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The paper deals with the results of dynamic tests carried out on a range of surface support liners consisting of combinations of mesh (various types), shotcrete, and wire rope lacing. The testing was carried out over the period 1993 to 1998. The dynamic testing method made use of drop weight impact loading of test samples which attempted to simulate realistic in situ conditions, and the range of loading imposed was equivalent to small to severe rockburst conditions. The results of the testing provide quantitative data, in the form of input energy, which is relevant for support design and for the choice of support types appropriate for situations in which significant mine-induced seismicity occurs or is expected to occur. In addition to the wire mesh and shotcrete liner systems tested, estimates of energy capacity are made for other, untested, systems.

Jan 1, 2001

By G. A. Craig

The Moon, asteroids, and planets of the solar system represent the most distant caches of wealth that humanity has ever considered recovering. Yet, in addition to the potentially recoverable values represented there, harvesting off-Earth resources has a second, almost incalculable sustainable benefit in that they can be retrieved with absolutely no damage to Earth. Previous research mostly assessed the potential of asteroids and the Moon for mining purposes from a theoretical and scientific point of view. These studies investigated drawbacks that could be experienced in this type of operation, but no detailed economic evaluation that is meaningful for mining project management has been conducted and the parameters that are most likely to make an operation feasible are unknown. This paper provides a preliminary economic and sensitivity analysis of a possible off-Earth mining business extracting minerals from an existing asteroid.

Jan 1, 2014

By M. S. Safarzadeh

Cu-As feedstocks are among the most problematic copper sources that have been avoided over the past years. The high arsenic content of such ores/concentrates combined with their refractory nature have directed the metallurgical industry towards developing efficient technologies for the treatment of high-arsenic copper ores/concentrates. As the most important member of Cu-As-S mineral system, enargite (Cu3AsS4) is frequently encountered in some of the important copper deposits. Several hydrometallurgical and pyrometallurgical processes have been examined for the treatment of enargite concentrates, but currently, no commercial operation exists. In an effort to develop an original processing option, an acid bake-leach process has been identified and applied to an enargite concentrate containing ~67% enargite, ~27% pyrite (FeS2), ~3% chalcopyrite (CuFeS2), ~6% sphalerite (ZnS) and <1% galena (PbS). Sulfuric acid baking of this concentrate resulted in the transformation of the concentrate to S8, As2O3, HFe(SO4)2?4H2O, PbSO4 and Cu0.47Fe0.53SO4?H2O, all of which (except elemental sulfur and PbSO4) dissolved during the water leaching step. More than 87% Cu and 64% As were leached when the concentrate was baked at 200°C over 7 h with a sulfuric acid to concentrate weight ratio of 1.6. Less than 1% As was lost to the gas phase. Upon water leaching, copper and arsenic were released to the solution at a concentration ratio of about 3:1. While enargite is very reactive during the sulfuric acid baking reaction, other minerals present in the concentrate such as pyrite, galena, and sphalerite may compete to consume sulfuric acid and be converted into their corresponding sulfates at different levels. The purpose of this paper is to evaluate phase transformations during the acid bake-leach process for the treatment of an enargite concentrate, and to study the effect of sulfuric acid dosage on the extraction of Cu, Fe, and As. In this regard, the concentrate, baked concentrate, and the leach residues are characterized and a conceptual process flowsheet is described for the acid bake-leach process for the treatment of enargite concentrates.

Feb 23, 2014

By A. Adu-Acheampong

Stope instability at Ashanti Goldfields Company Ltd. (AGC) is a major concern. Using information from field mapping, major discontinuity sets were defined, Rock Quality Designation (RQD) was determined. The stability of wedges in the stope walls was assessed using the commercially available computer program UNWEDGE(Rock Science, 1992). Analytical results indicate that the presence of graphite infilling in joints contributes to instability, while steeply dipping joints control wedge slabbing and wedge toppling in the hanging wall. Stable stope widths and dimensions were determined to range from8.1 to 30 meters (m).

Jan 1, 2003

By R. P. Mohring

Before we look at what the challenges and opportunities for future coal mining will be, it is appropriate to have a look at whether there will be a coal industry in the future. There is much talk about the damage caused by the burning of fossil fuels and the need to replace coal and oil with more environmentally friendly energy sources. Yes, there is evidence that the current practice in burning of fossil fuel has certain negative environmental effects, however, the adverse effects for global economic development from inappropriate measures to control greenhouse gas emissions would be severe.

Jan 1, 2001

By Paul J. Lewis

Estimation of the axial side shear resistance of drilled shaft rock sockets is directly related to the unconfined compressive strength of the bedrock. Commonly, the mean unconfined compressive strength value is calculated from a range of laboratory test results and is used to estimate the side shear of the bedrock. This paper presents the results from a full scale axial load test performed on an 8.5-feet-diameter drilled shaft rock socket, and compares measured side shear values to estimated values for two different rock strata. Measured side shear values correlated well with the design value calculated for the "strong" rock stratum, but did not correlate well with the design value calculated for the "weak" rock stratum. The mean unconfined compressive strength was used to calculate the side shear in both strata, but review of the laboratory data indicates that this value may not have been appropriate for the weak stratum due to a large variation in the laboratory test results. Also included in this paper is a discussion of the subsurface conditions, the laboratory test results, and the methodology used to design the drilled shaft rock sockets for axial and lateral resistance.

