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By Hiram C. Draper

The Mining Division of the Bureau of Mines, in cooperation with the Obstacle and Demolition Branch, Engineer Research and Development Laboratories, Department of the Army, undertook some extensive tests to determine the effectiveness and limitations of using standard demolition-type shaped charges in underground Mining. The tests proved the shaped charge has no practical application in the functions of mining covered by this report. At an approximate cost of 0 per foot hole plus spall produced by the most efficient single shots with the M3 shaped charge, the cost is over 20 times that of producing a better hole with a rock drill. The concussion would prohibit its use in many mines, and the excess carbon monoxide gas liberated by the pontolite explosive would be an additional hazard when used underground.

Jan 1, 1948

By C. A. D' Odorico

The zinc pressure leaching (ZPL) plant at Teck Cominco's Trail Operations was started up in 1981 and represented the world's first commercialization of the technology. From the outset, the process was designed to operate using iron-rich Sullivan Mine zinc concentrate. When the Sullivan Mine reached the end of its life in 2002, the ZPL plant underwent a significant process change with the treatment of 100% Red Dog zinc concentrate. Through careful improvements to existing plant processes, controlled changes to plant operating parameters and a rapid adjustment to the modified process by operations personnel, the plant has been successfully converted to processing a feed of 100% Red Dog zinc concentrate. This paper discusses the challenges faced during the conversion and describes the modifications to plant operating procedures, as well as changes to plant processes.

Jan 1, 2004

By K. K. Kelley

The first bulletin (269) 3 in this series, which appeared in 1932, compiled the entropy values then available for the elements and in-organic compounds, results being listed for some 150 substances. Elaborations and revisions followed in 1936 (272) and 1941 (280), when over 500 usable entropy values were tabulated. The present bulletin constitutes a further elaboration and revision. The accumulation of data since 1940 has been marked, and 800 entropy values now are available. The present bulletin also contains all the pertinent explanatory matter that appeared in its predecessors. Thus, it retains the same dual purpose of assembling the available values of the entropies at 298.16° K. of the elements and inorganic compounds and giving enough explanation of methods of calculating entropies to make the results comprehensible.

Jan 1, 1950

By AIME AIME

In the uniform of his country for the second time, Harry Phillip Stolz. Chairman of the A.I.M.E. Petroleum Division, holds a commission as Lieutenant-Commander in the Naval Reserve and is attached to the office of Inspector of Naval Petroleum Reserves in California. During World War I he left his studies at Stanford University to join the Army and was granted a commission as Second Lieutenant of Infantry. He remained in the Army Reserve until 1938 when he resigned to accept a commission as a member of the Naval Petroleum Reserves Advisory Board. Born in San Francisco Jan. 29,1899, where his father had lived since 1880, he was in that city during the turbulent year of 1906 where the city was ravaged by fire and earthquake.

Jan 1, 1942

By Sergio Godoy P.

The Los Bronces porphyry copper deposit is located in the high Andes of Central Chile. Ore is mined from several tourmaline breccias and from an earlier porphyry. After years of experience in the geostatistical estimation of reserves in different zones of the ore body, we believe that success lies in considering the evaluation as an integrated process beginning with the analyses of the drilling density and sampling methodology, ending with the critically important reconciliation between the estimated and the actually extracted ore, in general, when errors or differences occur, focus is centered in the calculation stages of geostatistics. However, this paper demonstrates that all the evaluation stages are equally important and require the direct and continuous geologic input to ensure the best possible estimate within the frame of the geologic constraints.

Jan 1, 1992

By Kr. J. Dedelyanova

Selective flocculation of iron minerals could improve the economics of high intensity magnetic separation as concomitant process. When the minerals are finely disseminated is necessary a finer grinding to be applied which generates a lot of slimes. The HIMS is not enough efficient for particles below 20 microns ? territory where the selective flocculation is already well known industrial practice, so the combination of these two methods of beneficiation can bring a higher grade at high recovery to be achieved. The dynamics and selectivity of the precipitation process is studied in batch tests with flocculant starch and dispersants sodium silicate and sodium hexametaphosphate. The influence of preliminary conditioning with nitrogen acid at pH 2 before flocculation is also investigated. Flowsheet including these two methods is tested and the distribution of iron is shown.

Jan 1, 2014

By Juliano Braz Possatti, José Fagundes Júnior

This project involved a teamwork including process control, maintenance and operation specialists, R&D and CTO experts to identify and actuate on each opportunity to increase charging temperature, furnace efficiency, decrease discharging temperature when possible, decrease FM and RM cycle time (mainly speed increase and interpass time decrease), tracking zones optimization, safe use of equipment power limits, safety interlocks revision and tune models for Mill Pacing Control and Slab Design.As result of these efforts, ArcelorMittal Tubarão HSM today occupies a prominent position among the best HSM of similar layout and produced mix of the group and worldwide. This paper will show the path which was followed by the AMT HSM team to achieve more than a 20% productivity increase resulting in a hot coils production per year more than 700 million tons higher.

