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The condition of the domestic mining industry is obviously affected by the cycles in general business conditions. This study, the results of which are presented in a series of 78 charts, attempts to examine the interrelationships between the general business indicators and the major statistical measures for the base-metals industries during the cycles in the United States economy following World War II. For these industries the cyclical problem is perhaps less acute than the secular-trend problem. However, short-run fluctuations in production and employment do have very important impacts upon the welfare of the regions which derive a significant portion of their income from base-metals mining and processing industries. Any information concerning the normal patterns of development as the industries enter into a cyclical recession will permit better forecasts and perhaps help promote measures to alleviate the distress that occurs. Also, a systematic study of the comparative movements among the statistical measures during a series of cycles can bring to the fore the economic causation involved, and perhaps, after intensive study, can lead to a better method of short-range forecasting for these industries. This study has not fully achieved these aims. However, observations which significantly aid the interpretation of the current monthly statistics on these commodities are made, and some very general conclusions are drawn. The charts are presented so the interested people can examine them and draw additional conclusions. The charts refer specifically to cyclical analysis. The technique of indexing each cycle to its turning point effectively subordinates the longer term trend movements of the data. Thus, certain general conclusions flowing from this study and from the continuing economic research of the Office of Chief Economist will aid the reader by clarifying the frame of reference within which the charts should be examined.

Jan 1, 1961

By M. R. Geer

Efforts to evaluate washery performance are nearly as old as the art of coal cleaning, and in former years there was no uniformity in either the methods used or the basic terminology employed. This situation, and the con- fusion it bred, prevailed until about the time of the First International Coal Preparation Conference in 1950, Largely because of the interest of the French coal research organization Cerchar, the subject of evaluating performance was given prime importance at this conference. As a result, there is now a much greater degree of uniformity in terminology and methods of expressing cleaning results. The International Standards Organization currently is working toward international standards of terminology and methods that should improve the situation even more. The various criteria that are used to evaluate the performance of coal- cleaning equipment fall into three categories, depending upon the extent to which they are dependent on the density composition of the raw coal; some are directly dependent, others are only indirectly dependent, and still others are substantially indenpendent.

Jan 1, 1962

By David J. Kusler

This Bureau of Mines study is an appraisal of the demand for platinum, should this strategic metal be used as a. catalyst in the National abatement of automobile exhaust pollution. The Clean Air Act 0f 1970, as amended, requires that automobiles produced in 1975 and thereafter be provided with antipollutive measures to control automotive exhaust emissions. The study considers the need for automobile pollution control, the methodology for such control, the annual primary (new) platinum demand for automobiles produced from 1975 to 1990, primary platinum availability, and supply-demand forecasts and outlook. The correlative demand for platinum for the production of the required unleaded gasoline is also considered. Methodology for the study included a forecast of new automobile production from 1975 to 1990, development of automobile survival and retirement data, estimates of new platinum demand under various conditions of salvage, and data on recycling the precious metal from the catalytic converters of scrapped vehicles and existing vehicles when their spent converters are exchanged for replacement units. The new platinum demand for automobile exhaust converters, based on a converter service life of 50,000 miles, is estimated to be 1.41 million troy ounces initially in 1975, rising to 1.68 million in 1980, and declining curvi-linearly to 0.94 million in 1990. The platinum demand for converter longevities other than 50,000 miles can be derived from the tabular data presented. An appendix to the report presents a comparison between longevities of 50,000 miles and 25,000 miles. The petroleum industry's demand for new platinum for the production of lead-free gasolines could total as high as 1 million troy ounces between 1972 and 1981, just for expansion of isomerization and reforming capacity, and is in addition to normal operating demand for this metal.

