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By Worthen Bradley

This paper describing the metallurgical practice and costs at the reduction plant of the. Sulphur Bank Syndicate, Clearlake, Calif., is one of a series of papers on the treatment of ores being prepared by the Bureau f Mines. The reduction plant and mine of the Sulphur Bank Syndicate are on the eastern shore of Clear Lake, in Lake County, Calif., 4 miles from the town of Clearlake and 125 miles north of San Francisco.

Jan 1, 1931

The first metal-mine accident-prevention course was prepared and published in 1942-45 as a series of seven miners' circulars (Nos. 51-57). The course has been broadened in scope, revised, and brought up to date and is being published as a similar series of seven miners' circulars (Nos. 51-57, revised) on accident prevention in metal and non-metallic mines. These circulars are as follows: Injury Statistics (Miners' Circular 51), dealing with general statistics on injuries from accidents at metal and nonmetallic mines, including causes, costs, and the use of investigations and reports of all injuries.

Jan 1, 1960

By Dale S. Preece, Ruilin Yang

"Air-decking has been used frequently in blasting for many decades. It has been asserted that an air-deckcan alleviate excessive shock pressure from the detonation of a charge thereby producing better energy distribution in a blast overburden, for example. Research on air-decking has been active and various theories have been postulated that mostly support the effectiveness of air-decking for improved blast efficiency."

Jan 1, 2017

In the spring of 1944 the Congress passed Public Law 290 (58 Stat. 190, 30 U. S. C. Sec. 321) "authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes." Section 2 reads: "In order to carry out the purpose of this act, the Secretary of the Interior is authorized- (a) to conduct laboratory research and development work, and, with pilot plants and semi-works plants, to make careful process engineering studies, along with structural engineering studies, in order to ascertain lowest investment and operating costs necessary to determine the best demonstration plant designs and conditions of operation;

Jan 1, 1948

By A. J. Kauffman

The alluvial deposits of the Pacific Northwest have been investigated and worked with varying degrees of intensity since about the middle of the 19th century. Earlier efforts, of course, were centered about the placer-gold content of the deposits; later, the Oregon beach sands were exploited for their chrome content, and, still more recently, deposits in Idaho were worked for their content of monazite, a rare-earth mineral which also contains significant quantities of thorium. The composition of alluvial deposits seems to depend mainly upon the nature of the source rock from which the detrital material was derived and upon the resistance of the individual mineral grains to the agencies of weathering and transportation. The processes of crushing and concentration used in ore dressing are applied in a leisurely but nonetheless effective manner when exposed rock masses are eroded by natural forces. Weathering effects a continuous disintegration and chemical decomposition, wherein resistant minerals are set free as individual grains and new minerals are formed. Erosion carries these detrital products down the slopes into natural waterways, where a mechanical separation of heavy particles from light is accomplished by the running water. The accumulation of such resistant, heavy particles through the ages has resulted in formation of the black-sand deposits. In addition to the associated gangue minerals, heavy sand deposits in the Pacific Northwest may contain the following constituents of possible economic value: Gold, platinum, chromite, ilmenite, magnetite, garnet, zircon, monazite, columbite-tantalite, and radioactive blacks.

Jan 1, 1956

INTERNATIONAL conferences on safety in mines originated in 1912 when, in response to an invitation issued by the United States, representatives of Austria-Hungary, Belgium, France, and Germany participated in a conference held in Pittsburgh, Pa The record shows that a permanent organization was proposed to be developed through. diplomatic channels. However, the advent of war 2 years later prevented this proposal from coming to fruition. No further cooperation between the Bureau of Mines and a group having: similar interests in a foreign country took place until 1924, when formal cooperation with the Safety in Mines Research Board of Great Britain was established. Interchange of personnel and results of research under that arrangement have resulted in a number of publications in both countries and more rapid advance in knowledge than could have been obtained through the same efforts exerted independently.