Jan 1, 2005

By M. Zhang, M. Menabde, R. Middleton

Whilst mine planners almost universally assume deterministic forward commodity prices when undertaking valuations of mining projects, historical data well demonstrates that those prices are quite volatile. This paper seeks to understand and quantify how this forward price uncertainty will impact mining project valuation. This paper will also present a way of computing an upper bound on the expected Net Present Value (NPV) of a mining project given forward commodity price uncertainty.

Jan 1, 2007

By Sidney Katell

The present report, a continuation of the series of Bibliography of Investment and Operating Costs for Chemical and Petroleum Plants, is concerned with articles published from January 1958 through December 1958. The periods covered in previous reports are as follows: January 1930 - August 1948 I. C. 7516 September 1948 - June 1952 I. C. 7705 July 1952 - June 1954 1. C. 7751 July 1954 - December 1956 I. C. 7847 January 1957 - December 1957 I. C. The following sources were used to obtain the references to and the abstracts of the published articles included in this report: 1. Bureau of Mines Information Circulars. 2. Bureau of Mines Reports of Investigations. 3. Chemical Engineering. 4. Chemical Engineering Progress. 5. Coal Age. 6. Coal Utilization. 7. Cost Engineering. 8. Industrial and Engineering Chemistry. 9. Nucleonics. 10. Oil and Gas Journal. 11. Petroleum Engineering. 12. Petroleum Refiner. 13. World Oil.

Jan 1, 1959

By A. Gene Collins

The Bureau of Mines undertook research to determine the bromide and iodide content of Mississippi and Alabama oilfield waters of the Tertiary and Cretaceous Period to determine genetic relationships of the ions, to determine their origin, and to determine their genetic relation to petroleum. The 280 samples were analyzed after a pretreatment to remove interferences. The iodide was oxidized to iodate and was titrated with thiosulfate. The bromide was oxidized to bromate and was determined iodometrically. A computer was used to calculate the correlation coefficients of iodide to bromide and to other ions. The other ions are sodium plus potassium, calcium, magnesium, chloride, bicarbonate, and sulfate. The mineral content of the samples ranged from 52 to 1,760 mg/l for bromide and from 2 to 65 mg/l for iodide. The mean bromide-to-chloride and iodide-to-chloride ratios were 0.0065 and 0.0002. The correlation coefficient matrix and linear plots indicated a definite bromide-to-calcium relationship for the brines investigated.

Jan 1, 1967

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

By S. Watkins, D. Apel, B. Gray, R. Moss

Currently, there are several techniques and technologies available which are used by mining industry in its attempts to remotely monitor the ground movements both at surface and underground mines. The currently available remote distance meters and distance change monitors mainly use phase change and time-of-flight techniques. The described monitor uses triangulation technique to track position of an optical spot projection and then image processing to measure mine wall movements. The system can be easily automated and poses no obstruction to mine traffic. The position of an off-normal laser spot will shift as the target wall moves. The described ground movement monitoring system has potential for superior accuracy and target monitoring can be made through air (gaseous) or other transparent media. The theoretical accuracy and range of this system depends solely on the resolution and focal length of the camera being used. The remote capabilities of the system make it uniquely suited to applications where monitoring is required in high-traffic, inaccessible, or unstable and dangerous areas of a mine.

Jan 1, 2007

By A. Azad

SAGD (Steam Assisted Gravity Drainage) is an in-situ oil recovery technique for heavy oil reservoirs. The technique has been successfully applied to many projects in the past 25 years and the process has been, now, well understood. It is now believed that geomechanics plays an important role in SAGD and should be considered in numerical or analytical modeling. Currently, geomechanics is numerically modeled through combining a multi-phase flow and a geomechanical simulator. Numerical modeling is, however, time consuming, need lots of input data, and could not be used for quick decision-making purposes. To decrease the modeling time, this study based on a new version of the Reis drainage model, proposes coupled mathematical model and reserves the effect of geomechanics in the process. Results showed a perfect match with the past experimental and numerical data.

May 1, 2009

The environmental impact of solid waste materials is closely linked to their potential to produce a hazardous leachate once deposited in a landfill. This potential is conventionally assessed with simple laboratory batch leach tests, which find more and more frequent application also in the minerals and metals industry. Such tests are intended to help distinguish between high and low risk wastes, but are completely unsuitable to allow quantitative prediction or modelling of the long-term leachate generation potential. In the present approach the leachate generation process is perceived as a combination of bulk convective transport, stagnant zone and inner particle diffusion, as well as reaction kinetic effects. Model equations are formulated accordingly. A modelling frame work, WASTESIM, has been developed at UCT, which allows flexible combination of the model components and simulation of leach scenarios. Quantitative model parameters are obtained from a systematic laboratory study on the waste material in question. The combined assessment and modelling approach is demonstrated with a study on Cr (VI) leaching from a ferro-chromium slag material. Although not straightforward, the approach is particularly useful in determining long-term liabilities in the context of waste disposal sites with considerably more reliability than has previously been possible. Keywords: waste deposits, waste leaching, heap leaching, environmental, risk assessment, Cr (VI), ferro-chromium, slag.