Jan 1, 1972

By Maya Kamenetsky, Khoi Nguyen, Natalee Bonnici, Steve Walters, Claire McMahon, Julie Hunt, Ron Berry

"The analysis of meso- and micro-scale textural attributes has been undertaken on ore samples from the Ernest Henry iron oxide-copper-gold (IOCG) deposit in NW QLD. Quantified textural data including grain size, shape and mineral association have been extracted from classified images of core with the aim to better predict potential mineral processing behaviours such as comminution, liberation and flotation. Data have been extracted from images of intact core at meso- and micro-scales using high resolution continuous images collected using automated core-logger technology, SEM-based and optical microscopy platforms.The results of this study will show examples of quantified size, shape and mineral association data from meso- and micro-scale classified images. Analysis of the data shows that there are domains of variable grain size and mineral association that can potentially be related to crushing and liberation behaviour. The trends that are observed at the drill-core (meso-) scale are consistent with those at the micro-scale. The results from the micro-scale analysis show that the domains defined at the core-scale have clearly different chalcopyrite sizes and shapes as well as variable bulk mineralogy.INTRODUCTIONInnovations in technology have allowed automated extraction of information about mineral shape, grain size and mineral association, i.e., texture, from meso- and micro-scale images of intact rocks. The overall aim of this research is to investigate trends in quantified textural data that can potentially give an early view of processing parameters such as predicted grind size and liberation behaviour."

Jan 1, 2009

By K. K. Kelley

Thermodynamics data for silicates have applications in the fields of extractive metallurgy, ceramics, and geochemistry. To facilitate these applications, up-to-date tables of heats and free energies of formation are needed. It is the purpose of this report to supply such tables for anhydrous silicates. During the last 15 years the heats of formation of a substantial number of anhydrous silicates have been reliably determined at or near room temperature. This resulted from the development (first by the Bureau of Mines and later by the Geophysical Laboratory of the Carnegie Institution of Washington, by the Institute of Geology of the University of Helsinki, Finland, and by the Department of Geology of the University of Chicago) of accurate solution calorimeters, employing hydrofluoric acid as the reaction medium. Specific references to work of these laboratories will be made in the next section of this report. Also, entropy data at 298.150 K. and high-temperature heat-content values are available for many of these silicates, mainly owing to work of the Bureau of Mines. Most of these entropy and heat-content data have been compiled in Bureau of Mines Bulletins (13, 15).3

Jan 1, 1962

By F. D. Ford, Z. Dai, A. Byers

Manitoba Mining and Milling operations consist of three underground mines (Thompson T1, T3 and Birchtree), feeding the Thompson Mill. Three years ago, a collaborative effort involving Mines Exploration, Mines Project Development Group, Mill Technical Services and Vale Base Metals Technical Excellence Center was initiated to establish and verify the cause of high variability in concentrate quality and Ni recovery at the Thompson Mill. One outcome of this work was a program to systematically characterize the mineralogy and metallurgical performance of current and future orebodies feeding the mill. Mineralogy results show that high value enabling ores typically have a high pentlandite to pyrrhotite ratio and benign silicate mineralogy (mostly quartz and feldspar from sedimentary host rocks), while metallurgically challenging ores contain some combination of pyrite and/or hexagonal (non-magnetic) pyrrhotite and/or elevated quantities of talc (with associated carbonates) derived from altered ultramafic host rocks. The metallurgical performance of these two ore types has been simulated by an Excel particle flotation model, which calculates the relative floatability of particles based on the particle’s mineral composition and mineral locking determined from MLA images. The relationship between these mineral properties measured by MLA and metallurgical performance was established using 13 monthly composite samples from Thompson Mill. The model was then validated with results of laboratory flotation experiments on individual orebodies submitted for evaluation. The validated model can be used to predict plant metallurgical performance based on individual ore bodies feeding the mill. Individual orebody’s grade-recovery curves are assumed to be additive, and can be weighted in proportion to the mill feed to predict mill recovery over the same time period. The ore mixing can be done with a simple Excel spreadsheet and comes with a graphical output for easy visualization of the resulting grade-recovery curve.

