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By M. D. Balen

The U. S. Bureau of Mines has undertaken the development of mineral industry cost escalation factors to enable the estimation of mineral development and extraction costs for mineralized sites in Alaska throught the use of the Bureau's Cost Estimating System v2.0 (CES 2.0). For the purposes of this document, all calculations are based on, and reflect the economic environment in Alaska in July 1992. The greater cost of mining in Alaska as compared to the contiguous-48 States can be estimated for Alaskan mining operations through (1 ) the analysis of capital and operating costs for analogous mine and mill plants in operation in the contiguous-48 States; (2) the hypothetical relocation of mine and mill plants from their actual location(s) to Alaska by making engineering modifications to the mine and mill plant design as required by the Alaskan site characteristics; (3) calculation of the cost of the required engineering modifications and; (4) the escalation of all costs to a level representative of the economic environment in Alaska at some specific point in time.

Jan 1, 2011

Misiman society is matrilineal and despite relatively long contact with Europeans and mining, it retains its traditional consensus style of decision making. Many Misimans at least understand English, and this has encouraged comfortable communication between the people and the company (Misima Mines Pty Limited). Company care in monitoring the environment (mostly using Misiman staff), its policy of maintaining a largely Misiman workforce, and its emphasis on training and safety, have all created an environment compatible with Misiman society. In addition, the company has constructed and/or upgraded community facilities such as the airstrip, roads, the health centre, police station and schools, and has actively promoted local business endeavours. All these initiatives have been accomplished by constant dialogue with the largely Misiman workforce, and with the Misiman people, both before and during implementation. Constant, careful communication, using traditional Misiman consensus methods, appears to be the key to continued community acceptance of the project.

Jan 1, 1991

By G. S. Maré

Tin plating operations are of a complex nature due to the many operational variables that need to be controlled in order to create a product of required quality. The work in this report lays the basics for the control of a halogen plating operation based on the DuPont tinplating set-up with regard to the chemical make-up of the plating solution, as well as operational variables such as temperature and current density. To evaluate these aspects of the process, a rotating cathode Hull-cell set-up was used. This allowed for a laboratory scale plating arrangement that simulates industry closely with regard to chemical and hydro-dynamic considerations. Typical industry accepted standards were obtained for the values of operational variables and a ?baseline? test was conducted employing these standards. All subsequent tests conducted were benchmarked against this baseline result. A large suite of results was obtained in which it was found that changes could be made to the industry accepted norm which would improve on the stability of the operation and therefore the quality of the final tin-plated product. Examples of these results are: an increase in stannous tin concentration, an increase in sodium chloride concentration and a slightly elevated plating temperature. In addition, conditions were found that must be avoided to prevent instability and poor product quality.

Jan 1, 2010

By R. I. Jaffee, J. G. Dunleavy, W. Hodge, H. R. Ogden

Jan 1, 1949

By George Mylonakis

The curvatures and subsequent bending imposed to piles by the surrounding soil during the passage of strong seismic waves is studied. This type of bending develops even in the absence of a superstructure and is referred to as "kinematic bending", to distinguish it from bending imposed to piles by loads generated from the inertia of the superstructure ("inertial bending"). Although kinematic loading may be severe in the presence of sharp stiffness discontinuities in the profile and may lead to damage, it has received little attention by engineers. The scope of the paper is twofold: (i) to discuss some fundamental aspects of seismic pile bending, and (ii) to review some existing design methods. To this end, a dimensionless bending strain parameter (instead of the more commonly used bending moment), and a strain transmissibility function relating pile bending strain and corresponding soil shear strain are introduced. Numerical examples are also presented.

