Search Documents

By Joseph J. Wallace

The 1952 Annual Report of the West Virginia Department of Mines lists seven beds that are being mined in Mingo County, of which the Cedar Grove is the most important. The Cedar Grove, Alma, and Coalburg contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 3,007 million short tons as of January 1, 1953. Of this total, 2,396 million short tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1954

By Richard E. Chism

SAN DIMAS, in the State of Durango, Mexico, on the frontier of the State of Sinaloa, is the centre of an extensive and rich mining region, which has been exploited for over a hundred years; and the patio process for working silver ores has there attained the highest perfection of which it is capable. Local modifications have been engrafted upon the underlying principles of the process, but, as a whole, the San Dimas practice so fully illustrates its typical capabilities, that I have undertaken to describe its workings in the hope of lightening, to some degree, the labors of my professional brethren who may have occasion to visit Mexico." As is tolerably well known, the patio process, like all other systems of free amalgamation, is not successful with ores containing more than a trace of zinc or lead, the presence of zincblende being especially obnoxious. Iron and copper in small quantities are not particularly disadvantageous. The process succeeds very well with all sulphide ores which do not contain much more than a trace of arsenic and antimony, provided the tailings are concentrated, although, of course, it is best adapted for free milling ores. For suitable silver ores that contain small amounts of free gold the process is still a good one, but where the gold is combined with sulphurets, a considerable and even an excessive loss is inevitable. Hitherto the Mexicans have submitted to this loss, but, since the introduction of American mills, they are gradually abandoning the patio process in favor of the other. The San Dimas ores have a gangue of quartz and feldspar. They are composed principally of silver sulphides, with some chloride and

Jan 1, 1883

By R. W. Charles

The Los Alamos National Laboratory, under the sponsorship of the U.S. Department of Energy; is involved with laboratory and field experiments to assist in development of the Hot Dry Rock concept of geothermal energy. The field program consists of experiments in which hot rock of low permeability is hydraulically fractured between two wellbores. Water is circulated from one well to the other through the fractured hot rock. Our field experiments are designed to test reservoir engineering parameters such as heat-extraction rates, water-loss rates, flow characteristics including impedance and buoyancy, seismic activity, and fluid chemistry. Laboratory experiments were designed to provide information on the mineral-water reactivity encountered during the field program. Two experimental circulation systems tested the rates of dissolution and alteration during dynamic flow. SOlubil ity of rock in agitated systems was studied. Moreover, pure minerals, samples of the granodiorite from the actual reservoir, and Tijeras Canyon granite have been reacted with distilled water and various solutions of NaCl, NaOH, and Na.CO.. The results of these experimental systems are compared to the observations made in field experiments done within the hot dry rock reservoir at a depth of approxi-mately 3 km where the initial rock temperature was 150 to 200°C.

Jan 1, 1981

By M. Hepokoski, M. Klein

"Mine refuge shelters are designed to protect mine workers from hazardous environmental conditions after a mine disaster, but high temperature and humidity levels inside these shelters may pose a significant safety risk. Due to the safety risks associated with human testing, detailed thermal models of shelters and human occupants have been developed using TAITherm simulation software. These models are used to predict the temperature and humidity within the shelter resulting from metabolic heating, evaporation due to sweat and respiration, moisture and heat from the shelter’s carbon dioxide scrubbing system, and heat transfer within the shelter. A detailed human thermoregulation model simulates the sensible and latent heat generated by the shelter occupants, and predicts the occupant’s body core temperature and moisture lost due to sweating and respiration. This information is used to assess the safety of the shelter. This paper presents the technical details of the human thermal model, validation comparing the human model to human subject test data, and results of a mine shelter analysis. IntroductionPortable mine refuge chambers are used in U.S. coal mines to provide protection to mine workers from hazardous conditions following a traumatic event. Although these shelters are designed to supply clean air and sustenance for up to 96 hours, prolonged exposure to the mine shelter environment itself can pose a substantial risk to human safety. Heat generated by the shelter occupants combined with heat from the carbon dioxide (CO2) scrubbing system can raise the shelter interior temperatures and relative humidity to dangerous levels that can lead to heat stress in humans. Unfortunately, the thermal burden associated with mine shelter exposure is not well characterized due to potential hazards associated with underground human subject testing. In order to assess the thermal burden on people within a mine shelter environment, a detailed thermal model was created to accurately predict the temperatures and humidity levels within the shelter, and the impact of these environmental conditions on human occupants. The model consists of a mobile inflatable tent-type mine shelter with 23 humans, and includes the surrounding mine environment. The thermal simulations were performed using a validated commercial heat transfer prediction computer software. Additionally, a module of the software provided the capability to simultaneously model the thermophysiology of 23 unique humans contained within the mine shelter. The human thermal models accounted for the thermal interaction with the environment and provided a core temperature response prediction that can be used to evaluate survivability in heat stress situations (U.S. Army, 2003). The models can also be used to determine maximum occupancy in order to maintain safe temperature and humidity levels inside the shelter in specific mine environments, to optimize shelter size for maximum heat dissipation, or to simulate active cooling systems."

