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By Alfred Bodenlos

El presente artículo describe la historia geológica pre-cretácica de la Cordillera Negra. En algunos intervalos predominaron los pantanos que dieron lugar a la formación de carbones. Luego, en el Valanginiano superior, la región estuvo sumergida, depositándose calizas delgadas. Los tufos que yacen sobre la secuencia de elásticos indican que hubo actividad volcánica a fines de este intervalo. Parte apreciable de los depósitos marinos del Cretácico medio está formado por calizas bituminosas obscuras.

Jul 1, 1957

By Qingzhu Li

The brewing industry byproduct, spent grain (SG), was evaluated for its ability to adsorb Ag(I) from aqueous solutions. Ag(I) adsorption was dependent on solution pH, contact time, adsorbent dose, initial Ag(I) concentration and temperature. The kinetic data were well described by pseudo-second-order kinetic model, indicating that chemical adsorption was the rate-controlling step. The equilibrium data followed Freundlich isotherm rather than Langmuir isotherm, suggesting heterogenity of the adsorption sites on spent grain. Ag(I) desorbed from Ag(I)-loaded spent grain was also evaluated in this study. HCl, NaOH, Na2S2O3 and ultrapure water were chosen as eluants and desorbed Ag(I)-loaded spent grain for 30min, Ag(I)-loaded spent grain desorbed in 0.1M Na2S2O3 exhibited higher elution efficiency as compared with other eluants. The results indicated that application of spent grain for adsorption and recovery of silver from aqueous solutions was feasible.

Jan 1, 2009

By J. P. BONARDI, J. C. Williams

Until the end of 1918 Boulder County ranked as one of the foremost tungsten-producing districts of the world, but in August, 1919, there was practically no production in the district. The operators there could not compete with tungsten ores from foreign sources, particularly China, Burma, and South America. As a. result there · has been a strong movement for placing a protective tariff on all imported tungsten ores and products; and it seems to be the general belief of tungsten producers that some form of protection is necessary to the maintenance of the industry in this country. The stimulus, due to the great demand for · tungsten alloys in the manufacture of munitions during the war, was felt in all the productive localities of the world. The ores of Boulder County were especially in demand on account of their comparative. freedom from • harmful impurities, and this demand greatly extended mining operations in the district and increased the efficiency of the gen~ral milling practice there.

Jan 1, 1921

By A. Fawcett, B. C. Dyer

Abstract - The basis of the tomographic velocity imaging technique is briefly described and an application of the method to detect and image a cross-section through a chromite pod is presented. Using the chromite application as an example, the relative costs of tomographic data acquisition and processing are compared with those of diamond drilling to obtain similar resolution. A number of different tomographic survey configurations and the potential role of the method in surface and underground exploration are discussed.

Jan 1, 1994

By Éder Domingos Oliveira, Carlos Antonio Morais, Ruberlan Gomes Silva

The objective of this work was to assess the influence of parameters such as residence time, solid content, and temperature in a process route towards purified rare earth liquor which could be adequate to produce marketable rare earth products. The steps of the process route proposed in this study comprised water leaching of a sulfated rare earth ore and removal of impurities through the purification of the rare earth sulfuric liquor, which is the product of the water leaching step. The sample used in the water leaching experiments was a sulfated rare earth ore produced by the reaction of a beneficiated rare earth ore with sulfuric acid followed by roasting at 700 °C for 2 h in a muffle furnace and cooling at 20 °C. The water leaching experiments showed that the best condition comprised a residence time of 30 min, temperature of 20 °C, and solid content of 10% w/w, resulting in a recovery of 71.3% of the rare earth elements (REE) and a lower impurity extraction, e.g., only 15.0% of Fe, representing the main impurity in the rare earth ore. Even when presenting low amounts of impurities, the rare earth sulfuric liquor still needed to be purified before it can be used in the production of marketable rare earth products. In the study, the rare earth sulfuric liquors were purified in two consecutive neutralization steps, first by dosing the limestone pulp to pH up to 3.5 and secondly by adding the lime pulp to raise the pH from 3.5 to 5.0. The application of two consecutive purification steps at 20 °C resulted in the highest overall REE recoveries (65.4%) throughout all the steps of the process, being 71.3% in the water leaching, 99.6% in the partial purification with limestone pulp, and 92.1% in the purification with lime pulp at 20 °C. Under this condition, there was a total elimination of Fe, P, and Th and a significant reduction in the Al, U, and sulfate concentrations in the purified rare earth liquor. The purified rare earth liquor attained through the experiment is expected to be amenable to be used in the production of marketable products due to the lower impurities/REO mass ratios.

