper Big Branch (UBB) disaster that took the lives of 29 miners, this effort has resulted in a generally decreasing trend from 57 fatalities (22 coal; 35 metal/non-metal) in 2005, to 45 (16 coal; 29 m/ nm) in 2014. Through August of this year, there have been 23 mining-related deaths (eight coal; 15 m/nm). These results reflect continued diligence and perseverance on the part of miners that stay true to our legacy; and demonstrate significant investments from mine-site leadership, mining corporations, and state and federal regulators. However, over the past five years there have been an average of 32 fatalities per year, with a low of 36 (2011 and 2012) to a high of 45 (2014). If we know that there will be somewhere between 30 and 50 mining related deaths next year, which of us will volunteer to be counted as one of the numbered? Clearly, we all agree that one fatality is too many; and as evidenced by changes following UBB, deaths in any sector are deaths reflective of all mining across all sectors.The impact of each miner death touches us all. Miner’s deaths are felt deeply by family and friends, most significantly the children; their communities in which they served, supported, and worshiped; and by society that has lost a hardworking, dependable contributor. Further, to take a slightly cynical, but realistic view, miner fatality events impact the financial vitality of mining and contracting companies and broadly diminish investor confidence. Just as important, these events significantly impact our communities and result in negative public perceptions, which ultimately drive regulatory policy and related compliance pressures. This resulting pressure forces operations to broadly address safety and health gaps in very specific ways (i.e., see U.S. Mine Safety and Health Administration (MSHA) regulations regarding lids for trash cans) minimizing a mine site’s opportunities for operational flexibility. To break this cycle that is the operational reality, mining companies are focusing tremendous efforts on fatality prevention and specifically on dedicated investment to prevent multiple fatality events."

Jan 1, 2015

By Ross L. Sherlock, David J. Scott, Gordon MacKay, Wayne Johnson

"Abstract - The demographics of Nunavut indicate a very young and poorly educated population spread over wide areas in small isolated communities. The current economic sectors will be unable to expand and meet the demands of this emerging workforce. Given the realities of Nunavut, the most promising direction in which the economy may expand is through mineral development. The Nunavut Land Claims Agreement (NLCA) has established the legislative framework for sustainable development in Nunavut through mineral development. The NLCA has transferred ownership for much of Nunavut’s potential mineral resources to beneficiaries of the lands claim. Royalties generated from mining operations on subsurface Inuit-owned lands, and to a lesser extent on Crown land, will flow back to beneficiaries of the lands claim through their administrative company, which may then be invested in the communities. Additional benefits of mineral resource development in Nunavut will be realized through impact and benefit agreements.To realize the benefits from mining operations, Nunavut has to be able to attract and support exploration and development companies through the release of high-quality geoscience data. However, due to Nunavut’s isolation and the expense of conducting geoscience fieldwork, the jurisdiction lags far behind the rest of Canada in terms of quality and quantity of government geoscience. About 70% of the territory is inadequately mapped to attract exploration companies or to make informed land-use decisions. The role of government-funded geoscience in Nunavut is to stimulate exploration and discovery through new framework mapping and focused thematic projects. The timely delivery of high-quality geoscience products will attract exploration companies to Nunavut and further their efforts to discover and develop mineral resources in order that the subsequent benefits of this activity may flow to the beneficiaries of the NLCA as well as all other residents of Nunavut."