Jan 5, 2017

(Read at the Amenia Meeting, October, 1877.) THE Committee on a Standard Gauge have been constantly engaged, since their appointment, in the duties assigned to them.§ They have corresponded with different persons interested in the manufacture and use of gauges in this country, and have received from several of them important information. They have also entered into correspondence with the governments of England, France, Germany, and Russia through their Consuls, and with Austria directly. The Consuls of Germany and France * Transactions, Vol. V, p. 575. t Transactions, Vol. III, p. 43. + Transactions, Vol. II, p. 224. §See Transactions, Vol. V, p.,48.

Jan 1, 1878

By J. Cheung, H. Rabia

The traditional methods for predicting mine air temperatures are based on steady state heat transfer models as developed by Voss (1969) and Starfield (1983). These models are useful in providing approximate predictions of air temperatures in trunk and gate roadways. More complex models are required to provide predictions along faces. In practice, the heat flow in underground mines is of transient nature and recent observations in some British Coal mines show temperature variations of up to 5°C during a working week at any one point. In addition, the recent introduction of district recirculation of mine air in British mines requires a more precise prediction of air temperatures during start up of the system or during breakdown. A transient heat transfer theory based on the work of Jordon is presented. The method lends itself easily to computers due to the large number of calculations involved. The proposed transient model is validated using actual temperature data collected in roadways in Wearmouth Colliery in the North East of England. The transient results are compared with the steady state predictions of Voss (1969). Finally, predictions of air temperature in roadways for a recirculation system will be made using both the transient and steady state models. Temperature predictions along faces will be made using a separate model.

Jan 1, 1989

By Russell R. Trengove

Exploring for additional ore bodies on the property of the New Idria Quicksilver Mining Co.'s property at Idria, Calif., was done by the Bureau of Mines in cooperation with the Geological Survey. It comprised a study of the geology, mapping, and searching for additional cinnabar by diamond drilling from both surface and underground. Diamond-drill equipment was moved to the project in November 1941, and drilling was completed in.May 1942. Sixteen holes aggregating 2,580 feet were drilled. Diamond drilling by the Bureau of Mines developed information regarding ore structures that proved valuable to the operators in planning underground prospecting that led directly to the discovery of high-grade ore.

Jan 1, 1949

By Brett Campbell

The San Vicente to 2nd Aqueduct Pipeline?Tunnel project is a raw water conveyance tunnel linking the San Vicente Reservoir (SVR) to the 2nd Aqueduct Pipeline via Rancho Penasquitos Pressure Control Facility (RPPCF). This 58,230 lf long tunnel will be 8.5? final ID, and has four points of construction access. The job is classified into 6 Reaches of tunnel, identified by the dominant geology within the reach. This paper will focus on Reach 3, specifically the measures necessary to drill and blast a 550 lineal foot section of granitic rock tunnel immediately in front of an open face digger shield.