By B. S. Crocker

Pebble grinding was used at Lake Shore Mines in 1949. A full description of experimental evidence and test plant results was published in 1952 1 and further operating details in 1954 2.' In more recent years the term autogenous grinding has been coined and is now frequently seen in the technical literature. Autogenous crushing and/or grinding covers any grinding mill in which the larger pieces of ore are made to grind the fine pieces; the crushing and grinding may be either dry or wet. This discussion deals only with wet autogenous grinding, and only in the fine grinding part of the circuit, i.e., from 6 mesh to 92 pct —325 mesh. The term pebble milling could apply to fine autogenous grinding in which the pebbles are made from the ore itself, or it could also refer to grinding with pebbles, such as flint pebbles, from a source outside the mine. The first mill to use screened ore to grind the ore (1949) was Lake Shore Mines, Kirkland Lake, Ont. Pebbles were screened from the jaw crusher discharge and used in 5x16-ft tube mills which had been converted to 6 ft 8 in. by 16-ft grate discharge pebble mills. The same general practice was adopted the following year by the Wright-Har-greaves Mine in Kirkland Lake. Shortly after that the Neptune Mines in Nicaragua started correspondence with the writer concerning the possibility of using screened ore for grinding in their plant. They first ran some plant-scale tests which confirmed the Lake Shore findings, with the ultimate result that their plant was successfully converted in 1956 to an autogenous grinding plant. In 1957-1958 the writer was successful in converting the grinding plant of Renabie Mines in northern Ontario to autogenous grinding. In all these plants the existing grinding equipment was converted, usually by expanding the diameter of the shell to make the change from steel grinding to ore pebble grinding mills. In all the above plants primary grinding was done in either small rod mills or ball mills. These mills first reduced the pebble mill feed to about 6 mesh. The final grinding in the pebble mills varied from 75 pct —200 mesh to 92 pct —325 mesh. At Lake Shore three stages of pebble milling were used, with a different size pebble in each stage. In other parts of the world interest was being shown in this form of grinding, and in March 1952 the writer had some correspondence with the mill staff at Outokumpu in Finland, with regard to the pebble system used at Lake Shore. At Stockholm in 1957 the account of the crushing and grinding system at Outokumpu was presented in a paper by H. Tanner and T. Heikkinen.V his is the only ore grinding plant that does not use grate discharges on its pebble mills; trunnion discharges equipped with heavy reverse spirals retain the pebble load. The first new mill designed to use screened ore as a grinding medium was the Bicroft mill at Bancroft, Ont., which began operation in the fall of 1956. In 1957 this plant was followed by similar installations at Faraday Mines, also in the Bancroft area, and the North Rankin Nickel Mines in the North West Territories. In 1958 the Dyno Mill at Bancroft was converted, using the same type of grinding. Since all these plants, designed by Kilborn Engineering (1954) Ltd., were originally planned as pebble grinding mills, they were able to take full advantage of the latest design and technique. They are neat in appearance and very efficient and easy to operate. Effect of Ore Hardness: It is often commented that this type of autogenous grinding applies only to hard siliceous ores. Experience has shown that this is not so. In the past ten years the author has had an opportunity to test more than a dozen ores, several of which were quite soft. One of these was shale. The softer ores actually make better looking pebbles than the hard ores. These soft ores produced no particles in the intermediate size range which could not be ground by the largest pebbles in the mill charge. Slabby ores, such as shales, make a suitable pebble for the —6 mesh grinding. It is not generally recognized that for fine grinding a spherical medium is not essential or more efficient. Another frequent objection to pebble grinding is the belief held by some operators that there is too much variation in the hardness of their particular ore to make it acceptable as a source of pebble media. Experience has also shown that this is not a serious problem at all. The variation in pebble load due to changes in the ore hardness is nothing like as great as most people would expect, and the method used for feeding the ore and controlling the the load in the mills is more than sufficient to take care of daily variations in ore hardness. This point