Jan 1, 1950

By D. W. Euler, D. G. Brophey

"In an attempt to address the issue of rising labour costs, and to improve productivity, a laser-based system to guide underground LHDs and trucks has been developed. This comprehensive system is known as the Opti-Trak system.Essentially, the vehicle is equipped with front and rear-mounted lasers which scan a reference strip mounted on the drift back. The vehicle follows this reference strip and in addition, based on reflective bar codes mounted beside the reference strip, initiates certain functions (i.e. dump cycle, speed change, brake check, etc.). Any programming that is drift-specific is handled by the positioning of the reference strips and bar codes. Consequently, the vehicle can easily travel to many different haulageways or branches, providing the reference strip and bar codes are in place.The advantages of this system are an immediate elimination of haulage operator costs and an increase in available hauling time to 7 hours out of an 8-hour shift as compared to the typical 5Y2 out of 8 hours that a manned haulage system offers.This paper describes the Opti-Trak system and the benefits to be realized from automation of mine haulage requirements."

Jan 1, 1994

By J. B. Carman

This paper, describing the mining practices and methods at the mine of the Molyb¬denum Corporation of America, is one of a series of similar papers on mining methods in the various mines of the United States being prepared by the Bureau of Mines. The mine of the Molybdenum Corporation of America is in the Red River mining dis¬trict, Taos County, northern New Mexico (fig. 1), The mill and camp are in the valley of Red River, about 7 miles east of the town of Questa; the mine is 1 ¼ miles away, in Sulphur Gulch, a tributary of Red River. The mine is about 600 feet higher than the mill, at an altitude of about 8,700 feet. The climate is cold in winter, but does not interfere serious¬ly with continuous operation. The mine normally produces about 40 tons of sulphide molybde¬num ore per day, which is concentrated at the local mill and chipped to the plant of the Molybdenum Corporation at Washington, Pa.; there it is made into either ferromelybdenum or "molyte" (calcium molybdate), for use in alloys. The ore is mined from narrow, irregular veins by the cut-and-fill method. About 65 men are normally employed underground and on the surface at the mine.

Jan 1, 1931

By M. Waladan

The top submerged lancing Sirosmelt system has been developed through laborator.y scale testwork and pilot plant trials for recovery of zinc from ISF slag. The effects of the process variables of gas injection rate, method of coal feeding, and temperature on zinc fuming rates were studied in the laboratory. It was found that the rate of zinc elimination was dependent on all of these variabl.es. The rate of zinc removal from slag was independent of zinc content of slag down to approximately 1.5% Zn, below which the rate was proportional to zinc content in slag. Pilot plant trials were carried out to evaluate a proposed process and results followed predictions from the laboratory scale tests. A comparison of the proposed process with conventional slag fuming operations is made and it is shown that the process has a number of advantages which have a significant impact on the economics of zinc slag fuming.

Jan 1, 1990

By C. Özgen Karacan

Gamma ray, density, sonic and core logs obtained from two boreholes drilled over a longwall panel in Southwestern (SW) Pennsylvania were analyzed for formation boundaries, log-derived porosities and densities and for rock elastic properties from sonic transit times. Gamma ray (GR) and density logs (DL) were analyzed using univariate statistical techniques and fractal statistics for similarity and ordering of the log data in depth. A Fourier transformation with low-pass filter was used as a noise elimination (filtering) technique from the original logs. Filtered data was tested using basic univariate and fractal statistics, rescaled range (R/S) and power spectrum (PS) analysis to compare the information characteristics of the filtered logs with the original data. The randomness of log data in depth was analyzed for fractional Gaussian noise (fGn) or fractional Brownian motion (fBm) character. A new prediction technique using radial basis function (RBF) networks was developed to calculate shear and Young?s moduli of the formations when sonic logs are not available. For this approach, the filtered logs were used as input to an RBF based upon a combination of supervised and unsupervised learning. The network was trained and tested using rock elastic properties calculated from the sonic log of one of the boreholes. The network was used to predict the elastic and shear moduli of the coal-measure rocks over a longwall coal mine in SW Pennsylvania. This approach demonstrated that it could be used for prediction of elastic and shear moduli of coal-measure rocks with reasonable accuracy.