Jan 1, 2008

By David J. Mack

A survey and critical appraisal of published information about Young's modulus was originally made by the writer because of a complete lack of information about this very important quantity in works on. mechanics, physical metallurgy, physics, and other sciences. It was felt that a comprehensive summary of such information about Young's modulus might be of general interest and may suggest new problems or lines of attack on other problems that involve E. Hence this paper has been prepared even though it is only a review, with no new ideas or experimental data. The references are only those used in assembling the paper. No attempt was made to compile a complete bibliography on the subject of Young's modulus. CalculatioX oP YouNg's Modulus from Theoretical or Empirical CoNsidera-tions Many attempts have been made to compute E from theoretical considerations. The earliest calculations were probably those of Tomlenson (1883) and Souther-land (1891), but Fess'enden4',~ made extensive calculations a few years later and arrived at the relationship: £ = 78.TOw(i)* where V is the atomic volume. In 1923, Peczalski, working from the same standpoint but with more information available on atomic structure, arrived at an identical relationship, which he expressed as: where B is a constant of value about 8 . 107, p is density and mis atomic weight; the atomic volume, of course, being ml p. Portevind4 immediately pointcd out that while the equations of Fessenden and Peczalski were true of the common metals, they gave low values for the refractory metals with high moduli (Fig. I). He showed (Fig. 2) that much better concordance was obtained by means of an empirical equation of the form: F- KT" where K is a constant; T the absolute melting point; V, atomic volume, and a and b constants of value approximately I and 2 respectively. This constant K in the Portevin equation is not necessarily the same for all elements, as shown by Thompson. Other equations for E based upon theoretical considerations have been derived by Honda and Yamada49 and Lasareff.50 The most recent calculations of elastic moduli based upon quantum mechanics are probably those of Fuchs He extended the method of Wigner and Seitz for calculating the lattice energy and compressibility of monovalent metals and computed the elastic constants of lithium, 18

Jan 1, 1946

By Jr. Chesson

"Phosphate" is a misnomer as often used. The word is increasingly used to refer to any material containing phosphorus - an element essential to any form of life. Phosphate rock, a mineral - fluorapitate - is recovered from Florida's sedimentary deposits in particle sires ranging from 0.1 to 13.0 millimeter. This product of mining, washing, screening, and flotation is commonly called "phosphate". Its phosphorus content, measured and reported as P2O5, varies from 29% to 35%, and is essentially insoluble. "Phosphate" is also used to describe products containing soluble phosphorus obtained from acidulation of phosphate rock with mineral acids; primarily, sulfuric acid. Many miners have nearby chemical plants wherein phosphate rock is converted into upgraded products such as phosphoric acid, superphosohates, and ammonium phosphates with 45% to 70% P205, soluble and suitable for use as fertilizer. The rock and upgraded products are all commonly called "phosphate"; the plants, "phosphate plants' and the producers collectively are known as the "phosphate industry". The public in Central Florida generally loses identification of the individual operators that include major corporations such as IMC. Williams Companies, W.R. Grace, Mobil, Embark, U.S. Steel, Borden, American Cyanamid and others. They all become just a "phosphate company".

Jan 1, 1978

By Nicolin Govender, Pramod Kumar, Raj Rajamani

Mill power models have been used in a variety of ways in industrial practice since power directly equates to throughput and fineness of ground product. We first start with Hogg-Fuerstenau Power Model and show how this model successfully predicted the power draw of many grinding mills in several mining operations. Then, we show how this model was on the verge of being able to predict the influence of lifter design on power draw. Next, we describe the discrete element model and how it overcame the issues faced by the previous power model. Using a DEM software known as Millsoft, we show the influence of lifter design geometry on power draw and analyze the power draw of rubber lifters versus the steel lifters via several case studies. As years passed, the two-dimensional discrete element model imbedded in Millsoft is superseded by three-dimensional discrete element method. Due to the gigantic computational power of graphic processing units, new computational codes that can do the tumbling motion along the entire length of the mill has come about. Here, we show the predictive capability of Blaze-DEM for ball and SAG mills.

For the convenience of those who are unfamilar with thermodynamics, the following brief description and explanation is given of the thermodynamical terms and methods used in this book. It must, however, be strongly emphasized that the account given below is not an introduction to chemical thermodynamics; its sole purpose is to give the reader a rough understanding of the methods used in the earlier chapters. For further information, reference must be made to the standard textbooks on chemical thermodynamics by Glasstone.

Jan 1, 1953

By Alexander Blatt, Franz-Werner Gerressen

Diaphragm wall technique is usually used to construct structural elements in the ground, commonly used for retention systems, permanent foundation elements or deep groundwater barriers, named Cut-Off-Walls (COW). Recent developments proof, that the technology also satisfies the demands for using the diaphragm wall technique for bulk sampling purposes. Such kind of new ideas required the adaption of equipment and tools for a depth capability never reached before by a trench cutter in any commercial application worldwide. Compared to the development of increasing depths, especially inner-city applications with limited space, demand a minimization of equipment to accommodate such projects. The paper will focus on the developments and solutions generated to fulfill these requirements and will give an outlook to future developments. Further it describes finalized reference projects and will give a general outlook on future trends and developments. The Paper/The Presentation explains as well the installation process in general.

