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By Charles Janin, HENNEN JENNINGS

Many articles have been written on the general principles and details of gold dredging, a but it is not possible within the limits of this paper to recapitulate them, and it is thus necessary to assume some knowledge of this literature by the readers of this paper. Although the purpose of this paper is to describe gold dredging in Montana, a brief mention of some early appliances used in New Zealand, Australia, and California may serve as a world-connecting link in our consideration of the development of gold dredging. DREDGES EARLY USED IN NEW ZEALAND, AUSTRALIA, AND CALIFORNIA. Spoon dredges operated by hand were tried in New Zealand on rich spots in the Clutha River with some success as early as 1865. A dredge of this kind is shown in Plate I, A. In 1870 a modification of the spoon, operated by steam and being thus a primitive steamshovel dredge, was worked in New Zealand. Steam-shovel dredging was attempted in California as early as 1888 and 1893, and with some success in later years. The elevator gold dredge with endless bucket chain was put into operation in New Zealand in 1882. Plate I, B, illustrates a type of this dredge operated by current wheels. Plate II, A, shows a steam-operated dredge of this class, also started in 1882. In 1897 R. H. Postlethwaite, connected with the Risdon Iron Works, San Francisco, introduced the dredging practice of New Zealand into California. The first dredge built sank in the turbulent current of the Yuba. The second at Oroville, owned and operated by W. P. Hammon, proved effective and was the start in California of successful gold dredging. Since then the growth of the golddredging industry in California has been so rapid that the gold output from dredges in that State exceeds that of all other States in the Union, and, in fact, of any other country of the world, the value of the gold produced in California by dredging from 1897 to the end of 1914 having been about $71,000,000.

Jan 1, 1916

POSITIONS VACANT (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Advertising Manager for Machinery Manufacturing Company. Must have technical training. No. 94. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, technical graduate in Mining, Chemistry and Metallurgy, Post-graduate, Royal School of Mines, Freiberg, Saxony, Germany and Columbia School of Mines. Aged 37, 14 years' experience in teaching mining metallurgy, chemistry and assaying. Available now. Willing to go anywhere. No. 278. Member, aged 33, mining engineer, 88 years' experience, desires position as mine safety and efficiency engineer with coal company. Best of references on request. No. 290.

Jan 5, 1916

By Simon McDonald

The Neptune Group was established in 1999 to apply for exploration permits within New Zealand’s 200nm EEZ. These applications were to investigate and commercialise hydrothermal Seafloor Massive Sulphide (SMS) deposits identified by international researchers and to locate others. SMS are volcanically related seafloor accumulations of copper, lead and zinc with high levels of gold and silver. Neptune has three granted exploration licenses within the New Zealand EEZ and has application in other jurisdictions. Neptune undertook the world’s first commercial drilling exploration work of SMS in December of 2005.

Aug 24, 2006

Despite the claims of energy efficiency and the considerable development that has gone into dramatically extending rolls? life and facilitating rolls? change-out, in the six years since the last SAG conference, only a few HPGR operations have entered the realm of mineral processing. Risk barriers to the take-up of new equipment or processes are: a massive increase in materials handling issues as well as in the number of pieces of equipment required, low total circuit potential energy savings, and similar or higher capital costs. An alternative route is to make use of the complementary strengths of the HPGR and SAG in hybrid circuits. Minimising materials handling issues, providing an ideal balanced feed to the AG or SAG mill, and improving controllability through shifting grinding load as the RoM feed changes, are all potential major advantages to this approach. Conceptual circuit layouts, based on real measured ore and equipment data, are presented here to illustrate the potential production upside, the reduction in operating costs and the reduction in the physical and energy footprints.