Jan 1, 2009

By Michael Lenz

Predictive maintenance technologies including vibration analysis, tribology, infrared thermography, ultrasonic detection, and electrical measurements have been applied to large electric mining shovels. The predictive program was initiated on the P&H Model 2300 and 4100 electric shovels. The utilization of these technologies has shown the potential for improving electric mining shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition based planning of component replacement. Maintenance costs are minimized by focusing resources through condition based prioritization.

Jan 1, 1997

By Raja V. Rarnani, Robert L. Frantz

"The more than 75 research projects funded throughout the first 10 years of the Dust Center's operation have resulted in numerous cumulative findings fulfilling the goals of the Center. These project descriptions present the methodologies and project-to-project relationships leading to their various accomplishments and demonstrate the mesh between project objectives and Center goals.To develop equipment for collecting respirable dust samples.To develop experimental methods for particle-by-particle characterization of morphology, size, and chemistry.To develop experimental methods for overall respirable dust sample characterization of size distribution, chemistry, and crystallography.The project directly addresses the Center's goals to enhance the understanding of the scientific and engineering characteristics of fine and respirable mineral particles found in mining and milling atmospheres and to establish the relationship between natural and cultural factors (mine geology, mineralogy, mining and milling methods, equipment, and control measures) in the generation of fine particles. The project also aims to contribute to the development of control mechanisms for reducing ambient respirable dust concentrations and worker exposures.The work on this project is related to similar work on Coal Mine Dust Characterization (Project No. 2701/MN1) and Characterization of Dust Particles (Project No. 4203/PS3).Airborne dust sampling was performed at the following locations: 1) a sand and gravel quarry in Southern New Hampshire, 2) a welding facility, 3) a ceramic powder facility, 4) a metal powder facility, and 5) the air in Cambridge, Massachusetts. A portable sampling box incorporating two Sierra personal cascade impactors was designed and produced. At a 2-LPM flow rate, the effective cut-off diameters of the Sierra impactors were 10.0, 6.0, 3.5, 2.0, 0.9, and 0.5 mm, respectively, for each stage, and the air passed through a PVC filter after the last stage. In addition, the sampling box contained a total respirable dust filter. The substrates were weighed carefully before and after collection, and the weight increases were recorded. All films, foils, and filters were put in the balance chamber for more than 8 hours to stabilize the temperature and humidity before weighing. A Cash 21 microbalance (±0.001 mg) was used to weigh the Mylar films, SS films, and filters."

Jan 1, 1995

By Weizhi Zeng, Michael L. Free, Shijie Wang

Copper electrorefining is an old technique that is generally performed in electrolytic cells with a bottom inlet and top outlet that are convenient for electrolyte flow control. Nevertheless, this configuration cannot effectively direct electrolyte flow to the regions between electrodes, which results in weak convection and inadequate delivery of chemical species and additives. In this article, we discuss the innovations in electrore fining cell design to improve electrolyte flow for better cathode quality and simulation of fluid flow field and particle movements based on finite element modeling method. The resulting fluid flows in cells can transport suspended slime particles to the cathode, where they can be incorporated as impurities. The concentration of suspended slime particles is inversely related to slime adhesion, which is strongly influenced by slime particle sintering, and sintering is dependent on temperature and slime particle composition. Thus, the combination of innovative fluid flow and slime particle sintering can play important roles in improving cathode quality.

Mar 1, 2017

By Joel A. Huffinan

"This presentation is being given to better inform the audience of the dependability of precious metal analysis by fire assay. A brief explanation, however, of standard fire assay exploration procedures will be given. An overview of other types of analyses by fire assay will be discussed as well, and the operation of a modern day assay laboratory.IntroductionThe use of lead oxide for the fire assay process dates back to the finds in Troy II and the Cappadocian Tablets about 3,000 B.C. Some advances have been made in the basic procedures due to instrumentation and electronics, but the fusion and cupellation procedures used in fire assay remain much the same as during this period.In 1600 AD. Agricola was the first to take a scientific approach to fire assay recording methods and procedures used (Hillerbrand and Allen, 1905) [1]. Since this period, much of the recognized research into the analysis of ores and metals was carried out in the late 1800's and early 1900's prior to World War II, and again after the deregulation of precious metals. The renewed interest in precious metals mining and metallurgy are due much to advances in precious metals heap leaching in late 1970's."