May 1, 2022

By Ebrahim Ghasemi, Mohammad Hossein Kadkhodaei, Mosareza Jalilian

Entry-type mining methods, such as cut and fill method, play a significant role in underground mining, and they are still suitable methods for extracting deposits with irregular shapes and with weak host rocks. In these mining methods, the stability of the open spans is important for improving worker safety and increasing ore recovery. This study focuses on the application of six data mining classification methods, namely multinomial logistic regression (MLR), classification and regression trees (CART), logistic model tree (LMT), decision tree (J48), multivariate adaptive regression spline (MARS), and gene expression programming (GEP), in order to develop predictive models for stability assessment of underground entry-type excavations. For this purpose, a database containing 399 case histories of entry-type excavations from seven Canada underground mines was used. These models predict the stability status of entry-type excavations based on two input parameters, dimensions of the span and rock mass rating (RMR). The performance of developed models was evaluated using six performance metrics namely accuracy (ACC), sensitivity (SE), precision (PR), Matthew’s correlation coefficient (MCC), area under the receiver operating characteristic (ROC) curve (AUC), and performance index (PI). The results showed that all developed models can be used to predict the excavation stability, but the comparison of models indicated that the J48 model provides the highest performance with ACC = 0.900, SE = 0.869, PR = 0.922, MCC = 0.835, AUC = 0.891, and PI = 4.417. Thus, the proposed J48 model can be applied to identify the susceptibility of span instability in the entry-type mining, and if instability has been predicted, the necessary measures, including the use of suitable support systems, can be considered to reduce the casualties resulting from span instability.

Feb 26, 2024

By L. B. Pankratz

Thermodynamic data on the sulfides were reviewed, evaluated, and compiled at the Bureau of Mines Albany Research Center. Values for Cp°, S°, H°298 -(G° - H°298)/T, ?Hf°, ?Gf°, and log Kf are given in tabular form. Cp°, H° - H°298, ?Hf°, and ?Gf° are also expressed algebraically.

Jan 1, 1987

By John A. Egan, Nathaniel Wagner, Micaela Largent, Jonathan P. Stewart, Debra Murphy, Jeremy Butkovich

The Millennium Tower is a 58-story reinforced concrete building that was constructed in San Francisco, California between 2005 and 2009. The Tower is founded on an embedded pile supported mat with pile tips bearing in dense marine deposits that overlie an over-consolidated marine clay layer known locally as Old Bay Clay. This clay layer experienced stress increases from Tower self-weight and from multiple episodes of de-watering between 2006 and 2018 at the Tower site and neighboring sites. Settlements of the Tower foundation have been measured since 2006 and lateral deflections of the Tower have been inferred and measured since 2009. Available information on this case history include geotechnical site conditions and data from a monitoring program that tracked foundation settlements, Tower tilt, groundwater levels at the Tower site, and ground inclinations over time. This presentation will discuss the ground deformation mechanisms that caused the observed movements, the degree to which the movements can be predicted, and lessons from this case history for the design of deep foundations for tall buildings in San Francisco and geologically similar regions.