Jan 1, 1960

By D. M. Hausen

A computer program has been developed by Newmont Exploration to convert mineralogic data by XRD into rock type and ore type classifications. This method has proven useful in identifying lithology from cuttings samples, where percussion drilling was an alternative to expensive core drilling. Computer printouts of rock type and ore type identifications can be generated simultaneously with mineralogic analyses, resulting in a considerable time savings in manual calculation. XRD-computer logging was first applied to the Carlin mine in north central Nevada, and later to the Maggie Creek and Gold Quarry gold deposits, southeast of the Carlin mine. Impure Paleozoic limestones of the "lower plate" Roberts Mountain Formation and the "upper plate" transitional facies have been decarbonatized to altered siltstones and shaley units along vertical faults and permeable stratiform horizons. Advanced stages of decarbonatization were accompanied by silicification. Quantitative XRD data are initially sorted into principal rock type units (limestones, siltstones, dolostones, shales) based on major mineralogic components (calcite, quartz, dolomite, clays). On the basis of relative amounts of less major constituents, descriptive subclassifications (dolomitic limestones, dolomitic siltstones, argillaceous cherts) are made. XRD lithologic data provide assistance in correlating lithologic units, and delineating favorable replacement horizons associated with gold mineralization.

Jan 1, 1982

By H. B. Humphrey

WHEN THE BUREAU OF MINES was created in 1910, the organic act had as one of its main provisions the following: That it shall be the province of said bureau and its director, under the direction of the Secretary of the Interior, to make diligent investigation of the methods of mining, especially in relation to the safely of miners and the appliances best adapted to prevent accidents, the possible improvement of renditions under which mining operations are carried on, the treatment of ores and other mineral substances, the use of explosives and electricity, the prevention of accidents, and other inquiries and technologic investigations pertinent to said industries, and from tinge to time make such public reports of the work, investigations, and information obtained as the Secretary of said department may direct, with the recommendations of such bureau. The nationwide nature of the health and safety work of the Bureau of Mines has given its representatives an opportunity to study and report on matters pertaining to health and safety in mines and related operations from the time the Bureau was established to the present. Regular annual reports and numerous additional papers and reports have been published each year to place on record and to make available the information gathered. While the basic purpose of this bulletin is to describe health and safety reports for the period January 1947 through June 1955, a selected number of earlier publica¬tions that are believed pertinent for reference purposes are included.

Jan 1, 1956

By Herbert Haas

The Bureau of Mines is endeavoring to reduce waste and increase efficiency in the production, refining, and utilization of petroleum . During the last few years the demand for petroleum and its products has increased so much more rapidly than the production that greater efficiency in utilization is now a matter of most serious importance . The Diesel engine, a comparatively new type of internal-combus- ' tion engine, is an important device for insuring more efficient utilization of petroleum and coal-tar products, for it consumes heavy liquid fuels such as can not be utilized in other types. Like the gas or the gasoline engine, it is revolutionary within its province. For some uses this engine is replacing gas and gasoline engines , but its most important duty will be to replace the wasteful consumption of fuel oil in steam engines. Not only will a wider use of the Diesel engine relieve the demand, but it will result in more power being obtained from the same consumption of fuel oils . In spite of these advantages, comparatively few Diesel engines are in use in the United States . In this report the author discusses recent developments in the design and construction of the Diesel engine, the fuels suitable for burning in it, and the uses to which it is particularly adapted .