Jan 1, 2015

By R. J. Matetic

The Bureau of Mines, as part of a program to improve mine planning and development, is currently investigating the effects of pillar load transfer, which can impact mining operations wi.thin a multiple-seam configuration. At two mine sites where such ground interactions were present, the Bureau performed a complete geological analysis and installed and monitored instrumentation to gather pertinent data on rock mechanics. Overburden depth varied dramatically in the vicinity of the study area and reached a maximum at the study site; innerburden thick-ness was less than a pillar width (40 to 4S ft); heaving was experienced in both mines where sandstone and/or shale floor units were observed; overlays of the mine layouts show pillars were not totally superpositioned; a maximum of S in of roof to floor convergence was measured; and pressure readings indicated pillar core loading only and increased to a maximum of 7,000 psig over instrument setting pressure.

Jan 1, 1987

Session 1 ? Intro to MiHR ? Business Case for Aboriginal Inclusion ? Overview of the Mining HR Guide for Aboriginal Communities ? Two presentations of Programs featured in the Guide ?? The RAP Program from NWCC ?? First Nations Youth Employment Program PDAC-MM Session 2 ? Presentation from MAC ? Taking up the AFN Corporate Challenge ? Presentation on Mastering Aboriginal Inclusion in Mining About MiHR Who we are: ? National Sector Council for the Minerals and Metals Sector ? 18-person Board of Directors ? 100+ Industry Leaders volunteer on our project committees ? PPP - Funded by HRSDC and industry What we do: ? Identify national HR challenges and opportunities for the minerals and metals industry ? Create national solutions through collaboration, partnerships and Synergy

May 1, 2009

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. It is used in all stages of the mining process, from site characterization to production operations. The goal of the International Workshop on Rock Mass Classification in Underground Mining was to provide a forum for leading practitioners of rock mass classification to come together and share their methods and experiences with the technique. The workshop was held in Vancouver, British Columbia, Canada, on May 31, 2007. It was co-chaired by Christopher Mark, Ph.D., P.E., National Institute for Occupational Safety and Health, Pittsburgh, PA, and Rimas Pakalnis, P.Eng., University of British Columbia, Vancouver, Canada. The proceedings of the workshop contain 16 invited papers from 9 countries, reflecting the international depth and breadth of current practice. Applications in both hard-rock and coal mining are well represented. Some of the topics that were addressed at the workshop include: • Major rock mass classification systems used in mining and their variants • Collection of input data through observation, rock testing, and geophysics • Design of mine layouts and rock support systems using classification • Estimation of rock mass strength and other input parameters for numerical models from classification • Applications in weak rock, raise boring, cavability assessment, and other special topics • Risk assessment using rock mass classification

Jan 5, 2007

By J. Mitchell Linne

In 1985, at the request of Bureau of Land Management, the U.S. Bureau of Mines studied a 54,480-acre portion of the 93,205-acre Dry Valley Rim Wilderness Study Area (CA-020-615), in order to evaluate its identified resources. The area studied is in Washoe County, NV, and Lassen County, CA, about 35 miles east of Susanville, CA. No metallic resources were identified. The Red Rock and Willow Springs areas contain 85 million tons of altered basalt with zeolite amygdules. This material, averaging more than 50 percent chabazite, constitutes a subeconomic zeolite resource. This zeolite-bearing material would require beneficiation to upgrade it for higher value uses. Natural zeolites have a small market in the United States, which is presently supplied by other higher grade material. There is low probability that these resources will be mined in the foreseeable future. The Capricorn claims, adjacent to the study area, are on alluvial sediments containing more than 30 percent montmorillonoid clays. The material is not usable as pozzolan and was not tested for other uses such as absorbency, oil clarification, or insecticide carrier. The term pozzolan refers to a number of siliceous materials which are combined with portland cement to enhance the physical properties of the resultant concrete. The area is remote from market and contains low value material. It is improbable that this occurrence will be mined in the foreseeable future.