Jan 1, 2003

Discussion of the paper of W. C. PHALEN, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2249 to 2265. DAVID T. DAY, Washington, D. C.-Consider the United States broadly and the distribution of the salt industry. Think of the old solar-evaporation process up in New York State, then of the more recent processes in Michigan and Kansas and Louisiana, where the rock salt furnishes a large industry, then of the solar-evaporation process at Salt Lake, then turn to the crucial place in the United States, where there is an embarrassment of salt, and that is California. I am not forgetting' the immense body of salt east of that in the Virgin River country of Utah; but in California the situation is interesting. There are very large quantities of salt in the Searles Marsh region; again, in Southern California, at the southern end of Death Valley, there are two or three mountains of salt which have been explored recently, where the salt is sufficiently pure to be used at once. There is also a large deposit of gypsum, and it would be possible there, by extremely cheap means, to produce an amount of salt sufficient to furnish the United States' greatest needs. The principal reason that capital has been deterred from developing such a large mass is not the fact that solar evaporation produces a great deal of salt around San Francisco, but the fact that if potash salt is to be produced in connection with the salt in the borax region a, great deal of ordinary salt must be disposed of. It cannot be dumped, for it would get back into the brine again; the first rains would bring that salt back into solution again. It must be sold, given away, or hauled to a distance, which would mean a considerable freight charge. The salt will be going begging. E. G. SPILSBURY, New York, N. Y.-The remark of Dr. Day's regarding the likelihood of the production of a large amount of waste salt brings to my mind the condition that obtains in Germany in all of the potash fields. In Germany salt is a government monopoly. In the development of the potash deposits, it becomes a grave question as to how much salt they may be allowed to extract and bring to the surface.

Jan 4, 1915

The current global economic climate has adversely affected the resources industry in general. For the gold mining industry, even though the gold price has been stable as compared to other resources, there is still a need to cut costs even further in order to be profitable and sustainable. Of all the costs that are associated with mining, comminution of ore accounts for the majority. Comminution costs constitute mainly electricity, grinding balls and liners. Of these three components, grinding balls form the major portion of the consumable costs, and can be as high as 40%?45% of the total. As a result, proper grinding ball selection is a key consideration towards reducing mining costs. This paper discusses quality control procedures that can be conducted in order to select the best grinding balls for a particular application. Keywords: grinding balls, forged, semi steel, hardness, chemical, metallography, wear testing, impact test

Jan 1, 2009

By H. B. Pulsifer

THIS paper outlines a method for rapid production of flat, granular surfaces on many of the medium hard- alloys. Grinding wheels and fabrics on wheels are not used; the purpose is accomplished by rubbing on emery papers and on fine abrasives heaped on hand boards. The advantages of chromic acid in the solutions for etching nickel and copper alloys are explained. Steels may require an additional step in the mechanical smoothing owing to the lack of an ideal etchant. Chloric acid is a. rapid etchant for steel. Thirty-six photomicrographs illustrate the steps in smoothing and the clearness with which structures can be rapidly exposed. New structures in low-carbon steels are announced. After a little practice, many materials can be finished within two or three minutes. CUPRONICKELS In the previous papers on the metallography of copper and magnesium which the author has presented to this Institute there has been an attempt to demonstrate the advantages of minimizing the mechanical work of surfacing and depending more on chemical means; the present paper continues the research into a still wider field. It is obvious that the success of a chemical method for smoothing and etching depends almost entirely on the use of a suitable reagent. The etchant must remove the surface granulations and outline the structures. A very special type of reaction between reagent and metal must be displayed. Promiscuous corrosion or the intensification of the attack about local couples -formed by impurities or components must not be in evidence. There are several reagents that etch highly polished nickel and copper alloys very well. Acidified ferric chloride solutions, concentrated and dilute nitric acid solutions, and nitric and acetic acids in acetone have -been used to good advantage for the purpose. However, if they are expected to etch rather deeply-that is, smooth as well as characterize-the results may be far from satisfactory.

Jan 1, 1928

Jan 1, 1998

By M. M. Hassan

This report describes the analysis tools developed at West Virginia University which can be implemented to optimally design coal mine electrical systems. The basic analytical tools for all power systems are the load-flow and short-circuit analysis. Well known programs have been developed for analysis of ac transmission and distribution systems, but they are not applicable to a system which has combined ac/dc distribution, such as a coal mine power system. Furthermore, the topology of a coal mine electrcal system changes continuously due to the movement of the locomotives on the track. In the first section of this report, algorithms for carrying out load flow and short-circuit analysis of a coal mine electrical system are described. Results from the study of a typical coal mine system are presented. In the second section a method is described to optimally size power cables for cyclic loads. The method is based on the development of a thermal-electric model for a low-voltage power cable. Results from experimental verification of the model are also presented. These techniques are useful in the safe, efficient, reliable and economical design of the coal mine electrical power systems.