Jan 1, 1918

By NORA Mining Sector Council

The National Occupational Research Agenda (NORA) is a partnership program to stimulate innovative research and workplace interventions. In combination with other initiatives, the products of this program are expected to reduce the occurrence of injuries and illnesses at work. Unveiled in 1996, NORA has become a research framework for the National Institute for Occupational Safety and Health (NIOSH) and the United States. Diverse parties collaborate to identify the most critical issues in workplace safety and health and develop research objectives for addressing those issues. NORA entered its third decade in 2016 with an enhanced structure. The 10 sectors formed for the second decade will continue to prioritize occupational safety and health research by major areas of the U.S. economy. In addition, NORA’s seven cross-sectors will continue to focus on the major health and safety issues affecting the U.S. working population. While NIOSH serves as the steward to move this effort forward, it is truly a national effort. NORA is carried out through councils comprised of members with many diverse interests that are developing and implementing research agendas for the occupational safety and health community over the third decade (2016-2026) of NORA. Councils address objectives through information exchange, partnership building, and enhanced dissemination and implementation of evidenced-based solutions. NORA groups industries into 10 sectors using North American Industry Classification System (NAICS) codes. The Mining Sector encompasses NAICS code grouping 21xxxx where “xxxx” represents the different subcodes of the mining “21” classification. Mining encompasses the extraction of solid mineral and mineral-like substances from their place in the Earth’s crust and supplies them to processing industries that produce economically valuable materials. It does not include oil and gas extraction. The Mine Safety and Health Administration, MSHA separates mining into coal, underground and surface, and metal and nonmetal, underground and surface.

Feb 1, 2024

By JOHN LANE DYNAN

HE Tonopah Extension property consisted originally of three claims, with an area of 38 acres. In 1902 a shaft, now known as No. 1, was started near the eastern end of the property, close to the Tonopah Mining Co.'s boundary line, in the. andesite cap rock' which covers the ore-bearing formations in the western end of the Tonopah district. A short distance below the 60-ft. level, the orebodies pinched out, although the veins continued. This shaft has not been used since 1916. Before 1910, the production was small, coming mostly from small shoots of high-grade shipping ore. In that : year, the, company started its 30-stamp mill and cyanide plant; the mill was later enlarged to 50 stamps, with a corresponding increase in the cyanide-plant capacity, which brought the capacity of the mill up to 350 .tons per day. The total production of the mine to Oct. 1, 1920, is 871,177 tons of ore, from which was recovered 15,267,216 oz. of silver and 156,241 oz. of gold.' This makes an average recovery per ton of 17.5 oz. silver and 0.179 oz. gold. The average price received for silver since' the beginning of operations is 65.87 c. per oz., and the average value recovered from the ore-'is $15.25. The area of the property has been gradually increased by purchases and consolidations of adjoining ground until it is now 647 acres. A new shaft, known as No. 2, was started in 1912, 1600 ft. west .of No. 1, and in the following year a crosscut on the 750-ft. level of this shaft resulted in the discovery of the. Murray Vein system, from which the greatest prosperity of the mine has come. This vein, with its related veins,

Jan 1, 1921

By Iván E, Alex Araya Jofre, Jean Guiroux Toro, Eduardo Valdés Guerra

Currently, it is important for companies to have controlled mining operations and adhere to production schedules. To achieve this, one of the key factors is maintaining high reliability in the P&T process, primarily the opening of ore stope, which could be delayed due to any unplanned or uncontrolled problem. These ore stope opening processes, whose main activity is generating free face, are a very important pillar for future mine planning. The possibility of ensuring their opening brings a series of downstream benefits: safety, economics, productivity, and compliance and adherence to plans. The process under discussion consists of developing free faces in a single blasting event. This will help us leverage greater reliability for overall production operation plans, reduce construction times, and open up opportunities for downstream improvements in the production process, considering technical factors in P&T designs. This study presents a developed methodology and shows the results of its implementation in ten (18) single-event free face blasts. The analysis includes cavity geometry, geology, rock qualities, drilling deviations, and the blasting strategy implemented for each event. The methodology used considered material fluffing processes, the actual drilling trajectory, the initiation sequence, QA/QC during explosive loading, monitoring instrumentation (vibrations), and VOD recording, among others. As a result, out of a total of 18 free-face events blasts in a single event, 16 were successful and two achieved 90% efficiency, reducing the stope's production start-up time by 50% compared to current operations. By implementing free face blasting in a single event, there are savings in operating costs, increased productivity of the mining equipment, and improved adherence to production plans. For applications with greater heights of free faces, where blasting cannot be carried out in a single event, we should consider performing them in two stages using wireless detonators already available on the market for mining operations.