Jan 1, 2002

By Eugene H. Skinner

This Bureau of Mines report describes the fieldwork and subsequent analysis to determine physical properties, stress distribution, and several aspects of rock behavior as a necessary evaluation for a typical mine opening. All work was done at a test site on the 3300 level, Crescent mine, Coeur d'Alene mining district, Idaho. Free field stress beyond the influence of the opening was also determined. Conventional overcore technique with the three-component borehole deformation gage developed by the Bureau of Mines was used in three drill holes. Three field verification tests were performed using a gage newly developed by the Spokane Mining Research Center in an approach herein termed "initial deformation method." Use of this method validated that aspect of overcore theory which predicts that similar deformation effect occurs in the wall rock around the perimeter of an opening in rock under stress. Also described are all drilling procedures and performances. Physical property determinations were made on rock samples obtained from the three overcore drill holes. Twelve physical properties with a total of [532] values were obtained at various drill hole orientations and depths. Exhaustive statistical tests were utilized in the analysis of these physical properties. Further elaborated are statistical inferences based on these analyses. Extensive analysis and interpretation of Crescent mine geology are also described.

Jan 1, 1974

By Zbigniew J. Hladysz

A Deep Underground Science and Engineering Laboratory (DUSEL) is being planned at the site of the former Homestake Gold Mine in Lead, South Dakota, under the sponsorship of the US National Science Foundation (NSF) in cooperation with the US Department of Energy (DOE). This national facility will host a variety of multidisciplinary science and engineering experiments including physics experiments that require shielding from cosmogenic radiation. Geotechnical mapping was performed in 2010 in large excavations of the Davis Campus at the 4850 Level of the former Homestake Mine. LIDAR mapping included laser scanning using a red light laser scanner and 288 Mpixels 360° still camera. The resulting vector map with the photographs digitally draped over the model, was used to create an accurate, virtual model of the excavations. For model verification, the laser scanning was accompanied by surveying and manual mapping of the geology and rock structure. The immediate use of the model was to perform structural analysis and interpretation of geology needed for the design of the DUSEL?s super large excavations. The second round of scanning, after the application of shotcrete to the excavations walls, will be used as a technical blueprint to assess the effectiveness of shotcrete application.

May 1, 2011

By Wingham D. W

Based upon the previous work of Norman & Loeb, a method was used to assess the comparative wearing properties of ten different alloys being used, or being considered for use, as mill liners and grinding media at Mount Isa, The materials to be tested were obtained in the form of large diameter balls, and were run, along with the regular ball charge, in a large ball mill operating under normal grinding conditions. At selected intervals, the test balls were removed from the mill, weighed and identified, and their relative wear rates determined.INTRODUCTIONInformation in metallurgical journals, from local iron and steel foundries, and from various metal promotional organizations has suggested that the various alloy compositions available should be examined and assessed for possible use as milllfners and grinding media.Previous attempts at evaluation of recommended materials for these applications elsewhere, have usually involved the purchase of large quantities of grinding balls or complete mill liner sets, requiring running periods of up to two years or more. As well as being both a costly and lengthy procedure, the information obtained may be of little significance, due to changes in milling practice, and ore characteristics during the period of operation.To overcome these difficuities, a method was adopted based on the short time wear rate test recommended by Norman & Loeb (1949) and Norman (1957) in which all the materialsunder consideration are ·subjected·concurrently to the conditions of service.Previous calculations of wear rates have been dependent1. Senior Metallurgist (Materials), Mount Isa Mines Limited.2. Metallographer, Mount Isa Mines Limited.Manuscript received at The Institute, 22nd April, 1963, and presented to the1963 Annual Conference.

Jan 1, 1963

By Ruth F. Brinkley

This circular describes the activities and publications of the Bureau of Mines, Explosives Research Laboratory4 for the fiscal year 1960 (July 1, 1959 -June 30, 1960). Part 1 describes briefly the principal projects that were active during the report period, and presents some data not scheduled for publication elsewhere in the near future. Certain of the results are only preliminary and should be regarded as tentative, pending the findings of the completed investigation. Publications that appeared during the report period are listed and described briefly in part 2. In general, the research activities reported in these publications antedate fiscal year 1960. The published material relating to activities that are still current is indicated by references in part 1.