Jan 1, 1979

By John B. Hastings

The origin of the watery vapors of vulcanism has always been an object of interest and speculation to the seismologist, and as theories of the genetic origin of ore-deposits have of late years been pretty well narrowed down to the expiring forces of plutonic action, the same question has attracted mining engineers and geologists, as is well shown by the discussions of the subject in our Transactions. The important part taken by volcanic emanations in the origin of pegmatites and quartz-veins, described in my paper, Origin of Pegmatite,' and their latent power to concentrate into useful deposits such scattered gold as occurs in the Hartsel granite, make a discussion of their derivation but a natural third and final step. It is coilceded that enormous amounts of vapor accompany vulcanism, though perhaps we are apt to forget that steam has 1,700 times the volume of water, besides which the column seen over Vesuvius and other volcanoes is greatly mixed with air; the immensity of such volumes compared with solids and liquids is shown by the experiment of Gautier, who, by heating dessicated granite to 100' C., evolved from it gases 20 times, and steam 90 times, its own volume. Dana appraised the average amount of water left in ordinary rocks as 2.5 per cent. T. M. Read estimated that the Mississippi river carries to the sea annually 150,000,000 tons of rock material. If these Mississippi sediments, as deposited, contained 20 per cent. of water, it would be 600,000,000 cu. ft., or 4,500,000,000 American gallons, annually. Allowing the vapor suspended over a volcanic cone to be mixed with 80 per cent. of air, this amount of water converted into steam would replenish anew, every 9 min., a column 15,000 ft. high, 2,000 ft. in diameter at the base, and • 10,000 ft. at the top. Read's estimate is only half of the amount given in a more recent and probably correct one.2

Jan 1, 1909

I TOLD you above that you should save the melted material that you extracted by smelting the ore. In substance this is copper, lead, silver, and perhaps gold, but all are like substances mixed in one body without any distinction. Now if you wish to separate these and to reduce them to their pure qualities, it is necessary to proceed with each one according to its own methods. Now in this method of separating lead in order to extract the silver and gold from the copper, it is necessary to return to the smelting and to follow one of two methods.* The first is to smelt it again with the addition of lead or lead ore, and to make it all run through the channel into the large forehearth that was made in front of the blast furnace, and, as it cools off, proceed to remove layer by layer with the fork, as I told you before and as you did the first time, until the work lead is reached. Then you assay what you have extracted and see whether it contains silver. If you consider that it has enough per hundred to justify the expense, return it again to the smelting. Continue to do this until you have extracted all the unctuousness and the work lead still remains. If it contains little or no silver, you must be satisfied with your work; otherwise return it again to smelt, always accompanying it with lead or galena and do as you did the other times until it

Jan 1, 1942

By Elard Miranda, Carlos Lopez

El éxito extractivo en el tratamiento de los minerales auríferos, depende fundamentalmente de su buena caracterización física y metalúrgica, de modo que para un determinado grado de liberación del mineral brinde información acerca de tamaño del elemento valioso y si este se encuentra liberado o incluido en alguna especie mineralógica; del mismo modo debe conocerse el tipo de elemento valioso, si es oro o electrum y los porcentajes de Plata que presenta este último.

Sep 1, 2017

By R. Corriveaau

This paper is about a horizontally curved conveyor, which carries 6,050 stph of limestone over land from a new quarry to the owner's plant. The conveyor is 5,012 ft long with a horizontal curve radius of5,OOOft Site conditions made a curved conveyor design the most optimal and economic solution. Using our unique custom conveyor calculation program, TKRI was able to accurately model and design the conveyor to properly track the belt and prevent any spillage through the horizontal curve radius. A data monitoring system was installed that allows monitoring of the conveyor both locally and remotely. The remote monitoring allows TKRI to contact the owner for preventive maintenance. Preventive maintenance can reduce the conveyor downtime during normal operating hours.