Jan 1, 1999

By Oliver Bowles

Limestone, including dolomite, is the most widely used of all rocks - nearly 300 million tons annually in the United States alone. It occurs in some form in every State and is produced in thousands of localities. Because of its attractiveness, substantiality, and durability it is employed extensively as a building stone. In crushed and broken form it is used for concrete aggregate and railroad ballast and in highway construction, metallurgy, agriculture, and a host of chemical and industrial processes. This paper proposes to furnish general information on the origin and occurrence of limestone and dolomite, chief production centers, major uses, and methods of quarrying and preparing stone for market. Footnote references will guide the reader to sources of more complete information.

Jan 1, 1956

By G. B. Amicucci

A Denver Autometrics Particle Size Monitor, PSM-400, was installed at Golden Sunlight Mines, Inc. in October 1988. The PSM-400 measures the grind product's particle size and percent solids. The particle size is used to control grind size by automatically adjusting mill feed rate. The PSM's continuous response to ore changes has improved grind product uniformity and mill throughput. Metallurgical testing has shown the PSM's accuracy to be +/-1 % + 150 µm (100 mesh).

Jan 1, 1991

By Patrik Bloemer

Reliable and accurate furnace bath level data during the melting process is invaluable for good decision making and furnace optimization, while obtaining such information rapidly and safely on a regular basis is of paramount importance. This paper shows how a melting process problem was identified as a concern, how a solution was sought and how a real-time measurement system was tested by simple modification to an existing temperature sampling manipulator. Also how, with furnace power on or off, taking reliable hot heel, fill and running levels could be used to assist melting control, aid decision making and improve safety.

Jul 30, 2018

By Alan Bauer

New developments in drilling, blasting and explosives in both open-pit and underground mining operations are discussed, as well as novel surface blasting techniques such as are used in tar sand mining.

Jan 1, 1978

By B. R. Arvidson

Sharper separation and improved control of the top size increases the fine particle product yield. As the milling circuit recycle stream is reduced, the overall capacity is increased. In some cases, a doubling of throughput is realized, although 25 to 30% increase is more typical. Alternatively, the energy demand may be reduced, although the best economic improvement results from higher capacity. A comparison with a high-pressure roller mill circuit shows that an optimized ball mill circuit retrofitted with the new air classifier has lower energy consumption. The new air classifier features low energy demand and substantially lower maintenance compared to similar equipment. Design and operation of this recently patented classifier are discussed. Several industrial installations will be described.

Jan 1, 1999

By R. Mulyanto, M. Siray, A. Parhusip, F. Hartono

"PT Freeport Indonesia is preparing the Deep Mill Level Zone (DMLZ) mine to be the successor of the currently operating Deep Ore Zone (DOZ) mine. The DMLZ is block cave mine situated 500 m below the DOZ mine and approximately 1600 m depth from surface. Both of the block caving mines require draw point construction in the extraction level to extract the ore from caved area above. Learning from the experience in DOZ, the construction & maintenance of draw points in the production panels is a significant challenge in supporting consistent production.The average DOZ draw point construction duration is approximately 46 shifts per draw point. The time frame for construction is dependent on several variables; availability of the conventional forming system, material availability, and development tolerances. The repair of concrete floors and lintel sets causes production downtime. Reviewing the old DOZ draw point design, there is an opportunity to increase constructability, durability, and reliability of DMLZ draw points. This paper discusses how the DMLZ has improved draw point construction productivity and is on track to significantly reduce costs whilst increasing the quality by using the Six Sigma Improvement Method.Introduction The DMLZ Mine is part of the PT. Freeport Indonesia (PTFI) future Expansion to its underground mining complexes. It is the fourth vertical lift in the East Ertsberg Skarn System (EESS) deposit (Figure 1).Currently, it is under development phase.The DMLZ mine will be a block cave mine using an advanced undercutting method. The DMLZ extraction level will be approximately 1,600 meters below the surface on the 2570 level with column heights of roughly 500 m. The Undercut is on 2590 level, some 20 meters above the extraction level."

Jan 1, 2016