Jan 26, 2026

By AIME AIME

THE John Fritz Medal Board of Award, at its annual meeting on Jan. 21, 1921, awarded its gold medal and diploma to Sir Robert Hadfield for the invention of manganese steel. On June 1, announcement was made that the Board of Award had awarded its gold medal and diploma to Charles Prosper Eughe Schneider for "achievement in metallurgy of iron and steel; for development of ordnance, especially the 75-mm. gun, and for notable patriotic contribution ' to the winning of the war." The award to Sir Robert Hadfield is for the year 1921; the award to Mr. Schneider is for 1922. The latter was made at this time in order that the medal might be presented by the group of American engineers now visiting England and France.*

Jan 1, 1921

By Harry T. Hamilton

THE genial assistant to the president of the New York Trust Co. is the latest addition to the Institute's board of directors, having been elected at the March meeting of the hoard to fill the unexpired term of the late E. E. Ellis. Usually when a banker is appointed to the board of a company the reason is obvious; the difference in this case is that the New York Trust Co. has some of the Institute's money, instead of vice versa. But Harry Hamilton is not really a banker-at least not primarily. Frefluently big financial institutions have a good mining engineer on their staffs to keep them from financing too many "cats and dogs." At any rate Mr. Hamilton gave up his consulting practice in San Francisco back in 1927, to accept his present position in New York. Until then, from the time he graduated from Yale in 1904, lie was constantly engaged in mining operations of one kind or another in the West and in Mexico. His first job was at Christmas, Ariz., where lie did "sampling and miscellaneous work" for the Saddle Mountain Mining Co. The writer tramped up to, all over, and through that property one hog day many years later, when it was run by the Christmas Mining Co., and carp assure the reader that without doubt the young Yale graduate got some good experience and was well broken in. From there Mr. Hamilton went to Cananea for a time, and then to the Copper Queen, at Bisbee, where he was a valued member of the rigging gang. An assignment of assaying and sampling for the Shan¬non Copper Co. at Metcalf lasted for a few months and then he accepted a job for a year with the geological department

Jan 1, 1936

By Julie Dénommé

Today few in business would argue with the idea that we are living in a world that is Volatile, Uncertain, Complex, and Ambiguous. Coined VUCA by the US Army War College, these four words define the ?turbulence? and ?continuous white water? that the business literature has been documenting for the last decade. This VUCA world became even more relevant to business in 2007 when the Institute for the Future fellow Bob Johansen published the idea of transforming VUCA into Vision, Understanding, Clarity, and Agility. We call this VUCA Prime (VUCA'), and place an infinity loop (8) between them to show their dynamic interaction. This paper presents an exploration of the impact of VUCA 8 VUCA' on business and the conditions under which these dynamic forces help to successfully navigate change.

Oct 1, 2010

By Carolina Rouillon

El presente documento señala dos experiencias aplicadas en la mina Yanacocha y Pierina exitosas donde se emplea las geomallas como parte del mejoramiento de suelos blandos con la finalidad de distribuir uniformemente las cargas impartidas por los grandes equipos mineros hacia la subrasante de mina típicamente conformada por suelos con alto contenidos de limos y arcillas húmedas y saturadas. Asimismo, los beneficios obtenidos por usar las mallas, no se limitan al ahorro en costo material de relleno, sino que se logra un mejor desempeño- en tanto optimiza la superficie de circulación de los vehículos mineros, reduciendo los tiempos de operación, así como prolonga los períodos de reparación y mantenimiento.