Jan 1, 2004

By Xia Guangxiang, R. Y. Wan, Yang Hanlin, M. C. Fuerstenau

The mechanism and kinetics of pretreatment on pyritic gold concentrate with the catalytic oxidation acid leach (COAL) process were studied in the temperature range of 80-100°C and oxygen pressure range of 230-1013 kPa, with sodium lignosulfonate (SL) and mixed medium of sulfuric acid (11 g/[ ]) and nitric acid (5.5 g/ [ ]). The results show that nitric acid acts as a catalyst, the surfactant changes the hydro-phobicity of resulting elemental sulfur to favor the oxidation of pyrite, and the oxidation-determining step would be the chemical reaction between nitric acid and pyrite. When about 80% of pyrite contained in the concentrate is oxidized, the gold cyanidation extraction exceeds 95 % . The nitric acid in solution can be recycled and used again.

Jan 1, 1993

By R. Pakalnis, C. A. Dreesbach, L. A. Martin

Instrumented cable bolts developed at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health were used in conjunction with existing ground control systems to monitor rock mass loads at Tg Soda Ash’s trona mine, Granger, WY. Axial and shear loads were determined to levels of strain gauge accuracy of ±5 N or ±5 microstrain. These gauges were embedded in a remanufactured king wire that replaced the conventional king wire. Cable bolt performance, quality of grout, and installation techniques were also assessed. By using instrumented cables, a mine operator can determine axial load along the cable at predefined gauge locations. These data provide necessary input for an operator to design a safer working environment for miners.

I have chosen this topic for my address with the intention of preserving a rather extraordinary record of recurrent additions of capital in the financing of one of the world's important silver-lead-zinc mines. The recitation of the trials and tribulations which fore-shadowed the rise of Mount Isa Mines to a position of relative prominence in the realm of non-ferrous mineral production may, I hope, be of assistance to some of the younger members of the Institute who may be called upon during their careers to meet similardevelopmental and financial problems.Mount Isa Mines Limited was incorporated in New South Wales in 1924 with an Authorised Capital of 40,000 shares of £20 each.In November 1925 the Company acquired the leases and water rights of the Mount Isa Proprietary Silver-Lead Limited for 6,250 fully paid £20 shares. Shortly thereafter, but in the same year, the £20 shares were split up into £1 shares, thus bringing the Authorised Capital to £800,000.The leases purchased consolidated and brought under one management the principal ore bodies of the Mount Isa area.Transportation facilities were indispensable to the economic future of the field, so the construction of a railway extending the Government line from Duchess, 54 ,miles to Mo.unt Isa, was assured by the passage of a bill in October 1925 by the Queensland Parliament. Under the provisions of the so-called Mount Isa Railway Act the Company was required to idemnify the Government against national loss on this branch line for a period of 10 years.

Jan 1, 1953

By G. P. Halliwell, C. R. Austin

The investigation described in this paper deals with the development of high-temperature alloys of the Konel series over a considerable period of time at t,he Research Laboratories of the Westinghouse Electric and Manufacturing Co. The word ''Konel" has been coined to designate a class of alloys which are essentially nickel-cobalt-iron with other elements added, usually in small quantities. Most of these alloys contain titanium, usually about 2.5 per cent. The main consideration related to strength at high temperatures but the thermionic characteristics of the alloys was also of considerable importance. It is, however, with the mechanical properties at elevated temperatures that we are herein concerned. Much attention has also been devoted to their age-hardening characteristics. There is little need to stress the utilitarian aspect of this subject, as it has been discussed frequently. Alloys exhibiting superior properties at normal or elevated temperatures rapidly find many suitable applications. There may be some question, however, as to what constitutes a "superior alloy," or an alloy that may have good service possibilities at high temperatures. The problem is complex and various means have been employed to predict the useful life that may be expected of a material. In recent years the "creep limitJ' has been used as the best means of evaluation. Such tests necessarily are prolonged and hence collection of data is very slow. In a general survey of many alloys therefore the creep test is not desirable and recourse must be had to much shorter time tests in order more rapidly to select alloys which appear to show promise. For this reason the present survey has been made using the high-temperature tensile test and a bend test developed by Howard Scott.' In the tensile test the conditions have been standardized for all tests, so that values obtained are at least comparable, one alloy with another, although the absolute values recorded merely indicate the mechanical properties at the given temperature under a definite rate of loading.