Jan 1, 1987

The effect of microwave radiation on the processing of Palabora open pit ore has been investigated. Significant reductions in Bond work index are demonstrated for microwave treated samples. Reductions in work index were found to be sensitive to applied power level and method of application. After single stage magnetic separation tests, improvements in recovery of FeO were noted. However, these were curtailed by oxidation of the magnetite species as a result of continued heating. The effects of microwave radiation upon the recovery of copper after froth flotation were also quantified. Small initial increases in recovery of copper were note dafter microwave treatment. However, with prolonged exposure, recovery was found to decrease. Overall recovery of copper was not affected except for samples treated for extended duration. The influence of microwave treatment upon the conventional Palabora grinding circuit has been quantified with the use of USIMPAC software. Conclusions are made regarding the economics of microwave treatment for this ore. Keywords : Microwave; Grinding; Magnetic Separation; Flotation; Economic Analysis

Jan 1, 2000

This paper was developed as part of an effort by the National Institute for Occupational Safety and Health (NIOSH) to identify risk factors associated with bumps in the prevention of fatalities and accidents in highly stressed, bump-prone ground conditions. Changes of failure mechanism with increasing confinement, from extensional- to shear-dominated failure, are widely observed in the rupture of intact specimens at the laboratory scale and in rock masses. In the previous analysis conducted in 2018, both unconfined and triaxial compressive tests were conducted to investigate the strength characteristics of some specimens of a Utah coal, including the spalling limits, the ratio of apparent unconfined compressive strength (AUCS) to unconfined compressive strength (UCS), the damage characteristics, and the post-yield dilatancy. These mechanical characteristics were found to be strongly anisotropic as a function of the orientation of the cleats relative to the loading direction.

Jan 7, 2020

By V. Izaxon

Current practice in mining frozen, underground placers is to support the mine openings by leaving remnant pillars, which are kept frozen to maintain their stability. These pillars may be partially extracted depending on mining conditions, but this practice may be risky, and roof falls are common. Instead of allowing the mined-out areas to cave, the extracted entries could be filled with waste material, which would then be frozen, using cold ventilation air. A finite difference model for analyzing the effects of various parameters on the freezing of backfill in underground mines in the Arctic has been developed and tested. The model also accounts for properties unique to a frozen rock mass, including those that change with temperature. Examination of the characteristics of ice-cemented mining waste materials as backfill indicates that with proper engineering control, a backfill system can be designed for use in production mines. The system will allow increased extraction ratio while maintaining the stability of underground openings with minimum heat impact on the surroundings. These simulated results establish the relationships among the strength, the temperature, and the freezing characteristics of a given material. When coupled with site observations these relationships will facilitate the optimal design of ore pillar recovery methods.

Jan 1, 2004

This publication is designed to be helpful in promoting health and safety in tunneling and related operations. The format has been selected and arranged to provide a condensed guide for safety personnel, inspection and investigative agencies, design and project engineers, and others responsible for the health and safety of workmen. All the precautionary measures recommended are based on actual conditions observed, from investigations of fatal or serious accidents, and from research conducted to find ways and means of alleviating hazards and unhealthful conditions. Many of the recommended rules are included in State laws and in the general safety requirements of the construction industry. Explanatory, descriptive, and qualifying information has been largely omitted in this publication to keep basic data in more useful and compact form. Included in the appendixes are special precautions for gassy (methane atmospheres) tunnels and tunnels where petroleum products are encountered.

Jan 1, 1968

By M. Z. A. Bakar

A series of full scale laboratory linear rock cutting tests was carried out with a long bladed single disc cutter (292 mm diameter, 11mm wide constant cross-section blade) on dry and water saturated sandstone blocks using a linear rock cutting machine (LRCM). The muck collected from the cutting tests has been analyzed to establish a link with the specific energy (SE) of the operation. Coarseness index (CI), a non dimensional parameter, has been found to be a useful indicator of the relative efficiency of the cutting operation. An inverse relationship of the form SE = k CI-n is observed between SE and CI with very high CI usually corresponding with the lowest values of SE. The power n of the relationship for both dry and saturated rock tests is much less than the values found in the previous studies using constant cross section disc cutters and is believed to be dependent on the strength of the rock and the cutter type used. Although the average CI is found to be lower for saturated rock than for dry rock, at the same time saturated rock cutting is found to be less energy intensive (in terms of SE) than dry rock cutting. Moderate correlation exists between the production rate or yield and the SE of the cutting operation for both dry and saturated rock, which can provide some useful information about the field production rate discounting the effect of discontinuities in the rock mass.