Jan 1, 1962

By Laird Crocker

A goal of the Federal Bureau of Mines is to minimize the undersirable environmental conflicts and impacts associated with mineral processing operations. To help reach this goal the Bureau operated a citrate-process pilot plant for the removal of sulfur dioxide from lead smelter sintering machine waste gases to test the process. The process uses a carboxylate solution such as citric acid to absorb sulfur dioxide from waste gases. The absorbed sulfur dioxide is subsequently reacted with hydrogen sulfide to precipitate sulfur and regenerate the solution for recycle. Nominal capacity of the pilot plant was 1,000 scfm of 0.5 vol-pct sulfur dioxide gas. The pilot plant was operated for over 5,400 hr and produced about 55 net tons of sulfur. The operation demonstrated that (1) 99 pct of the sulfur dioxide could be removed from lead smelter sintering machining waste gases containing from 0.1 to 0.6 vol-pct sulfur dioxide, (2) sulfur precipitation and solution regeneration with hydrogen sulfide in conventional stirred vessels was readily controlled, (3) precipitated sulfur could be continuously recovered as a 99.S-pct-pure product by flotation and melting, and (4) 78 dry-vol-pct hydrogen sulfide gas could be produced from pilot-plant product sulfur, natural gas, and steam.

Jan 1, 1979

By R. A. Beall

Homogeneous zirconium-alloy ingots have been cast on a production basis by the consumable-electrode arc-melting process at the Northwest Electrodevelopment Experiment Station, Bureau of Mines, Albany, Oreg. This paper describes the various methods used to introduce alloying materials into the ingot and evaluates 1 each method by the degree of homogeneity of resulting ingots, as determined in tests on sections cut from the ingots. As many as 30 or more ingots, each 6 to 10 inches in diameter and weighing 300 to 500 pounds, were melted, using each method; and, as most of them subsequently were fabricated to strip 0.1 inch thick, the test results are considered to be representative of production practice. Ingot homogeneity has been considered more difficult to achieve in arc-melting practice than by methods where the molten metal is poured into molds and the addition can be stirred into the total mass of metal before casting. Owing to the unique requirements of consumable-electrode arc melting the addition can be made only to that part of the total mass of the ingot that is molten at one time. Observation of the flowlines in 500-pound ingots produced at Albany indicates that the molten pool has a maximum depth about equal to the ingot diameter. The weight of metal molten at one time is, therefore, not over 100 pounds. Characteristically, the arc-melting process is conducive to segregation, which can be overcome, at least partly, by adding the alloy constituents almost continuously during casting.

Jan 1, 1956

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 published health and safety statistics. This report includes data for 1964 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, 1967

By G. Ward Wilson

Waste rock and tailings may be combined through intimate blending to create new materials with superior physical and hydraulic properties. The new material, termed Co-Mix, has high shear strength characteristics, low compressibility, low hydraulic conductivity, and a high water retaining capacity. Co-Mixed tailings and waste rock may be used to construct cover systems, internal barriers and seals, confinement structures and full depth waste repositories. Field scale test trials using Co-Mixed blends of waste rock, tailings and slag have been constructed at the Copper Cliff Mine in Sudbury, Canad. These lysimeters will be used to evaluate the performance of the new material for cover systems that may potentially be constructed on the tailings impoundment upon closure. In this sense, the paper point out the construction of the lysimeters with respect to expected field performance during the spring snow melt period and summer to produce cover systems for closure.

Sep 12, 2005

Recently, work was carried out by the Shotcrete Working Group to study anisotropy in steel fibre reinforced shotcrete using strain-controlled, compressive strength testing methods. The shotcrete materials used and specimen preparation procedures as well as testing methods are described. The test results are discussed and it is concluded that, because of the anisotropic nature of fibre reinforced shotcrete, it may be worthwhile investigating the degree of such anisotropy in practice using strain-controlled, strength testing techniques.