Sep 8, 2021

By Yuliy Rubinstein

"The paper presents a analysis of the history and the trends of development of flotation apparatus. The laws of their evolution are stated and the place and role of column flotation are indicated. It is demonstrate development and different design of column apparatus. The major parameters of column cell such as diameter and height are discussed. Options are proposed on optimization of hydrodynamic characteristics of columns with large-capacity cells. High efficiency of columns with cell height of 4-6 m is shown on examples of coal preparation. A new generation of multi sectional column cells has been developed. In the cells are zones with different aerohydrodynamic parameters: combined in the machine are co-and counter- counter flows of phases. The transition from single-chamber column to multi-sectional apparatus makes it possible to create favourable hydrodynamic and aeration regimes in each section of the column dependent on the pattern of material distribution by floatability. Efficiency of application different designs column apparatus uses shown on the example of enrichment of various non-ferrous metals ores and coal. The principles of mathematical simulation of the flotation process are developed. A scaling-up procedure for column cells was based on flotation macro- and micro- dynamics simulation.INTRODUCTIONColumn flotation is considered to be one of the most significant achievement in the field of mineral processing in the end of last century. We cannot but agree with this statement but would like to understand what underlies this success. History of the flotation column can not be considered in isolation from the development of flotation apparatus on the whole. It can be argued that the first attempt to switch from oil flotation to the use of bubbles during flotation was performed Bessel brothers in 1877 (Berlin patent 42 class 22, July 2) and in 1886 (Berlin patent 39,369 May 12). According to these patents, the crushed ore was mixed with oils , hydrocarbons and water. Then the pulp received in this way was heated up to boiling . Air bubbles and steam formed during boiling facilitate the flotation of ore particles coated with oil (first patent) or bubbles been generated by the reaction of lime with acid (second patent). The evolution in the design of the flotation apparatus incorporates the following key stages. Further development is connected with the Francis Elmore’s idea to use gas bubbles received at water electrolysis (UK, 13578; 1904). This method was not introduced then, but much later, in our time and on the essentially new technical basis it found a use for sewage treatment (electroflotation). Gas bubbling under vacuum patented also by Elmore (UK, 17816; 1904) obtained a practical use. It should be noted that the method did not lose its importance till now. The design of the camera has been surely optimized (Glembotskii etal, 1963). A year later A. Macquisten (UK, 26712) developed pressure (compression) flotation. Thus, the H.Sulman, H.Picard, D. Bell’s (US, 853120, May 29, 1905) basic patent and the adjoining T. Goover’s patent 1910 (US, 953746) formed the basis of the first and most important element of modern flotation: flotation with air bubbles sucked in from the environment. In 1914, J.Callow received a patent for on an apparatus where air was sparged through the porous false bottom of the cell ( US, 1104755). Woolen fabric folded four times was fixed on a perforated metal frame to be used for air sparging (Gaudin, 1932). The following year Durrel created the prototype of the injection (ejector) apparatus. The jet aerator made it possible to significantly reduce the size of the bubbles, in comparison with the filter cloth. An apparatus with slurry pre-aeration in an airlift prior to feeding into separation cell was developed Wagner in 1917 (US, 1235083). And finally, the first column apparatus with a counter-current of slurry and air was developed by M. Towne and S. Flynn in 1919(US, 1,295,817). ("

Jan 1, 2018

By Frank J. Wiebelt

The Carbonate King zinc mine is on the west slope of Kokoweef Peak, Ivanpah Mountains, San Bernardino County, Calif. It has produced more-than 10,000 tons of ore with a 39-percent?zinc content since mining operations began in 1940. The ore, consisting principally of calamine and smithsonite, occurs in replacements of the YellowPine limestone. Milling, has been done from the surface to a depth of 275 feet. Eight holes, aggregating 2,121, feet were drilled by the Bureau of Mines in an endeavor to establish extensions of the worked-out ore bodies and to develop new ones. Although indication of mineralization was found in several of the holes, no new ore bodies were developed.

Jan 1, 1949

By Stanley F. French, Bruno F. Koch

Although the amount of dust that will be actually recovered in the six main dust-control systems cannot be accurately stated until the tests mentioned previously are carried out, it is estimated that the average air entering the wet collectors will contain around 5 grains of dust particles per cubic foot. This means that the six systems handling a total of about 133,000 cu.ft. of air per minute will return about 68 1/2 tons of dust to the concentrator per day and since the copper in this dust will average around 2 per cent, the total recovery is approximately 1.37 tons of copper every 24 hours. This important copper recovery is not due entirely to the dust-control system since in a plant without control only the duct that is dispersed to the atmosphere represents a loss. A conservative estimate of the recovery of copper solely due to the dust control system would be about half of the total or approximately 0.70 tons of copper per day.

Jan 1, 1942

By Fumito Tanaka

The Mitsubishi process is the sole pyrometallurgical process for the continuous production of blister copper from copper concentrates and has been successfully operated around the world. The development of calcium ferrite slag (CaO-FeOx-Cu20), the so-called "C-slag", has enabled continuous converting from matte to blister copper in the commercial scale operations. Commercial interests in the slag led to many papers over the CaO-FeOx slag. However, CU2O- bearing slag has not been studied well due to experimental difficulties. The authors have quantified the thermodynamic properties ofthe CaO-FeOx-Cu2O system. The results have been utilized to analyze various issues related to the converting furnace, such as the magnetite precipitation from the slag or from blister copper and to develop better controlling criteria for the continuous converting operation.

Jan 1, 2003