Jan 1, 2012

Bioleaching Metals from Waste Printed Circuit Boards and the Shapes of Microorganisms

Sep 13, 2010

By S. A. Sayed, M. N. M. Ahmed, M. A. Doheim

The performance of a 12.7 cm hydrocyclone was investigated by considering the effect of design variables (diameters of the vortex finder and apex) and operating variables (pressure drop and solids content of the feed) at a medium feed solids concentration of mixed minerals. Cut-size was found to be the most important parameter in hydrocyclone design and operation. The effect of feed pressure in reducing hydrocyclone cut-size is less pronounced at medium feed solids concentration with a mixed mineral feed. The choice of vortex finder diameter and apex diameter becomes more sensitive at medium feed solids concentrations. The effect of feed solids concentration in increasing the cut-size becomes less marked at higher concentrations. Predictions of an empirical model were found to be in good agreement with experimental data. Comparison of results obtained from the model with those predicted by theoretically derived models showed the latter to be more promising, with the turbulent two-phase model giving closer agreement with the experimental data

Apr 1, 1995

By Harry G. Poulos

Ground movements can arise from a large number of sources and can have a significant effect on nearby piles and deep foundations. The loading of the piles by ground movements is a different mechanism to that arising from direct applied loading to the pile head, and consequently it is not generally possible to adequately analyze the effects of ground movements simply by applying some type of equivalent loading to the pile head. The main effects of ground movements are the development of additional movements, axial forces and bending moments in the piles, and thus the key design aspects are related to movements and to the structural integrity of the pile. However, the ultimate geotechnical load carrying capacity is generally not affected by the ground movements themselves. This paper will describe an approach to the analysis of ground movement effects on piles, considering axial and lateral movements separately. Some of the main features of pile response will be discussed for three specific problems involving ground movements: 1. Piles near and within embankments; 2. Piles near an excavation for a pile cap; 3. Piles subjected to seismic ground motions.

Jan 1, 2007

By Peter Barker, Terry Jones

"The Kelsey Centrifugal Jig (KCJ) utilizes the application of centrifugal force (and the resultant enhanced gravitational field) to conventional jigging technology principles to successfully and efficiently process materials where the valuable constituent particulates are very fine and/or where there is a small specific gravity differential between these and the gangue minerals.The KCJ is applicable to a broad range of fine mineral recovery duties, with current installations in the mineral sands, tin, tantalum, gold and nickel industries. Other areas of application are being developed with mineral commodities including tungsten, base metals, iron ore, chromite and apatite/feldspar.Information on the principles of operation of the KCJ, typical performance figures in a number of application areas, comparison to centrifugal concentrators, key elements for a successful KCJ operation and recent developments with the KCJ are presented in this paper to demonstrate the capabilities of the KCJ.INTRODUCTIONAfter a number of years of development by inventor Chris Kelsey, the first commercial KCJ unit was installed at the Renison Bell tin mine in Tasmania, Australia, in 1992. The subsequent decade saw the installation of further KCJ units in applications including tin, tantalum and mineral sands.Development and improvement in KCJ hardware continued and culminated in the introduction of the high-capacity Model J1800 KCJ and standard features such as an automatic screen cleaning system. This opened up further markets and resulted in Model J1800 KCJ installations in the gold and nickel industries, as well as further KCJ installations in the mineral sands and tin industries. In recent years, work has continued on application of the KCJ to many other duties in industries including tungsten, base metals, iron ore, chromite, apatite/feldspar, etc."

Jan 1, 2007

By H. K. Taylor

Ore reserves are inadequately defined. Geological reconnaissance and pre-feasibility mining work generate a broad range of valid tonnage estimates, many published for the benefit of various interests, who may view all figures as reserves. This work reviews the regular estimation of tonnages, grades and relevant factors for single deposits. A consistent framework of definition is suggested which, by conforming to the known structures of feasibility studies and long-range plans, avoids the pitfalls of over-categorisation and of unrealistic promises. Applications are based on North American experience but are intended for general use

Sep 1, 1991