Sep 21, 2013

By M. J. Collins

"Autoclaves were first used in the metallurgical industry in 1893 to recover alumina from bauxite. In the 1940s and 1950s, several high temperature and pressure processes were invented in the laboratory of Professor Frank Forward at The University of British Columbia, in parallel with advances in equipment and processes by the Chemical Construction Corporation. Sherritt Gordon Mines Limited enlisted these groups to help develop the nickel sulfide ammonia leach process that was commercialized in 1954. Autoclave processes that have since been commercialized include high-pressure acid leaching of laterites, zinc pressure leaching, and pressure oxidation of refractory gold feedstocks. RÉSUMÉ En 1893, l’industrie métallurgique est la première à utiliser les autoclaves pour l’extraction de l’alumine dans la bauxite. Dans les années 1940 et 1950, plusieurs procédés à haute température et à haute pression sont inventés dans le laboratoire du Pr Frank Forward de l’université de la Colombie-Britannique (UBC) ; parallèlement, la Chemical Construction Corporation fait de grands progrès en matière d’équipement et de procédés. Sherritt Gordon Mines Limited fait appel à ces groupes pour qu’ils aident la société à développer le procédé de lixiviation du sulfure de nickel dans de l’ammoniaque, commercialisé en 1954. Les procédés de lixiviation en autoclave commercialisés depuis incluent notamment la lixiviation acide à haute pression de latérites, la lixiviation sous pression du zinc et l’oxydation sous pression des matières premières de l’or réfractaire.INTRODUCTION Autoclaves are chemical reactors that are built to contain processes taking place at elevated pressure. They are used in metallurgical refineries throughout the world to take advantage of the increased reaction kinetics and different reaction products that can be obtained in aqueous systems above the boiling temperature at atmospheric pressure. The word autoclave comes from the French “auto” and the Latin “clavis” and literally means self-locking—that is, the core distinguishing feature of an autoclave is that it includes a means for pressure regulation (e.g., a pressure relief valve). Denis Papin (Figure 1a), one of the inventors of the steam engine, was the first to make use of a safety valve to control steam pressure. He is credited with inventing the autoclave in 1679. Papin’s “digester” (Figure 1b) was a type of pressure cooker that was originally used to liquefy bones. Most commercial autoclaves are horizontal, multicompartment vessels with mechanical agitation, as shown in Figure 2a; however, the steam-agitated Pachuca vessels used to leach laterite ore in Moa, Cuba (Figure 2b), are also classified as autoclaves according to the self-locking definition provided above."

Jan 1, 2018

This report, 27th in a continuing series1, describes Bureau of Mines research and technologic work on coal and related investigations during 1962. While the brief discussion in each section of the report presents only the highlights of Bureau work during the year, details of many investigations can be found in publications cited in this text. Other work, reported here for the first time, will be covered in greater detail in later publications. Recent trends in coal research and technology both at home and abroad were reviewed in several publications2. Bureau research, as in the past3, continued to stress improved methods of mining, preparing, processing, and using coal. The program included a wide variety of applied and basic studies for developing information useful to the coal mining industry and the coal consumer while promoting wise conservation and utilization of our coal resources.

Jan 1, 1963

By Dan Preston, Shane Yanagisawa, Robert Marshall, Don Deere

Geotechnical Baseline Reports often estimate the number of cobbles that will be encountered in terms of volume or weight. These estimates are practically impossible to verify in the field. ClaroVia Holdings in conjunction with Frontier Kemper Constructors Inc. developed Digital Geologist 2.0 to classify and count cobbles discharged from an EPB TBM at the RSC7 project in Burbank, CA. The system worked by using two stereoscopic laser sensors with a global shutter to scan and count cobbles at 12 frames per second. Results of the effort are revealed along with lessons learned and paths for improvement.

Jun 13, 2023

By R. H. Pemberton

"THE Mattagami district of Quebec has, during the past few years, experienced intense exploration by virtually every mining company operating in Canada. As a result of this activity, a number of well-mineralized zinc-copper bearing bodies have been found, some of which will almost certainly go into production. Much of the area has undergone what is now termed ""Saturation Prospecting"" or intense and detailed geological and geophysical surveying, followed by the drilling of nearly all possible bets. Considering only the airborne geophysical surveying, some blocks of ground have been flown by virtually every geophysical instrument which has to date been installed in an aircraft. A list of these different geophysical instruments would include: l. Fluxgate-type total field magnetometers 2. Vertical field magnetometer ,3. Nuclear-precession magnetometers 4. Single-frequency out-of-phase electromagnetometers 5. Dual-frequency out-of-phase electromagnetometers 6. Horizontal component measuring electromagnetometers 7. In-phase and out-of-phase electromagnetometers8. Dip-angle measuring electromagnetometers."

Jan 1, 1961