Jan 1, 2001

At the inception of the gold-mining industry at Kalgoorlie the small supply of firewood required for steaming purposes was naturally all drawn from the limited local areas, which promised soon to become denuded. With the advent of the railway toKalgoorlie came the ever increasing machinery and steam power, and the accompanying demand for firewood so increased that the fuel contractors began their operations, by following the timber belts along the Yilgarn railway line, and graduallygetting further westward, until at present we find them as far as Woolgangie, 63 miles from Kalgoorlie, and with the regular railway rates, I0. per ton per mile, this maybe considered the limit of payable timber at current rates. Although in the early days the reserve of timber along the railway line must have appeared as incalculable and inexhaustible as that of coal did in Europe a couple of centurys ago, the day is now near us when even this source will fail to meet the demands made upon it, for, although a good two years' supply is available or the areas under the axe, yet it is time to look ahead and find from whence the future supplies are to be drawn. Along the railways we find the zone of felling operations limited for want ofcommunication, and only such portions of the forests as are within six or seven miles of the railway come under the axe at present while virgin forests to the rear remain practically unexploited. It is only in the course of the past sixteen months that the firewood industry has developed...

Jan 1, 1901

By Michael V. Mergentime, Prakash M. Donde

The Nutley Quarry Trunk Sewer Project is a good example of a tunnel that went through difficult and complex ground. The 2 m (7ft.) diameter and 840 m (2,750 ft.)long tunnel passed through soft ground, mixed face, and hard sandstone. The soft ground and mixed face tunneling provided several challenges. During excavation of the tunnel, the Contractor encountered a number of unanticipated large boulders. In addition, the length of the mixed face portion of the tunnel increased by 100%. The Contractor tried various construction techniques to overcome the difficult ground conditions and complete the project. The tunneling progress was slower than expected. The Contractor claimed extra costs for differing site conditions. Through discussions and negotiations between the Contractor, Engineer, and Owner, all of the changed condition claims were settled before the construction of the project was completed. This paper addresses the difficult ground conditions, claims evaluation, and how they were resolved by cooperative efforts between the Contractor and the Owner/Engineer.

Jan 1, 2001

By H. Demirel

This paper deals with concentration of hematitic-limonitic iron ores. The ore sample obtained from Karakuz (Turkey) contain:. about 40-46 I Fe. First, a low intensity magnetic separation process was employed to separate the strongly magnetic particles cf "-10+2 mm" and "-2+0.075 mm" size fractions and magnetic concentrates with 59.1 % Fe aid % 58.0 Fe were obtained respectively. The non-magnetics of both fractions were then fed to a nigh intensity permanent magnetic separator. The Fe contents of "-10+2 nun" and "2+0.075 mm" size fractions were increased from 28.2 to 51.13 and from 35.4 7. to 43.25 respectively after single pass. Easing on these results, it was concluded that the high intensity permanent magnetic separator could he used as a pre-concentrator f.7.1- hematitic-limonitic Karakuz iron ore.

Jan 1, 1991

By Parameswaran V. S, Anshuman Singh

This is a case study on ground improvement using Stone columns at Kokrajhar in Assam which comes under seismic Zone V as per IS: 1893. The strata at site comprised of mostly fine sands with low SPTN values, fine content less than 10% and ground water table (GWT) at shallow depth. As ground water table subjected to seasonal variation, water table is considered at ground level for designing purpose. The geotechnical profile of the boreholes was analysed on the guidelines of IS 1893 (Part 1) -2016 and it was observed that the liquefaction potential of the soil layers is prominent and ground improvement is inevitable up to a depth of 9.5 m below existing ground level. In order to mitigate the liquefaction of soil layer, Stone columns were proposed. The in-situ soil is densified using wet top feed vibroreplacement method with an area replacement ratio of 16%, so that the relative density of the soil can be enhanced to prevent liquefaction risk. Correlation between relative density, fines content and increment of SPT N –value given by Tokimatsu and Yoshimi (1983) was used for designing purpose. Field tests such as SPTs were carried out at site to validate the extent of SPT (N) improvement. Detail comparison of pre and post density, SPT N values and CRR values were discussed in this paper.