Jan 1, 2012

By Carl Hendricks

Aquila Mining Systems Ltd., is the world leader in drill monitoring, control and GPS-based machine navigation systems for the mining industry. This paper will review the design and application of AQUILA’s drill monitoring, control and positioning systems currently in use throughout the world and some of the benefits that derive through their use. In 1993, AQUILA became the first company to install a high precision, cm level, real-time GPS receiver on a blasthole drill. In fact, this was likely the first application of GPS on any form of production mining equipment. To date, AQUILA has installed over 90 GPS based drill monitoring systems worldwide. Since 1992 AQUILA has continued to lead in the advancement of new technologies for drilling including real-time geology recognition and automated drilling control systems. The AQUILA DMseries drill systems offer mines the ability to collect and transmit to the mine office; drill production statistics, ore and waste intersections, exact collar elevations, hole positions and depths, maintenance information and consumables tracking. Unique office software developed by AQUILA provides an encompassing Windows environment within which to manage and coordinate all aspects of data communications and information management between the drills and various mine departments. AQUILA and Caterpillar, along with Mincom and Trimble Navigation are partners in a technology alliance that is providing the surface mining industry with vehicle tracking and navigation systems for all mobile production equipment.

Jan 1, 2000

Over 45 of the Best Qualified Technical Specialists, Consultants, Engineers, Scientists, Explosive Supplies, Educators and Mine Operators in the World!

Jan 1, 2000

This paper deals chiefly with the preliminary examination, when a decision has to be made as to whether a prospect has a chance of developing into a mine or not. At this stage it is important to have a fairly clear conception of what is expected of the prospect, andjust what type of mine is sought. Much money can be wasted testing a prospect suitable for a prospector or small syndicate, but which never looked like becoming a mine of sufficient size to interest a company. When undertaking an inspection, therefore, it is necessary to have a broad outline, at least, of the policy of the principals for whom the report is intended.At this early stage it is frequently necessary to form an opinion of the prospects of a property on very meagre data. When new to this type of work one's first reaction is often th~t it is impossible to pass an opinion on the data available. It. is absolutely necessary,however, that an opinion of the possibilities and chances of favourable development be given; The report should strive to convey this information, making quite ::lear the risk involved, how complete are the data on which this opinion is based, and the possible magnitude of the prize. A Preliminary report has to state whether a property has sufficient prospects to warrant testing.The following procedure is suggested in order to make best use of the data and minimise hasty conclusions influenced by preconceived ideas-an ever-present danger.Examination.The first stage is the examination. This should aim at collecting all available significant data, but avoid clouding the issue with detail which, at this stage, will not affect the decision. The following points are considered to be the main ones for which to look:-Geological Environment.As good a working knowledge as possible'of the geology of the area should be obtained. Government Geological Survey reports and maps, if available, will be a big help. A detailed knowledge of the regional geology is not necessary a,t this stage, but a broad outline of the geological setting of the prospect under review, and also of any other important mines in the district, is often helpful in the final decision.The Nature of the Ore-Body.Any facts concerning the nature or occurrence of the lode should be noted as, coupled with experience of similar bodies, they affect the ultimate decision.Structural Control.This is probably the most important factor, in the light of present geological knowledge. Its chief importance is due to two facts:-(a) Structure plays one of the prime parts in ore deposition.(b) Geological knowledge, of structure is somewhat in advance of knowledge of other factors influencing ore deposition.

Jan 1, 1950

By Forrest T. Moyer

To keep the mineral and allied industries informed of trends in the causes of accidents, and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and periodically publishes health and safety statistics. This report includes data for 1963 on injury experience, with related employment statistics, at coal mines in the United States. These data are presented in tabular form under the following headings: General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1966