Jan 1, 2000

By F. W. Lee

The paramount importance of water to life of all forms on the earth is too well known to require elaboration in this brief paper. It has repeatedly been termed the most valuable of all our mineral resources. Its importance is justifiably recognized in the extensive areas covering the earth which receive sufficient rainfall to sustain a relatively luxuriant vegetation; but in those areas where rainfall is insufficient to support anything but a relatively meager plant growth, the location of a water supply and its development become of even more vital interest to those attempting to obtain a living from the soil. Geological investigations concerning the water supply of the United States have been most extensive, important work having been accomplished by Federal, State, and local governments and by private enterprise. A casual examination of the titles of the 739 Water-Supply Papers published by the United States Geological Survey3/ alone testifies &apos;to the vital nature of our water resources and the extensive work that has been done on them.

Jan 1, 1936

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the "fire door" type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in &apos;Guidelines for the Design and Installation of Devices for Deenergization of Self-Propelled Electric Face Equipment/ Automatic Emergency Brakes" by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

In its largest product launch in company history, Cummins Engines welcomed more than 200 customers, vendors and media to witness the unveiling of its new QSK95 engine at its Seymour Engine Plant in Seymour, IN on Nov. 1. It took the efforts of 150 engineers to design the QSK95 and more than $100 million in investments to establish a new production line and test facility at Cummins? Seymour Engine plant. The result of these efforts is a new platform of engines that Cummins says will provide as much as 2,983 kW (4,000 hp) and will be the most powerful, high-speed diesel engine ever built.

Jan 1, 2012

By Hanns J. Billmayer

Optimized Operator Compartment layouts based on previous Bureau of Mines activities in standardization and optimization of controls were designed and installed in three operating vehicles. Two National Mine Service 48A-36 TorKars were modified in production prior to delivery to the Quarto Mining Company. An Elkhorn AR-4 scoop owned by Adanac Coal Company was modified in a local rebuild shop. The modified vehicles were then evaluated underground under normal production conditions for a 60 day period. Vehicle operators and management appear well satisfied with the compartment modifications.

Jan 1, 1976

By G. S. Littlejohn

In anticipation of the flooding of an adjacent dolomitic groundwater compartment, five rough parallel sided boundary plugs at 58 and 50levels have been designed to resist safely hydrostatic heads of 1500and 1250 metres, respectively, over a service life of 100 years. Following a description of the engineering properties of the surrounding rocks, the paper details the design considerations relating to structural length and strength, hydraulic gradient, rock mass watertightness, constituent materials of mortar intruded concrete, pregrouting of permeable discontinuities within the surrounding rock mass, a bentonite barrier to resist aggressive mine water, plug tightening and design performance requirements. Routine quality control tests include permeability of the rock mass, fluidity, bleed and strength development of the intruded mortar, and temperature of the intruded concrete during curing. A special test programme includes determination of strength and stiffness of cored concrete and rock samples, shear strength of the rock/plug interface and associated in situ contact stress in order toe stimate the load safety factor against plug failure by shear.

Jan 1, 2006

By Dan Witkowsky

For the 36th consecutive summer, the Colorado Mining Association Education Foundation and the Colorado School of Mines have sponsored “A Total Concept of the Mining Industry” for kindergarten through grade 12 teachers. Teachers from 34 states, plus the District of Columbia and two foreign countries, have graduated from the four-week course. They received six hours of recertification credit. This summer 31 teachers from Colorado, Kentucky, Virginia and Alaska completed the program. The course is unique from other shorter courses in that it solicits teachers of all disciplines from all K-12classes. In addition to the expected earth science and mathematics teachers, the Class of 2004 consisted of educators who teach music, chemistry, biology, social studies, history, basic English and world history. Others in the program included those who teach American history, physical and life science, remedial reading, consumer/family studies, “world of work,” language arts, engineering technology, environmental science, world geography, human anatomy and physiology, and business.

Jan 1, 2004

By Oliver C. Fursman

The Bureau of Mines undertook this investigation in order to determine the feasibility of producing commercially acceptable alumina and iron by application of the Pedersen process to high-silica, high-titania, ferruginous bauxites of the Pacific Northwest. Calcium aluminate slags were produced by smelting bauxite with coke and lime in an electric-arc furnace. Over 90 percent of the total alumina can be extracted by sodium carbonate solution from slags of properly controlled ternary-phase composition (CaO-Al203-SiO2) that are cooled slowly enough to permit adequate crystallization of the 2CaO-SiO2 and the calcium aluminate compounds. Most of the iron charged was recovered in the regulus; the slag contained about 2 percent iron (as iron oxide), regardless of smelting time.

Jan 1, 1968