Nov 1, 2022

By I Clark, S C. Dominy

Bulk sampling programs are typically applied in coarse gold mineralised systems to verify resource/reserve grades. In recent years, there have been controversies surrounding some results of underground bulk sampling exercises compared to the predictions using diamond drill data. Just how realistic is it to predict 100 t lots from drilling that was designed to model blocks of several thousand tonnes? This study looks at the variation of relatively small units within larger planned mining units and compares some of the geostatistical techniques which purport to provide tools for such studies. Relative difficulty of application, computer timings and summaries of results will be used to illustrate the likely variation in bulk sampling units as opposed to mining units and large-scale planning units. A case study based on publicly available data from a gold project in North America is presented. A simplistic and unconditional geostatistical simulation model demonstrated that up to 50 per cent of a relatively high-grade mining block could show as uneconomic low-grade subblocks. A subsequent study will consider a similar demonstration using uniform conditioning. Erroneous impressions of early sampling results can lead to unsupported prejudgements of the final results. Bulk sampling programs require detailed planning based on ore characteristics, where protocols must fit the mineralisation type. Any program requires definition of aims and data quality objectives across grade, geological, geotechnical and geometallurgical parameters.CITATION:Clark, I and Dominy, S C, 2017. Underground bulk sampling, uniform conditioning and conditional simulation – unrealistic expectations?, in Proceedings Eighth World Conference on Sampling and Blending , pp 3–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Flavio Rojos-Tapia, Oscar Pereira-Cerda, Samuel Sánchez-Pino, Samuel Sánchez-Baquedano

"Pneumatic flotation was introduced to the Chilean Copper Mining Industry in 1993 by Ingeniería de Minerales S.A. (IDM). The technology is based on the designs of Dr. Rainer Imhof from Germany, who is the designer of several different types of pneumatic flotation cells, already sold through his Company Maelgwyn Mineral Service Limited (MMH). The company is represented by Ingenieria de Minerales S.A. (IDM) in South America.Pneumatic flotation, has been used in tough industrial applications .It has been successfully used for metallic ores such as copper sulphide and oxide minerals, copper slag, silica and silicates from iron magnetic preconcentrate (reverse flotation) and gold. It has also provided promising results when applied to molybdenum flotation. The latest applications, with ultrafine molybdenum particles in operating plants, is showing the V and G Cell (end model designed) as a real technological alternative to conventional flotation., The G Cell is an extremely high speed flotation machine with high selectivity which introduces the possibility of producing a final molybdenum concentrate with only one stage of cleaning. This is a completely new development in molybdenum flotation in the industrial circuit which has the potential to dramatically reduce the circulating load in the cleaning circuit. As a consequence the capital costs of future Molybdenum plants may also be reduced. The suitability of the G Cell will have to be determined on a case by case basis but it provides the metallurgist with an alternate flowsheet for consideration.The good performance of the G Cell can be explained by the high gas hold-up and very effective micro-turbulence which helps improve the attachment of solid particles to the bubbles. This technology may change our traditional concept of residence time in flotation. Additionally, the rotation phenomena introduced in the vessel of the G Cell ,creates radial separation forces which are critical to achieving a more rapid separation of the target minerals from the tailing. This results in a much reduced residence time requirement in the flotation machine. Some benefits associated with the use of the new G Cell are: less energy consumption, less maintenance costs, simple and reliable circuit to operate and a small area required for installing the circuits.As a result of the industrial experience in the Chile, the pneumatic flotation type G Cell can be regarded as a technology which must be considered as a replacement technology for the rougher and cleaner stages for fine particle flotation."

Jan 1, 2008