By R. R. Sayers

That the maintenance of proper air conditions is a most important factor in the control of occupational hazards is shown by the large amount of material presented each year through the technical journal's on the effects on workers of injurious dusts, gases, and variations in temperature and humidity.. SUMMARY OF RECENT LITERATURE ON EFFECTS ON WORKERS OF EXPOSURE TO DUSTS The subject of the control of dust and dust diseases continues to be a matter of serious concern in most of the industrial countries of the world, as indicated by the following summary of reports published in a number of foreign countries as well as in the United States. Australia. The Workmen's Compensation Act of 1920 for New South Wales3 provided for the promulgation of schemes for the compensation of workers dis- abled by silica or other dust. In 1924 the prevalence of silicosis and tuberculosis among Sydney stonemasons, quarrymen, sewer miners and rockchoppers was investigated by a Technical Committee of Inquiry, appointed upon the recommendation of the New South Wales Board of Trade. The findings of this committee were published by the Government in 1925. No scheme was promulgated by the Government and in 1926 the Act was amended limiting its scope to workmen disabled by disease caused by silica-dust. This was promulgated and gazetted on September 16, 1927, and applies to men working in sandstone as stonemasons, quarrymen, rockchoppers, and sewer miners in the County of Cumberland.

Feb 1, 1931

By M. A. Mahtab

This report describes the procedures used by the Bureau of Mines for obtaining attitudes of joints surveyed with a borescope in inclined boreholes. An algorithm for computing the dips and azimuths of the observed joints is presented. The algorithm is used to solve an example problem. A computer program based on the algorithm is listed. It is hoped that the procedures described here will be useful in treating large quantities of data obtained from comprehensive borehole surveys.

Jan 1, 1973

By Wllliam D. Davis

C OMMERCIAL production of oil in northeastern Oklahoma began in 1897 and in the next two decades this area became one of the greatest oil districts of the time. Its importance is now secondary, but thousands of wells in this area have produced uninterruptedly for more than thirty years. They are now classified as stripper wells. By means of what is known as water flooding their L. production can be considerably in- creased. This practice consists in injecting water under pressure into the sand surrounding an oil well, thus displacing the oil in the pores of the sand and forcing it into the oil well.

Jan 1, 1940

By Ellsworth Daggett

THE ore smelted in the Winnamuck furnace during the year 1872 consisted, for the most part, of oxidized ores from the Winnamuck mine, only sixty tons of outside ore (from the Spanish mine) having been smelted. The latter, like the principal Winnamuck ore, was oxidized or so-called carbonate ore. There was mixed with these oxidized ores three hundred to four hundred tons, or 7 to 10 per cent. of galena, some of which was mined with the oxidized ore, while a part was mined separately from the lower portion of the mine, and afterwards mixed with the ore, with a view of preventing the formation of deposits of metallic iron in the furnaces. The average assay in silver of all the ore handled was 51.46 oz. per ton, most of it existing as chloride of silver. The lead contents were 34.98 per cent., all, or nearly all, in the form of carbonate of lead. The relative amount of silver is not at all constant, the best silver ore often being poorest in lead. The predominant gangue was silica, several determinations of which have been made on representative samples, yielding in three such samples 26, 38, and 58 per cent. silica, the latter test being ore containing but little lead. The average contents in silica are about 35 per cent., with 6 to 7 per cent. sesquioxide of iron, and small quantities of alumina and lime. Mechanically, the ore was very fine, and so thoroughly disintegrated that it presented few distin¬guishing characteristics, rendering sorting or separating of ore from waste difficult, and often impracticable. Experiments on a small scale have been tried, with a view to separate the silica by washing; but these were unsuccessful, as the finest slime, requiring a long time to settle in still water, contained a large amount of silver; and on a careful sizing and washing of the sands and coarser parts, the silver contents were found to be less dependent upon specific gravity

Jan 1, 1874

By Zoë Mullard

The introduction of Web 2.0 platforms (also referred to as social media), with their architectures of participation, has ushered in a new era of technological interaction and information exchange that is changing the nature of corporate-community communications. Web 2.0 platforms give users the ability to generate data collaboratively, meaning that more stakeholders maintain the expectation of being able to contribute to online dialogue. In light of these changes, it is important for business to consider how social media can be used strategically to enhance stakeholder relationships and increase business efficiencies. This article provides three case studies of how different stakeholders in the mining industry are strategically using Web 2.0 platforms to communicate with target audiences. The case studies are based on the experience of respondents and from website observations, which were undertaken as part of a thesis research project by the first author (Mullard, 2010), focusing on the application of social media in the mining industry.