Oct 1, 2019

By J. Lee

A monolithic caisson is one of the major structural components commonly used in the construction of docks, breakwaters, and container terminal quay walls. Since the structure of monolithic caissons is typical and somewhat simple, its design process is also typical and repetitive, but still time consuming. To reduce the total time and enhance productivity, we developed a parametric model in Revit to automatically generate a 3D model of a monolithic caisson. It is designed to generate the Revit model of a caisson with concrete body and reinforcing bars. The size of caisson, the number of reinforcing bars, and the space between reinforcing bars are automatically changed when users update parameters. This paper presents how we developed this parametric family in Revit for monolithic caisson design and how it would enhance its design process.

Aug 1, 2013

By Werner Joseph, Richard R. Knobler

When the first batch of refined copper ingots was cast at Mantos Blancos in January 1961, eight years of exploration, development and metallurgical pioneering by Mauricio Hochschild & Co. had come to a successful conclusion. This Chilean copper deposit, located in the Atacama Desert 30 miles from Antofagasta, is now producing approximately 20,000 tons of copper per year. The Mantos Blancos deposit has been known since 1912 and various attempts had been made to work the high-grade zones before the present operation was started. The major drawback of the ore to any previous development was its chloride content which varies between 0.4% and 1.5% C1. Although the chloride ruled out the conventional leaching-electrolysis scheme, it did lend itself to the process of precipitating the copper as cuprous chloride.

Jan 1, 1962

By Han Yihua, Zhang Caijun, Zhu Liguang, Zhang Qingjun, Wang Shuoming, Wang Yan

An industrial test on 210 t converter-LF-CC production line on high heat input welding shipbuilding structure steel DH36 has been taken in a factory in north China, the effect of adding microalloy elements V and Mg on casting billet microstructure has been researched. It was found that when the composition of V was between 0.03 and 0.05% and the composition of Mg was between 0.002 and 0.005%, a large number of acicular ferrite precipitate in austenitic crystal in as-cast structure and cross into a net structure. The inclusions size which induced intra-granular ferrite are mainly less than 4 lm, especially those between 2 and 3 lm account for 50.80%, in these inclusions the composite inclusions mixed with Mg accounted for more than 60%.

Mar 1, 2017

By H. A. Watson

Fluorine-containing polymers are comparatively new materials that exhibit very desirable characteristics not usually found in non-fluorine containing polymers. Among these characteristics are heat and flame resistance, desirable electrical properties, and chemical inertness. Polytetrafluoroethylene and polymonochlorotrifluoroethylene are examples of such polymers commercially available. In practical applications it is reasonable to expect thermal position of these materials if they are subject to high enough temperatures. The temperatures at which thermal decomposition takes place and the nature of the gaseous products of decomposition are considered pertinent data in intelligent use of these materials. The purpose of the tests discussed herein was to determine: (1) The temperatures at which gases were produced when small specimens of the two polymers were located and (2) determine the identity of the major constituents of gaseous products.

Jan 1, 1950

By Paul Guliov

Coal-bearing Tertiary sediments of the Ravenscrag Formation in southern Saskatchewan host numerous deposits of clinker resulting from in situ coal combustion. Clinker deposits form when sediments of relatively low temperature firing properties overlie coal seams which are undergoing prolonged spontaneous combustion. The resulting fired material is useful for decorative landscaping aggregate, rock gardens, driveways, mud control and others. Predicting the occurrence of clinker deposits requires a knowledge of the spatial distribution of coal seams and the nature ofoverlying sediments. Knowledge ofpaleotopography at the time of coal combustion can assist in locating more highly-fused material which can yield greater block sizes. Coal data bases can be used as a predictive tool by outlining areas where coal is or was at or near surface and therefore may have been susceptible to spontaneous combustion.

Jan 1, 2001

By J. B. Hiskey

Thiourea is a reagent capable of complexing gold and silver. With the proper oxidant, thiourea can effectively dissolve metallic gold and silver. A thiourea leaching system possesses potential advantages over conventional cyanidation including acidic solutions instead of alkaline, cationic complexes in contrast to metal-cyanide anionic complexes, and faster leaching rates with acidic solution of thiourea. Generally, the rate of metal dissolution in thiourea solutions is fastest when ferric ion is employed as an oxidant. Acidic thiourea solutions for certain applications could offer a nontoxic and noncorrosive option for processing gold and silver. This paper provides information regarding the fundamental chemistry of the acidic thiourea system, and reviews the dissolution of both silver and gold in acidic solutions of thiourea. The recovery of gold and silver from acidic thiourea solution is discussed.