Jan 1, 1932

By B. Ancker, E. R. Parker

The small-angle dislocation-boundary density of nickel and some of its alloys was investigated as a function of strength. It was found that the strength is a linear function of the density for pure nickel and for Ni-Ti alloys, but not for Ni-Co alloys. The results are interpreted in terms of dislocation theory. THE processes by which metals deform are still poorly understood, even though there has been a concentrated research effort in this field during the past fifteen years. Single crystals and individual grains in polycrystalline aggregates often develop a subgrain structure when deformed. Substructure formation occurs as a result of local plastic bending and its development is augmented by annealing at moderate temperatures.' Investigations made to date, largely qualitative in nature, have shown that the substructure is composed of a network of small-angle boundaries. The purpose of the present paper is to present some quantitative data on substructure (obtained by X-ray techniques) and to correlate the results with the strength of the metal in which the substructure existed. Nickel and some of its alloys were used for the experiments. The presence of certain kinds of foreign atoms greatly alters the formation and effect of the substructure. Polycrystalline tensile specimens were prepared from high purity nickel, two Ni-Ti alloys, and two Ni-Co alloys; the composition of these materials is given in Table I. Tensile specimens having a reduced section 1/4 in. diam by 3 in. long were machined from materials which were refined, cast, forged, and swaged in the authors' laboratories. The specimens were annealed for 1/2 hr at 1150°C, a treatment which produced grains having a diameter of approximately 0.5 mm. This rather large grain size was used to facilitate later examination of the substructure. Duplicate specimens of pure nickel and of each alloy were strained various controlled amounts in tension at room temperature and recovered for 1 hr at 800°C. (This strain induced prior to recovery will be referred to hereafter as the "prestrain.") One of each of the recovered specimens was pulled in tension at room temperature to obtain the stress-strain curves. The other bar was cross-sectioned in the gage length, carefully polished, and deeply etched to remove all cold-worked material. This specimen was then examined by the X-ray microscopic technique2 to determine the nature and magnitude of the substructure. The use of duplicate specimens permitted a direct correlation between tensile properties and substructure characteristics. X-ray microscopic studies were made with an apparatus constructed to have an average resolving power of about 4 microns. The monochromatic radiation reflected from grains which were oriented favorably was recorded on fine-grain photographic plates. These were examined at Xl00 which represents the true magnification, since there was essentially none in the X-ray system. This permitted detection of angular differences between subgrains of as little as 10 min. A very large number (over 100) of grains for each specimen was examined at this magnification and the number of substructure boundaries per grain was tabulated. An accurate relative measure was obtained under fixed experimental conditions, e.g., same grain size, resolving power, magnification, etc. The greatest source of error lay in counting the subboundaries, but this proved to be surprisingly small when repeated counts were made by different investigators. Furthermore, as the subsequent analysis indicates, whatever human error was introduced was not significant. Analysis of the Substructure Data When the number of substructure boundaries per grain was plotted against the frequency, skew (asymmetrical) distribution curves of the type shown in Fig. 1 were obtained. These are smoothed curves for the 1 atomic pct Ti in nickel alloy subjected to various prestrains and are representative of the curves obtained with all the metals. Since skew-distribution curves cannot be analyzed by elementary statistical methods, detailed investigations were undertaken in order to 1—test the consistency

Jan 1, 1955

If problems are opportunities in disguise, the mining industry certainly had plenty of "opportunities" in 1975. Considering the industry's generally lackluster 1975 profit record, and in view of the slowdown in inflation, there's some hope that 1976 might be a better year in spite of the increasing risks and uncertainties that plague the mining industry.

Jan 2, 1976