Jan 1, 2011

By J. C. Poulos

The West Elk Mine is located near Somerset, Colorado approximately 70 miles southeast of Grand Junction, Colorado and 72 miles southwest of Glenwood Springs, Colorado on state highway 133 (Figure 1). The West Elk Mine was opened January 20, 1982 as the Mount Gunnison #1 Mine operated by the West Elk Coal Company, a division of ARCO Coal. In the early 1990?s ARCO changed the mine name to West Elk Mine and the operating company was renamed Mountain Coal Company. Arch Coal, Inc. purchased the West Elk Mine in 1998. West Elk Mine has produced coal from three different seams. Coal was first mined from the F Seam, the upper most seam in the stratigraphic sequence, from 1982 through 1991. Coal was produced from the B Seam, the lower most seam, starting with continuous miners in 1991 and transitioning to longwall mining in 1992and continued on through October 2008. The development of the E Seam, which is the middle seam in the stratigraphic column, started in 2004 with longwall production commencing in 2008. The ventilation conversion from exhausting to forcing for the E Seam portion of the West Elk Mine was implemented in late October 2009.

Feb 27, 2013

By D Mcleod, S Brindley, S Green

The design and engineering of flotation circuits is driven by numerous inputs, including (in no particular order) testwork outcomes, site considerations, type of separation required, energy sensitivity of the flotation response, personal experience and preference for flotation machines, maintenance access requirements, operability, level of automation and capital constraints.This paper discusses these and other issues in the Australian context and covers the flotation of copper/gold ores and polymetallic (copper/lead/zinc) ores. The paper discusses aspects of the following: how should testwork be done and what are the important inputs and outcomes? how should testwork results be interpreted and how does this impact on equipment selection? what processes can have a critical impact on flotation circuit performance, eg thickening and regrind? what options are available with the typical æflatÆ Australia site? how do you minimise capital cost and what impact can this have on flotation circuit operation and maintenance? how should circuits be controlled and operated? Particular focus is placed on some practical aspects of process design and engineering and the potential impact that engineering decisions can have on flotation plant operation.

Jan 1, 2005

By G. L. Oldright

The first Report of Investigations of the present series (No. 4562) was on the fundamental properties of lead compounds, and the manner in which they set limits to the richness of lead products treated in the usual sintering-blast furnace units. These properties of the compounds were emphasized, as' it was desired, also, to learn the limitations of smelting the same compounds in present ore hearth practice; the hearth has a competitor in these "usual" units, even with the rich lead feeds best adapted for the hearths. Operating conditions that were followed in older metallurgical processes, when rich products, were treated, were outlined. The second report of the series (R. I. 4563) was on the development of the ore hearths of the types now used in the Tri-State from the viewpoint of the features, functions, and dimensions of the earlier hearths that had been most changed. Experimental data, for both well and poorly desulfurized charges being considered, were given to show the relative changes in the sizes and compositions of the charges after they were added to the ore (Scotch) hearths. A general picture was given of the charge column and of the conditions prevailing there when the operation was satisfactory. In this third paper, the composition of the gases prevailing in the charge column at various elevations will be correlated with what has been learned of the nature of the charge column in order to trace the steps of operation by which lead sulfide is converted into metallic lead. The metallurgical factors that govern operation and the lines along which improvements may be made will be noted.