Jan 1, 1981

By Masanori Mori, Hajime Miki, Osamu Ichikawa, Tsuyoshi Hirajima, Mitsuru Sawada, Keiko Sasaki

For pretreatment of selective flotation, surface oxidation of chalcopyrite and molybdenite was applied by oxygen plasma then the minerals were washed by solution at pH 9 with oxygen bubbling. Surface characteristics of these minerals were investigated with AFM, XPS, zeta potential and contact angle measurements. Contact angle of chalcopyrite and molybdenite decreased a lot by plasma treatment. When they were washed with pH 9 solution with oxygen bubbling, contact angle of molybdenite increased whereas chalcopyrite one kept low. Adhesion force measurements indicated similar behavior. Result of flotation experiments indicated low recovery of both chalcopyrite and molybdenite after plasma treatment and only molybdenite recovery became higher after washing. Selective flotation of chalcopyrite and molybdenite could be achieved with this process. Possible mechanism of selective flotation was proposed from the results of XPS, AFM, etc.

Jan 1, 2014

By N. J. Sather

The history of the Bunker Hill mine dates back to August 26, 1885, when Noah S. Kellogg found the outcrop of the Bunker Hill orebody on the hillside of Milo Gulch above the present town of Wardner, Idaho. A small concentrator was erected in 1886, and before the railroad came, the mine output was transported by mule teams to the head of navigation on Coeur d'Alene Lake. After ten years of production, an interest was purchased in the Tacoma smelter at Tacoma, Wash., to which the entire output was shipped. In 1916 and 1917, a modern lead smelting plant and refinery was erected, and a modern electrolytic zinc reduction plant was built in 1927-1928 by the Sullivan Mining Co. which was 50 pct owned (and now totally owned) by the Bunker Hill Co.

Jan 6, 1961

By M. B. Shirts

Numerous alternative processes have been proposed as being potentially more economical or less polluting than the traditional smelting of copper sulfide concentrates. One such process as recently developed in the laboratory by the Bureau of Mines is composed of a two-stage fluid-bed, oxidation-reduction roasting followed by ammoniacal leaching, solvent extraction, and electrowinning. A copper-leaching recovery of 97.4 percent was obtained, and electrolysis of the acid strip solution deposited metal assaying 99.99 percent copper. The roaster gases contain over 95 percent of the sulfur at a concentration of 12 percent which is better suited for acid making or elemental sulfur production than conventional smelter gas. When considering byproduct recovery, a preliminary estimate indicates copper production costs are com-parable to the conventional smelters.

Jan 1, 1975

By K. Biswas

In general, it cannot be assumed that the strength of coal pillars remains constant over long time periods. Field observations indicate that a coal seam, especially when it contains a parting layer, deteriorates over time, reducing load-bearing capacity of the pillars. This paper discusses a unique approach to determine the time dependent strength of coal pillars in the field. Three coal pillars that were developed 5, 15 and 50 years ago were chosen for the study. Holes were drilled in coal and parting layers in each pillar and the strength profiles were determined for each hole using the Borehole Penetrometer. The strength data were treated statistically to establish time dependent strength equations for different layers. The results can be used to help estimate the loss of pillar capacity over time.

Jan 1, 1999

By Donald W. Trepp

Colony Development Operation is a joint venture currently consisting of four active members; The Oil Shale Corporation (TOSCO); Ashland Oil Inc.; Shell Oil Company and Atlantic Richfield Company, operator of the project. The initial efforts on the Colony project began in the spring of 1965. Pilot mining and semi-works engineering programs continued, in phases, to completion in the fall of 1972 when commercialization of oil shale was deemed realistic. Since that time, Colony efforts have been directed toward evaluation of the data collected during the semi-works operation and in designing a commercial operation. In October of 1974, Colony announced: "because of economic and national energy policy uncertainties it was suspending plans to start construction of a commercial oil shale plant on private lands in northwestern Colorado, scheduled for spring of 1975."

Jan 1, 1975

By Rajat Gangrade, Haotian Zheng, Jarrett Smith, Daniele Nebbia, Mike Mooney

The application of artificial intelligence (AI) to improve tunnel boring machine (TBM) operations requires a significant amount of information to train robust performance prediction models, e.g., for tunneling-induced settlement, productivity, tool wear, etc. This paper presents the AI framework applied to the North-East Boundary Tunnel (NEBT), the largest component of the Clean Rivers Project in Washington, DC. The paper focuses on required elements for real-time AI use to estimate tunneling-induced ground and building deformation and cutter tool wear. Keys to the framework include defining the necessary quantities of data required as well as the process of windowed training, validation and model testing. To date, the models developed for ground deformation and tool wear show satisfactory performance when compared to observed field observations during tunneling.

Jun 13, 2021

By M. E. Volin

To extend or delimit the known ore reserves of the Black Wonder manganese de-posit, the Bureau of Mines undertook an exploration project consisting of trenching, underground excavation, long-hole drilling, and sampling. The mineralization is spread over 6 square miles containing numerous small individual manganese deposits. There has been only small production from some of these deposits; however, simultaneous operations from many such small deposits could contribute considerably to the production from the district. A custom mill to treat oxide ore for battery use was built near Patterson in 1942 by the General Dry Batteries Co., Inc. It operated during World War II and was removed in 1944 when the manganese mines ceased operation. Except for some small experimental shipments, there has been no activity in the district since that time.

Jan 1, 1956