Jan 1, 1949

By Max J. Spendlove

The Federal Bureau of Mines has been a leader in resource recovery research since it was founded in 1910. Until the early 19601s, most of the projects were concerned primarily with the task of extending and improving conventional technology oriented to secondary metals and minerals upgrading and processing for marketable products of highest value. By the mid-1960's with the passage of the Solid Waste Disposal Act of 1965, all resource recovery research programs were increased in scope and intensity as an effort to solve the growing number of environmental problems and the rapid depletion of domestic energy and mineral resources. Many new materials were investigated including urban refuse, manufacturing, industrial wastes, and stockyard wastes. The objective was to promote maximum recycling as the most practical answer to problems of waste disposal, pollution control, and the short supply of minerals and energy. The new research projects ranged from the conversion of animal manure and other organics to oil, to the recovery of precious and common metals from demolished aircraft and electronic scrap. This profile includes brief descriptions of many selected research projects that typify, the total spectrum of Bureau of Mines research in the important field of resource recovery.

Jan 1, 1977

By Dmitri Nassyrov, In-ho Jung

"All relevant thermodynamic and phase diagram data in the CaO-Fe10-CaF2 system were critically reviewed. One set of model parameters describing the Gibbs energy of all phases has been obtained as a result of critical evaluation of the available data and optimization of the model parameters. The Modified Quasichemical Model was used to describe the interactions in the liquid phase. All calculations were performed using the FactSage thermochemical software.IntroductionSlags contaimng CaF2 are of significant interest to the steelmaking community. Notable examples of slags containing significant amounts of CaF2 include Electro-slag Remelting (ESR) slags [1] and mould flux for continuous casting [2]. The role of these slags is, among other things, to refine steel by absorbing inclusions and dissolved impurities. During slag-steel interaction, some iron from the steel will inevitably get oxidized and form iron oxides which will dissolve into the slag. With this in mind, it is important to understand the interaction between CaF2 and Fe,0 for accurate prediction of slag composition and process optimization. A thermodynamic optimization of the CaO-FetO-CaF2 was thus undertaken."

Jan 1, 2013

By Earl C. Redman

The Juneau Gold Belt, centered on Juneau and approximately 120 miles long by 10 miles wide, stretches from Berners Bay on the north to Windham Bay on the south (fig. D-l). Access within the Juneau Gold Belt is provided by the Glacier, Thane, and North Douglas Highways. The Glacier Highway extends northwest from Juneau for approximately 40 miles to Echo Cove, and the other two roads end 5.5 miles southeast and 12.6 miles west from Juneau, respectively. None of these roads connect with other highway systems and access to other areas is restricted to airplanes, the State ferry system, and commercial barge lines. BUREAU ACTIVITIES The majority of lode gold produced in Alaska came from the Juneau Gold Belt portion of the Juneau Mining District. To evaluate the economic potential of the Gold Belt, the Bureau located 173 mines and prospects within the area. A total of 263 ad its and shafts were found and 56,650 feet of underground workings were mapped. The Bureau collected and analyzed 1,557 samples during the study. In addition, considerable detailed geologic map-ping was done in the vicinity of the mines and prospects from which ore control models were developed.

Jan 1, 2012

By E. Swartzman

"IntroductionGENERALLY, the necessity for mining coals of higher impurity content, the drive for lower costs by intensive mine mechanization, changing market requirements, and the increasing competition of oil and natural gas, have continued to result in an upward rise in coal preparation, and have necessitated a more intensive study of coal preparation problems.Increasing adoption of •continuous mining equipment, for example, is introducing new problems in coal preparation. Limited experimental work in the United States (1) shows that the effect of the continuous miner on size distribution varies with the characteristics of the seam. In some seams, the fines problem is lessened, in others it is greatly aggravated. Generally there is a decrease in the relative amount of the top sizes (plus 2 in.) and a substantial increase in the intermediate sizes (down to about 1/8 in.). Contrary to expected results•, where continuous miners with vertical-moving cutting heads are used, an increase in impurities in the slack sizes does not necessarily occur where draw-slate is taken. This is because the draw-slate tends to be kicked out in lump form. However, if a seam contains bands •and lenses of impurities they are bound to be in the mined product."

Jan 1, 1952